Do not process commands coming from ourselves (help text)

Quite a few changes involved. Mostly variable renames and a few changes to `await`s.

Not ready yet because bot cannot login due to some arcane error of `expected value at line 1 column 1`.

Co-authored-by: projectmoon <projectmoon@noreply.git.agnos.is>
Reviewed-on: #98

.drone.yml

@@ -0,0 +1,27 @@
+kind: pipeline
+name: build-and-test
+
+steps:
+- name: test
+  image: rust:1.80
+  commands:
+  - apt-get update
+  - apt-get install -y cmake
+  - rustup component add rustfmt
+  - cargo build --verbose --all
+  - cargo test --verbose --all
+
+- name: docker
+  image: plugins/docker
+  when:
+    ref:
+    - refs/tags/v*
+    - refs/heads/master
+  settings:
+    auto_tag: true
+    username:
+      from_secret: docker_username
+    password:
+      from_secret: docker_password
+    repo: ghcr.io/projectmoon/chronicle-dicebot
+    registry: ghcr.io

.env

@@ -0,0 +1,2 @@
+DATABASE_URL="sqlite://test-db/dicebot.sqlite"
+SQLX_OFFLINE="true"

.github/workflows/dicebot-ci.yml

@@ -0,0 +1,68 @@
+name: Dicebot CI
+
+on:
+  push:
+    branches:
+      - master
+
+    # Publish `v1.2.3` tags as releases.
+    tags:
+      - v*
+
+  # Run tests for any PRs.
+  pull_request:
+
+env:
+  IMAGE_NAME: chronicle-dicebot
+  CARGO_TERM_COLOR: always
+
+jobs:
+  build_and_test:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Build
+      run: cargo build --verbose
+    - name: Run tests
+      run: cargo test --verbose
+
+  # # Push image to GitHub Packages.
+  # # See also https://docs.docker.com/docker-hub/builds/
+  # push:
+  #   # Ensure test job passes before pushing image.
+  #   needs: build_and_test
+
+  #   runs-on: ubuntu-latest
+  #   if: github.event_name == 'push'
+
+  #   steps:
+  #     - uses: actions/checkout@v2
+
+  #     - name: Build image
+  #       run: docker build . --file Dockerfile --tag $IMAGE_NAME
+
+  #     - name: Log into GitHub Container Registry
+  #     # TODO: Create a PAT with `read:packages` and `write:packages` scopes and save it as an Actions secret `CR_PAT`
+  #       run: echo "${{ secrets.CR_PAT }}" | docker login https://ghcr.io -u ${{ github.actor }} --password-stdin
+
+  #     - name: Push image to GitHub Container Registry
+  #       run: |
+  #         IMAGE_ID=ghcr.io/${{ github.repository_owner }}/$IMAGE_NAME
+
+  #         # Change all uppercase to lowercase
+  #         IMAGE_ID=$(echo $IMAGE_ID | tr '[A-Z]' '[a-z]')
+
+  #         # Strip git ref prefix from version
+  #         VERSION=$(echo "${{ github.ref }}" | sed -e 's,.*/\(.*\),\1,')
+
+  #         # Strip "v" prefix from tag name
+  #         [[ "${{ github.ref }}" == "refs/tags/"* ]] && VERSION=$(echo $VERSION | sed -e 's/^v//')
+
+  #         # Use Docker `latest` tag convention
+  #         [ "$VERSION" == "master" ] && VERSION=latest
+
+  #         echo IMAGE_ID=$IMAGE_ID
+  #         echo VERSION=$VERSION
+
+  #         docker tag $IMAGE_NAME $IMAGE_ID:$VERSION
+  #         docker push $IMAGE_ID:$VERSION

.gitignore

@@ -1,6 +1,14 @@
 target/
 dicebot-config
 todo
+todo.org
 cache
 *.tar
 *.tar.gz
+test-db/
+bot-db*
+# We store a disabled async test in this file
+bigboy
+.#*
+*.sqlite
+.tmp*

Cargo.toml

@@ -1,36 +1,6 @@
-[package]
-name = "chronicle-dicebot"
-version = "0.3.0"
-authors = ["Taylor C. Richberger <taywee@gmx.com>", "projectmoon <projectmoon@agnos.is>"]
-edition = "2018"
-license = 'MIT'
-description = 'A simple async Matrix dicebot'
-readme = 'README.md'
-repository = 'https://github.com/ProjectMoon/matrix-dicebot'
-keywords = ["games", "dice", "matrix", "bot"]
-categories = ["games"]
+[workspace]
 
-[dependencies]
-toml = "0.5"
-nom = "5"
-rand = "0.7"
-thiserror = "1.0"
-itertools = "0.9"
-async-trait = "0.1"
-url = "2.1"
-dirs = "3.0"
-
-# The versioning of the matrix SDK follows its Cargo.toml. The SDK and
-# macros are on master, but it imports the common and base from 0.1.0.
-matrix-sdk = { git = "https://github.com/matrix-org/matrix-rust-sdk", rev = "master" }
-matrix-sdk-common-macros = { git = "https://github.com/matrix-org/matrix-rust-sdk", rev = "master" }
-matrix-sdk-common = { git = "https://github.com/matrix-org/matrix-rust-sdk", rev = "0.1.0" }
-matrix-sdk-base = { git = "https://github.com/matrix-org/matrix-rust-sdk", rev = "0.1.0", default_features = false }
-
-[dependencies.serde]
-version = "1"
-features = ['derive']
-
-[dependencies.tokio]
-version = "0.2"
-features = ["rt-core", "macros", "time", "signal"]
+members = [
+    "dicebot",
+    "rpc"
+]

Dockerfile

@@ -1,21 +1,16 @@
-# Builder image
-FROM bougyman/voidlinux:glibc as builder
-RUN xbps-install -Sy base-devel libressl-devel wget gnupg rustup
+# Builder image with development dependencies.
+FROM ghcr.io/void-linux/void-linux:latest-mini-x86_64 as builder
+RUN xbps-install -S
+RUN xbps-install -yu xbps
+RUN xbps-install -Syu
+RUN xbps-install -Sy base-devel rustup cmake wget gnupg
+RUN xbps-install -Sy openssl-devel libstdc++-devel
 RUN rustup-init -qy
 
 # Install tini for signal processing and zombie killing
-ENV TINI_VERSION v0.18.0
-ENV TINI_SIGN_KEY 595E85A6B1B4779EA4DAAEC70B588DFF0527A9B7
-RUN set -eux; \
-  wget -O /usr/local/bin/tini "https://github.com/krallin/tini/releases/download/${TINI_VERSION}/tini"; \
-  wget -O /usr/local/bin/tini.asc "https://github.com/krallin/tini/releases/download/${TINI_VERSION}/tini.asc"; \
-  export GNUPGHOME="$(mktemp -d)"; \
-  gpg --batch --keyserver ha.pool.sks-keyservers.net --recv-keys "$TINI_SIGN_KEY"; \
-  gpg --batch --verify /usr/local/bin/tini.asc /usr/local/bin/tini; \
-  command -v gpgconf && gpgconf --kill all || :; \
-  rm -r "$GNUPGHOME" /usr/local/bin/tini.asc; \
-  chmod +x /usr/local/bin/tini; \
-	tini --version
+ENV TINI_VERSION v0.19.0
+ADD https://github.com/krallin/tini/releases/download/${TINI_VERSION}/tini /usr/local/bin/tini
+RUN chmod +x /usr/local/bin/tini
 
 # Build dicebot
 RUN mkdir -p /root/src
@@ -24,7 +19,10 @@ ADD . ./
 RUN . /root/.cargo/env && cargo build --release
 
 # Final image
-FROM bougyman/voidlinux:latest
+FROM ghcr.io/void-linux/void-linux:latest-mini-x86_64
+RUN xbps-install -S
+RUN xbps-install -yu xbps
+RUN xbps-install -Syu
 RUN xbps-install -Sy ca-certificates libstdc++
 COPY --from=builder \
     /root/src/target/release/dicebot \
@@ -34,4 +32,5 @@ COPY --from=builder \
     /usr/local/bin/
 
 ENV XDG_CACHE_HOME "/cache"
+ENV DATABASE_PATH "/cache/bot-db"
 ENTRYPOINT [ "/usr/local/bin/tini", "-v", "--", "/usr/local/bin/dicebot", "/config/dicebot-config.toml" ]

LICENSE

@@ -1,3 +1,16 @@
+This software is governed by the terms of the Affero GNU General
+Public License. Portions of the code come from the original
+MIT-licensed project, and the terms of the MIT license also apply to
+those portions. In files that are partially or wholly subject to the
+MIT license in addition to the Affero GNU General Public License, this
+is noted with a header at the top of the file.
+
+Original upstream project: https://gitlab.com/Taywee/axfive-matrix-dicebot
+
+For code from the original project that is governed by the MIT license
+in addition to the Affero GNU General Public License, the following
+terms apply:
+
 MIT License
 
 Copyright (c) 2020 Taylor C. Richberger
@@ -19,3 +32,668 @@ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
+
+The project as a whole is governed by the terms of the Affero GNU
+General Public License:
+
+                    GNU AFFERO GENERAL PUBLIC LICENSE
+                       Version 3, 19 November 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
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+<https://www.gnu.org/licenses/>.

README.md

@@ -1,10 +1,103 @@
-# axfive-matrix-dicebot
+# Tenebrous Dicebot
 
-This is a fork of the
-[axfive-matrix-dicebot](https://gitlab.com/Taywee/axfive-matrix-dicebot)
-with basic support for the Chronicles of Darkness 2E Storytelling
-System, with future plans to extend the codebase further to support
-variables and perhaps character sheet management.
+[![Build Status](https://drone.agnos.is/api/badges/projectmoon/tenebrous-dicebot/status.svg)](https://drone.agnos.is/projectmoon/tenebrous-dicebot)
+[![Matrix Chat](https://img.shields.io/matrix/tenebrous:agnos.is?label=matrix&server_fqdn=matrix.org)][matrix-room]
+
+_This repository is hosted on [Agnos.is Git][main-repo] and mirrored
+to [GitHub][github-repo]._
+
+This is a dice rolling bot for facilitating roleplaying games on the
+Matrix messaging platform. It currently has basic support for the
+Chronicles of Darkness 2E Storytelling System and Call of Cthulhu,
+with plans to extend the codebase further to support other systems and
+character sheet management.
+
+## Features
+
+`tenebrous-dicebot` is a dice rolling bot for facilitating
+role-playing games over Matrix (and anything that Matrix can bridge
+to, like Discord). It currently has the following features:
+
+* Rolling arbitrary dice expressions (e.g. 1d4, 1d20+5, 1d8+1d6, etc).
+* Rolling dice pools for the Chronicles of Darkness 2E Storytelling
+System.
+* Rolling dice for the Call of Cthulhu system.
+* Works in encrypted or unencrypted Matrix rooms.
+* Storing variables created by the user.
+
+## Support and Community
+
+The project has a Matrix room at [#tenebrous:agnos.is][matrix-room].
+It is also possible to make a post in [GitHub
+Discussions][github-discussions].
+
+For reporting bugs, we prefer that you open an issue on
+[git.agnos.is][agnosis-git-issues]. However, you may also open an
+issue on [GitHub][github-issues].
+
+### Development and Contributions
+
+All development occurs on [git.agnos.is][main-repo]. If you wish to
+contribute, please open a pull request there. In some cases, pull
+requests from GitHub may be accepted. All contributions must be
+licensed under [AGPL 3.0 or later][agpl] to be accepted.
+
+## Building and Installation
+
+### Docker Image
+
+The easiest way to run the dice bot is to use the [official Docker
+image][docker-image]. It is distributed on GitHub Container Registry
+by a CI pipeline.
+
+The `latest` tag always points to the most recent successfully built
+master commit and is considered unstable, while individual tags are
+considered stable.
+
+* Unstable: `docker pull ghcr.io/projectmoon/chronicle-dicebot:latest`
+* Stable: `docker pull ghcr.io/projectmoon/chronicle-dicebot:X.Y.Z`
+
+This image is based on [Void Linux](https://voidlinux.org/). To build
+the image yourself, run `docker build -t chronicle-dicebot .` in the
+root of the repository.
+
+After pulling or building the image, see [instructions on how to use
+the Docker image](#running-the-bot).
+
+### Install from crates.io
+
+The project can be from [crates.io][crates-io]. To install it, execute
+`cargo install tenebrous-dicebot`. This will make the following
+executables available on your system:
+
+* `dicebot`: Main dicebot executable.
+* `dicebot-cmd`: Run dicebot commands from the command line.
+* `dicebot_migrate`: Standalone database migrator (not required).
+* `tonic_client`: Test client for the gRPC connection (not required).
+
+### Build from Source
+
+Precompiled executables are not yet available. Clone this repository
+and run `cargo install`.
+
+Building the project requires:
+
+* Basic build environment (`build-essential` on Ubuntu, `base-devel`
+  on Void and Arch, etc).
+* Rust 1.45.0 or higher.
+* OpenSSL/LibreSSL development headers installed.
+* `olm-sys` crate dependencies: cmake, libstdc++.
+* glibc.
+
+#### Why doesn't it build on musl libc?
+
+As far as I can tell, the project doesn't build on musl libc. It
+certainly doesn't build a static binary out of the box using the
+rust-musl-builder. This appears to be due to a transitive dependency
+of the Rust Matrix SDK.
+
+Any PRs to get the project or Matrix SDK to properly be built into a
+static binary using musl would be very useful.
 
 ## Usage
 
@@ -12,7 +105,12 @@ To use it, you can invite the bot to any room you want, and it will
 automatically jump in. Then you can simply give a dice expressions for
 either the Storytelling System or more traditional RPG dice rolls.
 
-The commands `!roll` and `!r` can handle arbitrary dice roll expressions.
+The bot supports a `!help` command for basic help information about
+its capabilities.
+
+### Basic Dice Rolling
+The commands `!roll` and `!r` can handle arbitrary dice roll
+expressions.
 
 ```
 !roll 4d6
@@ -20,56 +118,183 @@ The commands `!roll` and `!r` can handle arbitrary dice roll expressions.
 !r 3d12 - 5d2 + 3 - 7d3 + 20d20
 ```
 
+#### Keep/Drop Dice
+The bot supports either keeping the highest dice in a roll, or
+dropping the highest dice in a roll.  This allows the bot to handle 
+things like D&D 5e advantage or disadvantage.
+
+```
+!roll 2d20k1
+!r 2d20dh1 + 5
+!r 10d10k5 + 10d10dh5 - 2
+```
+
+### Storytelling System
+
 The commands `!pool` (or `!rp`) and `!chance` are for the Storytelling
 System, and they use a specific syntax to support the dice system. The
 simplest version of the command is `!pool <num>` to roll a pool of the
 given size using the most common type of roll.
 
-The type of roll can be controlled by adding `n`, `e`, or `r` after
+The type of roll can be controlled by adding `n`, `e`, or `r` before
 the number, for 9-again, 8-again, and rote quality rolls. The number
 of successes required for an exceptional success can be controlled by
 `s<num>`, e.g. `s3` to only need 3 successes for an exceptional
-success.
+success. All modifiers should come before the number, with a `:`
+colon.
 
 Examples:
 
 ```
 !pool 8      //regular pool of 8 dice
-!pool 8n    //roll 8 dice, 9-again
-!pool 8ns3  //roll 8 dice, 9-again with only 3 successes for exceptional
-!pool 5rs2  //5 dice, rote quality, 2 successes for exceptional
+!pool n:8    //roll 8 dice, 9-again
+!pool ns3:8  //roll 8 dice, 9-again with only 3 successes for exceptional
+!pool rs2:5  //5 dice, rote quality, 2 successes for exceptional
+```
+
+### Call of Cthulhu System
+
+The commands `!cthRoll`, `!cthroll`, `!cthARoll` and `!cthadv` are for
+the Call of Cthulhu system. `!cthRoll` and `!cthroll` are for rolling
+percentile dice against a target number. A `b:` or `bb:` can be
+prepended to get one or two bonus dice.
+
+`!cthARoll` and `!cthadv` are for skill advancement.
+
+Examples:
 
 ```
+!cthRoll 50     //roll against a target of 50
+!cthRoll bb:60  //roll against a target of 60 with 2 bonus dice
+!cthARoll 30    //advancement roll against a target of 30
+```
+
+### User Variables
+
+Users can store variables for use with the Storytelling dice pool
+system. Variables are stored on a per-room, per-user basis in the
+database (currently located in the cache directory if using the Docker
+image).
+
+Examples:
+
+```
+!set myvar 5 //stores 5 for this room under the name "myvar"
+!get myvar //will print 5
+```
+
+Variables can be referenced in dice pool and Call of Cthulhu rolling
+expressions, for example `!pool myvar` or `!pool myvar+3` or `!cthroll
+myvar`. The Call of Cthulhu advancement roll also accepts variables,
+and if a variable is used, and the roll is successful, it will update
+the variable with the new skill.
 
 ## Running the Bot
-You can run the bot by creating a bot account, building the dicebot
-program (either from this repo, and creating a config file that looks
-like this:
 
-```ini
-[matrix]
-home_server = 'matrix.org'
+The easiest way to run the bot is to use the [official Docker
+image][docker-image], although you can also [run the binary
+directly](#running-binary-directly).
 
-[matrix.login]
-password = 'thisismypassword'
-type = 'm.login.password'
-user = 'axfive-dicebot'
+A typical docker run command using the official Docker image should
+look something like this:
+
+```
+# Run unstable version of the bot
+VERSION="latest"
+docker run --rm -d --name dicebot \
+-v /path/to/dicebot-config.toml:/config/dicebot-config.toml:ro \
+-v /path/to/cache/:/cache \
+ghcr.io/projectmoon/chronicle-dicebot:$VERSION
 ```
 
-Of course replacing all the necessary fields. Then you can run the
-"dicebot" binary pointing at that, and it will log in and hum along
-and do its thing.
+The Docker image requires two volume mounts: the location of the
+[config file][config-file], which should be mounted at
+`/config/dicebot-config.toml`, and a cache directory to store the
+database and client state after initial sync. That should be mounted
+at `/cache/`in the container.
 
-You can also just run it on the command line with the `dicebot-cmd`
-command, which expects you to feed it one of the command expressions
-as shown above, and will give you the plaintext response.
+### Configuration File
+
+The configuration file is a TOML file with three sections.
+
+```toml
+[matrix]
+home_server = 'https://example.com'
+username = 'thisismyusername'
+password = 'thisismypassword'
+
+[database]
+path = '/path/to/database/directory/'
+
+[bot]
+oldest_message_age = 300
+```
+
+The `[matrix]` section contains the information for logging in to the
+bot's matrix account.
+
+ - `home_server`: The URL for the Matrix homeserver the bot should log
+   in to. This should be the proper hostname of the homeserver that
+   you would enter into the login box, which might be different than
+   the server name that is displayed to other users.
+ - `username`: Bot account username.
+ - `password`: Bot account password.
+
+The `[database]` section contains information for connecting to the
+embedded database. Note: **you do not need this** if you are using the
+Docker image.
+ - `path`: Path on the filesystem to use as the database storage
+   directory.
+
+The `[bot]` section has settings for controlling how the bot operates.
+This section is optional and the settings will fall back to their
+default values if the section or setting is not present.
+
+ - `oldest_message_age`: the oldest time (in seconds) in the past that
+   a message can be before being ignored. This prevents the bot from
+   processing out-of-context old commands received while offline. The
+   default value is 900 seconds (15 minutes).
+
+### Running Binary Directly
+
+If you have [built the application from source](#build-from-source),
+you can invoke the dice bot directly instead of using Docker by
+running `dicebot /path/to/config.toml`. By default, the user account
+cache is stored in a [platform-dependent location][dirs]. If you want
+to change the cache location on Linux, for example, you can run
+`export XDG_CACHE_HOME=/path/to/cache` before invoking the bot.
+
+Installing the application directly also installs `dicebot-cmd`, which
+allows you to run arbitrary bot commands on the command line. This
+does not connect to a running instance of the bot; it just processes
+commands locally.
 
 ## Future plans
 
 The most basic plans are:
 
-* To add support for simple per-user variable management, e.g. setting
-  a name to a value (`gnosis = 3`) and then using those in dice rolls.
+* Resource counting: creation of custom counters that can go up and
+  down.
 * Perhaps some sort of character sheet integration. But for that, we
   would need a sheet service.
-* Robustness fixes if necessary, which will be sent upstream.
+* Use environment variables instead of config file in Docker image.
+* Per-system game rules.
+
+## Credits
+
+This was orignally a fork of the [axfive-matrix-dicebot][axfive], with
+support added for Chronicles of Darkness and Call of Cthulhu.
+
+[axfive]: https://gitlab.com/Taywee/axfive-matrix-dicebot
+[config-file]: #Configuration-File
+[docker-image]: https://github.com/users/ProjectMoon/packages/container/package/chronicle-dicebot
+[dirs]: https://docs.rs/dirs/2.0.2/dirs/
+[main-repo]: https://git.agnos.is/projectmoon/tenebrous-dicebot
+[github-repo]: https://github.com/ProjectMoon/matrix-dicebot
+[roadmap]: https://git.agnos.is/projectmoon/tenebrous-dicebot/wiki/Roadmap
+[crates-io]: https://crates.io/crates/tenebrous-dicebot
+[matrix-room]: https://matrix.to/#/#tenebrous:agnos.is
+[agnosis-git-issues]: https://git.agnos.is/projectmoon/tenebrous-dicebot/issues
+[github-discussions]: https://github.com/ProjectMoon/matrix-dicebot/discussions
+[github-issues]: https://github.com/ProjectMoon/matrix-dicebot/issues
+[agpl]: https://www.gnu.org/licenses/agpl-3.0.en.html

axfive-matrix-dicebot.code-workspace

@@ -1,8 +0,0 @@
-{
-	"folders": [
-		{
-			"path": "."
-		}
-	],
-	"settings": {}
-}

dicebot/Cargo.toml

@@ -0,0 +1,57 @@
+[package]
+name = "tenebrous-dicebot"
+version = "0.13.2"
+rust-version = "1.68"
+authors = ["projectmoon <projectmoon@agnos.is>", "Taylor C. Richberger <taywee@gmx.com>"]
+edition = "2018"
+license = 'AGPL-3.0-or-later'
+description = 'An async Matrix dice bot for role-playing games'
+readme = '../README.md'
+repository = 'https://git.agnos.is/projectmoon/matrix-dicebot'
+keywords = ["games", "dice", "matrix", "bot"]
+categories = ["games"]
+
+[build-dependencies]
+tonic-build = "0.4"
+
+[dependencies]
+# indexmap version locked fixes a dependency cycle.
+# indexmap = "=1.6.2"
+log = "0.4"
+tracing-subscriber = "0.2"
+toml = "0.5"
+nom = "5"
+rand = "0.8"
+rust-argon2 = "0.8"
+thiserror = "1.0"
+itertools = "0.10"
+async-trait = "0.1"
+url = "2.1"
+dirs = "3.0"
+indoc = "1.0"
+combine = "4.5"
+futures = "0.3"
+html2text = "0.2"
+phf = { version = "0.8", features = ["macros"] }
+matrix-sdk = { version = "0.6" }
+refinery = { version = "0.8", features = ["rusqlite"]}
+barrel = { version = "0.7", features = ["sqlite3"] }
+strum = { version = "0.22", features = ["derive"] }
+tempfile = "3"
+substring = "1.4"
+fuse-rust = "0.2"
+tonic = "0.4"
+prost = "0.7"
+tenebrous-rpc = { path = "../rpc", version = "0.1.0" }
+
+[dependencies.sqlx]
+version = "0.6"
+features = [ "offline", "sqlite", "runtime-tokio-native-tls" ]
+
+[dependencies.serde]
+version = "1"
+features = ['derive']
+
+[dependencies.tokio]
+version = "1"
+features = [ "full" ]

dicebot/sqlx-data.json

@@ -0,0 +1,139 @@
+{
+  "db": "SQLite",
+  "19d89370cac05c1bc4de0eb3508712da9ca133b1cf9445b5407d238f89c3ab0c": {
+    "query": "SELECT device_id FROM bot_state limit 1",
+    "describe": {
+      "columns": [
+        {
+          "name": "device_id",
+          "ordinal": 0,
+          "type_info": "Text"
+        }
+      ],
+      "parameters": {
+        "Right": 0
+      },
+      "nullable": [
+        false
+      ]
+    }
+  },
+  "26903a92a7de34df3e227fe599e41ae1bb61612eb80befad398383af36df0ce4": {
+    "query": "DELETE FROM accounts WHERE user_id = ?",
+    "describe": {
+      "columns": [],
+      "parameters": {
+        "Right": 1
+      },
+      "nullable": []
+    }
+  },
+  "2d4a32735da04509c2e3c4f99bef79ef699964f58ae332b0611f3de088596e1e": {
+    "query": "INSERT INTO accounts (user_id, password, account_status)\n               VALUES (?, ?, ?)\n               ON CONFLICT(user_id) DO\n               UPDATE SET password = ?, account_status = ?",
+    "describe": {
+      "columns": [],
+      "parameters": {
+        "Right": 5
+      },
+      "nullable": []
+    }
+  },
+  "59313c67900a1a9399389720b522e572f181ae503559cd2b49d6305acb9e2207": {
+    "query": "SELECT key, value as \"value: i32\" FROM user_variables\n               WHERE room_id = ? AND user_id = ?",
+    "describe": {
+      "columns": [
+        {
+          "name": "key",
+          "ordinal": 0,
+          "type_info": "Text"
+        },
+        {
+          "name": "value: i32",
+          "ordinal": 1,
+          "type_info": "Int64"
+        }
+      ],
+      "parameters": {
+        "Right": 2
+      },
+      "nullable": [
+        false,
+        false
+      ]
+    }
+  },
+  "636b1b868eaf04cd234fbf17747d94a66e81f7bc1b060ba14151dbfaf40eeefc": {
+    "query": "SELECT value as \"value: i32\" FROM user_variables\n               WHERE user_id = ? AND room_id = ? AND key = ?",
+    "describe": {
+      "columns": [
+        {
+          "name": "value: i32",
+          "ordinal": 0,
+          "type_info": "Int64"
+        }
+      ],
+      "parameters": {
+        "Right": 3
+      },
+      "nullable": [
+        false
+      ]
+    }
+  },
+  "667b26343ce44e1c48ac689ce887ef6a0558a2ce199f7372a5dce58672499c5a": {
+    "query": "INSERT INTO user_state (user_id, active_room)\n               VALUES (?, ?)\n               ON CONFLICT(user_id) DO\n               UPDATE SET active_room = ?",
+    "describe": {
+      "columns": [],
+      "parameters": {
+        "Right": 3
+      },
+      "nullable": []
+    }
+  },
+  "711d222911c1258365a6a0de1fe00eeec4686fd3589e976e225ad599e7cfc75d": {
+    "query": "SELECT count(*) as \"count: i32\" FROM user_variables\n               WHERE room_id = ? and user_id = ?",
+    "describe": {
+      "columns": [
+        {
+          "name": "count: i32",
+          "ordinal": 0,
+          "type_info": "Int"
+        }
+      ],
+      "parameters": {
+        "Right": 2
+      },
+      "nullable": [
+        false
+      ]
+    }
+  },
+  "bba0fc255e7c30d1d2d9468c68ba38db6e8a13be035aa1152933ba9247b14f8c": {
+    "query": "SELECT event_id FROM room_events\n               WHERE room_id = ? AND event_id = ?",
+    "describe": {
+      "columns": [
+        {
+          "name": "event_id",
+          "ordinal": 0,
+          "type_info": "Text"
+        }
+      ],
+      "parameters": {
+        "Right": 2
+      },
+      "nullable": [
+        false
+      ]
+    }
+  },
+  "dce9bb45cf954054a920ee8b53852c6d562e3588d76bbfaa1433d8309d4e4921": {
+    "query": "DELETE FROM user_state WHERE user_id = ?",
+    "describe": {
+      "columns": [],
+      "parameters": {
+        "Right": 1
+      },
+      "nullable": []
+    }
+  }
+}

dicebot/src/basic/dice.rs

@@ -1,23 +1,57 @@
-pub mod parser;
-
+/**
+ * In addition to the terms of the AGPL, this file is governed by the
+ * terms of the MIT license, from the original axfive-matrix-dicebot
+ * project.
+ */
 use std::fmt;
 use std::ops::{Deref, DerefMut};
 
+/// A basic dice roll, in XdY notation, like "1d4" or "3d6".
+/// Optionally supports D&D advantage/disadvantge keep-or-drop
+/// functionality.
 #[derive(Debug, PartialEq, Eq, Clone, Copy)]
 pub struct Dice {
     pub(crate) count: u32,
     pub(crate) sides: u32,
+    pub(crate) keep_drop: KeepOrDrop,
+}
+
+/// Enum indicating how to handle bonuses or penalties using extra
+/// dice. If set to Keep, the roll will keep the highest X number of
+/// dice in the roll, and add those together. If set to Drop, the
+/// opposite is performed, and the lowest X number of dice are added
+/// instead. If set to None, then all dice in the roll are added up as
+/// normal.
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
+pub enum KeepOrDrop {
+    /// Keep only the X highest dice for adding up to the total.
+    Keep(u32),
+
+    /// Keep only the X lowest dice (i.e. drop the highest) for adding
+    /// up to the total.
+    Drop(u32),
+
+    /// Add up all dice in the roll for the total.
+    None,
 }
 
 impl fmt::Display for Dice {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "{}d{}", self.count, self.sides)
+        match self.keep_drop {
+            KeepOrDrop::Keep(keep) => write!(f, "{}d{}k{}", self.count, self.sides, keep),
+            KeepOrDrop::Drop(drop) => write!(f, "{}d{}dh{}", self.count, self.sides, drop),
+            KeepOrDrop::None => write!(f, "{}d{}", self.count, self.sides),
+        }
     }
 }
 
 impl Dice {
-    fn new(count: u32, sides: u32) -> Dice {
-        Dice { count, sides }
+    pub fn new(count: u32, sides: u32, keep_drop: KeepOrDrop) -> Dice {
+        Dice {
+            count,
+            sides,
+            keep_drop,
+        }
     }
 }
 
@@ -52,7 +86,7 @@ impl fmt::Display for SignedElement {
 }
 
 #[derive(Debug, PartialEq, Eq, Clone)]
-pub struct ElementExpression(Vec<SignedElement>);
+pub struct ElementExpression(pub Vec<SignedElement>);
 
 impl Deref for ElementExpression {
     type Target = Vec<SignedElement>;

dicebot/src/basic/mod.rs

@@ -0,0 +1,3 @@
+pub mod dice;
+pub mod parser;
+pub mod roll;

dicebot/src/basic/parser.rs

@@ -0,0 +1,360 @@
+/**
+ * In addition to the terms of the AGPL, this file is governed by the
+ * terms of the MIT license, from the original axfive-matrix-dicebot
+ * project.
+ */
+use nom::bytes::complete::take_while;
+use nom::error::ErrorKind as NomErrorKind;
+use nom::Err as NomErr;
+use nom::{
+    alt, bytes::complete::tag, character::complete::digit1, complete, many0, named,
+    sequence::tuple, tag, IResult,
+};
+
+use super::dice::*;
+
+//******************************
+//Legacy Code
+//******************************
+
+fn is_whitespace(input: char) -> bool {
+    input == ' ' || input == '\n' || input == '\t' || input == '\r'
+}
+
+/// Eat whitespace, returning it
+pub fn eat_whitespace(input: &str) -> IResult<&str, &str> {
+    let (input, whitespace) = take_while(is_whitespace)(input)?;
+    Ok((input, whitespace))
+}
+
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
+enum Sign {
+    Plus,
+    Minus,
+}
+
+/// Intermediate parsed value for a keep-drop expression to indicate
+/// which one it is.
+enum ParsedKeepOrDrop<'a> {
+    Keep(&'a str),
+    Drop(&'a str),
+    NotPresent,
+}
+
+macro_rules! too_big {
+    ($input: expr) => {
+        NomErr::Error(($input, NomErrorKind::TooLarge))
+    };
+}
+
+/// Parse a dice expression.  Does not eat whitespace
+fn parse_dice(input: &str) -> IResult<&str, Dice> {
+    let (input, (count, _, sides)) = tuple((digit1, tag("d"), digit1))(input)?;
+    let count: u32 = count.parse().map_err(|_| too_big!(count))?;
+    let sides = sides.parse().map_err(|_| too_big!(sides))?;
+    let (input, keep_drop) = parse_keep_or_drop(input, count)?;
+    Ok((input, Dice::new(count, sides, keep_drop)))
+}
+
+/// Extract keep/drop number as a string. Fails if the value is not a
+/// string.
+fn parse_keep_or_drop_text<'a>(
+    symbol: &'a str,
+    input: &'a str,
+) -> IResult<&'a str, ParsedKeepOrDrop<'a>> {
+    let (parsed_kd, input) = match tuple::<&str, _, (_, _), _>((tag(symbol), digit1))(input) {
+        // if ok, one of the expressions is present
+        Ok((rest, (_, kd_expr))) => match symbol {
+            "k" => (ParsedKeepOrDrop::Keep(kd_expr), rest),
+            "dh" => (ParsedKeepOrDrop::Drop(kd_expr), rest),
+            _ => panic!("Unrecogized keep-drop symbol: {}", symbol),
+        },
+        // otherwise absent (attempt to keep all dice)
+        Err(_) => (ParsedKeepOrDrop::NotPresent, input),
+    };
+
+    Ok((input, parsed_kd))
+}
+
+/// Parse keep/drop expression, which consits of "k" or "dh" following
+/// a dice expression. For example, "1d4h3" or "1d4dh2".
+fn parse_keep_or_drop<'a>(input: &'a str, count: u32) -> IResult<&'a str, KeepOrDrop> {
+    let (input, keep) = parse_keep_or_drop_text("k", input)?;
+    let (input, drop) = parse_keep_or_drop_text("dh", input)?;
+
+    use ParsedKeepOrDrop::*;
+    let keep_drop: KeepOrDrop = match (keep, drop) {
+        //Potential valid Keep expression.
+        (Keep(keep), NotPresent) => match keep.parse().map_err(|_| too_big!(input))? {
+            _i if _i > count || _i == 0 => Ok(KeepOrDrop::None),
+            i => Ok(KeepOrDrop::Keep(i)),
+        },
+        //Potential valid Drop expression.
+        (NotPresent, Drop(drop)) => match drop.parse().map_err(|_| too_big!(input))? {
+            _i if _i >= count => Ok(KeepOrDrop::None),
+            i => Ok(KeepOrDrop::Drop(i)),
+        },
+        //No Keep or Drop specified; regular behavior.
+        (NotPresent, NotPresent) => Ok(KeepOrDrop::None),
+        //Anything else is an error.
+        _ => Err(NomErr::Error((input, NomErrorKind::Many1))),
+    }?;
+
+    Ok((input, keep_drop))
+}
+
+// Parse a single digit expression.  Does not eat whitespace
+fn parse_bonus(input: &str) -> IResult<&str, u32> {
+    let (input, bonus) = digit1(input)?;
+    Ok((input, bonus.parse().unwrap()))
+}
+
+// Parse a sign expression.  Eats whitespace.
+fn parse_sign(input: &str) -> IResult<&str, Sign> {
+    let (input, _) = eat_whitespace(input)?;
+    named!(sign(&str) -> Sign, alt!(
+            complete!(tag!("+")) => { |_| Sign::Plus } |
+            complete!(tag!("-")) => { |_| Sign::Minus }
+    ));
+
+    let (input, sign) = sign(input)?;
+    Ok((input, sign))
+}
+
+// Parse an element expression.  Eats whitespace.
+fn parse_element(input: &str) -> IResult<&str, Element> {
+    let (input, _) = eat_whitespace(input)?;
+    named!(element(&str) -> Element, alt!(
+            parse_dice => { |d| Element::Dice(d) } |
+            parse_bonus => { |b| Element::Bonus(b) }
+    ));
+
+    let (input, element) = element(input)?;
+    Ok((input, element))
+}
+
+// Parse a signed element expression.  Eats whitespace.
+fn parse_signed_element(input: &str) -> IResult<&str, SignedElement> {
+    let (input, _) = eat_whitespace(input)?;
+    let (input, sign) = parse_sign(input)?;
+    let (input, _) = eat_whitespace(input)?;
+
+    let (input, element) = parse_element(input)?;
+    let element = match sign {
+        Sign::Plus => SignedElement::Positive(element),
+        Sign::Minus => SignedElement::Negative(element),
+    };
+    Ok((input, element))
+}
+
+// Parse a full element expression.  Eats whitespace.
+pub fn parse_element_expression(input: &str) -> IResult<&str, ElementExpression> {
+    named!(first_element(&str) -> SignedElement, alt!(
+            parse_signed_element => { |e| e } |
+            parse_element => { |e| SignedElement::Positive(e) }
+    ));
+    let (input, first) = first_element(input)?;
+    let (input, rest) = if input.trim().is_empty() {
+        (input, vec![first])
+    } else {
+        named!(rest_elements(&str) -> Vec<SignedElement>, many0!(parse_signed_element));
+        let (input, mut rest) = rest_elements(input)?;
+        rest.insert(0, first);
+        (input, rest)
+    };
+
+    Ok((input, ElementExpression(rest)))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn dice_test() {
+        assert_eq!(
+            parse_dice("2d4"),
+            Ok(("", Dice::new(2, 4, KeepOrDrop::None)))
+        );
+        assert_eq!(
+            parse_dice("20d40"),
+            Ok(("", Dice::new(20, 40, KeepOrDrop::None)))
+        );
+        assert_eq!(
+            parse_dice("8d7"),
+            Ok(("", Dice::new(8, 7, KeepOrDrop::None)))
+        );
+        assert_eq!(
+            parse_dice("2d20k1"),
+            Ok(("", Dice::new(2, 20, KeepOrDrop::Keep(1))))
+        );
+        assert_eq!(
+            parse_dice("100d10k90"),
+            Ok(("", Dice::new(100, 10, KeepOrDrop::Keep(90))))
+        );
+        assert_eq!(
+            parse_dice("11d10k10"),
+            Ok(("", Dice::new(11, 10, KeepOrDrop::Keep(10))))
+        );
+        assert_eq!(
+            parse_dice("12d10k11"),
+            Ok(("", Dice::new(12, 10, KeepOrDrop::Keep(11))))
+        );
+        assert_eq!(
+            parse_dice("12d10k13"),
+            Ok(("", Dice::new(12, 10, KeepOrDrop::None)))
+        );
+        assert_eq!(
+            parse_dice("12d10k0"),
+            Ok(("", Dice::new(12, 10, KeepOrDrop::None)))
+        );
+        assert_eq!(
+            parse_dice("20d40dh5"),
+            Ok(("", Dice::new(20, 40, KeepOrDrop::Drop(5))))
+        );
+        assert_eq!(
+            parse_dice("8d7dh9"),
+            Ok(("", Dice::new(8, 7, KeepOrDrop::None)))
+        );
+        assert_eq!(
+            parse_dice("8d7dh8"),
+            Ok(("", Dice::new(8, 7, KeepOrDrop::None)))
+        );
+    }
+
+    #[test]
+    fn cant_have_both_keep_and_drop_test() {
+        let res = parse_dice("1d4k3dh2");
+        assert!(res.is_err());
+        match res {
+            Err(NomErr::Error((_, kind))) => {
+                assert_eq!(kind, NomErrorKind::Many1);
+            }
+            _ => panic!("Got success, expected error"),
+        }
+    }
+
+    #[test]
+    fn big_number_of_dice_doesnt_crash_test() {
+        let res = parse_dice("64378631476346123874527551481376547657868536d4");
+        assert!(res.is_err());
+        match res {
+            Err(NomErr::Error((input, kind))) => {
+                assert_eq!(kind, NomErrorKind::TooLarge);
+                assert_eq!(input, "64378631476346123874527551481376547657868536");
+            }
+            _ => panic!("Got success, expected error"),
+        }
+    }
+
+    #[test]
+    fn big_number_of_sides_doesnt_crash_test() {
+        let res = parse_dice("1d423562312587425472658956278456298376234876");
+        assert!(res.is_err());
+        match res {
+            Err(NomErr::Error((input, kind))) => {
+                assert_eq!(kind, NomErrorKind::TooLarge);
+                assert_eq!(input, "423562312587425472658956278456298376234876");
+            }
+            _ => panic!("Got success, expected error"),
+        }
+    }
+
+    #[test]
+    fn element_test() {
+        assert_eq!(
+            parse_element("  \t\n\r\n 8d7 \n"),
+            Ok((" \n", Element::Dice(Dice::new(8, 7, KeepOrDrop::None))))
+        );
+        assert_eq!(
+            parse_element("  \t\n\r\n 3d20k2 \n"),
+            Ok((" \n", Element::Dice(Dice::new(3, 20, KeepOrDrop::Keep(2)))))
+        );
+        assert_eq!(
+            parse_element("  \t\n\r\n 8 \n"),
+            Ok((" \n", Element::Bonus(8)))
+        );
+    }
+
+    #[test]
+    fn signed_element_test() {
+        assert_eq!(
+            parse_signed_element("+ 7"),
+            Ok(("", SignedElement::Positive(Element::Bonus(7))))
+        );
+        assert_eq!(
+            parse_signed_element("  \t\n\r\n- 8 \n"),
+            Ok((" \n", SignedElement::Negative(Element::Bonus(8))))
+        );
+        assert_eq!(
+            parse_signed_element("  \t\n\r\n- 8d4 \n"),
+            Ok((
+                " \n",
+                SignedElement::Negative(Element::Dice(Dice::new(8, 4, KeepOrDrop::None)))
+            ))
+        );
+        assert_eq!(
+            parse_signed_element("  \t\n\r\n- 8d4k4 \n"),
+            Ok((
+                " \n",
+                SignedElement::Negative(Element::Dice(Dice::new(8, 4, KeepOrDrop::Keep(4))))
+            ))
+        );
+        assert_eq!(
+            parse_signed_element("  \t\n\r\n+ 8d4 \n"),
+            Ok((
+                " \n",
+                SignedElement::Positive(Element::Dice(Dice::new(8, 4, KeepOrDrop::None)))
+            ))
+        );
+    }
+
+    #[test]
+    fn element_expression_test() {
+        assert_eq!(
+            parse_element_expression("8d4"),
+            Ok((
+                "",
+                ElementExpression(vec![SignedElement::Positive(Element::Dice(Dice::new(
+                    8,
+                    4,
+                    KeepOrDrop::None
+                )))])
+            ))
+        );
+        assert_eq!(
+            parse_element_expression("\t2d20k1 + 5"),
+            Ok((
+                "",
+                ElementExpression(vec![
+                    SignedElement::Positive(Element::Dice(Dice::new(2, 20, KeepOrDrop::Keep(1)))),
+                    SignedElement::Positive(Element::Bonus(5)),
+                ])
+            ))
+        );
+        assert_eq!(
+            parse_element_expression(" -  8d4 \n "),
+            Ok((
+                " \n ",
+                ElementExpression(vec![SignedElement::Negative(Element::Dice(Dice::new(
+                    8,
+                    4,
+                    KeepOrDrop::None
+                )))])
+            ))
+        );
+        assert_eq!(
+            parse_element_expression("\t3d4k2 + 7 - 5 - 6d12dh3 + 1d1 + 53 1d5 "),
+            Ok((
+                " 1d5 ",
+                ElementExpression(vec![
+                    SignedElement::Positive(Element::Dice(Dice::new(3, 4, KeepOrDrop::Keep(2)))),
+                    SignedElement::Positive(Element::Bonus(7)),
+                    SignedElement::Negative(Element::Bonus(5)),
+                    SignedElement::Negative(Element::Dice(Dice::new(6, 12, KeepOrDrop::Drop(3)))),
+                    SignedElement::Positive(Element::Dice(Dice::new(1, 1, KeepOrDrop::None))),
+                    SignedElement::Positive(Element::Bonus(53)),
+                ])
+            ))
+        );
+    }
+}

dicebot/src/basic/roll.rs

@@ -1,4 +1,10 @@
-use crate::dice;
+/**
+ * In addition to the terms of the AGPL, this file is governed by the
+ * terms of the MIT license, from the original axfive-matrix-dicebot
+ * project.
+ */
+use crate::basic::dice;
+use crate::basic::dice::KeepOrDrop;
 use rand::prelude::*;
 use std::fmt;
 use std::ops::{Deref, DerefMut};
@@ -14,15 +20,27 @@ pub trait Rolled {
 }
 
 #[derive(Debug, PartialEq, Eq, Clone)]
-pub struct DiceRoll(pub Vec<u32>);
+/// array of rolls in order, how many dice to keep, and how many to drop
+///   keep indicates how many of the highest dice to keep
+///   drop indicates how many of the highest dice to drop
+pub struct DiceRoll (pub Vec<u32>, usize, usize);
 
 impl DiceRoll {
     pub fn rolls(&self) -> &[u32] {
         &self.0
     }
 
+    pub fn keep(&self) -> usize {
+        self.1
+    }
+
+    pub fn drop(&self) -> usize {
+        self.2
+    }
+
+    // only count kept dice in total
     pub fn total(&self) -> u32 {
-        self.0.iter().sum()
+        self.0[self.2..self.1].iter().sum()
     }
 }
 
@@ -36,11 +54,21 @@ impl fmt::Display for DiceRoll {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "{}", self.rolled_value())?;
         let rolls = self.rolls();
-        let mut iter = rolls.iter();
+        let keep  = self.keep();
+        let drop  = self.drop();
+        let mut iter = rolls.iter().enumerate();
         if let Some(first) = iter.next() {
-            write!(f, " ({}", first)?;
+            if drop != 0 {
+                write!(f, " ([{}]", first.1)?;
+            } else {
+                write!(f, " ({}", first.1)?;
+            }
             for roll in iter {
-                write!(f, " + {}", roll)?;
+                if roll.0 >= keep || roll.0 < drop {
+                    write!(f, " + [{}]", roll.1)?;
+                } else {
+                    write!(f, " + {}", roll.1)?;
+                }
             }
             write!(f, ")")?;
         }
@@ -53,11 +81,17 @@ impl Roll for dice::Dice {
 
     fn roll(&self) -> DiceRoll {
         let mut rng = rand::thread_rng();
-        let rolls: Vec<_> = (0..self.count)
-            .map(|_| rng.gen_range(1, self.sides + 1))
+        let mut rolls: Vec<_> = (0..self.count)
+            .map(|_| rng.gen_range(1..=self.sides))
             .collect();
+        // sort rolls in descending order
+        rolls.sort_by(|a, b| b.cmp(a));
 
-        DiceRoll(rolls)
+        match self.keep_drop {
+            KeepOrDrop::Keep(k)  => DiceRoll(rolls,k as usize, 0),
+            KeepOrDrop::Drop(dh) => DiceRoll(rolls,self.count as usize, dh as usize),
+            KeepOrDrop::None     => DiceRoll(rolls,self.count as usize, 0),
+        }
     }
 }
 
@@ -193,18 +227,26 @@ mod tests {
     use super::*;
     #[test]
     fn dice_roll_display_test() {
-        assert_eq!(DiceRoll(vec![1, 3, 4]).to_string(), "8 (1 + 3 + 4)");
-        assert_eq!(DiceRoll(vec![]).to_string(), "0");
+        assert_eq!(DiceRoll(vec![1, 3, 4], 3, 0).to_string(), "8 (1 + 3 + 4)");
+        assert_eq!(DiceRoll(vec![], 0, 0).to_string(), "0");
         assert_eq!(
-            DiceRoll(vec![4, 7, 2, 10]).to_string(),
+            DiceRoll(vec![4, 7, 2, 10], 4, 0).to_string(),
             "23 (4 + 7 + 2 + 10)"
         );
+        assert_eq!(
+            DiceRoll(vec![20, 13, 11, 10], 3, 0).to_string(),
+            "44 (20 + 13 + 11 + [10])"
+        );
+        assert_eq!(
+            DiceRoll(vec![20, 13, 11, 10], 4, 1).to_string(),
+            "34 ([20] + 13 + 11 + 10)"
+        );
     }
 
     #[test]
     fn element_roll_display_test() {
         assert_eq!(
-            ElementRoll::Dice(DiceRoll(vec![1, 3, 4])).to_string(),
+            ElementRoll::Dice(DiceRoll(vec![1, 3, 4], 3, 0)).to_string(),
             "8 (1 + 3 + 4)"
         );
         assert_eq!(ElementRoll::Bonus(7).to_string(), "7");
@@ -213,11 +255,11 @@ mod tests {
     #[test]
     fn signed_element_roll_display_test() {
         assert_eq!(
-            SignedElementRoll::Positive(ElementRoll::Dice(DiceRoll(vec![1, 3, 4]))).to_string(),
+            SignedElementRoll::Positive(ElementRoll::Dice(DiceRoll(vec![1, 3, 4], 3, 0))).to_string(),
             "8 (1 + 3 + 4)"
         );
         assert_eq!(
-            SignedElementRoll::Negative(ElementRoll::Dice(DiceRoll(vec![1, 3, 4]))).to_string(),
+            SignedElementRoll::Negative(ElementRoll::Dice(DiceRoll(vec![1, 3, 4], 3, 0))).to_string(),
             "-8 (1 + 3 + 4)"
         );
         assert_eq!(
@@ -234,14 +276,14 @@ mod tests {
     fn element_expression_roll_display_test() {
         assert_eq!(
             ElementExpressionRoll(vec![SignedElementRoll::Positive(ElementRoll::Dice(
-                DiceRoll(vec![1, 3, 4])
+                DiceRoll(vec![1, 3, 4], 3, 0)
             )),])
             .to_string(),
             "8 (1 + 3 + 4)"
         );
         assert_eq!(
             ElementExpressionRoll(vec![SignedElementRoll::Negative(ElementRoll::Dice(
-                DiceRoll(vec![1, 3, 4])
+                DiceRoll(vec![1, 3, 4], 3, 0)
             )),])
             .to_string(),
             "-8 (1 + 3 + 4)"
@@ -258,8 +300,8 @@ mod tests {
         );
         assert_eq!(
             ElementExpressionRoll(vec![
-                SignedElementRoll::Positive(ElementRoll::Dice(DiceRoll(vec![1, 3, 4]))),
-                SignedElementRoll::Negative(ElementRoll::Dice(DiceRoll(vec![1, 2]))),
+                SignedElementRoll::Positive(ElementRoll::Dice(DiceRoll(vec![1, 3, 4], 3, 0))),
+                SignedElementRoll::Negative(ElementRoll::Dice(DiceRoll(vec![1, 2], 2, 0))),
                 SignedElementRoll::Positive(ElementRoll::Bonus(4)),
                 SignedElementRoll::Negative(ElementRoll::Bonus(7)),
             ])
@@ -268,13 +310,33 @@ mod tests {
         );
         assert_eq!(
             ElementExpressionRoll(vec![
-                SignedElementRoll::Negative(ElementRoll::Dice(DiceRoll(vec![1, 3, 4]))),
-                SignedElementRoll::Positive(ElementRoll::Dice(DiceRoll(vec![1, 2]))),
+                SignedElementRoll::Negative(ElementRoll::Dice(DiceRoll(vec![1, 3, 4], 3, 0))),
+                SignedElementRoll::Positive(ElementRoll::Dice(DiceRoll(vec![1, 2], 2, 0))),
                 SignedElementRoll::Negative(ElementRoll::Bonus(4)),
                 SignedElementRoll::Positive(ElementRoll::Bonus(7)),
             ])
             .to_string(),
             "-2 (-8 (1 + 3 + 4) + 3 (1 + 2) - 4 + 7)"
         );
+        assert_eq!(
+            ElementExpressionRoll(vec![
+                SignedElementRoll::Negative(ElementRoll::Dice(DiceRoll(vec![4, 3, 1], 3, 0))),
+                SignedElementRoll::Positive(ElementRoll::Dice(DiceRoll(vec![12, 2], 1, 0))),
+                SignedElementRoll::Negative(ElementRoll::Bonus(4)),
+                SignedElementRoll::Positive(ElementRoll::Bonus(7)),
+            ])
+            .to_string(),
+            "7 (-8 (4 + 3 + 1) + 12 (12 + [2]) - 4 + 7)"
+        );
+        assert_eq!(
+            ElementExpressionRoll(vec![
+                SignedElementRoll::Negative(ElementRoll::Dice(DiceRoll(vec![4, 3, 1], 3, 1))),
+                SignedElementRoll::Positive(ElementRoll::Dice(DiceRoll(vec![12, 2], 2, 0))),
+                SignedElementRoll::Negative(ElementRoll::Bonus(4)),
+                SignedElementRoll::Positive(ElementRoll::Bonus(7)),
+            ])
+            .to_string(),
+            "13 (-4 ([4] + 3 + 1) + 14 (12 + 2) - 4 + 7)"
+        );
     }
 }

dicebot/src/bin/dicebot-cmd.rs

@@ -0,0 +1,51 @@
+use matrix_sdk::ruma::room_id;
+use matrix_sdk::Client;
+use tenebrous_dicebot::commands;
+use tenebrous_dicebot::commands::ResponseExtractor;
+use tenebrous_dicebot::context::{Context, RoomContext};
+use tenebrous_dicebot::db::sqlite::Database;
+use tenebrous_dicebot::error::BotError;
+use tenebrous_dicebot::models::Account;
+use url::Url;
+
+#[tokio::main]
+async fn main() -> Result<(), BotError> {
+    let input = std::env::args().skip(1).collect::<Vec<String>>().join(" ");
+    let command = match commands::parser::parse_command(&input) {
+        Ok(command) => command,
+        Err(e) => return Err(e),
+    };
+
+    let homeserver = Url::parse("http://example.com")?;
+    let db_path = tempfile::NamedTempFile::new_in(".").unwrap();
+    let db = Database::new(
+        db_path
+            .path()
+            .to_str()
+            .expect("Could not get path to temporary db"),
+    )
+    .await?;
+
+    let context = Context {
+        db,
+        account: Account::default(),
+        matrix_client: Client::new(homeserver).await.expect("Could not create matrix client"),
+        origin_room: RoomContext {
+            id: &room_id!("!fakeroomid:example.com"),
+            display_name: "fake room".to_owned(),
+            secure: false,
+        },
+        active_room: RoomContext {
+            id: &room_id!("!fakeroomid:example.com"),
+            display_name: "fake room".to_owned(),
+            secure: false,
+        },
+        username: "@localuser:example.com",
+        message_body: &input,
+    };
+
+    let message = command.execute(&context).await.message_html("fakeuser");
+    let message = html2text::from_read(message.as_bytes(), 80);
+    println!("{}", message.trim());
+    Ok(())
+}

dicebot/src/bin/dicebot.rs

@@ -0,0 +1,73 @@
+//Needed for nested Result handling from tokio. Probably can go away after 1.47.0.
+#![type_length_limit = "7605144"]
+use futures::try_join;
+use log::error;
+use matrix_sdk::Client;
+use std::env;
+use std::sync::{Arc, RwLock};
+use tenebrous_dicebot::bot::DiceBot;
+use tenebrous_dicebot::config::*;
+use tenebrous_dicebot::db::sqlite::Database;
+use tenebrous_dicebot::error::BotError;
+use tenebrous_dicebot::rpc;
+use tenebrous_dicebot::state::DiceBotState;
+use tracing_subscriber::filter::EnvFilter;
+
+/// Attempt to create config object and ddatabase connection pool from
+/// the given config path. An error is returned if config creation or
+/// database pool creation fails for some reason.
+async fn init(config_path: &str) -> Result<(Arc<Config>, Database, Client), BotError> {
+    let cfg = read_config(config_path)?;
+    let cfg = Arc::new(cfg);
+    let sqlite_path = format!("{}/dicebot.sqlite", cfg.database_path());
+    let db = Database::new(&sqlite_path).await?;
+    let client = tenebrous_dicebot::matrix::create_client(&cfg).await?;
+    Ok((cfg, db, client))
+}
+
+#[tokio::main]
+async fn main() -> Result<(), BotError> {
+    let filter = if env::var("RUST_LOG").is_ok() {
+        EnvFilter::from_default_env()
+    } else {
+        EnvFilter::new("tonic=info,tenebrous_dicebot=info,dicebot=info,refinery=info")
+    };
+
+    tracing_subscriber::fmt().with_env_filter(filter).init();
+
+    match run().await {
+        Ok(_) => (),
+        Err(e) => error!("Error: {}", e),
+    }
+
+    Ok(())
+}
+
+async fn run() -> Result<(), BotError> {
+    let config_path = std::env::args()
+        .skip(1)
+        .next()
+        .expect("Need a config as an argument");
+
+    let (cfg, db, client) = init(&config_path).await?;
+    let grpc = rpc::serve_grpc(&cfg, &db, &client);
+    let bot = run_bot(&cfg, &db, &client);
+
+    match try_join!(bot, grpc) {
+        Ok(_) => (),
+        Err(e) => error!("Error: {:?}", e),
+    };
+
+    Ok(())
+}
+
+async fn run_bot(cfg: &Arc<Config>, db: &Database, client: &Client) -> Result<(), BotError> {
+    let state = Arc::new(RwLock::new(DiceBotState::new(&cfg)));
+
+    match DiceBot::new(cfg, &state, db, client) {
+        Ok(bot) => bot.run().await?,
+        Err(e) => println!("Error connecting: {:?}", e),
+    };
+
+    Ok(())
+}

dicebot/src/bin/dicebot_migrate.rs

@@ -0,0 +1,16 @@
+use std::env;
+use tenebrous_dicebot::db::sqlite::migrator;
+
+#[tokio::main]
+async fn main() -> Result<(), migrator::MigrationError> {
+    let args: Vec<String> = env::args().collect();
+    let db_path: &str = match &args[..] {
+        [_, path] => path.as_ref(),
+        [_, _, ..] => panic!("Expected exactly 0 or 1 argument"),
+        _ => "dicebot.sqlite",
+    };
+
+    println!("Using database: {}", db_path);
+
+    migrator::migrate(db_path).await
+}

dicebot/src/bin/tonic_client.rs

@@ -0,0 +1,33 @@
+use tenebrous_rpc::protos::dicebot::UserIdRequest;
+use tenebrous_rpc::protos::dicebot::{dicebot_client::DicebotClient};
+use tonic::{metadata::MetadataValue, transport::Channel, Request};
+
+async fn create_client(
+    shared_secret: &str,
+) -> Result<DicebotClient<Channel>, Box<dyn std::error::Error>> {
+    let channel = Channel::from_static("http://0.0.0.0:9090")
+        .connect()
+        .await?;
+
+    let bearer = MetadataValue::from_str(&format!("Bearer {}", shared_secret))?;
+
+    let client = DicebotClient::with_interceptor(channel, move |mut req: Request<()>| {
+        req.metadata_mut().insert("authorization", bearer.clone());
+        Ok(req)
+    });
+
+    Ok(client)
+}
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let mut client = create_client("example-key").await?;
+
+    let request = tonic::Request::new(UserIdRequest {
+        user_id: "@projectmoon:agnos.is".into(),
+    });
+
+    let response = client.rooms_for_user(request).await?.into_inner();
+    println!("Rooms: {:?}", response.rooms);
+    Ok(())
+}

dicebot/src/bot/command_execution.rs

@@ -0,0 +1,173 @@
+use crate::context::{Context, RoomContext};
+use crate::db::sqlite::Database;
+use crate::error::BotError;
+use crate::logic;
+use crate::matrix;
+use crate::{
+    commands::{execute_command, ExecutionResult, ResponseExtractor},
+    models::Account,
+};
+use futures::stream::{self, StreamExt};
+use matrix_sdk::ruma::{OwnedEventId, RoomId};
+use matrix_sdk::{self, room::Joined, Client};
+use std::clone::Clone;
+use std::convert::TryFrom;
+
+/// Handle responding to a single command being executed. Wil print
+/// out the full result of that command.
+pub(super) async fn handle_single_result(
+    client: &Client,
+    cmd_result: &ExecutionResult,
+    respond_to: &str,
+    room: &Joined,
+    event_id: OwnedEventId,
+) {
+    let html = cmd_result.message_html(respond_to);
+    let plain = cmd_result.message_plain(respond_to);
+    matrix::send_message(client, room.room_id(), (&html, &plain), Some(event_id)).await;
+}
+
+/// Format failure messages nicely in either HTML or plain text. If
+/// plain is true, plain-text will be returned. Otherwise, formatted
+/// HTML.
+fn format_failures(
+    errors: &[(&str, &BotError)],
+    commands_executed: usize,
+    respond_to: &str,
+    plain: bool,
+) -> String {
+    let respond_to = match plain {
+        true => respond_to.to_owned(),
+        false => format!(
+            "<a href=\"https://matrix.to/#/{}\">{}</a>",
+            respond_to, respond_to
+        ),
+    };
+
+    let failures: Vec<String> = errors
+        .iter()
+        .map(|&(cmd, err)| format!("<strong>{}:</strong> {}", cmd, err))
+        .collect();
+
+    let message = format!(
+        "{}: Executed {} commands ({} failed)\n\nFailures:\n{}",
+        respond_to,
+        commands_executed,
+        errors.len(),
+        failures.join("\n")
+    )
+    .replace("\n", "<br/>");
+
+    match plain {
+        true => html2text::from_read(message.as_bytes(), message.len()),
+        false => message,
+    }
+}
+
+/// Handle responding to multiple commands being executed. Will print
+/// out how many commands succeeded and failed (if any failed).
+pub(super) async fn handle_multiple_results(
+    client: &Client,
+    results: &[(String, ExecutionResult)],
+    respond_to: &str,
+    room: &Joined,
+) {
+    let user_pill = format!(
+        "<a href=\"https://matrix.to/#/{}\">{}</a>",
+        respond_to, respond_to
+    );
+
+    let errors: Vec<(&str, &BotError)> = results
+        .into_iter()
+        .filter_map(|(cmd, result)| match result {
+            Err(e) => Some((cmd.as_ref(), e)),
+            _ => None,
+        })
+        .collect();
+
+    let (message, plain) = if errors.len() == 0 {
+        (
+            format!("{}: Executed {} commands", user_pill, results.len()),
+            format!("{}: Executed {} commands", respond_to, results.len()),
+        )
+    } else {
+        (
+            format_failures(&errors, results.len(), respond_to, false),
+            format_failures(&errors, results.len(), respond_to, true),
+        )
+    };
+
+    matrix::send_message(client, room.room_id(), (&message, &plain), None).await;
+}
+
+/// Map an account's active room value to an actual matrix room, if
+/// the account has an active room. This only retrieves the
+/// user-specified active room, and doesn't perform any further
+/// filtering.
+fn get_account_active_room(client: &Client, account: &Account) -> Result<Option<Joined>, BotError> {
+    let active_room = account
+        .registered_user()
+        .and_then(|u| u.active_room.as_deref())
+        .map(|room_id| <&RoomId>::try_from(room_id))
+        .transpose()?
+        .and_then(|active_room_id| client.get_joined_room(active_room_id));
+
+    Ok(active_room)
+}
+
+/// Execute a single command in the list of commands. Can fail if the
+/// Account value cannot be created/fetched from the database, or if
+/// room display names cannot be calculated. Otherwise, the success or
+/// error of command execution itself is returned.
+async fn execute_single_command(
+    command: &str,
+    db: &Database,
+    client: &Client,
+    origin_room: &Joined,
+    sender: &str,
+) -> ExecutionResult {
+    let origin_ctx = RoomContext::new(origin_room, sender).await?;
+    let account = logic::get_account(db, sender).await?;
+    let active_room = get_account_active_room(client, &account)?;
+
+    // Active room is used in secure command-issuing rooms. In
+    // "public" rooms, where other users are, treat origin as the
+    // active room.
+    let active_room = active_room
+        .as_ref()
+        .filter(|_| origin_ctx.secure)
+        .unwrap_or(origin_room);
+
+    let active_ctx = RoomContext::new(active_room, sender).await?;
+
+    let ctx = Context {
+        account,
+        db: db.clone(),
+        matrix_client: client.clone(),
+        origin_room: origin_ctx,
+        username: &sender,
+        active_room: active_ctx,
+        message_body: &command,
+    };
+
+    execute_command(&ctx).await
+}
+
+/// Attempt to execute all commands sent to the bot in a message. This
+/// asynchronously executes all commands given to it. A Vec of all
+/// commands and their execution results are returned.
+pub(super) async fn execute(
+    commands: Vec<&str>,
+    db: &Database,
+    client: &Client,
+    room: &Joined,
+    sender: &str,
+) -> Vec<(String, ExecutionResult)> {
+    stream::iter(commands)
+        .then(|command| async move {
+            let result = execute_single_command(command, db, client, room, sender).await;
+            (command.to_owned(), result)
+        })
+        .collect()
+        .await
+}

dicebot/src/bot/event_handlers.rs

@@ -0,0 +1,163 @@
+use super::DiceBot;
+use crate::db::sqlite::Database;
+use crate::db::Rooms;
+use crate::error::BotError;
+use log::{debug, error, info, warn};
+use matrix_sdk::ruma::events::room::member::RoomMemberEventContent;
+use matrix_sdk::ruma::events::{StrippedStateEvent, SyncMessageLikeEvent};
+use matrix_sdk::{self, room::Room, ruma::events::room::message::RoomMessageEventContent};
+use matrix_sdk::{Client, DisplayName};
+use std::ops::Sub;
+use std::time::UNIX_EPOCH;
+use std::time::{Duration, SystemTime};
+
+/// Check if a message is recent enough to actually process. If the
+/// message is within "oldest_message_age" seconds, this function
+/// returns true. If it's older than that, it returns false and logs a
+/// debug message.
+fn check_message_age(
+    event: &SyncMessageLikeEvent<RoomMessageEventContent>,
+    oldest_message_age: u64,
+) -> bool {
+    let sending_time = event
+        .origin_server_ts()
+        .to_system_time()
+        .unwrap_or(UNIX_EPOCH);
+
+    let oldest_timestamp = SystemTime::now().sub(Duration::from_secs(oldest_message_age));
+
+    if sending_time > oldest_timestamp {
+        true
+    } else {
+        let age = match oldest_timestamp.duration_since(sending_time) {
+            Ok(n) => format!("{} seconds too old", n.as_secs()),
+            Err(_) => "before the UNIX epoch".to_owned(),
+        };
+
+        debug!("Ignoring message because it is {}: {:?}", age, event);
+        false
+    }
+}
+
+/// Determine whether or not to process a received message. This check
+/// is necessary in addition to the event processing check because we
+/// may receive message events when entering a room for the first
+/// time, and we don't want to respond to things before the bot was in
+/// the channel, but we do want to respond to things that were sent if
+/// the bot left and rejoined quickly.
+async fn should_process_message<'a>(
+    bot: &DiceBot,
+    event: &SyncMessageLikeEvent<RoomMessageEventContent>,
+) -> Result<(String, String), BotError> {
+    //Ignore messages that are older than configured duration.
+    if !check_message_age(event, bot.config.oldest_message_age()) {
+        let state_check = bot.state.read().unwrap();
+        if !((*state_check).logged_skipped_old_messages()) {
+            drop(state_check);
+            let mut state = bot.state.write().unwrap();
+            (*state).skipped_old_messages();
+        }
+
+        return Err(BotError::ShouldNotProcessError);
+    }
+
+    let msg_body: String = event
+        .as_original()
+        .map(|e| e.content.body())
+        .map(str::to_string)
+        .unwrap_or_else(|| String::new());
+
+    let sender_username: String = format!(
+        "@{}:{}",
+        event.sender().localpart(),
+        event.sender().server_name()
+    );
+
+    // Do not process messages from the bot itself. Otherwise it might
+    // try to execute its own commands.
+    let bot_username = bot
+        .client
+        .user_id()
+        .map(|u| format!("@{}:{}", u.localpart(), u.server_name()))
+        .unwrap_or_default();
+
+    if sender_username == bot_username {
+        return Err(BotError::ShouldNotProcessError);
+    }
+
+    Ok((msg_body, sender_username))
+}
+
+async fn should_process_event(db: &Database, room_id: &str, event_id: &str) -> bool {
+    db.should_process(room_id, event_id)
+        .await
+        .unwrap_or_else(|e| {
+            error!(
+                "Database error when checking if we should process an event: {}",
+                e.to_string()
+            );
+            false
+        })
+}
+
+pub(super) async fn on_stripped_state_member(
+    event: StrippedStateEvent<RoomMemberEventContent>,
+    client: Client,
+    room: Room,
+) {
+    let room = match room {
+        Room::Invited(invited_room) => invited_room,
+        _ => return,
+    };
+
+    if room.own_user_id().as_str() != event.state_key {
+        return;
+    }
+
+    info!(
+        "Autojoining room {}",
+        room.display_name()
+            .await
+            .ok()
+            .unwrap_or_else(|| DisplayName::Named("[error]".to_string()))
+    );
+
+    if let Err(e) = client.join_room_by_id(&room.room_id()).await {
+        warn!("Could not join room: {}", e.to_string())
+    }
+}
+
+pub(super) async fn on_room_message(
+    event: SyncMessageLikeEvent<RoomMessageEventContent>,
+    room: Room,
+    bot: DiceBot,
+) {
+    let room = match room {
+        Room::Joined(joined_room) => joined_room,
+        _ => return,
+    };
+
+    let room_id = room.room_id().as_str();
+    if !should_process_event(&bot.db, room_id, event.event_id().as_str()).await {
+        return;
+    }
+
+    let (msg_body, sender_username) =
+        if let Ok((msg_body, sender_username)) = should_process_message(&bot, &event).await {
+            (msg_body, sender_username)
+        } else {
+            return;
+        };
+
+    let results = bot
+        .execute_commands(&room, &sender_username, &msg_body)
+        .await;
+
+    bot.handle_results(
+        &room,
+        &sender_username,
+        event.event_id().to_owned(),
+        results,
+    )
+    .await;
+}

dicebot/src/bot/mod.rs

@@ -0,0 +1,172 @@
+use crate::commands::ExecutionResult;
+use crate::config::*;
+use crate::db::sqlite::Database;
+use crate::db::DbState;
+use crate::error::BotError;
+use crate::state::DiceBotState;
+use log::info;
+use matrix_sdk::room::Room;
+use matrix_sdk::ruma::events::room::message::RoomMessageEventContent;
+use matrix_sdk::ruma::events::SyncMessageLikeEvent;
+use matrix_sdk::ruma::OwnedEventId;
+use matrix_sdk::{self, room::Joined, Client};
+use matrix_sdk::config::SyncSettings;
+use std::clone::Clone;
+use std::sync::{Arc, RwLock};
+
+mod command_execution;
+pub mod event_handlers;
+
+/// How many commands can be in one message. If the amount is higher
+/// than this, we reject execution.
+const MAX_COMMANDS_PER_MESSAGE: usize = 50;
+
+/// The DiceBot struct represents an active dice bot. The bot is not
+/// connected to Matrix until its run() function is called.
+#[derive(Clone)]
+pub struct DiceBot {
+    /// A reference to the configuration read in on application start.
+    config: Arc<Config>,
+
+    /// The matrix client.
+    client: Client,
+
+    /// State of the dicebot
+    state: Arc<RwLock<DiceBotState>>,
+
+    /// Active database layer
+    db: Database,
+}
+
+impl DiceBot {
+    /// Create a new dicebot with the given configuration and state
+    /// actor. This function returns a Result because it is possible
+    /// for client creation to fail for some reason (e.g. invalid
+    /// homeserver URL).
+    pub fn new(
+        config: &Arc<Config>,
+        state: &Arc<RwLock<DiceBotState>>,
+        db: &Database,
+        client: &Client,
+    ) -> Result<Self, BotError> {
+        Ok(DiceBot {
+            client: client.clone(),
+            config: config.clone(),
+            state: state.clone(),
+            db: db.clone(),
+        })
+    }
+
+    /// Logs in to matrix and potentially records a new device ID. If
+    /// no device ID is found in the database, a new one will be
+    /// generated by the matrix SDK, and we will store it.
+    async fn login(&self, client: &Client) -> Result<(), BotError> {
+        let username = self.config.matrix_username();
+        let password = self.config.matrix_password();
+
+        // Pull device ID from database, if it exists. Then write it
+        // to DB if the library generated one for us.
+        let device_id: Option<String> = self.db.get_device_id().await?;
+        let device_id: Option<&str> = device_id.as_deref();
+
+        let no_device_ld_login = || client.login_username(username, password);
+        let device_id_login = |id| client.login_username(username, password).device_id(id);
+        let login = device_id.map_or_else(no_device_ld_login, device_id_login);
+
+        login.send().await?;
+
+        if device_id.is_none() {
+            let device_id = client.device_id().ok_or(BotError::NoDeviceIdFound)?;
+            self.db.set_device_id(device_id.as_str()).await?;
+            info!("Recorded new device ID: {}", device_id.as_str());
+        } else {
+            info!("Using existing device ID: {}", device_id.unwrap());
+        }
+
+        info!("Logged in as {}", username);
+        Ok(())
+    }
+
+    async fn bind_events(&self) {
+        //on room message: need closure to pass bot ref in.
+        self.client
+            .add_event_handler({
+                let bot: DiceBot = self.clone();
+                move |event: SyncMessageLikeEvent<RoomMessageEventContent>, room: Room| {
+                    let bot = bot.clone();
+                    async move { event_handlers::on_room_message(event, room, bot).await }
+                }
+            });
+
+        //auto-join handler
+        self.client
+            .add_event_handler(event_handlers::on_stripped_state_member);
+    }
+
+    /// Logs the bot in to Matrix and listens for events until program
+    /// terminated, or a panic occurs. Originally adapted from the
+    /// matrix-rust-sdk command bot example.
+    pub async fn run(self) -> Result<(), BotError> {
+        let client = self.client.clone();
+        self.login(&client).await?;
+        self.bind_events().await;
+
+        info!("Listening for commands");
+
+        // TODO replace with sync_with_callback for cleaner shutdown
+        // process.
+        client.sync(SyncSettings::default()).await?;
+        Ok(())
+    }
+
+    async fn execute_commands(
+        &self,
+        room: &Joined,
+        sender: &str,
+        msg_body: &str,
+    ) -> Vec<(String, ExecutionResult)> {
+        let commands: Vec<&str> = msg_body
+            .lines()
+            .filter(|line| line.starts_with("!"))
+            .take(MAX_COMMANDS_PER_MESSAGE + 1)
+            .collect();
+
+        //Up to 50 commands allowed, otherwise we send back an error.
+        let results: Vec<(String, ExecutionResult)> = if commands.len() < MAX_COMMANDS_PER_MESSAGE {
+            command_execution::execute(commands, &self.db, &self.client, room, sender).await
+        } else {
+            vec![("".to_owned(), Err(BotError::MessageTooLarge))]
+        };
+
+        results
+    }
+
+    pub async fn handle_results(
+        &self,
+        room: &Joined,
+        sender_username: &str,
+        event_id: OwnedEventId,
+        results: Vec<(String, ExecutionResult)>,
+    ) {
+        if results.len() >= 1 {
+            if results.len() == 1 {
+                command_execution::handle_single_result(
+                    &self.client,
+                    &results[0].1,
+                    sender_username,
+                    &room,
+                    event_id,
+                )
+                .await;
+            } else if results.len() > 1 {
+                command_execution::handle_multiple_results(
+                    &self.client,
+                    &results,
+                    sender_username,
+                    &room,
+                )
+                .await;
+            }
+        }
+    }
+}

dicebot/src/cofd/dice.rs

@@ -0,0 +1,779 @@
+use crate::context::Context;
+use crate::error::{BotError, DiceRollingError};
+use crate::parser::dice::{Amount, Element, Operator};
+use itertools::Itertools;
+use std::convert::TryFrom;
+use std::fmt;
+
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
+pub enum DicePoolQuality {
+    TenAgain,
+    NineAgain,
+    EightAgain,
+    Rote,
+    ChanceDie,
+    NoExplode,
+}
+
+impl fmt::Display for DicePoolQuality {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            DicePoolQuality::TenAgain => write!(f, "ten-again"),
+            DicePoolQuality::NineAgain => write!(f, "nine-again"),
+            DicePoolQuality::EightAgain => write!(f, "eight-again"),
+            DicePoolQuality::Rote => write!(f, "rote quality"),
+            DicePoolQuality::ChanceDie => write!(f, "chance die"),
+            DicePoolQuality::NoExplode => write!(f, "no roll-agains"),
+        }
+    }
+}
+
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
+pub struct DicePoolModifiers {
+    pub(crate) success_on: i32,
+    pub(crate) exceptional_on: i32,
+    pub(crate) quality: DicePoolQuality,
+}
+
+impl DicePoolModifiers {
+    pub fn default() -> DicePoolModifiers {
+        DicePoolModifiers {
+            success_on: 8,
+            exceptional_on: 5,
+            quality: DicePoolQuality::TenAgain,
+        }
+    }
+
+    pub fn custom_quality(quality: DicePoolQuality) -> DicePoolModifiers {
+        let success_on = if quality != DicePoolQuality::ChanceDie {
+            8
+        } else {
+            10
+        };
+        DicePoolModifiers {
+            success_on: success_on,
+            exceptional_on: 5,
+            quality: quality,
+        }
+    }
+
+    pub fn custom_exceptional_on(exceptional_on: i32) -> DicePoolModifiers {
+        DicePoolModifiers {
+            success_on: 8,
+            exceptional_on: exceptional_on,
+            quality: DicePoolQuality::TenAgain,
+        }
+    }
+
+    pub fn custom(quality: DicePoolQuality, exceptional_on: i32) -> DicePoolModifiers {
+        DicePoolModifiers {
+            success_on: 8,
+            exceptional_on: exceptional_on,
+            quality: quality,
+        }
+    }
+}
+
+#[derive(Debug, PartialEq)]
+pub struct DicePool {
+    pub(crate) amounts: Vec<Amount>,
+    pub(crate) sides: i32,
+    pub(crate) modifiers: DicePoolModifiers,
+}
+
+impl DicePool {
+    pub fn easy_pool(dice_amount: i32, quality: DicePoolQuality) -> DicePool {
+        DicePool {
+            amounts: vec![Amount {
+                operator: Operator::Plus,
+                element: Element::Number(dice_amount),
+            }],
+            sides: 10,
+            modifiers: DicePoolModifiers::custom_quality(quality),
+        }
+    }
+
+    pub fn easy_with_modifiers(dice_amount: i32, modifiers: DicePoolModifiers) -> DicePool {
+        DicePool {
+            amounts: vec![Amount {
+                operator: Operator::Plus,
+                element: Element::Number(dice_amount),
+            }],
+            sides: 10,
+            modifiers: modifiers,
+        }
+    }
+
+    pub fn new(amounts: Vec<Amount>, modifiers: DicePoolModifiers) -> DicePool {
+        DicePool {
+            amounts: amounts,
+            sides: 10, //TODO make configurable
+            //TODO make configurable
+            modifiers: modifiers,
+        }
+    }
+
+    pub fn chance_die() -> DicePool {
+        DicePool::easy_pool(1, DicePoolQuality::ChanceDie)
+    }
+}
+
+///The result of a successfully executed roll of a dice pool. Does not
+///contain the heavy information of the DicePool instance.
+pub struct RolledDicePool {
+    pub(crate) num_dice: i32,
+    pub(crate) roll: DicePoolRoll,
+    pub(crate) modifiers: DicePoolModifiers,
+}
+
+impl RolledDicePool {
+    fn from(pool: &DicePool, num_dice: i32, rolls: Vec<i32>) -> RolledDicePool {
+        RolledDicePool {
+            modifiers: pool.modifiers,
+            num_dice: num_dice,
+            roll: DicePoolRoll {
+                rolls: rolls,
+                modifiers: pool.modifiers,
+            },
+        }
+    }
+}
+
+impl fmt::Display for RolledDicePool {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let dice_plural = if self.num_dice == 1 { "die" } else { "dice" };
+        write!(
+            f,
+            "{} {} ({}, exceptional on {} successes)",
+            self.num_dice, dice_plural, self.modifiers.quality, self.modifiers.exceptional_on
+        )
+    }
+}
+
+///Store all rolls of the dice pool dice into one struct.
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub struct DicePoolRoll {
+    modifiers: DicePoolModifiers,
+    rolls: Vec<i32>,
+}
+
+/// Amount of dice to display before cutting off and showing "and X
+/// more", so we don't spam the room with huge messages.
+const MAX_DISPLAYED_ROLLS: usize = 15;
+
+fn fmt_rolls(pool: &DicePoolRoll) -> String {
+    let rolls = pool.rolls();
+    if rolls.len() > MAX_DISPLAYED_ROLLS {
+        let shown_amount = rolls.into_iter().take(MAX_DISPLAYED_ROLLS).join(", ");
+        format!(
+            "{}, and {} more",
+            shown_amount,
+            rolls.len() - MAX_DISPLAYED_ROLLS
+        )
+    } else {
+        rolls.into_iter().join(", ")
+    }
+}
+
+fn fmt_for_failure(pool: &DicePoolRoll) -> String {
+    match pool.modifiers.quality {
+        //There should only be 1 die in a chance die roll.
+        DicePoolQuality::ChanceDie if pool.rolls().first() == Some(&1) => {
+            String::from("dramatic failure!")
+        }
+        _ => String::from("failure!"),
+    }
+}
+
+impl DicePoolRoll {
+    pub fn rolls(&self) -> &[i32] {
+        &self.rolls
+    }
+
+    pub fn successes(&self) -> i32 {
+        let successes: usize = self
+            .rolls
+            .iter()
+            .filter(|&roll| *roll >= self.modifiers.success_on)
+            .count();
+
+        i32::try_from(successes).unwrap_or(0)
+    }
+
+    pub fn is_exceptional(&self) -> bool {
+        self.successes() >= self.modifiers.exceptional_on
+    }
+}
+
+/// Attach a Context to a dice pool. Needed for database access.
+pub struct DicePoolWithContext<'a>(pub &'a DicePool, pub &'a Context<'a>);
+
+impl fmt::Display for DicePoolRoll {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let successes = self.successes();
+        if successes > 0 {
+            let success_msg = if self.is_exceptional() {
+                format!("{} successes (exceptional!)", successes)
+            } else {
+                format!("{} successes", successes)
+            };
+
+            write!(f, "{} ({})", success_msg, fmt_rolls(&self))?;
+        } else {
+            write!(f, "{} ({})", fmt_for_failure(&self), fmt_rolls(&self))?;
+        }
+
+        Ok(())
+    }
+}
+
+trait DieRoller {
+    fn roll_number(&mut self, sides: i32) -> i32;
+}
+
+///A version of DieRoller that uses a rand::Rng to roll numbers.
+struct RngDieRoller<R: rand::Rng>(R);
+
+impl<R: rand::Rng> DieRoller for RngDieRoller<R> {
+    fn roll_number(&mut self, sides: i32) -> i32 {
+        self.0.gen_range(1..=sides)
+    }
+}
+
+///Roll a die in the pool, that "explodes" on a given number or higher. Dice will keep
+///being rolled until the result is lower than the explode number, which is normally 10.
+///Statistically speaking, usually one result will be returned from this function.
+fn roll_exploding_die<R: DieRoller>(
+    roller: &mut R,
+    sides: i32,
+    explode_on_or_higher: i32,
+) -> Vec<i32> {
+    let mut results = vec![];
+    loop {
+        let roll = roller.roll_number(sides);
+        results.push(roll);
+        if roll < explode_on_or_higher {
+            break;
+        }
+    }
+    results
+}
+
+///A die with the rote quality is re-rolled once if the roll fails. Otherwise, it obeys
+///all normal rules (re-roll 10s). Re-rolled dice are appended to the result set, so we
+///can keep track of the actual dice that were rolled.
+fn roll_rote_die<R: DieRoller>(roller: &mut R, sides: i32, success_on: i32) -> Vec<i32> {
+    let mut rolls = roll_exploding_die(roller, sides, 10);
+
+    if rolls.len() == 1 && rolls[0] < success_on {
+        rolls.append(&mut roll_exploding_die(roller, sides, 10));
+    }
+
+    rolls
+}
+
+///Roll a single die in the pool, potentially rolling additional dice depending on  pool
+///behavior. The default ten-again will "explode" the die if the result is 10 (repeatedly, if
+///there are multiple 10s). Nine- and eight-again will explode similarly if the result is
+///at least that number. Rote quality will re-roll a failure once, while also exploding
+///on 10. The function returns a Vec of all rolled dice (usually 1).
+fn roll_die<R: DieRoller>(roller: &mut R, pool: &DicePool) -> Vec<i32> {
+    let mut results = vec![];
+    let sides = pool.sides;
+    let success_on = pool.modifiers.success_on;
+
+    match pool.modifiers.quality {
+        DicePoolQuality::TenAgain => results.append(&mut roll_exploding_die(roller, sides, 10)),
+        DicePoolQuality::NineAgain => results.append(&mut roll_exploding_die(roller, sides, 9)),
+        DicePoolQuality::EightAgain => results.append(&mut roll_exploding_die(roller, sides, 8)),
+        DicePoolQuality::Rote => results.append(&mut roll_rote_die(roller, sides, success_on)),
+        DicePoolQuality::ChanceDie | DicePoolQuality::NoExplode => {
+            results.push(roller.roll_number(sides))
+        }
+    }
+
+    results
+}
+
+fn roll_dice<'a, R: DieRoller>(pool: &DicePool, num_dice: i32, roller: &mut R) -> Vec<i32> {
+    (0..num_dice)
+        .flat_map(|_| roll_die(roller, &pool))
+        .collect()
+}
+
+///Roll the dice in a dice pool, according to behavior documented in the various rolling
+///methods.
+pub async fn roll_pool(pool: &DicePoolWithContext<'_>) -> Result<RolledDicePool, BotError> {
+    if pool.0.amounts.len() > 100 {
+        return Err(DiceRollingError::ExpressionTooLarge.into());
+    }
+
+    let num_dice = crate::logic::calculate_dice_amount(&pool.0.amounts, &pool.1).await?;
+    let mut roller = RngDieRoller(rand::thread_rng());
+
+    if num_dice > 0 {
+        let rolls = roll_dice(&pool.0, num_dice, &mut roller);
+        Ok(RolledDicePool::from(&pool.0, num_dice, rolls))
+    } else {
+        let chance_die = DicePool::chance_die();
+        let pool = DicePoolWithContext(&chance_die, &pool.1);
+        let rolls = roll_dice(&pool.0, 1, &mut roller);
+        Ok(RolledDicePool::from(&pool.0, 1, rolls))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::db::sqlite::Database;
+    use crate::db::Variables;
+    use url::Url;
+
+    macro_rules! dummy_room {
+        () => {
+            crate::context::RoomContext {
+                id: &matrix_sdk::ruma::room_id!("!fakeroomid:example.com"),
+                display_name: "displayname".to_owned(),
+                secure: false,
+            }
+        };
+    }
+
+    ///Instead of being random, generate a series of numbers we have complete
+    ///control over.
+    struct SequentialDieRoller {
+        results: Vec<i32>,
+        position: usize,
+    }
+
+    impl SequentialDieRoller {
+        fn new(results: Vec<i32>) -> SequentialDieRoller {
+            SequentialDieRoller {
+                results: results,
+                position: 0,
+            }
+        }
+    }
+
+    impl DieRoller for SequentialDieRoller {
+        fn roll_number(&mut self, _sides: i32) -> i32 {
+            let roll = self.results[self.position];
+            self.position += 1;
+            roll
+        }
+    }
+
+    //Sanity checks
+    #[test]
+    pub fn chance_die_has_success_on_10_test() {
+        assert_eq!(10, DicePool::chance_die().modifiers.success_on);
+    }
+
+    #[test]
+    pub fn non_chance_die_has_success_on_8_test() {
+        fn check_success_on(quality: DicePoolQuality) {
+            let modifiers = DicePoolModifiers::custom_quality(quality);
+            let amount = vec![Amount {
+                operator: Operator::Plus,
+                element: Element::Number(1),
+            }];
+            assert_eq!(8, DicePool::new(amount, modifiers).modifiers.success_on);
+        }
+
+        check_success_on(DicePoolQuality::TenAgain);
+        check_success_on(DicePoolQuality::NineAgain);
+        check_success_on(DicePoolQuality::EightAgain);
+        check_success_on(DicePoolQuality::Rote);
+        check_success_on(DicePoolQuality::NoExplode);
+    }
+
+    //Dice rolling tests.
+    #[test]
+    pub fn ten_again_test() {
+        let mut roller = SequentialDieRoller::new(vec![10, 8, 1]);
+        let rolls = roll_exploding_die(&mut roller, 10, 10);
+        assert_eq!(vec![10, 8], rolls);
+    }
+
+    #[test]
+    pub fn nine_again_test() {
+        let mut roller = SequentialDieRoller::new(vec![10, 9, 8, 1]);
+        let rolls = roll_exploding_die(&mut roller, 10, 9);
+        assert_eq!(vec![10, 9, 8], rolls);
+    }
+
+    #[test]
+    pub fn eight_again_test() {
+        let mut roller = SequentialDieRoller::new(vec![10, 9, 8, 8, 1]);
+        let rolls = roll_exploding_die(&mut roller, 10, 8);
+        assert_eq!(vec![10, 9, 8, 8, 1], rolls);
+    }
+
+    #[test]
+    pub fn rote_quality_fail_then_succeed_test() {
+        let mut roller = SequentialDieRoller::new(vec![5, 8, 1]);
+        let rolls = roll_rote_die(&mut roller, 10, 8);
+        assert_eq!(vec![5, 8], rolls);
+    }
+
+    #[test]
+    pub fn rote_quality_fail_twice_test() {
+        let mut roller = SequentialDieRoller::new(vec![5, 6, 10]);
+        let rolls = roll_rote_die(&mut roller, 10, 8);
+        assert_eq!(vec![5, 6], rolls);
+    }
+
+    #[test]
+    pub fn rote_quality_fail_then_explode_test() {
+        let mut roller = SequentialDieRoller::new(vec![5, 10, 8, 1]);
+        let rolls = roll_rote_die(&mut roller, 10, 8);
+        assert_eq!(vec![5, 10, 8], rolls);
+    }
+
+    #[test]
+    pub fn rote_quality_obeys_success_on_test() {
+        //With success_on = 8, should only roll once.
+        let mut roller = SequentialDieRoller::new(vec![8, 7]);
+        let rolls = roll_rote_die(&mut roller, 10, 8);
+        assert_eq!(vec![8], rolls);
+
+        //With success_on = 9, we should re-roll if it's an 8.
+        roller = SequentialDieRoller::new(vec![8, 7]);
+        let rolls = roll_rote_die(&mut roller, 10, 9);
+        assert_eq!(vec![8, 7], rolls);
+    }
+
+    #[test]
+    fn dice_pool_modifiers_chance_die_test() {
+        let modifiers = DicePoolModifiers::custom_quality(DicePoolQuality::ChanceDie);
+        assert_eq!(10, modifiers.success_on);
+    }
+
+    #[test]
+    fn dice_pool_modifiers_default_sanity_check() {
+        let modifiers = DicePoolModifiers::default();
+        assert_eq!(8, modifiers.success_on);
+        assert_eq!(5, modifiers.exceptional_on);
+        assert_eq!(DicePoolQuality::TenAgain, modifiers.quality);
+    }
+
+    #[test]
+    pub fn no_explode_roll_test() {
+        let pool = DicePool::easy_pool(1, DicePoolQuality::NoExplode);
+        let mut roller = SequentialDieRoller::new(vec![10, 8]);
+        let roll = roll_dice(&pool, 1, &mut roller);
+        assert_eq!(vec![10], roll);
+    }
+
+    #[test]
+    fn number_of_dice_equality_test() {
+        let num_dice = 5;
+        let rolls = vec![1, 2, 3, 4, 5];
+        let pool = DicePool::easy_pool(5, DicePoolQuality::TenAgain);
+        let rolled_pool = RolledDicePool::from(&pool, num_dice, rolls);
+        assert_eq!(5, rolled_pool.num_dice);
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn rejects_large_expression_test() {
+        let db_path = tempfile::NamedTempFile::new_in(".").unwrap();
+        let homeserver = Url::parse("http://example.com").unwrap();
+        let db = Database::new(db_path.path().to_str().unwrap())
+            .await
+            .unwrap();
+
+        let ctx = Context {
+            account: crate::models::Account::default(),
+            db: db,
+            matrix_client: matrix_sdk::Client::new(homeserver).await.unwrap(),
+            origin_room: dummy_room!(),
+            active_room: dummy_room!(),
+            username: "username",
+            message_body: "message",
+        };
+
+        let mut amounts = vec![];
+
+        for _ in 0..500 {
+            amounts.push(Amount {
+                operator: Operator::Plus,
+                element: Element::Number(1),
+            });
+        }
+
+        let pool = DicePool::new(amounts, DicePoolModifiers::default());
+        let pool_with_ctx = DicePoolWithContext(&pool, &ctx);
+        let result = roll_pool(&pool_with_ctx).await;
+        assert!(matches!(
+            result,
+            Err(BotError::DiceRollingError(
+                DiceRollingError::ExpressionTooLarge
+            ))
+        ));
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn converts_to_chance_die_test() {
+        let db_path = tempfile::NamedTempFile::new_in(".").unwrap();
+        crate::db::sqlite::migrator::migrate(db_path.path().to_str().unwrap())
+            .await
+            .unwrap();
+
+        let db = Database::new(db_path.path().to_str().unwrap())
+            .await
+            .unwrap();
+
+        let homeserver = Url::parse("http://example.com").unwrap();
+        let ctx = Context {
+            account: crate::models::Account::default(),
+            db: db,
+            matrix_client: matrix_sdk::Client::new(homeserver).await.unwrap(),
+            origin_room: dummy_room!(),
+            active_room: dummy_room!(),
+            username: "username",
+            message_body: "message",
+        };
+
+        let mut amounts = vec![];
+
+        amounts.push(Amount {
+            operator: Operator::Plus,
+            element: Element::Number(-1),
+        });
+
+        let pool = DicePool::new(amounts, DicePoolModifiers::default());
+        let pool_with_ctx = DicePoolWithContext(&pool, &ctx);
+        let result = roll_pool(&pool_with_ctx).await;
+        assert!(result.is_ok());
+
+        let roll = result.unwrap();
+        assert_eq!(DicePoolQuality::ChanceDie, roll.modifiers.quality);
+        assert_eq!(1, roll.num_dice);
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn can_resolve_variables_test() {
+        let db_path = tempfile::NamedTempFile::new_in(".").unwrap();
+        crate::db::sqlite::migrator::migrate(db_path.path().to_str().unwrap())
+            .await
+            .unwrap();
+
+        let db = Database::new(db_path.path().to_str().unwrap())
+            .await
+            .unwrap();
+
+        let homeserver = Url::parse("http://example.com").unwrap();
+        let ctx = Context {
+            account: crate::models::Account::default(),
+            db: db.clone(),
+            matrix_client: matrix_sdk::Client::new(homeserver).await.unwrap(),
+            origin_room: dummy_room!(),
+            active_room: dummy_room!(),
+            username: "username",
+            message_body: "message",
+        };
+
+        db.set_user_variable(
+            &ctx.username,
+            &ctx.origin_room.id.as_str(),
+            "myvariable",
+            10,
+        )
+        .await
+        .expect("could not set myvariable to 10");
+
+        let amounts = vec![Amount {
+            operator: Operator::Plus,
+            element: Element::Variable("myvariable".to_owned()),
+        }];
+
+        let pool = DicePool::new(amounts, DicePoolModifiers::default());
+
+        assert_eq!(
+            crate::logic::calculate_dice_amount(&pool.amounts, &ctx)
+                .await
+                .unwrap(),
+            10
+        );
+    }
+
+    //DicePool tests
+    #[test]
+    fn easy_pool_chance_die_test() {
+        let pool = DicePool::easy_pool(1, DicePoolQuality::ChanceDie);
+        assert_eq!(10, pool.modifiers.success_on);
+    }
+
+    #[test]
+    fn easy_pool_quality_test() {
+        fn check_quality(quality: DicePoolQuality) {
+            let pool = DicePool::easy_pool(1, quality);
+            assert_eq!(quality, pool.modifiers.quality);
+        }
+
+        check_quality(DicePoolQuality::TenAgain);
+        check_quality(DicePoolQuality::NineAgain);
+        check_quality(DicePoolQuality::EightAgain);
+        check_quality(DicePoolQuality::Rote);
+        check_quality(DicePoolQuality::ChanceDie);
+        check_quality(DicePoolQuality::NoExplode);
+    }
+
+    #[test]
+    fn is_successful_on_equal_test() {
+        let result = DicePoolRoll {
+            rolls: vec![8],
+            modifiers: DicePoolModifiers {
+                exceptional_on: 5,
+                success_on: 8,
+                quality: DicePoolQuality::TenAgain,
+            },
+        };
+
+        assert_eq!(1, result.successes());
+    }
+
+    #[test]
+    fn chance_die_success_test() {
+        let result = DicePoolRoll {
+            rolls: vec![10],
+            modifiers: DicePoolModifiers {
+                exceptional_on: 5,
+                success_on: 10,
+                quality: DicePoolQuality::ChanceDie,
+            },
+        };
+
+        assert_eq!(1, result.successes());
+    }
+
+    #[test]
+    fn chance_die_fail_test() {
+        let result = DicePoolRoll {
+            rolls: vec![9],
+            modifiers: DicePoolModifiers {
+                exceptional_on: 5,
+                success_on: 10,
+                quality: DicePoolQuality::ChanceDie,
+            },
+        };
+
+        assert_eq!(0, result.successes());
+    }
+
+    #[test]
+    fn is_exceptional_test() {
+        let result = DicePoolRoll {
+            rolls: vec![8, 8, 9, 10, 8],
+            modifiers: DicePoolModifiers {
+                exceptional_on: 5,
+                success_on: 8,
+                quality: DicePoolQuality::TenAgain,
+            },
+        };
+
+        assert_eq!(5, result.successes());
+        assert_eq!(true, result.is_exceptional());
+    }
+
+    #[test]
+    fn is_not_exceptional_test() {
+        let result = DicePoolRoll {
+            rolls: vec![8, 8, 9, 10],
+            modifiers: DicePoolModifiers::default(),
+        };
+
+        assert_eq!(4, result.successes());
+        assert_eq!(false, result.is_exceptional());
+    }
+
+    //Format tests
+    #[test]
+    fn formats_rolled_dice_pool_single_die() {
+        let pool = DicePool::easy_pool(5, DicePoolQuality::TenAgain);
+        let rolled_pool = RolledDicePool::from(&pool, 1, vec![1]);
+        let message = format!("{}", rolled_pool);
+        assert!(message.starts_with("1 die"));
+    }
+
+    #[test]
+    fn formats_rolled_dice_pool_multiple_dice() {
+        let pool = DicePool::easy_pool(5, DicePoolQuality::TenAgain);
+        let rolled_pool = RolledDicePool::from(&pool, 2, vec![1, 2]);
+        let message = format!("{}", rolled_pool);
+        assert!(message.starts_with("2 dice"));
+    }
+
+    #[test]
+    fn formats_rolled_dice_pool_zero_dice() {
+        let pool = DicePool::easy_pool(5, DicePoolQuality::TenAgain);
+        let rolled_pool = RolledDicePool::from(&pool, 0, vec![]);
+        let message = format!("{}", rolled_pool);
+        assert!(message.starts_with("0 dice"));
+    }
+
+    #[test]
+    fn formats_dramatic_failure_test() {
+        let result = DicePoolRoll {
+            rolls: vec![1],
+            modifiers: DicePoolModifiers::custom_quality(DicePoolQuality::ChanceDie),
+        };
+
+        assert_eq!("dramatic failure!", fmt_for_failure(&result));
+    }
+
+    #[test]
+    fn formats_regular_failure_when_not_chance_die_test() {
+        let result = DicePoolRoll {
+            rolls: vec![1],
+            modifiers: DicePoolModifiers {
+                quality: DicePoolQuality::TenAgain,
+                exceptional_on: 5,
+                success_on: 10,
+            },
+        };
+
+        assert_eq!("failure!", fmt_for_failure(&result));
+    }
+
+    #[test]
+    fn formats_lots_of_dice_test() {
+        let result = DicePoolRoll {
+            modifiers: DicePoolModifiers::default(),
+            rolls: vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1, 2, 3, 4, 5, 6, 7, 8, 9],
+        };
+
+        assert_eq!(
+            "1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1, 2, 3, 4, 5, and 4 more",
+            fmt_rolls(&result)
+        );
+    }
+
+    #[test]
+    fn shows_more_than_10_dice_test() {
+        //Make sure we display more than 10 dice when below the display limit (15).
+        let result = DicePoolRoll {
+            modifiers: DicePoolModifiers::default(),
+            rolls: vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14],
+        };
+
+        assert_eq!(
+            "1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14",
+            fmt_rolls(&result)
+        );
+    }
+
+    #[test]
+    fn shows_exactly_15_dice_test() {
+        //If we are at format limit (15), make sure all are shown
+        let result = DicePoolRoll {
+            modifiers: DicePoolModifiers::default(),
+            rolls: vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15],
+        };
+
+        assert_eq!(
+            "1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15",
+            fmt_rolls(&result)
+        );
+    }
+}

dicebot/src/cofd/mod.rs

@@ -0,0 +1,2 @@
+pub mod dice;
+pub mod parser;

dicebot/src/cofd/parser.rs

@@ -0,0 +1,233 @@
+use crate::cofd::dice::{DicePool, DicePoolModifiers, DicePoolQuality};
+use crate::error::BotError;
+use crate::parser::dice::{parse_amounts, DiceParsingError};
+use combine::parser::char::{digit, spaces, string};
+use combine::{choice, count, many1, one_of, Parser};
+
+#[derive(Debug, Clone, Copy, PartialEq)]
+enum ParsedInfo {
+    Quality(DicePoolQuality),
+    ExceptionalOn(i32),
+}
+
+pub fn parse_modifiers(input: &str) -> Result<DicePoolModifiers, DiceParsingError> {
+    if input.len() == 0 {
+        return Ok(DicePoolModifiers::default());
+    }
+
+    let input = input.trim();
+
+    let quality = one_of("nerx".chars())
+        .skip(spaces().silent())
+        .map(|quality| match quality {
+            'n' => ParsedInfo::Quality(DicePoolQuality::NineAgain),
+            'e' => ParsedInfo::Quality(DicePoolQuality::EightAgain),
+            'r' => ParsedInfo::Quality(DicePoolQuality::Rote),
+            'x' => ParsedInfo::Quality(DicePoolQuality::NoExplode),
+            _ => ParsedInfo::Quality(DicePoolQuality::TenAgain), //TODO add warning log
+        });
+
+    let exceptional_on = string("s")
+        .and(many1(digit()))
+        .map(|s| s.1) //Discard the s; only need the number
+        .skip(spaces().silent())
+        .map(|num_as_str: String| {
+            ParsedInfo::ExceptionalOn(match num_as_str.parse::<i32>() {
+                Ok(success_on) => success_on,
+                Err(_) => 5, //TODO add warning log
+            })
+        });
+
+    let mut parser = count(2, choice((quality, exceptional_on)))
+        .skip(spaces().silent())
+        .map(|modifiers: Vec<ParsedInfo>| modifiers);
+
+    let (result, rest) = parser.parse(input)?;
+
+    if rest.len() == 0 {
+        convert_to_modifiers(&result)
+    } else {
+        Err(DiceParsingError::UnconsumedInput)
+    }
+}
+
+fn convert_to_modifiers(parsed: &Vec<ParsedInfo>) -> Result<DicePoolModifiers, DiceParsingError> {
+    use ParsedInfo::*;
+    if parsed.len() == 0 {
+        Ok(DicePoolModifiers::default())
+    } else if parsed.len() == 1 {
+        match parsed[0] {
+            ExceptionalOn(exceptional_on) => {
+                Ok(DicePoolModifiers::custom_exceptional_on(exceptional_on))
+            }
+            Quality(quality) => Ok(DicePoolModifiers::custom_quality(quality)),
+        }
+    } else if parsed.len() == 2 {
+        match parsed[..] {
+            [ExceptionalOn(exceptional_on), Quality(quality)] => {
+                Ok(DicePoolModifiers::custom(quality, exceptional_on))
+            }
+            [Quality(quality), ExceptionalOn(exceptional_on)] => {
+                Ok(DicePoolModifiers::custom(quality, exceptional_on))
+            }
+            _ => Err(DiceParsingError::InvalidModifiers.into()),
+        }
+    } else {
+        //We don't expect this clause to be hit, because the parser works 0 to 2 times.
+        Err(DiceParsingError::InvalidModifiers.into())
+    }
+}
+
+pub fn parse_dice_pool(input: &str) -> Result<DicePool, BotError> {
+    let (amounts, modifiers_str) = parse_amounts(input)?;
+    let modifiers = parse_modifiers(modifiers_str)?;
+    Ok(DicePool::new(amounts, modifiers))
+}
+
+pub fn create_chance_die() -> Result<DicePool, BotError> {
+    Ok(DicePool::chance_die())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn quality_test() {
+        let result = parse_modifiers("n");
+        assert!(result.is_ok());
+        assert_eq!(
+            result.unwrap(),
+            DicePoolModifiers::custom_quality(DicePoolQuality::NineAgain)
+        );
+
+        let result = parse_modifiers("e");
+        assert!(result.is_ok());
+        assert_eq!(
+            result.unwrap(),
+            DicePoolModifiers::custom_quality(DicePoolQuality::EightAgain)
+        );
+
+        let result = parse_modifiers("r");
+        assert!(result.is_ok());
+        assert_eq!(
+            result.unwrap(),
+            DicePoolModifiers::custom_quality(DicePoolQuality::Rote)
+        );
+
+        let result = parse_modifiers("x");
+        assert!(result.is_ok());
+        assert_eq!(
+            result.unwrap(),
+            DicePoolModifiers::custom_quality(DicePoolQuality::NoExplode)
+        );
+
+        let result = parse_modifiers("b");
+        assert!(result.is_err());
+        assert!(matches!(result, Err(DiceParsingError::UnconsumedInput)));
+    }
+
+    #[test]
+    fn multiple_quality_failure_test() {
+        let result = parse_modifiers("ne");
+        assert!(result.is_err());
+        assert!(matches!(result, Err(DiceParsingError::InvalidModifiers)));
+    }
+
+    #[test]
+    fn exceptional_success_test() {
+        let result = parse_modifiers("s3");
+        assert!(result.is_ok());
+        assert_eq!(result.unwrap(), DicePoolModifiers::custom_exceptional_on(3));
+
+        let result = parse_modifiers("s33");
+        assert!(result.is_ok());
+        assert_eq!(
+            result.unwrap(),
+            DicePoolModifiers::custom_exceptional_on(33)
+        );
+
+        let result = parse_modifiers("s3q");
+        assert!(result.is_err());
+        assert!(matches!(result, Err(DiceParsingError::UnconsumedInput)));
+    }
+
+    #[test]
+    fn dice_pool_number_only_test() {
+        let result = parse_dice_pool("8");
+        assert!(result.is_ok());
+        assert_eq!(
+            result.unwrap(),
+            DicePool::easy_pool(8, DicePoolQuality::TenAgain)
+        );
+    }
+
+    #[test]
+    fn dice_pool_number_with_quality() {
+        let result = parse_dice_pool("8 n");
+        assert!(result.is_ok());
+        assert_eq!(
+            result.unwrap(),
+            DicePool::easy_pool(8, DicePoolQuality::NineAgain)
+        );
+    }
+
+    #[test]
+    fn dice_pool_number_with_success_change() {
+        let modifiers = DicePoolModifiers::custom_exceptional_on(3);
+        let result = parse_dice_pool("8 s3");
+        assert!(result.is_ok());
+        assert_eq!(result.unwrap(), DicePool::easy_with_modifiers(8, modifiers));
+    }
+
+    #[test]
+    fn dice_pool_with_quality_and_success_change() {
+        let modifiers = DicePoolModifiers::custom(DicePoolQuality::Rote, 3);
+        let result = parse_dice_pool("8 rs3");
+        assert!(result.is_ok());
+        assert_eq!(result.unwrap(), DicePool::easy_with_modifiers(8, modifiers));
+    }
+
+    #[test]
+    fn dice_pool_complex_expression_test() {
+        use crate::parser::dice::*;
+        let modifiers = DicePoolModifiers::custom(DicePoolQuality::Rote, 3);
+        let amounts = vec![
+            Amount {
+                operator: Operator::Plus,
+                element: Element::Number(8),
+            },
+            Amount {
+                operator: Operator::Plus,
+                element: Element::Number(10),
+            },
+            Amount {
+                operator: Operator::Minus,
+                element: Element::Number(2),
+            },
+            Amount {
+                operator: Operator::Plus,
+                element: Element::Variable("varname".to_owned()),
+            },
+        ];
+
+        let expected = DicePool::new(amounts, modifiers);
+
+        let result = parse_dice_pool("8+10-2+varname rs3");
+        assert!(result.is_ok());
+        assert_eq!(result.unwrap(), expected);
+
+        let result = parse_dice_pool("8+10-   2 + varname      rs3");
+        assert!(result.is_ok());
+        assert_eq!(result.unwrap(), expected);
+
+        let result = parse_dice_pool("8+ 10 -2 + varname           rs3");
+        assert!(result.is_ok());
+        assert_eq!(result.unwrap(), expected);
+
+        //This one has tabs in it.
+        let result = parse_dice_pool(" 	8	+ 10 -2 + varname	r	s3");
+        assert!(result.is_ok());
+        assert_eq!(result.unwrap(), expected);
+    }
+}

dicebot/src/commands/basic_rolling.rs

@@ -0,0 +1,48 @@
+use super::{Command, Execution, ExecutionResult};
+use crate::basic::dice::ElementExpression;
+use crate::basic::parser::parse_element_expression;
+use crate::basic::roll::Roll;
+use crate::context::Context;
+use crate::error::BotError;
+use async_trait::async_trait;
+use nom::Err as NomErr;
+use std::convert::TryFrom;
+
+pub struct RollCommand(pub ElementExpression);
+
+impl TryFrom<String> for RollCommand {
+    type Error = BotError;
+
+    fn try_from(input: String) -> Result<Self, Self::Error> {
+        let result = parse_element_expression(&input);
+        match result {
+            Ok((rest, expression)) if rest.len() == 0 => Ok(RollCommand(expression)),
+            //"Legacy code boundary": translates Nom errors into BotErrors.
+            Ok(_) => Err(BotError::NomParserIncomplete),
+            Err(NomErr::Error(e)) => Err(BotError::NomParserError(e.1)),
+            Err(NomErr::Failure(e)) => Err(BotError::NomParserError(e.1)),
+            Err(NomErr::Incomplete(_)) => Err(BotError::NomParserIncomplete),
+        }
+    }
+}
+
+#[async_trait]
+impl Command for RollCommand {
+    fn name(&self) -> &'static str {
+        "roll regular dice"
+    }
+
+    fn is_secure(&self) -> bool {
+        false
+    }
+
+    async fn execute(&self, _ctx: &Context<'_>) -> ExecutionResult {
+        let roll = self.0.roll();
+        let html = format!(
+            "<strong>Dice:</strong> {}</p><p><strong>Result</strong>: {}",
+            self.0, roll
+        );
+
+        Execution::success(html)
+    }
+}

dicebot/src/commands/cofd.rs

@@ -0,0 +1,48 @@
+use super::{Command, Execution, ExecutionResult};
+use crate::cofd::dice::{roll_pool, DicePool, DicePoolWithContext};
+use crate::cofd::parser::{create_chance_die, parse_dice_pool};
+use crate::context::Context;
+use crate::error::BotError;
+use async_trait::async_trait;
+use std::convert::TryFrom;
+
+pub struct PoolRollCommand(pub DicePool);
+
+impl PoolRollCommand {
+    pub fn chance_die() -> Result<PoolRollCommand, BotError> {
+        let pool = create_chance_die()?;
+        Ok(PoolRollCommand(pool))
+    }
+}
+
+impl TryFrom<String> for PoolRollCommand {
+    type Error = BotError;
+
+    fn try_from(input: String) -> Result<Self, Self::Error> {
+        let pool = parse_dice_pool(&input)?;
+        Ok(PoolRollCommand(pool))
+    }
+}
+
+#[async_trait]
+impl Command for PoolRollCommand {
+    fn name(&self) -> &'static str {
+        "roll dice pool"
+    }
+
+    fn is_secure(&self) -> bool {
+        false
+    }
+
+    async fn execute(&self, ctx: &Context<'_>) -> ExecutionResult {
+        let pool_with_ctx = DicePoolWithContext(&self.0, ctx);
+        let rolled_pool = roll_pool(&pool_with_ctx).await?;
+
+        let html = format!(
+            "<strong>Pool:</strong> {}</p><p><strong>Result</strong>: {}",
+            rolled_pool, rolled_pool.roll
+        );
+
+        Execution::success(html)
+    }
+}

dicebot/src/commands/cthulhu.rs

@@ -0,0 +1,77 @@
+use super::{Command, Execution, ExecutionResult};
+use crate::context::Context;
+use crate::cthulhu::dice::{
+    advancement_roll, regular_roll, AdvancementRoll, AdvancementRollWithContext, DiceRoll,
+    DiceRollWithContext,
+};
+use crate::cthulhu::parser::{parse_advancement_roll, parse_regular_roll};
+use crate::error::BotError;
+use async_trait::async_trait;
+use std::convert::TryFrom;
+
+pub struct CthRoll(pub DiceRoll);
+
+impl TryFrom<String> for CthRoll {
+    type Error = BotError;
+
+    fn try_from(input: String) -> Result<Self, Self::Error> {
+        let roll = parse_regular_roll(&input)?;
+        Ok(CthRoll(roll))
+    }
+}
+
+#[async_trait]
+impl Command for CthRoll {
+    fn name(&self) -> &'static str {
+        "roll percentile dice"
+    }
+
+    fn is_secure(&self) -> bool {
+        false
+    }
+
+    async fn execute(&self, ctx: &Context<'_>) -> ExecutionResult {
+        let roll_with_ctx = DiceRollWithContext(&self.0, ctx);
+        let executed_roll = regular_roll(&roll_with_ctx).await?;
+
+        let html = format!(
+            "<strong>Roll:</strong> {}</p><p><strong>Result</strong>: {}",
+            executed_roll, executed_roll.roll
+        );
+
+        Execution::success(html)
+    }
+}
+
+pub struct CthAdvanceRoll(pub AdvancementRoll);
+
+impl TryFrom<String> for CthAdvanceRoll {
+    type Error = BotError;
+
+    fn try_from(input: String) -> Result<Self, Self::Error> {
+        let roll = parse_advancement_roll(&input)?;
+        Ok(CthAdvanceRoll(roll))
+    }
+}
+
+#[async_trait]
+impl Command for CthAdvanceRoll {
+    fn name(&self) -> &'static str {
+        "roll skill advancement dice"
+    }
+
+    fn is_secure(&self) -> bool {
+        false
+    }
+
+    async fn execute(&self, ctx: &Context<'_>) -> ExecutionResult {
+        let roll_with_ctx = AdvancementRollWithContext(&self.0, ctx);
+        let executed_roll = advancement_roll(&roll_with_ctx).await?;
+        let html = format!(
+            "<strong>Roll:</strong> {}</p><p><strong>Result</strong>: {}",
+            executed_roll, executed_roll.roll
+        );
+
+        Execution::success(html)
+    }
+}

dicebot/src/commands/management.rs

@@ -0,0 +1,200 @@
+use super::{Command, Execution, ExecutionResult};
+use crate::db::Users;
+use crate::error::BotError::{AccountDoesNotExist, PasswordCreationError};
+use crate::logic::hash_password;
+use crate::models::{AccountStatus, User};
+use crate::{context::Context, error::BotError};
+use async_trait::async_trait;
+use std::convert::{Into, TryFrom};
+
+pub struct RegisterCommand;
+
+impl TryFrom<String> for RegisterCommand {
+    type Error = BotError;
+
+    fn try_from(_: String) -> Result<Self, Self::Error> {
+        Ok(RegisterCommand)
+    }
+}
+
+#[async_trait]
+impl Command for RegisterCommand {
+    fn name(&self) -> &'static str {
+        "register user account"
+    }
+
+    fn is_secure(&self) -> bool {
+        true
+    }
+
+    async fn execute(&self, ctx: &Context<'_>) -> ExecutionResult {
+        if ctx.account.is_registered() {
+            return Err(BotError::AccountAlreadyExists);
+        }
+
+        let user = User {
+            username: ctx.username.to_owned(),
+            password: None,
+            account_status: AccountStatus::Registered,
+            ..Default::default()
+        };
+
+        ctx.db.upsert_user(&user).await?;
+
+        Execution::success(format!(
+            "User account {} registered for bot commands.",
+            ctx.username
+        ))
+    }
+}
+
+pub struct UnlinkCommand(pub String);
+
+impl TryFrom<String> for UnlinkCommand {
+    type Error = BotError;
+
+    fn try_from(value: String) -> Result<Self, Self::Error> {
+        Ok(UnlinkCommand(value))
+    }
+}
+
+#[async_trait]
+impl Command for UnlinkCommand {
+    fn name(&self) -> &'static str {
+        "unlink user accountx from external applications"
+    }
+
+    fn is_secure(&self) -> bool {
+        true
+    }
+
+    async fn execute(&self, ctx: &Context<'_>) -> ExecutionResult {
+        let mut user = ctx
+            .db
+            .get_user(&ctx.username)
+            .await?
+            .ok_or(BotError::AccountDoesNotExist)?;
+
+        user.password = None;
+        ctx.db.upsert_user(&user).await?;
+
+        Execution::success(format!(
+            "Accounted {} is now inaccessible to external applications.",
+            ctx.username
+        ))
+    }
+}
+
+pub struct LinkCommand(pub String);
+
+impl TryFrom<String> for LinkCommand {
+    type Error = BotError;
+
+    fn try_from(value: String) -> Result<Self, Self::Error> {
+        Ok(LinkCommand(value))
+    }
+}
+
+#[async_trait]
+impl Command for LinkCommand {
+    fn name(&self) -> &'static str {
+        "link user account to external applications"
+    }
+
+    fn is_secure(&self) -> bool {
+        true
+    }
+
+    async fn execute(&self, ctx: &Context<'_>) -> ExecutionResult {
+        let mut user = ctx
+            .db
+            .get_user(&ctx.username)
+            .await?
+            .ok_or(BotError::AccountDoesNotExist)?;
+
+        let pw_hash = hash_password(&self.0).map_err(|e| PasswordCreationError(e))?;
+        user.password = Some(pw_hash);
+        ctx.db.upsert_user(&user).await?;
+
+        Execution::success(format!(
+            "Accounted now available for external use. Please log in to \
+             external applications with username {} and the password you set.",
+            ctx.username
+        ))
+    }
+}
+
+pub struct CheckCommand;
+
+impl TryFrom<String> for CheckCommand {
+    type Error = BotError;
+
+    fn try_from(_: String) -> Result<Self, Self::Error> {
+        Ok(CheckCommand)
+    }
+}
+
+#[async_trait]
+impl Command for CheckCommand {
+    fn name(&self) -> &'static str {
+        "check user account status"
+    }
+
+    fn is_secure(&self) -> bool {
+        true
+    }
+
+    async fn execute(&self, ctx: &Context<'_>) -> ExecutionResult {
+        let user = ctx.db.get_user(&ctx.username).await?;
+
+        match user {
+            Some(user) => match user.password {
+                Some(_) => Execution::success(
+                    "Account exists, and is available to external applications with a password. \
+                     If you forgot your password, change it with !link."
+                        .to_string(),
+                ),
+                None => Execution::success(
+                    "Account exists, but is not available to external applications.".to_string(),
+                ),
+            },
+            None => Execution::success(
+                "No account registered. Only simple commands in public rooms are available."
+                    .to_string(),
+            ),
+        }
+    }
+}
+
+pub struct UnregisterCommand;
+
+impl TryFrom<String> for UnregisterCommand {
+    type Error = BotError;
+
+    fn try_from(_: String) -> Result<Self, Self::Error> {
+        Ok(UnregisterCommand)
+    }
+}
+
+#[async_trait]
+impl Command for UnregisterCommand {
+    fn name(&self) -> &'static str {
+        "unregister user account"
+    }
+
+    fn is_secure(&self) -> bool {
+        true
+    }
+
+    async fn execute(&self, ctx: &Context<'_>) -> ExecutionResult {
+        let user = ctx.db.get_user(&ctx.username).await?;
+
+        match user {
+            Some(_) => {
+                ctx.db.delete_user(&ctx.username).await?;
+                Execution::success("Your user account has been removed.".to_string())
+            }
+            None => Err(AccountDoesNotExist.into()),
+        }
+    }
+}

dicebot/src/commands/misc.rs

@@ -0,0 +1,38 @@
+use super::{Command, Execution, ExecutionResult};
+use crate::context::Context;
+use crate::error::BotError;
+use crate::help::{parse_help_topic, HelpTopic};
+use async_trait::async_trait;
+use std::convert::TryFrom;
+
+pub struct HelpCommand(pub Option<HelpTopic>);
+
+impl TryFrom<String> for HelpCommand {
+    type Error = BotError;
+
+    fn try_from(input: String) -> Result<Self, Self::Error> {
+        let topic = parse_help_topic(&input);
+        Ok(HelpCommand(topic))
+    }
+}
+
+#[async_trait]
+impl Command for HelpCommand {
+    fn name(&self) -> &'static str {
+        "help information"
+    }
+
+    fn is_secure(&self) -> bool {
+        false
+    }
+
+    async fn execute(&self, _ctx: &Context<'_>) -> ExecutionResult {
+        let help = match &self.0 {
+            Some(topic) => topic.message(),
+            _ => "There is no help for this topic",
+        };
+
+        let html = format!("<strong>Help:</strong> {}", help.replace("\n", "<br/>"));
+        Execution::success(html)
+    }
+}

dicebot/src/commands/mod.rs

@@ -0,0 +1,301 @@
+use crate::context::Context;
+use crate::error::BotError;
+use async_trait::async_trait;
+use log::{error, info};
+use thiserror::Error;
+
+pub mod basic_rolling;
+pub mod cofd;
+pub mod cthulhu;
+pub mod management;
+pub mod misc;
+pub mod parser;
+pub mod rooms;
+pub mod variables;
+
+/// A custom error type specifically related to parsing command text.
+/// Does not wrap an execution failure.
+#[derive(Error, Debug)]
+pub enum CommandError {
+    #[error("invalid command: {0}")]
+    InvalidCommand(String),
+
+    #[error("command can only be executed from encrypted direct message")]
+    InsecureExecution,
+
+    #[error("ignored command")]
+    IgnoredCommand,
+}
+
+/// A successfully executed command returns a message to be sent back
+/// to the user in HTML (plain text used as a fallback by message
+/// formatter).
+#[derive(Debug)]
+pub struct Execution {
+    html: String,
+}
+
+impl Execution {
+    pub fn success(html: String) -> ExecutionResult {
+        Ok(Execution { html })
+    }
+
+    /// Response message in HTML.
+    pub fn html(&self) -> String {
+        self.html.clone()
+    }
+}
+
+/// Wraps either a successful command execution response, or an error
+/// that occurred.
+pub type ExecutionResult = Result<Execution, BotError>;
+
+/// Extract response messages out of a type, whether it is success or
+/// failure.
+pub trait ResponseExtractor {
+    /// HTML representation of the message, directly mentioning the
+    /// username.
+    fn message_html(&self, username: &str) -> String;
+
+    fn message_plain(&self, username: &str) -> String;
+}
+
+impl ResponseExtractor for ExecutionResult {
+    /// Error message in bolded HTML.
+    fn message_html(&self, username: &str) -> String {
+        // TODO use user display name too (element seems to render this
+        // without display name)
+        let username = format!(
+            "<a href=\"https://matrix.to/#/{}\">{}</a>",
+            username, username
+        );
+
+        match self {
+            Ok(resp) => format!("<p>{}</p>", resp.html).replace("\n", "<br/>"),
+            Err(e) => format!("<p>{}: <strong>{}</strong></p>", username, e).replace("\n", "<br/>"),
+        }
+    }
+
+    fn message_plain(&self, username: &str) -> String {
+        let message = match self {
+            Ok(resp) => format!("{}", resp.html),
+            Err(e) => format!("{}", e),
+        };
+
+        format!(
+            "{}:\n{}",
+            username,
+            html2text::from_read(message.as_bytes(), message.len())
+        )
+    }
+}
+
+/// The trait that any command that can be executed must implement.
+#[async_trait]
+pub trait Command: Send + Sync {
+    async fn execute(&self, ctx: &Context<'_>) -> ExecutionResult;
+    fn name(&self) -> &'static str;
+    fn is_secure(&self) -> bool;
+}
+
+/// Determine if we are allowed to execute this command. Currently the
+/// rules are that secure commands must be executed in secure rooms
+/// (encrypted + direct), and anything else can be executed where
+/// ever. Later, we can add stuff like admin/regular user power
+/// separation, etc.
+fn execution_allowed(cmd: &(impl Command + ?Sized), ctx: &Context<'_>) -> Result<(), CommandError> {
+    match cmd {
+        cmd if cmd.is_secure() && ctx.is_secure() => Ok(()),
+        cmd if cmd.is_secure() && !ctx.is_secure() => Err(CommandError::InsecureExecution),
+        _ => Ok(()),
+    }
+}
+
+/// Attempt to execute a command, and return the content that should
+/// go back to Matrix, if the command was executed, whether or not the
+/// command was successful.
+pub async fn execute_command(ctx: &Context<'_>) -> ExecutionResult {
+    let cmd = parser::parse_command(&ctx.message_body)?;
+
+    let result = match execution_allowed(cmd.as_ref(), ctx) {
+        Ok(_) => cmd.execute(ctx).await,
+        Err(e) => Err(e.into()),
+    };
+
+    log_command(cmd.as_ref(), ctx, &result);
+    result
+}
+
+/// Log result of an executed command.
+fn log_command(cmd: &(impl Command + ?Sized), ctx: &Context, result: &ExecutionResult) {
+    use substring::Substring;
+    let command = match cmd.is_secure() {
+        true => cmd.name(),
+        false => ctx.message_body,
+    };
+
+    let dots = match command.len() {
+        _len if _len > 30 => "[...]",
+        _ => "",
+    };
+
+    let command = command.substring(0, 30);
+
+    match result {
+        Ok(_) => {
+            info!(
+                "[{}] {} <{}{}> - success",
+                ctx.origin_room.display_name, ctx.username, command, dots
+            );
+        }
+        Err(e) => {
+            error!(
+                "[{}] {} <{}{}> - {}",
+                ctx.origin_room.display_name, ctx.username, command, dots, e
+            );
+        }
+    };
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use management::RegisterCommand;
+    use url::Url;
+    use matrix_sdk::ruma::room_id;
+
+    macro_rules! dummy_room {
+        () => {
+            crate::context::RoomContext {
+                id: &room_id!("!fakeroomid:example.com"),
+                display_name: "displayname".to_owned(),
+                secure: false,
+            }
+        };
+    }
+
+    macro_rules! secure_room {
+        () => {
+            crate::context::RoomContext {
+                id: &room_id!("!fakeroomid:example.com"),
+                display_name: "displayname".to_owned(),
+                secure: true,
+            }
+        };
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn secure_context_secure_command_allows_execution() {
+        let db_path = tempfile::NamedTempFile::new_in(".").unwrap();
+        let db = crate::db::sqlite::Database::new(db_path.path().to_str().unwrap())
+            .await
+            .unwrap();
+
+        let homeserver = Url::parse("http://example.com").unwrap();
+
+        let ctx = Context {
+            account: crate::models::Account::default(),
+            db: db,
+            matrix_client: matrix_sdk::Client::new(homeserver).await.unwrap(),
+            origin_room: secure_room!(),
+            active_room: secure_room!(),
+            username: "myusername",
+            message_body: "!notacommand",
+        };
+
+        let cmd = RegisterCommand;
+        assert_eq!(execution_allowed(&cmd, &ctx).is_ok(), true);
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn secure_context_insecure_command_allows_execution() {
+        let db_path = tempfile::NamedTempFile::new_in(".").unwrap();
+        let db = crate::db::sqlite::Database::new(db_path.path().to_str().unwrap())
+            .await
+            .unwrap();
+
+        let homeserver = Url::parse("http://example.com").unwrap();
+
+        let ctx = Context {
+            account: crate::models::Account::default(),
+            db: db,
+            matrix_client: matrix_sdk::Client::new(homeserver).await.unwrap(),
+            origin_room: secure_room!(),
+            active_room: secure_room!(),
+            username: "myusername",
+            message_body: "!notacommand",
+        };
+
+        let cmd = variables::GetVariableCommand("".to_owned());
+        assert_eq!(execution_allowed(&cmd, &ctx).is_ok(), true);
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn insecure_context_insecure_command_allows_execution() {
+        let db_path = tempfile::NamedTempFile::new_in(".").unwrap();
+        let db = crate::db::sqlite::Database::new(db_path.path().to_str().unwrap())
+            .await
+            .unwrap();
+
+        let homeserver = Url::parse("http://example.com").unwrap();
+
+        let ctx = Context {
+            account: crate::models::Account::default(),
+            db: db,
+            matrix_client: matrix_sdk::Client::new(homeserver).await.unwrap(),
+            origin_room: dummy_room!(),
+            active_room: dummy_room!(),
+            username: "myusername",
+            message_body: "!notacommand",
+        };
+
+        let cmd = variables::GetVariableCommand("".to_owned());
+        assert_eq!(execution_allowed(&cmd, &ctx).is_ok(), true);
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn insecure_context_secure_command_denies_execution() {
+        let db_path = tempfile::NamedTempFile::new_in(".").unwrap();
+        let db = crate::db::sqlite::Database::new(db_path.path().to_str().unwrap())
+            .await
+            .unwrap();
+
+        let homeserver = Url::parse("http://example.com").unwrap();
+
+        let ctx = Context {
+            account: crate::models::Account::default(),
+            db: db,
+            matrix_client: matrix_sdk::Client::new(homeserver).await.unwrap(),
+            origin_room: dummy_room!(),
+            active_room: dummy_room!(),
+            username: "myusername",
+            message_body: "!notacommand",
+        };
+
+        let cmd = RegisterCommand;
+        assert_eq!(execution_allowed(&cmd, &ctx).is_err(), true);
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn unrecognized_command() {
+        let db_path = tempfile::NamedTempFile::new_in(".").unwrap();
+        let db = crate::db::sqlite::Database::new(db_path.path().to_str().unwrap())
+            .await
+            .unwrap();
+
+        let homeserver = Url::parse("http://example.com").unwrap();
+
+        let ctx = Context {
+            account: crate::models::Account::default(),
+            db: db,
+            matrix_client: matrix_sdk::Client::new(homeserver).await.unwrap(),
+            origin_room: dummy_room!(),
+            active_room: dummy_room!(),
+            username: "myusername",
+            message_body: "!notacommand",
+        };
+
+        let result = execute_command(&ctx).await;
+        assert!(result.is_err());
+    }
+}

dicebot/src/commands/parser.rs

@@ -0,0 +1,247 @@
+/**
+ * In addition to the terms of the AGPL, portions of this file are
+ * governed by the terms of the MIT license, from the original
+ * axfive-matrix-dicebot project.
+ */
+use crate::commands::{
+    basic_rolling::RollCommand,
+    cofd::PoolRollCommand,
+    cthulhu::{CthAdvanceRoll, CthRoll},
+    management::{CheckCommand, LinkCommand, RegisterCommand, UnlinkCommand, UnregisterCommand},
+    misc::HelpCommand,
+    rooms::{ListRoomsCommand, SetRoomCommand},
+    variables::{
+        DeleteVariableCommand, GetAllVariablesCommand, GetVariableCommand, SetVariableCommand,
+    },
+    Command,
+};
+use crate::error::BotError;
+use combine::parser::char::{char, letter, space};
+use combine::{any, many1, optional, Parser};
+use std::convert::TryFrom;
+use thiserror::Error;
+
+#[derive(Debug, Clone, PartialEq, Error)]
+pub enum CommandParsingError {
+    #[error("unrecognized command: {0}")]
+    UnrecognizedCommand(String),
+
+    #[error("parser error: {0}")]
+    InternalParseError(#[from] combine::error::StringStreamError),
+}
+
+/// Split an input string into its constituent command and "everything
+/// else" parts. Extracts the command separately from its input (i.e.
+/// rest of the line) and returns a tuple of (command_input, command).
+/// Whitespace at the start and end of the command input is removed.
+fn split_command(input: &str) -> Result<(String, String), CommandParsingError> {
+    let input = input.trim();
+
+    let exclamation = char('!');
+    let word = many1(letter()).map(|value: String| value);
+    let at_least_one_space = many1(space().silent()).map(|value: String| value);
+    let cmd_input = optional(at_least_one_space.and(many1(any()).map(|value: String| value)));
+
+    let mut parser = exclamation.and(word).and(cmd_input);
+
+    //TODO make less wacky, possibly by mapping it into a struct and
+    // making use of skip. This super-wacky tuple is:
+    //  (parsed_input, rest)
+    //Where parsed_input is:
+    //  (!command, option<arguments>)
+    //Where !command is:
+    //  ('!', command)
+    //Were option<arguments> is:
+    // Option tuple of (whitespace, arguments)
+    let (command, command_input) = match parser.parse(input)? {
+        (((_, command), Some((_, command_input))), _) => (command, command_input),
+        (((_, command), None), _) => (command, "".to_string()),
+    };
+
+    Ok((command, command_input))
+}
+
+/// Atempt to convert text input to a Boxed command type. Shortens
+/// boilerplate.
+macro_rules! convert_to {
+    ($type:ident, $input: expr) => {
+        $type::try_from($input).map(|cmd| Box::new(cmd) as Box<dyn Command>)
+    };
+}
+
+/// Potentially parse a command expression. If we recognize the
+/// command, an error should be raised if the command is misparsed. If
+/// we don't recognize the command, return an error.
+pub fn parse_command(input: &str) -> Result<Box<dyn Command>, BotError> {
+    match split_command(input) {
+        Ok((cmd, cmd_input)) => match cmd.to_lowercase().as_ref() {
+            "variables" => convert_to!(GetAllVariablesCommand, cmd_input),
+            "get" => convert_to!(GetVariableCommand, cmd_input),
+            "set" => convert_to!(SetVariableCommand, cmd_input),
+            "del" => convert_to!(DeleteVariableCommand, cmd_input),
+            "r" | "roll" => convert_to!(RollCommand, cmd_input),
+            "rp" | "pool" => convert_to!(PoolRollCommand, cmd_input),
+            "chance" => PoolRollCommand::chance_die().map(|cmd| Box::new(cmd) as Box<dyn Command>),
+            "cthroll" => convert_to!(CthRoll, cmd_input),
+            "cthadv" | "ctharoll" => convert_to!(CthAdvanceRoll, cmd_input),
+            "help" => convert_to!(HelpCommand, cmd_input),
+            "register" => convert_to!(RegisterCommand, cmd_input),
+            "link" => convert_to!(LinkCommand, cmd_input),
+            "unlink" => convert_to!(UnlinkCommand, cmd_input),
+            "check" => convert_to!(CheckCommand, cmd_input),
+            "unregister" => convert_to!(UnregisterCommand, cmd_input),
+            "rooms" => convert_to!(ListRoomsCommand, cmd_input),
+            "room" => convert_to!(SetRoomCommand, cmd_input),
+            _ => Err(CommandParsingError::UnrecognizedCommand(cmd).into()),
+        },
+        //All other errors passed up.
+        Err(e) => Err(e.into()),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    //TODO these errors don't seem to implement the right traits to do
+    //eq checks or even unwrap_err!
+
+    #[test]
+    fn non_command_test() {
+        let result = parse_command("not a command");
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn empty_message_test() {
+        let result = parse_command("");
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn just_exclamation_mark_test() {
+        let result = parse_command("!");
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn newline_test() {
+        assert!(parse_command("\n!roll 1d4").is_ok());
+    }
+
+    #[test]
+    fn whitespace_and_newline_test() {
+        assert!(parse_command("    \n!roll 1d4").is_ok());
+    }
+
+    #[test]
+    fn newline_and_whitespace_test() {
+        assert!(parse_command("\n    !cthroll 50").is_ok());
+    }
+
+    #[test]
+    fn word_with_exclamation_mark_test() {
+        let result1 = parse_command("hello !notacommand");
+        assert!(result1.is_err());
+
+        let result2 = parse_command("hello!");
+        assert!(result2.is_err());
+
+        let result3 = parse_command("hello!notacommand");
+        assert!(result3.is_err());
+    }
+
+    #[test]
+    fn basic_command_test() {
+        assert_eq!(
+            ("roll".to_string(), "1d4".to_string()),
+            split_command("!roll 1d4").expect("got parsing error")
+        );
+    }
+
+    #[test]
+    fn whitespace_at_start_test() {
+        assert_eq!(
+            ("roll".to_string(), "1d4".to_string()),
+            split_command("   !roll 1d4").expect("got parsing error")
+        );
+    }
+
+    #[test]
+    fn whitespace_at_end_test() {
+        assert_eq!(
+            ("roll".to_string(), "1d4".to_string()),
+            split_command("!roll 1d4   ").expect("got parsing error")
+        );
+    }
+
+    #[test]
+    fn whitespace_on_both_ends_test() {
+        assert_eq!(
+            ("roll".to_string(), "1d4".to_string()),
+            split_command("   !roll 1d4   ").expect("got parsing error")
+        );
+    }
+
+    #[test]
+    fn single_command_test() {
+        assert_eq!(
+            ("roll".to_string(), "".to_string()),
+            split_command("!roll").expect("got parsing error")
+        );
+
+        assert_eq!(
+            ("thisdoesnotexist".to_string(), "".to_string()),
+            split_command("!thisdoesnotexist").expect("got parsing error")
+        );
+    }
+
+    #[test]
+    fn bad_command_test() {
+        assert!(split_command("roll 1d4").is_err());
+        assert!(split_command("roll").is_err());
+    }
+
+    #[test]
+    fn chance_die_is_not_malformed() {
+        assert!(parse_command("!chance").is_ok());
+    }
+
+    #[test]
+    fn roll_malformed_expression_test() {
+        assert!(parse_command("!roll 1d20asdlfkj").is_err());
+        assert!(parse_command("!roll 1d20asdlfkj   ").is_err());
+    }
+
+    #[test]
+    fn roll_dice_pool_malformed_expression_test() {
+        assert!(parse_command("!pool 8abc").is_err());
+        assert!(parse_command("!pool 8abc    ").is_err());
+    }
+
+    #[test]
+    fn pool_whitespace_test() {
+        parse_command("!pool 8   ns3    ").expect("was error");
+        parse_command("   !pool 8 ns3").expect("was error");
+        parse_command("   !pool 8   ns3    ").expect("was error");
+    }
+
+    #[test]
+    fn help_whitespace_test() {
+        parse_command("!help stuff   ").expect("was error");
+        parse_command("   !help stuff").expect("was error");
+        parse_command("   !help stuff   ").expect("was error");
+    }
+
+    #[test]
+    fn roll_whitespace_test() {
+        parse_command("!roll 1d4 + 5d6 -3   ").expect("was error");
+        parse_command("!roll 1d4 + 5d6 -3   ").expect("was error");
+        parse_command("   !roll 1d4 + 5d6 -3   ").expect("was error");
+    }
+
+    #[test]
+    fn case_insensitive_test() {
+        parse_command("!CTHROLL 40").expect("command parsing is not case sensitive.");
+    }
+}

dicebot/src/commands/rooms.rs

@@ -0,0 +1,187 @@
+use super::{Command, Execution, ExecutionResult};
+use crate::context::Context;
+use crate::db::Users;
+use crate::error::BotError;
+use crate::matrix;
+use async_trait::async_trait;
+use fuse_rust::{Fuse, FuseProperty, Fuseable};
+use futures::stream::{self, StreamExt, TryStreamExt};
+use matrix_sdk::{ruma::OwnedUserId, Client};
+use std::convert::TryFrom;
+
+/// Holds matrix room ID and display name as strings, for use with
+/// searching. See search_for_room.
+#[derive(Clone, Debug, Eq, PartialEq)]
+struct RoomNameAndId {
+    id: String,
+    name: String,
+}
+
+/// Allows searching for a room name and ID struct, instead of just
+/// searching room display names directly.
+impl Fuseable for RoomNameAndId {
+    fn properties(&self) -> Vec<FuseProperty> {
+        vec![FuseProperty {
+            value: String::from("name"),
+            weight: 1.0,
+        }]
+    }
+
+    fn lookup(&self, key: &str) -> Option<&str> {
+        match key {
+            "name" => Some(&self.name),
+            _ => None,
+        }
+    }
+}
+
+/// Attempt to find a room by either name or Matrix Room ID query
+/// string. It prefers the exact room ID first, and then falls back to
+/// fuzzy searching based on room display name. The best match is
+/// returned, or None if no matches were found.
+fn search_for_room<'a>(
+    rooms_for_user: &'a [RoomNameAndId],
+    search_for: &str,
+) -> Option<&'a RoomNameAndId> {
+    //Lowest score is the best match.
+    let best_fuzzy_match = || -> Option<&RoomNameAndId> {
+        Fuse::default()
+            .search_text_in_fuse_list(search_for, &rooms_for_user)
+            .into_iter()
+            .min_by(|r1, r2| r1.score.partial_cmp(&r2.score).unwrap())
+            .and_then(|result| rooms_for_user.get(result.index))
+    };
+
+    rooms_for_user
+        .iter()
+        .find(|room| room.id == search_for)
+        .or_else(best_fuzzy_match)
+}
+
+async fn get_rooms_for_user(
+    client: &Client,
+    user_id: &str,
+) -> Result<Vec<RoomNameAndId>, BotError> {
+    let user_id = OwnedUserId::try_from(user_id)?;
+    let rooms_for_user = matrix::get_rooms_for_user(client, &user_id).await?;
+    let mut rooms_for_user: Vec<RoomNameAndId> = stream::iter(rooms_for_user)
+        .filter_map(|room| async move {
+            Some(room.display_name().await.map(|room_name| RoomNameAndId {
+                id: room.room_id().to_string(),
+                name: room_name.to_string(),
+            }))
+        })
+        .try_collect()
+        .await?;
+
+    //Alphabetically descending, symbols first, ignore case.
+    let sort = |r1: &RoomNameAndId, r2: &RoomNameAndId| {
+        r1.name.to_lowercase().cmp(&r2.name.to_lowercase())
+    };
+
+    rooms_for_user.sort_by(sort);
+    Ok(rooms_for_user)
+}
+
+pub struct ListRoomsCommand;
+
+impl TryFrom<String> for ListRoomsCommand {
+    type Error = BotError;
+
+    fn try_from(_: String) -> Result<Self, Self::Error> {
+        Ok(ListRoomsCommand)
+    }
+}
+
+#[async_trait]
+impl Command for ListRoomsCommand {
+    fn name(&self) -> &'static str {
+        "list rooms"
+    }
+
+    fn is_secure(&self) -> bool {
+        true
+    }
+
+    async fn execute(&self, ctx: &Context<'_>) -> ExecutionResult {
+        let rooms_for_user: Vec<String> = get_rooms_for_user(&ctx.matrix_client, ctx.username)
+            .await
+            .map(|rooms| {
+                rooms
+                    .into_iter()
+                    .map(|room| format!("  {}  |  {}", room.id, room.name))
+                    .collect()
+            })?;
+
+        let html = format!("<pre>{}</pre>", rooms_for_user.join("\n"));
+        Execution::success(html)
+    }
+}
+
+pub struct SetRoomCommand(String);
+
+impl TryFrom<String> for SetRoomCommand {
+    type Error = BotError;
+
+    fn try_from(input: String) -> Result<Self, Self::Error> {
+        Ok(SetRoomCommand(input))
+    }
+}
+
+#[async_trait]
+impl Command for SetRoomCommand {
+    fn name(&self) -> &'static str {
+        "set active room"
+    }
+
+    fn is_secure(&self) -> bool {
+        true
+    }
+
+    async fn execute(&self, ctx: &Context<'_>) -> ExecutionResult {
+        if !ctx.account.is_registered() {
+            return Err(BotError::AccountDoesNotExist);
+        }
+
+        let rooms_for_user = get_rooms_for_user(&ctx.matrix_client, ctx.username).await?;
+        let room = search_for_room(&rooms_for_user, &self.0);
+
+        if let Some(room) = room {
+            let mut new_user = ctx
+                .account
+                .registered_user()
+                .cloned()
+                .ok_or(BotError::AccountDoesNotExist)?;
+
+            new_user.active_room = Some(room.id.clone());
+            ctx.db.upsert_user(&new_user).await?;
+            Execution::success(format!(r#"Active room set to "{}""#, room.name))
+        } else {
+            Err(BotError::RoomDoesNotExist)
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn set_room_prefers_room_id_over_name() {
+        let rooms = vec![
+            RoomNameAndId {
+                id: "roomid".to_string(),
+                name: "room_name".to_string(),
+            },
+            RoomNameAndId {
+                id: "anotherone".to_string(),
+                name: "roomid".to_string(),
+            },
+        ];
+
+        let found_room = search_for_room(&rooms, "roomid");
+
+        assert!(found_room.is_some());
+        assert_eq!(found_room.unwrap(), &rooms[0]);
+    }
+}

dicebot/src/commands/variables.rs

@@ -0,0 +1,161 @@
+use super::{Command, Execution, ExecutionResult};
+use crate::context::Context;
+use crate::db::errors::DataError;
+use crate::db::Variables;
+use crate::error::BotError;
+use async_trait::async_trait;
+use std::convert::TryFrom;
+
+pub struct GetAllVariablesCommand;
+
+impl TryFrom<String> for GetAllVariablesCommand {
+    type Error = BotError;
+
+    fn try_from(_: String) -> Result<Self, Self::Error> {
+        Ok(GetAllVariablesCommand)
+    }
+}
+
+#[async_trait]
+impl Command for GetAllVariablesCommand {
+    fn name(&self) -> &'static str {
+        "get all variables"
+    }
+
+    fn is_secure(&self) -> bool {
+        false
+    }
+
+    async fn execute(&self, ctx: &Context<'_>) -> ExecutionResult {
+        let variables = ctx
+            .db
+            .get_user_variables(&ctx.username, ctx.active_room_id().as_str())
+            .await?;
+
+        let mut variable_list: Vec<String> = variables
+            .into_iter()
+            .map(|(name, value)| format!(" - {} = {}", name, value))
+            .collect();
+
+        variable_list.sort();
+
+        let value = variable_list.join("\n");
+        let html = format!(
+            "<strong>Variables:</strong><br/>{}",
+            value.replace("\n", "<br/>")
+        );
+
+        Execution::success(html)
+    }
+}
+
+pub struct GetVariableCommand(pub String);
+
+impl TryFrom<String> for GetVariableCommand {
+    type Error = BotError;
+
+    fn try_from(input: String) -> Result<Self, Self::Error> {
+        Ok(GetVariableCommand(input))
+    }
+}
+
+#[async_trait]
+impl Command for GetVariableCommand {
+    fn name(&self) -> &'static str {
+        "retrieve variable value"
+    }
+
+    fn is_secure(&self) -> bool {
+        false
+    }
+
+    async fn execute(&self, ctx: &Context<'_>) -> ExecutionResult {
+        let name = &self.0;
+        let result = ctx
+            .db
+            .get_user_variable(&ctx.username, ctx.active_room_id().as_str(), name)
+            .await;
+
+        let value = match result {
+            Ok(num) => format!("{} = {}", name, num),
+            Err(DataError::KeyDoesNotExist(_)) => format!("{} is not set", name),
+            Err(e) => return Err(e.into()),
+        };
+
+        let html = format!("<strong>Variable:</strong> {}", value);
+        Execution::success(html)
+    }
+}
+
+pub struct SetVariableCommand(pub String, pub i32);
+
+impl TryFrom<String> for SetVariableCommand {
+    type Error = BotError;
+
+    fn try_from(input: String) -> Result<Self, Self::Error> {
+        let (variable_name, value) = crate::parser::variables::parse_set_variable(&input)?;
+        Ok(SetVariableCommand(variable_name, value))
+    }
+}
+
+#[async_trait]
+impl Command for SetVariableCommand {
+    fn name(&self) -> &'static str {
+        "set variable value"
+    }
+
+    fn is_secure(&self) -> bool {
+        false
+    }
+
+    async fn execute(&self, ctx: &Context<'_>) -> ExecutionResult {
+        let name = &self.0;
+        let value = self.1;
+
+        ctx.db
+            .set_user_variable(&ctx.username, ctx.active_room_id().as_str(), name, value)
+            .await?;
+
+        let content = format!("{} = {}", name, value);
+        let html = format!("<strong>Set Variable:</strong> {}", content);
+        Execution::success(html)
+    }
+}
+
+pub struct DeleteVariableCommand(pub String);
+
+impl TryFrom<String> for DeleteVariableCommand {
+    type Error = BotError;
+
+    fn try_from(input: String) -> Result<Self, Self::Error> {
+        Ok(DeleteVariableCommand(input))
+    }
+}
+
+#[async_trait]
+impl Command for DeleteVariableCommand {
+    fn name(&self) -> &'static str {
+        "delete variable"
+    }
+
+    fn is_secure(&self) -> bool {
+        false
+    }
+
+    async fn execute(&self, ctx: &Context<'_>) -> ExecutionResult {
+        let name = &self.0;
+        let result = ctx
+            .db
+            .delete_user_variable(&ctx.username, ctx.active_room_id().as_str(), name)
+            .await;
+
+        let value = match result {
+            Ok(()) => format!("{} now unset", name),
+            Err(DataError::KeyDoesNotExist(_)) => format!("{} is not currently set", name),
+            Err(e) => return Err(e.into()),
+        };
+
+        let html = format!("<strong>Remove Variable:</strong> {}", value);
+        Execution::success(html)
+    }
+}

dicebot/src/config.rs

@@ -0,0 +1,342 @@
+use serde::{self, Deserialize, Serialize};
+use std::env;
+use std::fs;
+use std::path::PathBuf;
+use thiserror::Error;
+
+#[derive(Error, Debug)]
+pub enum ConfigError {
+    #[error("i/o error: {0}")]
+    IoError(#[from] std::io::Error),
+
+    #[error("toml parsing error: {0}")]
+    TomlParsingError(#[from] toml::de::Error),
+}
+
+pub fn read_config<P: Into<PathBuf>>(config_path: P) -> Result<Config, ConfigError> {
+    let config_path = config_path.into();
+    let config = {
+        let contents = fs::read_to_string(&config_path)?;
+        deserialize_config(&contents)?
+    };
+
+    Ok(config)
+}
+
+fn deserialize_config(contents: &str) -> Result<Config, ConfigError> {
+    let config = toml::from_str(&contents)?;
+    Ok(config)
+}
+
+/// The "matrix" section of the config, which gives home server, login information, and etc.
+#[derive(Serialize, Deserialize, Clone, Debug)]
+struct MatrixConfig {
+    /// Your homeserver of choice, as an FQDN without scheme or path
+    home_server: String,
+
+    /// Username to login as. Only the localpart.
+    username: String,
+
+    /// Bot account password.
+    password: String,
+}
+
+const DEFAULT_OLDEST_MESSAGE_AGE: u64 = 15 * 60;
+
+fn db_path_from_env() -> String {
+    env::var("DATABASE_PATH")
+        .expect("could not find database path in config or environment variable")
+}
+
+/// The "bot" section of the config file, for bot settings.
+#[derive(Serialize, Deserialize, Clone, Debug, Default)]
+struct BotConfig {
+    /// How far back from current time should we process a message?
+    oldest_message_age: Option<u64>,
+
+    /// What address and port to run the RPC service on. If not
+    /// specified, RPC will not be enabled.
+    rpc_addr: Option<String>,
+
+    /// The shared secret key between the bot and any RPC clients that
+    /// want to connect to it. The RPC server will reject any clients
+    /// that don't present the shared key.
+    rpc_key: Option<String>,
+}
+
+/// The "database" section of the config file.
+#[derive(Serialize, Deserialize, Clone, Debug)]
+struct DatabaseConfig {
+    /// Path to the database storage directory. Required.
+    path: Option<String>,
+}
+
+impl DatabaseConfig {
+    #[inline]
+    #[must_use]
+    fn path(&self) -> String {
+        self.path.clone().unwrap_or_else(|| db_path_from_env())
+    }
+}
+
+impl BotConfig {
+    /// Determine the oldest allowable message age, in seconds. If the
+    /// setting is defined, use that value. If it is not defined, fall
+    /// back to DEFAULT_OLDEST_MESSAGE_AGE (15 minutes).
+    #[inline]
+    #[must_use]
+    fn oldest_message_age(&self) -> u64 {
+        self.oldest_message_age
+            .unwrap_or(DEFAULT_OLDEST_MESSAGE_AGE)
+    }
+
+    #[inline]
+    #[must_use]
+    fn rpc_addr(&self) -> Option<String> {
+        self.rpc_addr.clone()
+    }
+
+    #[inline]
+    #[must_use]
+    fn rpc_key(&self) -> Option<String> {
+        self.rpc_key.clone()
+    }
+}
+
+/// Represents the toml config file for the dicebot. The sections of
+/// the config are not directly accessible; instead the config
+/// provides friendly methods that handle default values, etc.
+#[derive(Serialize, Deserialize, Clone, Debug)]
+pub struct Config {
+    matrix: MatrixConfig,
+    database: Option<DatabaseConfig>,
+    bot: Option<BotConfig>,
+}
+
+impl Config {
+    /// The matrix homeserver URL.
+    #[inline]
+    #[must_use]
+    pub fn matrix_homeserver(&self) -> &str {
+        &self.matrix.home_server
+    }
+
+    /// The username used to connect to the matrix server.
+    #[inline]
+    #[must_use]
+    pub fn matrix_username(&self) -> &str {
+        &self.matrix.username
+    }
+
+    /// The password used to connect to the matrix server.
+    #[inline]
+    #[must_use]
+    pub fn matrix_password(&self) -> &str {
+        &self.matrix.password
+    }
+
+    /// The path to the database storage directory.
+    #[inline]
+    #[must_use]
+    pub fn database_path(&self) -> String {
+        self.database
+            .as_ref()
+            .map(|db| db.path())
+            .unwrap_or_else(|| db_path_from_env())
+    }
+
+    /// Figure out the allowed oldest message age, in seconds. This will
+    /// be the defined oldest message age in the bot config, if the bot
+    /// configuration and associated "oldest_message_age" setting are
+    /// defined. If the bot config or the message setting are not defined,
+    /// it will default to 15 minutes.
+    #[inline]
+    #[must_use]
+    pub fn oldest_message_age(&self) -> u64 {
+        self.bot
+            .as_ref()
+            .map(|bc| bc.oldest_message_age())
+            .unwrap_or(DEFAULT_OLDEST_MESSAGE_AGE)
+    }
+
+    #[inline]
+    #[must_use]
+    pub fn rpc_addr(&self) -> Option<String> {
+        self.bot.as_ref().and_then(|bc| bc.rpc_addr())
+    }
+
+    #[inline]
+    #[must_use]
+    pub fn rpc_key(&self) -> Option<String> {
+        self.bot.as_ref().and_then(|bc| bc.rpc_key())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn oldest_message_default_no_setting_test() {
+        let cfg = Config {
+            matrix: MatrixConfig {
+                home_server: "".to_owned(),
+                username: "".to_owned(),
+                password: "".to_owned(),
+            },
+            database: Some(DatabaseConfig {
+                path: Some("".to_owned()),
+            }),
+            bot: Some(BotConfig {
+                oldest_message_age: None,
+                ..Default::default()
+            }),
+        };
+
+        assert_eq!(15 * 60, cfg.oldest_message_age());
+    }
+
+    #[test]
+    fn oldest_message_default_no_bot_config_test() {
+        let cfg = Config {
+            matrix: MatrixConfig {
+                home_server: "".to_owned(),
+                username: "".to_owned(),
+                password: "".to_owned(),
+            },
+            database: Some(DatabaseConfig {
+                path: Some("".to_owned()),
+            }),
+            bot: None,
+        };
+
+        assert_eq!(15 * 60, cfg.oldest_message_age());
+    }
+
+    #[test]
+    fn db_path_uses_setting_first_test() {
+        let cfg = Config {
+            matrix: MatrixConfig {
+                home_server: "".to_owned(),
+                username: "".to_owned(),
+                password: "".to_owned(),
+            },
+            database: Some(DatabaseConfig {
+                path: Some("the-db-path".to_owned()),
+            }),
+            bot: None,
+        };
+
+        assert_eq!("the-db-path".to_owned(), cfg.database_path());
+    }
+
+    #[test]
+    fn db_path_uses_env_if_setting_not_defined_test() {
+        env::set_var("DATABASE_PATH", "the-db-path");
+
+        let cfg = Config {
+            matrix: MatrixConfig {
+                home_server: "".to_owned(),
+                username: "".to_owned(),
+                password: "".to_owned(),
+            },
+            database: Some(DatabaseConfig { path: None }),
+            bot: None,
+        };
+
+        assert_eq!("the-db-path".to_owned(), cfg.database_path());
+
+        env::remove_var("DATABASE_PATH");
+    }
+
+    #[test]
+    fn db_path_uses_env_if_section_not_defined_test() {
+        env::set_var("DATABASE_PATH", "the-db-path");
+
+        let cfg = Config {
+            matrix: MatrixConfig {
+                home_server: "".to_owned(),
+                username: "".to_owned(),
+                password: "".to_owned(),
+            },
+            database: None,
+            bot: None,
+        };
+
+        assert_eq!("the-db-path".to_owned(), cfg.database_path());
+
+        env::remove_var("DATABASE_PATH");
+    }
+
+    use indoc::indoc;
+
+    #[test]
+    fn deserialize_config_without_bot_section_test() {
+        let contents = indoc! {"
+            [matrix]
+            home_server = 'https://matrix.example.com'
+            username = 'username'
+            password = 'password'
+
+            [database]
+            path = ''
+        "};
+
+        let cfg: Result<_, _> = deserialize_config(contents);
+        assert_eq!(true, cfg.is_ok());
+    }
+
+    #[test]
+    fn deserialize_config_without_oldest_message_setting_test() {
+        let contents = indoc! {"
+            [matrix]
+            home_server = 'https://matrix.example.com'
+            username = 'username'
+            password = 'password'
+
+            [database]
+            path = ''
+
+            [bot]
+            not_a_real_setting = 2
+        "};
+
+        let cfg: Result<_, _> = deserialize_config(contents);
+        assert_eq!(true, cfg.is_ok());
+    }
+
+    #[test]
+    fn deserialize_config_without_db_path_setting_test() {
+        let contents = indoc! {"
+            [matrix]
+            home_server = 'https://matrix.example.com'
+            username = 'username'
+            password = 'password'
+
+            [database]
+            not_a_real_setting = 1
+
+            [bot]
+            not_a_real_setting = 2
+        "};
+
+        let cfg: Result<_, _> = deserialize_config(contents);
+        assert_eq!(true, cfg.is_ok());
+    }
+
+    #[test]
+    fn deserialize_config_without_db_section_test() {
+        let contents = indoc! {"
+            [matrix]
+            home_server = 'https://matrix.example.com'
+            username = 'username'
+            password = 'password'
+
+            [bot]
+            not_a_real_setting = 2
+        "};
+
+        let cfg: Result<_, _> = deserialize_config(contents);
+        assert_eq!(true, cfg.is_ok());
+    }
+}

dicebot/src/context.rs

@@ -0,0 +1,76 @@
+use crate::db::sqlite::Database;
+use crate::error::BotError;
+use crate::models::Account;
+use matrix_sdk::room::Joined;
+use matrix_sdk::ruma::{RoomId, UserId};
+use matrix_sdk::Client;
+use std::convert::TryFrom;
+
+/// A context carried through the system providing access to things
+/// like the database.
+#[derive(Clone)]
+pub struct Context<'a> {
+    pub db: Database,
+    pub matrix_client: Client,
+    pub origin_room: RoomContext<'a>,
+    pub active_room: RoomContext<'a>,
+    pub username: &'a str,
+    pub message_body: &'a str,
+    pub account: Account,
+}
+
+impl Context<'_> {
+    pub fn active_room_id(&self) -> &RoomId {
+        self.active_room.id
+    }
+
+    pub fn room_id(&self) -> &RoomId {
+        self.origin_room.id
+    }
+
+    pub fn is_secure(&self) -> bool {
+        self.origin_room.secure
+    }
+}
+
+#[derive(Clone)]
+pub struct RoomContext<'a> {
+    pub id: &'a RoomId,
+    pub display_name: String,
+    pub secure: bool,
+}
+
+impl RoomContext<'_> {
+    pub async fn new_with_name<'a>(
+        room: &'a Joined,
+        sending_user: &str,
+    ) -> Result<RoomContext<'a>, BotError> {
+        // TODO is_direct is a hack; the bot should set eligible rooms
+        // to Direct Message upon joining, if other contact has
+        // requested it. Waiting on SDK support.
+        let display_name =
+            room
+            .display_name()
+            .await
+            .ok()
+            .map(|d| d.to_string())
+            .unwrap_or_default();
+
+        let sending_user = <&UserId>::try_from(sending_user)?;
+        let user_in_room = room.get_member(sending_user).await.ok().is_some();
+        let is_direct = room.active_members().await?.len() == 2;
+
+        Ok(RoomContext {
+            id: room.room_id(),
+            display_name,
+            secure: room.is_encrypted() && is_direct && user_in_room,
+        })
+    }
+
+    pub async fn new<'a>(
+        room: &'a Joined,
+        sending_user: &'a str,
+    ) -> Result<RoomContext<'a>, BotError> {
+        Self::new_with_name(room, sending_user).await
+    }
+}

dicebot/src/cthulhu/dice.rs

@@ -0,0 +1,775 @@
+use crate::context::Context;
+use crate::db::Variables;
+use crate::error::{BotError, DiceRollingError};
+use crate::logic::calculate_single_die_amount;
+use crate::parser::dice::{Amount, DiceParsingError, Element};
+use rand::rngs::StdRng;
+use rand::Rng;
+use rand::SeedableRng;
+use std::convert::TryFrom;
+use std::fmt;
+
+/// A planned dice roll.
+#[derive(Clone, Debug, PartialEq)]
+pub struct DiceRoll {
+    pub amount: Amount,
+    pub modifier: DiceRollModifier,
+}
+
+pub struct DiceRollWithContext<'a>(pub &'a DiceRoll, pub &'a Context<'a>);
+
+/// Potential modifier on the die roll to be made.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum DiceRollModifier {
+    /// No bonuses or penalties.
+    Normal,
+
+    /// Roll one extra die and pick the lower of two results.
+    OneBonus,
+
+    /// Roll two extra dice and pick the lower of all results.
+    TwoBonus,
+
+    /// Roll one extra die and pick the higher of two results.
+    OnePenalty,
+
+    /// Roll two extra dice and pick the higher of all results.
+    TwoPenalty,
+}
+
+impl fmt::Display for DiceRollModifier {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let message = match self {
+            Self::Normal => "no modifiers",
+            Self::OneBonus => "one bonus die",
+            Self::TwoBonus => "two bonus dice",
+            Self::OnePenalty => "one penalty die",
+            Self::TwoPenalty => "two penalty dice",
+        };
+
+        write!(f, "{}", message)?;
+        Ok(())
+    }
+}
+
+/// The outcome of a die roll, either some kind of success or failure.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum RollResult {
+    /// Basic success. The rolled number was equal to or less than the target number.
+    Success,
+
+    /// Hard success means the rolled number was equal to or less than
+    /// the target number divided by 2 (rounded down).
+    HardSuccess,
+
+    /// Extreme success means the rolled number was equal to or less
+    /// than the target number divided by 5 (rounded down).
+    ExtremeSuccess,
+
+    /// A critical success occurs on a roll of 1.
+    CriticalSuccess,
+
+    /// A basic failure means that the roll was above the target number.
+    Failure,
+
+    /// A fumble occurs if the target number is below 50 and the roll
+    /// was 96 - 100, OR if the roll result was 100. This means lower
+    /// target numbers are more likely to produce a fumble.
+    Fumble,
+}
+
+impl fmt::Display for RollResult {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let message = match self {
+            Self::Success => "success!",
+            Self::HardSuccess => "hard success!",
+            Self::ExtremeSuccess => "extreme success!",
+            Self::CriticalSuccess => "critical success!",
+            Self::Failure => "failure!",
+            Self::Fumble => "fumble!",
+        };
+
+        write!(f, "{}", message)?;
+        Ok(())
+    }
+}
+
+/// A struct wrapping the target and the actual dice roll result. This
+/// is done for formatting purposes, so we can display the target
+/// number (calculated from resolving variables) separately from the
+/// result.
+pub struct ExecutedDiceRoll {
+    /// The number we must meet for the roll to be considered a
+    /// success.
+    pub target: u32,
+
+    /// Stored for informational purposes in display.
+    pub modifier: DiceRollModifier,
+
+    /// The actual roll result.
+    pub roll: RolledDice,
+}
+
+impl fmt::Display for ExecutedDiceRoll {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let message = format!("target: {}, with {}", self.target, self.modifier);
+        write!(f, "{}", message)?;
+        Ok(())
+    }
+}
+
+/// A struct wrapping the target and the actual advancement roll
+/// result. This is done for formatting purposes, so we can display
+/// the target number (calculated from resolving variables) separately
+/// from the result.
+pub struct ExecutedAdvancementRoll {
+    /// The number we must exceed for the roll to be considered a
+    /// success.
+    pub target: u32,
+
+    /// The actual roll result.
+    pub roll: RolledAdvancement,
+}
+
+impl fmt::Display for ExecutedAdvancementRoll {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let message = format!("target: {}", self.target);
+        write!(f, "{}", message)?;
+        Ok(())
+    }
+}
+
+//TODO need to keep track of all rolled numbers for informational purposes!
+/// The outcome of a roll.
+pub struct RolledDice {
+    /// The d100 result actually rolled.
+    num_rolled: u32,
+
+    /// The number we must meet for the roll to be considered a
+    /// success.
+    target: u32,
+}
+
+impl RolledDice {
+    /// Calculate what type of success or failure this roll is.
+    /// Consult the RollResult enum for descriptions of what each
+    /// result requires.
+    pub fn result(&self) -> RollResult {
+        let hard_target = self.target / 2u32;
+        let extreme_target = self.target / 5u32;
+        if (self.target < 50 && self.num_rolled > 95) || self.num_rolled == 100 {
+            RollResult::Fumble
+        } else if self.num_rolled == 1 {
+            RollResult::CriticalSuccess
+        } else if self.num_rolled <= extreme_target {
+            RollResult::ExtremeSuccess
+        } else if self.num_rolled <= hard_target {
+            RollResult::HardSuccess
+        } else if self.num_rolled <= self.target {
+            RollResult::Success
+        } else {
+            RollResult::Failure
+        }
+    }
+}
+
+impl fmt::Display for RolledDice {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let message = format!(
+            "{} against {}: {}",
+            self.num_rolled,
+            self.target,
+            self.result()
+        );
+        write!(f, "{}", message)?;
+        Ok(())
+    }
+}
+
+/// A planned advancement roll, where the target number is the
+/// existing skill amount.
+#[derive(Clone, Debug, PartialEq)]
+pub struct AdvancementRoll {
+    /// The amount (0 to 100) of the existing skill. We must beat this
+    /// target number to advance the skill, or roll above a 95.
+    pub existing_skill: Amount,
+}
+
+impl fmt::Display for AdvancementRoll {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let message = format!("advancement for skill of {:?}", self.existing_skill);
+        write!(f, "{}", message)?;
+        Ok(())
+    }
+}
+
+/// A struct holding an advancement roll and the context, so we can
+/// translate variables to numbers.
+pub struct AdvancementRollWithContext<'a>(pub &'a AdvancementRoll, pub &'a Context<'a>);
+
+/// A completed advancement roll.
+pub struct RolledAdvancement {
+    existing_skill: u32,
+    num_rolled: u32,
+    advancement: u32,
+    successful: bool,
+}
+
+impl RolledAdvancement {
+    /// The new skill amount, which will be the same if the roll was a
+    /// failure.
+    pub fn new_skill_amount(&self) -> u32 {
+        self.existing_skill + self.advancement
+    }
+
+    /// How much the skill advanced (1 to 10). 0 if the advancement
+    /// roll failed.
+    pub fn advancement(&self) -> u32 {
+        self.advancement
+    }
+
+    /// Whether or not the advancement roll was successful.
+    pub fn successful(&self) -> bool {
+        self.successful
+    }
+}
+
+impl fmt::Display for RolledAdvancement {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let message = if self.successful {
+            format!(
+                "success! new skill is {} (advanced by {}).",
+                self.new_skill_amount(),
+                self.advancement
+            )
+        } else {
+            format!("failure! skill remains at {}", self.existing_skill)
+        };
+
+        write!(
+            f,
+            "rolled {} against {}: {}",
+            self.num_rolled, self.existing_skill, message
+        )?;
+        Ok(())
+    }
+}
+
+/// This is a trait so we can inject controlled dice rolls in unit
+/// tests.
+trait DieRoller {
+    fn roll(&mut self) -> u32;
+}
+
+/// Macro to determine if an Amount is a variable.
+macro_rules! is_variable {
+    ($existing_skill:ident) => {
+        matches!(
+            $existing_skill,
+            Amount {
+                element: Element::Variable(_),
+                ..
+            }
+        )
+    };
+}
+
+/// A die roller than can have an RNG implementation injected, but
+/// must be thread-safe. Required for the async dice rolling code.
+struct RngDieRoller<R: Rng + ?Sized + Send>(R);
+
+impl<R: Rng + ?Sized + Send> DieRoller for RngDieRoller<R> {
+    fn roll(&mut self) -> u32 {
+        self.0.gen_range(0..=9)
+    }
+}
+
+/// Roll a single percentile die according to the rules. We cannot
+/// simply roll a d100 due to the way the game calculates roll results
+/// with bonus/penalty dice. The unit roll (ones place) is added to
+/// the tens roll, unless both results are 0, in which case the result
+/// is 100.
+fn roll_percentile_dice<R: DieRoller>(roller: &mut R, unit_roll: u32) -> u32 {
+    let tens_roll = roller.roll() * 10;
+
+    if tens_roll == 0 && unit_roll == 0 {
+        100
+    } else {
+        tens_roll + unit_roll
+    }
+}
+
+fn roll_regular_dice<R: DieRoller>(
+    modifier: &DiceRollModifier,
+    target: u32,
+    roller: &mut R,
+) -> RolledDice {
+    use DiceRollModifier::*;
+
+    let num_rolls = match modifier {
+        Normal => 1,
+        OneBonus | OnePenalty => 2,
+        TwoBonus | TwoPenalty => 3,
+    };
+
+    let unit_roll = roller.roll();
+
+    let rolls: Vec<u32> = (0..num_rolls)
+        .map(|_| roll_percentile_dice(roller, unit_roll))
+        .collect();
+
+    let num_rolled = match modifier {
+        Normal => rolls.first(),
+        OneBonus | TwoBonus => rolls.iter().min(),
+        OnePenalty | TwoPenalty => rolls.iter().max(),
+    }
+    .unwrap();
+
+    RolledDice {
+        num_rolled: *num_rolled,
+        target: target,
+    }
+}
+
+fn roll_advancement_dice<R: DieRoller>(target: u32, roller: &mut R) -> RolledAdvancement {
+    let unit_roll = roller.roll();
+    let percentile_roll = roll_percentile_dice(roller, unit_roll);
+
+    if percentile_roll > target || percentile_roll > 95 {
+        RolledAdvancement {
+            num_rolled: percentile_roll,
+            existing_skill: target,
+            advancement: roller.roll() + 1,
+            successful: true,
+        }
+    } else {
+        RolledAdvancement {
+            num_rolled: percentile_roll,
+            existing_skill: target,
+            advancement: 0,
+            successful: false,
+        }
+    }
+}
+
+/// Make a roll with a target number and potential modifier. In a
+/// normal roll, only one percentile die is rolled (1d100). With
+/// bonuses or penalties, more dice are rolled, and either the lowest
+/// (in case of bonus) or highest (in case of penalty) result is
+/// picked. Rolls are not simply d100; the unit roll (ones place) is
+/// rolled separately from the tens place, and then the unit number is
+/// added to each potential roll before picking the lowest/highest
+/// result.
+pub async fn regular_roll(
+    roll_with_ctx: &DiceRollWithContext<'_>,
+) -> Result<ExecutedDiceRoll, BotError> {
+    let target = calculate_single_die_amount(&roll_with_ctx.0.amount, roll_with_ctx.1).await?;
+    let target = u32::try_from(target).map_err(|_| DiceRollingError::InvalidAmount)?;
+
+    let mut roller = RngDieRoller::<StdRng>(SeedableRng::from_entropy());
+    let rolled_dice = roll_regular_dice(&roll_with_ctx.0.modifier, target, &mut roller);
+
+    Ok(ExecutedDiceRoll {
+        target,
+        modifier: roll_with_ctx.0.modifier,
+        roll: rolled_dice,
+    })
+}
+
+async fn update_skill(ctx: &Context<'_>, variable: &str, value: u32) -> Result<(), BotError> {
+    use std::convert::TryInto;
+    let value: i32 = value.try_into()?;
+    ctx.db
+        .set_user_variable(
+            &ctx.username,
+            &ctx.active_room_id().as_str(),
+            variable,
+            value,
+        )
+        .await?;
+    Ok(())
+}
+
+fn extract_variable(amount: &Amount) -> Result<&str, DiceParsingError> {
+    match amount.element {
+        Element::Variable(ref varname) => Ok(&varname[..]),
+        _ => Err(DiceParsingError::WrongElementType),
+    }
+}
+pub async fn advancement_roll(
+    roll_with_ctx: &AdvancementRollWithContext<'_>,
+) -> Result<ExecutedAdvancementRoll, BotError> {
+    let existing_skill = &roll_with_ctx.0.existing_skill;
+    let target = calculate_single_die_amount(existing_skill, roll_with_ctx.1).await?;
+
+    let target = u32::try_from(target).map_err(|_| DiceRollingError::InvalidAmount)?;
+
+    if target > 100 {
+        return Err(DiceRollingError::InvalidAmount.into());
+    }
+
+    let mut roller = RngDieRoller::<StdRng>(SeedableRng::from_entropy());
+    let roll = roll_advancement_dice(target, &mut roller);
+
+    drop(roller);
+
+    if roll.successful && is_variable!(existing_skill) {
+        let variable_name: &str = extract_variable(existing_skill)?;
+        update_skill(roll_with_ctx.1, variable_name, roll.new_skill_amount()).await?;
+    }
+
+    Ok(ExecutedAdvancementRoll { target, roll })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::db::sqlite::Database;
+    use crate::parser::dice::{Amount, Element, Operator};
+    use url::Url;
+    use matrix_sdk::ruma::room_id;
+
+    macro_rules! dummy_room {
+        () => {
+            crate::context::RoomContext {
+                id: &room_id!("!fakeroomid:example.com"),
+                display_name: "displayname".to_owned(),
+                secure: false,
+            }
+        };
+    }
+
+    /// Generate a series of numbers manually for testing. For this
+    /// die system, the first roll in the Vec should be the unit roll,
+    /// and any subsequent rolls should be the tens place roll. The
+    /// results rolled must come from a d10 (0 to 9).
+    struct SequentialDieRoller {
+        results: Vec<u32>,
+        position: usize,
+    }
+
+    impl SequentialDieRoller {
+        fn new(results: Vec<u32>) -> SequentialDieRoller {
+            SequentialDieRoller {
+                results,
+                position: 0,
+            }
+        }
+    }
+
+    impl DieRoller for SequentialDieRoller {
+        fn roll(&mut self) -> u32 {
+            let roll = self.results[self.position];
+            self.position += 1;
+            roll
+        }
+    }
+
+    #[test]
+    fn extract_variable_gets_variable_name() {
+        let amount = Amount {
+            operator: Operator::Plus,
+            element: Element::Variable("abc".to_string()),
+        };
+
+        let result = extract_variable(&amount);
+
+        assert!(result.is_ok());
+        assert_eq!(result.unwrap(), "abc");
+    }
+
+    #[test]
+    fn extract_variable_fails_on_number() {
+        let result = extract_variable(&Amount {
+            operator: Operator::Plus,
+            element: Element::Number(1),
+        });
+
+        assert!(result.is_err());
+        assert!(matches!(result, Err(DiceParsingError::WrongElementType)));
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn regular_roll_rejects_negative_numbers() {
+        let roll = DiceRoll {
+            amount: Amount {
+                operator: Operator::Plus,
+                element: Element::Number(-10),
+            },
+            modifier: DiceRollModifier::Normal,
+        };
+
+        let db_path = tempfile::NamedTempFile::new_in(".").unwrap();
+        crate::db::sqlite::migrator::migrate(db_path.path().to_str().unwrap())
+            .await
+            .unwrap();
+
+        let db = Database::new(db_path.path().to_str().unwrap())
+            .await
+            .unwrap();
+
+        let homeserver = Url::parse("http://example.com").unwrap();
+        let ctx = Context {
+            account: crate::models::Account::default(),
+            db: db,
+            matrix_client: matrix_sdk::Client::new(homeserver).await.unwrap(),
+            origin_room: dummy_room!(),
+            active_room: dummy_room!(),
+            username: "username",
+            message_body: "message",
+        };
+
+        let roll_with_ctx = DiceRollWithContext(&roll, &ctx);
+        let result = regular_roll(&roll_with_ctx).await;
+        assert!(result.is_err());
+        assert!(matches!(
+            result,
+            Err(BotError::DiceRollingError(DiceRollingError::InvalidAmount))
+        ));
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn advancement_roll_rejects_negative_numbers() {
+        let roll = AdvancementRoll {
+            existing_skill: Amount {
+                operator: Operator::Plus,
+                element: Element::Number(-10),
+            },
+        };
+
+        let db_path = tempfile::NamedTempFile::new_in(".").unwrap();
+        crate::db::sqlite::migrator::migrate(db_path.path().to_str().unwrap())
+            .await
+            .unwrap();
+
+        let db = Database::new(db_path.path().to_str().unwrap())
+            .await
+            .unwrap();
+
+        let homeserver = Url::parse("http://example.com").unwrap();
+        let ctx = Context {
+            account: crate::models::Account::default(),
+            db: db,
+            matrix_client: matrix_sdk::Client::new(homeserver).await.unwrap(),
+            origin_room: dummy_room!(),
+            active_room: dummy_room!(),
+            username: "username",
+            message_body: "message",
+        };
+
+        let roll_with_ctx = AdvancementRollWithContext(&roll, &ctx);
+        let result = advancement_roll(&roll_with_ctx).await;
+        assert!(result.is_err());
+        assert!(matches!(
+            result,
+            Err(BotError::DiceRollingError(DiceRollingError::InvalidAmount))
+        ));
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn advancement_roll_rejects_big_numbers() {
+        let roll = AdvancementRoll {
+            existing_skill: Amount {
+                operator: Operator::Plus,
+                element: Element::Number(3000),
+            },
+        };
+
+        let db_path = tempfile::NamedTempFile::new_in(".").unwrap();
+        crate::db::sqlite::migrator::migrate(db_path.path().to_str().unwrap())
+            .await
+            .unwrap();
+
+        let db = Database::new(db_path.path().to_str().unwrap())
+            .await
+            .unwrap();
+
+        let homeserver = Url::parse("http://example.com").unwrap();
+        let ctx = Context {
+            account: crate::models::Account::default(),
+            db: db,
+            matrix_client: matrix_sdk::Client::new(homeserver).await.unwrap(),
+            origin_room: dummy_room!(),
+            active_room: dummy_room!(),
+            username: "username",
+            message_body: "message",
+        };
+
+        let roll_with_ctx = AdvancementRollWithContext(&roll, &ctx);
+        let result = advancement_roll(&roll_with_ctx).await;
+        assert!(result.is_err());
+        assert!(matches!(
+            result,
+            Err(BotError::DiceRollingError(DiceRollingError::InvalidAmount))
+        ));
+    }
+
+    #[test]
+    fn is_variable_macro_succeds_on_variable() {
+        let amount = Amount {
+            operator: Operator::Plus,
+            element: Element::Variable("abc".to_string()),
+        };
+
+        assert_eq!(is_variable!(amount), true);
+    }
+
+    #[test]
+    fn is_variable_macro_fails_on_number() {
+        let amount = Amount {
+            operator: Operator::Plus,
+            element: Element::Number(1),
+        };
+
+        assert_eq!(is_variable!(amount), false);
+    }
+
+    #[test]
+    fn regular_roll_succeeds_when_below_target() {
+        //Roll 30, succeeding.
+        let mut roller = SequentialDieRoller::new(vec![0, 3]);
+        let rolled = roll_regular_dice(&DiceRollModifier::Normal, 50, &mut roller);
+        assert_eq!(RollResult::Success, rolled.result());
+    }
+
+    #[test]
+    fn regular_roll_hard_success_when_rolling_half() {
+        //Roll 25, succeeding.
+        let mut roller = SequentialDieRoller::new(vec![5, 2]);
+        let rolled = roll_regular_dice(&DiceRollModifier::Normal, 50, &mut roller);
+        assert_eq!(RollResult::HardSuccess, rolled.result());
+    }
+
+    #[test]
+    fn regular_roll_extreme_success_when_rolling_one_fifth() {
+        //Roll 10, succeeding extremely.
+        let mut roller = SequentialDieRoller::new(vec![0, 1]);
+        let rolled = roll_regular_dice(&DiceRollModifier::Normal, 50, &mut roller);
+        assert_eq!(RollResult::ExtremeSuccess, rolled.result());
+    }
+
+    #[test]
+    fn regular_roll_extreme_success_target_above_100() {
+        //Roll 30, succeeding extremely.
+        let mut roller = SequentialDieRoller::new(vec![0, 3]);
+        let rolled = roll_regular_dice(&DiceRollModifier::Normal, 150, &mut roller);
+        assert_eq!(RollResult::ExtremeSuccess, rolled.result());
+    }
+
+    #[test]
+    fn regular_roll_critical_success_on_one() {
+        //Roll 1.
+        let mut roller = SequentialDieRoller::new(vec![1, 0]);
+        let rolled = roll_regular_dice(&DiceRollModifier::Normal, 50, &mut roller);
+        assert_eq!(RollResult::CriticalSuccess, rolled.result());
+    }
+
+    #[test]
+    fn regular_roll_fail_when_above_target() {
+        //Roll 60.
+        let mut roller = SequentialDieRoller::new(vec![0, 6]);
+        let rolled = roll_regular_dice(&DiceRollModifier::Normal, 50, &mut roller);
+        assert_eq!(RollResult::Failure, rolled.result());
+    }
+
+    #[test]
+    fn regular_roll_is_fumble_when_skill_below_50_and_roll_at_least_96() {
+        //Roll 96.
+        let mut roller = SequentialDieRoller::new(vec![6, 9]);
+        let rolled = roll_regular_dice(&DiceRollModifier::Normal, 49, &mut roller);
+        assert_eq!(RollResult::Fumble, rolled.result());
+    }
+
+    #[test]
+    fn regular_roll_is_failure_when_skill_at_or_above_50_and_roll_at_least_96() {
+        //Roll 96.
+        let mut roller = SequentialDieRoller::new(vec![6, 9]);
+        let rolled = roll_regular_dice(&DiceRollModifier::Normal, 50, &mut roller);
+        assert_eq!(RollResult::Failure, rolled.result());
+
+        //Roll 96.
+        let mut roller = SequentialDieRoller::new(vec![6, 9]);
+        let rolled = roll_regular_dice(&DiceRollModifier::Normal, 68, &mut roller);
+        assert_eq!(RollResult::Failure, rolled.result());
+    }
+
+    #[test]
+    fn regular_roll_always_fumble_on_100() {
+        //Roll 100.
+        let mut roller = SequentialDieRoller::new(vec![0, 0]);
+        let rolled = roll_regular_dice(&DiceRollModifier::Normal, 100, &mut roller);
+        assert_eq!(RollResult::Fumble, rolled.result());
+    }
+
+    #[test]
+    fn one_penalty_picks_highest_of_two() {
+        //Should only roll 30 and 40, not 50.
+        let mut roller = SequentialDieRoller::new(vec![0, 3, 4, 5]);
+        let rolled = roll_regular_dice(&DiceRollModifier::OnePenalty, 50, &mut roller);
+        assert_eq!(40, rolled.num_rolled);
+    }
+
+    #[test]
+    fn two_penalty_picks_highest_of_three() {
+        //Should only roll 30, 40, 50, and not 60.
+        let mut roller = SequentialDieRoller::new(vec![0, 3, 4, 5, 6]);
+        let rolled = roll_regular_dice(&DiceRollModifier::TwoPenalty, 50, &mut roller);
+        assert_eq!(50, rolled.num_rolled);
+    }
+
+    #[test]
+    fn one_bonus_picks_lowest_of_two() {
+        //Should only roll 30 and 40, not 20.
+        let mut roller = SequentialDieRoller::new(vec![0, 3, 4, 2]);
+        let rolled = roll_regular_dice(&DiceRollModifier::OneBonus, 50, &mut roller);
+        assert_eq!(30, rolled.num_rolled);
+    }
+
+    #[test]
+    fn two_bonus_picks_lowest_of_three() {
+        //Should only roll 30, 40, 50, and not 20.
+        let mut roller = SequentialDieRoller::new(vec![0, 3, 4, 5, 2]);
+        let rolled = roll_regular_dice(&DiceRollModifier::TwoBonus, 50, &mut roller);
+        assert_eq!(30, rolled.num_rolled);
+    }
+
+    #[test]
+    fn normal_modifier_rolls_once() {
+        //Should only roll 30, not 40.
+        let mut roller = SequentialDieRoller::new(vec![0, 3, 4]);
+        let rolled = roll_regular_dice(&DiceRollModifier::Normal, 50, &mut roller);
+        assert_eq!(30, rolled.num_rolled);
+    }
+
+    #[test]
+    fn advancement_succeeds_on_above_skill() {
+        //Roll 52, then advance skill by 5. (advancement adds +1 to 0-9 roll)
+        let mut roller = SequentialDieRoller::new(vec![2, 5, 4]);
+
+        let rolled = roll_advancement_dice(30, &mut roller);
+        assert!(rolled.successful());
+        assert_eq!(5, rolled.advancement());
+        assert_eq!(35, rolled.new_skill_amount());
+    }
+
+    #[test]
+    fn advancement_succeeds_on_above_95() {
+        //Roll 96, then advance skill by 1. (advancement adds +1 to 0-9 roll)
+        let mut roller = SequentialDieRoller::new(vec![6, 9, 0]);
+
+        let rolled = roll_advancement_dice(97, &mut roller);
+        assert!(rolled.successful());
+        assert_eq!(1, rolled.advancement());
+        assert_eq!(98, rolled.new_skill_amount());
+    }
+
+    #[test]
+    fn advancement_fails_on_below_skill() {
+        //Roll 25, failing.
+        let mut roller = SequentialDieRoller::new(vec![5, 2]);
+
+        let rolled = roll_advancement_dice(30, &mut roller);
+        assert!(!rolled.successful());
+        assert_eq!(0, rolled.advancement());
+    }
+}

dicebot/src/cthulhu/mod.rs

@@ -0,0 +1,2 @@
+pub mod dice;
+pub mod parser;

dicebot/src/cthulhu/parser.rs

@@ -0,0 +1,242 @@
+use super::dice::{AdvancementRoll, DiceRoll, DiceRollModifier};
+use crate::parser::dice::DiceParsingError;
+
+//TOOD convert these to use parse_amounts from the common dice code.
+
+fn parse_modifier(input: &str) -> Result<DiceRollModifier, DiceParsingError> {
+    match input.trim() {
+        "bb" => Ok(DiceRollModifier::TwoBonus),
+        "b" => Ok(DiceRollModifier::OneBonus),
+        "pp" => Ok(DiceRollModifier::TwoPenalty),
+        "p" => Ok(DiceRollModifier::OnePenalty),
+        "" => Ok(DiceRollModifier::Normal),
+        _ => Err(DiceParsingError::InvalidModifiers),
+    }
+}
+
+//Make diceroll take a vec of Amounts
+//Split based on :, send first part to parse_modifier.
+//Send second part to parse_amounts
+pub fn parse_regular_roll(input: &str) -> Result<DiceRoll, DiceParsingError> {
+    let (amount, modifiers_str) = crate::parser::dice::parse_single_amount(input)?;
+    let modifier = parse_modifier(modifiers_str)?;
+    Ok(DiceRoll { modifier, amount })
+}
+
+pub fn parse_advancement_roll(input: &str) -> Result<AdvancementRoll, DiceParsingError> {
+    let input = input.trim();
+    let (amounts, unconsumed_input) = crate::parser::dice::parse_single_amount(input)?;
+
+    if unconsumed_input.len() == 0 {
+        Ok(AdvancementRoll {
+            existing_skill: amounts,
+        })
+    } else {
+        Err(DiceParsingError::InvalidAmount)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::parser::dice::{Amount, DiceParsingError, Element, Operator};
+
+    #[test]
+    fn parse_modifier_rejects_bad_value() {
+        let modifier = parse_modifier("qqq");
+        assert!(matches!(modifier, Err(DiceParsingError::InvalidModifiers)))
+    }
+
+    #[test]
+    fn parse_modifier_accepts_one_bonus() {
+        let modifier = parse_modifier("b");
+        assert!(matches!(modifier, Ok(DiceRollModifier::OneBonus)))
+    }
+
+    #[test]
+    fn parse_modifier_accepts_two_bonus() {
+        let modifier = parse_modifier("bb");
+        assert!(matches!(modifier, Ok(DiceRollModifier::TwoBonus)))
+    }
+
+    #[test]
+    fn parse_modifier_accepts_two_penalty() {
+        let modifier = parse_modifier("pp");
+        assert!(matches!(modifier, Ok(DiceRollModifier::TwoPenalty)))
+    }
+
+    #[test]
+    fn parse_modifier_accepts_one_penalty() {
+        let modifier = parse_modifier("p");
+        assert!(matches!(modifier, Ok(DiceRollModifier::OnePenalty)))
+    }
+
+    #[test]
+    fn parse_modifier_accepts_normal() {
+        let modifier = parse_modifier("");
+        assert!(matches!(modifier, Ok(DiceRollModifier::Normal)))
+    }
+
+    #[test]
+    fn parse_modifier_accepts_normal_unaffected_by_whitespace() {
+        let modifier = parse_modifier("         ");
+        assert!(matches!(modifier, Ok(DiceRollModifier::Normal)))
+    }
+
+    #[test]
+    fn regular_roll_accepts_single_number() {
+        let result = parse_regular_roll("60");
+        assert!(result.is_ok());
+        assert_eq!(
+            DiceRoll {
+                amount: Amount {
+                    operator: Operator::Plus,
+                    element: Element::Number(60)
+                },
+                modifier: DiceRollModifier::Normal
+            },
+            result.unwrap()
+        );
+    }
+
+    #[test]
+    fn regular_roll_rejects_complex_expressions() {
+        let result = parse_regular_roll("3 + abc + bob - 4");
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn regular_roll_accepts_two_bonus() {
+        let result = parse_regular_roll("60 bb");
+        assert!(result.is_ok());
+        assert_eq!(
+            DiceRoll {
+                amount: Amount {
+                    operator: Operator::Plus,
+                    element: Element::Number(60)
+                },
+                modifier: DiceRollModifier::TwoBonus
+            },
+            result.unwrap()
+        );
+    }
+
+    #[test]
+    fn regular_roll_accepts_one_bonus() {
+        let result = parse_regular_roll("60 b");
+        assert!(result.is_ok());
+        assert_eq!(
+            DiceRoll {
+                amount: Amount {
+                    operator: Operator::Plus,
+                    element: Element::Number(60)
+                },
+                modifier: DiceRollModifier::OneBonus
+            },
+            result.unwrap()
+        );
+    }
+
+    #[test]
+    fn regular_roll_accepts_two_penalty() {
+        let result = parse_regular_roll("60 pp");
+        assert!(result.is_ok());
+        assert_eq!(
+            DiceRoll {
+                amount: Amount {
+                    operator: Operator::Plus,
+                    element: Element::Number(60)
+                },
+                modifier: DiceRollModifier::TwoPenalty
+            },
+            result.unwrap()
+        );
+    }
+
+    #[test]
+    fn regular_roll_accepts_one_penalty() {
+        let result = parse_regular_roll("60 p");
+        assert!(result.is_ok());
+        assert_eq!(
+            DiceRoll {
+                amount: Amount {
+                    operator: Operator::Plus,
+                    element: Element::Number(60)
+                },
+                modifier: DiceRollModifier::OnePenalty
+            },
+            result.unwrap()
+        );
+    }
+
+    #[test]
+    fn regular_roll_accepts_whitespace() {
+        assert!(parse_regular_roll("60     ").is_ok());
+        assert!(parse_regular_roll("   60").is_ok());
+        assert!(parse_regular_roll("   60    ").is_ok());
+
+        assert!(parse_regular_roll("60bb     ").is_ok());
+        assert!(parse_regular_roll("   60 bb").is_ok());
+        assert!(parse_regular_roll("   60   bb    ").is_ok());
+
+        assert!(parse_regular_roll("60b     ").is_ok());
+        assert!(parse_regular_roll("   60 b").is_ok());
+        assert!(parse_regular_roll("   60  b    ").is_ok());
+
+        assert!(parse_regular_roll("60pp     ").is_ok());
+        assert!(parse_regular_roll("   60 pp").is_ok());
+        assert!(parse_regular_roll("   60 pp   ").is_ok());
+
+        assert!(parse_regular_roll("60p     ").is_ok());
+        assert!(parse_regular_roll("   60p  ").is_ok());
+        assert!(parse_regular_roll("   60  p    ").is_ok());
+    }
+
+    #[test]
+    fn advancement_roll_accepts_whitespacen() {
+        assert!(parse_advancement_roll("60     ").is_ok());
+        assert!(parse_advancement_roll("   60").is_ok());
+        assert!(parse_advancement_roll("   60    ").is_ok());
+    }
+
+    #[test]
+    fn advancement_roll_accepts_single_number() {
+        let result = parse_advancement_roll("60");
+        assert!(result.is_ok());
+        assert_eq!(
+            AdvancementRoll {
+                existing_skill: Amount {
+                    operator: Operator::Plus,
+                    element: Element::Number(60)
+                }
+            },
+            result.unwrap()
+        );
+    }
+
+    #[test]
+    fn advancement_roll_allows_big_numbers() {
+        assert!(parse_advancement_roll("3000").is_ok());
+    }
+
+    #[test]
+    fn advancement_roll_allows_variables() {
+        let result = parse_advancement_roll("abc");
+        assert!(result.is_ok());
+        assert_eq!(
+            AdvancementRoll {
+                existing_skill: Amount {
+                    operator: Operator::Plus,
+                    element: Element::Variable(String::from("abc"))
+                }
+            },
+            result.unwrap()
+        );
+    }
+
+    #[test]
+    fn advancement_roll_rejects_complex_expressions() {
+        let result = parse_advancement_roll("3 + abc + bob - 4");
+        assert!(result.is_err());
+    }
+}

dicebot/src/db/errors.rs

@@ -0,0 +1,32 @@
+use std::num::TryFromIntError;
+use thiserror::Error;
+
+#[derive(Error, Debug)]
+pub enum DataError {
+    #[error("value does not exist for key: {0}")]
+    KeyDoesNotExist(String),
+
+    #[error("too many entries")]
+    TooManyEntries,
+
+    #[error("expected i32, but i32 schema was violated")]
+    I32SchemaViolation,
+
+    #[error("unexpected or corruptd data bytes")]
+    InvalidValue,
+
+    #[error("expected string ref, but utf8 schema was violated: {0}")]
+    Utf8RefSchemaViolation(#[from] std::str::Utf8Error),
+
+    #[error("expected string, but utf8 schema was violated: {0}")]
+    Utf8SchemaViolation(#[from] std::string::FromUtf8Error),
+
+    #[error("data migration error: {0}")]
+    MigrationError(#[from] crate::db::sqlite::migrator::MigrationError),
+
+    #[error("internal database error: {0}")]
+    SqlxError(#[from] sqlx::Error),
+
+    #[error("numeric conversion error")]
+    NumericConversionError(#[from] TryFromIntError),
+}

dicebot/src/db/mod.rs

@@ -0,0 +1,70 @@
+use crate::error::BotError;
+use crate::models::User;
+use async_trait::async_trait;
+use errors::DataError;
+use std::collections::HashMap;
+
+pub mod errors;
+pub mod sqlite;
+
+#[async_trait]
+pub(crate) trait DbState {
+    async fn get_device_id(&self) -> Result<Option<String>, DataError>;
+
+    async fn set_device_id(&self, device_id: &str) -> Result<(), DataError>;
+}
+
+#[async_trait]
+pub(crate) trait Users {
+    async fn upsert_user(&self, user: &User) -> Result<(), DataError>;
+
+    async fn get_user(&self, username: &str) -> Result<Option<User>, DataError>;
+
+    async fn delete_user(&self, username: &str) -> Result<(), DataError>;
+
+    async fn authenticate_user(
+        &self,
+        username: &str,
+        raw_password: &str,
+    ) -> Result<Option<User>, BotError>;
+}
+
+#[async_trait]
+pub(crate) trait Rooms {
+    async fn should_process(&self, room_id: &str, event_id: &str) -> Result<bool, DataError>;
+}
+
+// TODO move this up to the top once we delete sled. Traits will be the
+// main API, then we can have different impls for different DBs.
+#[async_trait]
+pub trait Variables {
+    async fn get_user_variables(
+        &self,
+        user: &str,
+        room_id: &str,
+    ) -> Result<HashMap<String, i32>, DataError>;
+
+    async fn get_variable_count(&self, user: &str, room_id: &str) -> Result<i32, DataError>;
+
+    async fn get_user_variable(
+        &self,
+        user: &str,
+        room_id: &str,
+        variable_name: &str,
+    ) -> Result<i32, DataError>;
+
+    async fn set_user_variable(
+        &self,
+        user: &str,
+        room_id: &str,
+        variable_name: &str,
+        value: i32,
+    ) -> Result<(), DataError>;
+
+    async fn delete_user_variable(
+        &self,
+        user: &str,
+        room_id: &str,
+        variable_name: &str,
+    ) -> Result<(), DataError>;
+}

dicebot/src/db/sqlite/migrator/migrations/V10__add_game_system.rs

@@ -0,0 +1,22 @@
+use crate::systems::GameSystem;
+use barrel::backend::Sqlite;
+use barrel::{types, types::Type, Migration};
+use itertools::Itertools;
+use strum::IntoEnumIterator;
+
+fn primary_id() -> Type {
+    types::text().unique(true).primary(true).nullable(false)
+}
+
+pub fn migration() -> String {
+    let mut m = Migration::new();
+
+    //Normally we would add a CHECK clause here, but types::custom requires a 'static string.
+    //Which means we can't automagically generate one from the enum.
+    m.create_table("room_info", move |t| {
+        t.add_column("room_id", primary_id());
+        t.add_column("game_system", types::text().nullable(false));
+    });
+
+    m.make::<Sqlite>()
+}

dicebot/src/db/sqlite/migrator/migrations/V1__variables.rs

@@ -0,0 +1,15 @@
+use barrel::backend::Sqlite;
+use barrel::{types, Migration};
+
+pub fn migration() -> String {
+    let mut m = Migration::new();
+
+    m.create_table("user_variables", |t| {
+        t.add_column("room_id", types::text());
+        t.add_column("user_id", types::text());
+        t.add_column("key", types::text());
+        t.add_column("value", types::integer());
+    });
+
+    m.make::<Sqlite>()
+}

dicebot/src/db/sqlite/migrator/migrations/V2__room_info.rs

@@ -0,0 +1,18 @@
+use barrel::backend::Sqlite;
+use barrel::{types, types::Type, Migration};
+
+fn primary_uuid() -> Type {
+    types::text().unique(true).primary(true).nullable(false)
+}
+
+pub fn migration() -> String {
+    let mut m = Migration::new();
+
+    //Table for basic room information: room ID, room name
+    m.create_table("room_info", move |t| {
+        t.add_column("room_id", primary_uuid());
+        t.add_column("room_name", types::text());
+    });
+
+    m.make::<Sqlite>()
+}

dicebot/src/db/sqlite/migrator/migrations/V3__dbstate.rs

@@ -0,0 +1,13 @@
+use barrel::backend::Sqlite;
+use barrel::{types, Migration};
+
+pub fn migration() -> String {
+    let mut m = Migration::new();
+
+    //Basic state table with only device ID for now. Uses only one row.
+    m.create_table("bot_state", move |t| {
+        t.add_column("device_id", types::text());
+    });
+
+    m.make::<Sqlite>()
+}

dicebot/src/db/sqlite/migrator/migrations/V4__room_events.rs

@@ -0,0 +1,23 @@
+use barrel::backend::Sqlite;
+use barrel::{types, Migration};
+
+pub fn migration() -> String {
+    let mut m = Migration::new();
+
+    //Table of room ID, event ID, event timestamp
+    m.create_table("room_events", move |t| {
+        t.add_column("room_id", types::text().nullable(false));
+        t.add_column("event_id", types::text().nullable(false));
+        t.add_column("event_timestamp", types::integer());
+    });
+
+    let mut res = m.make::<Sqlite>();
+
+    //This is a hack that gives us a composite primary key.
+    if res.ends_with(");") {
+        res.pop();
+        res.pop();
+    }
+
+    format!("{}, PRIMARY KEY (room_id, event_id));", res)
+}

dicebot/src/db/sqlite/migrator/migrations/V5__room_users.rs

@@ -0,0 +1,22 @@
+use barrel::backend::Sqlite;
+use barrel::{types, Migration};
+
+pub fn migration() -> String {
+    let mut m = Migration::new();
+
+    //Table of users in rooms.
+    m.create_table("room_users", move |t| {
+        t.add_column("room_id", types::text());
+        t.add_column("username", types::text());
+    });
+
+    let mut res = m.make::<Sqlite>();
+
+    //This is a hack that gives us a composite primary key.
+    if res.ends_with(");") {
+        res.pop();
+        res.pop();
+    }
+
+    format!("{}, PRIMARY KEY (room_id, username));", res)
+}

dicebot/src/db/sqlite/migrator/migrations/V6__user_accounts.rs

@@ -0,0 +1,18 @@
+use barrel::backend::Sqlite;
+use barrel::{types, types::Type, Migration};
+
+fn primary_uuid() -> Type {
+    types::text().unique(true).primary(true).nullable(false)
+}
+
+pub fn migration() -> String {
+    let mut m = Migration::new();
+
+    //Table of room ID, event ID, event timestamp
+    m.create_table("accounts", move |t| {
+        t.add_column("user_id", primary_uuid());
+        t.add_column("password", types::text().nullable(false));
+    });
+
+    m.make::<Sqlite>()
+}

dicebot/src/db/sqlite/migrator/migrations/V7__no_more_room_state.rs

@@ -0,0 +1,10 @@
+use barrel::backend::Sqlite;
+use barrel::Migration;
+
+pub fn migration() -> String {
+    let mut m = Migration::new();
+
+    m.drop_table_if_exists("room_info");
+    m.drop_table_if_exists("room_users");
+    m.make::<Sqlite>()
+}

dicebot/src/db/sqlite/migrator/migrations/V8__user_state.rs

@@ -0,0 +1,18 @@
+use barrel::backend::Sqlite;
+use barrel::{types, types::Type, Migration};
+
+fn primary_uuid() -> Type {
+    types::text().unique(true).primary(true).nullable(false)
+}
+
+pub fn migration() -> String {
+    let mut m = Migration::new();
+
+    // Keep track of contextual user state.
+    m.create_table("user_state", move |t| {
+        t.add_column("user_id", primary_uuid());
+        t.add_column("active_room", types::text().nullable(true));
+    });
+
+    m.make::<Sqlite>()
+}

dicebot/src/db/sqlite/migrator/migrations/V9__nullable_password_and_account_status.rs

@@ -0,0 +1,17 @@
+pub fn migration() -> String {
+    // sqlite does really support alter column, and barrel does not
+    // implement the required workaround, so we do it ourselves!
+    r#"
+      CREATE TABLE IF NOT EXISTS "accounts2" (
+         "user_id" TEXT PRIMARY KEY NOT NULL UNIQUE,
+         "password" TEXT NULL,
+         "account_status" TEXT NOT NULL CHECK(
+             account_status IN ('not_registered', 'registered', 'awaiting_activation'
+         ))
+      );
+      INSERT INTO accounts2 select *, 'registered' FROM accounts;
+      DROP TABLE accounts;
+      ALTER TABLE accounts2 RENAME TO accounts;
+    "#
+    .to_string()
+}

dicebot/src/db/sqlite/migrator/migrations/mod.rs

@@ -0,0 +1 @@
+

dicebot/src/db/sqlite/migrator/mod.rs

@@ -0,0 +1,38 @@
+use log::info;
+use refinery::config::{Config, ConfigDbType};
+use sqlx::sqlite::SqliteConnectOptions;
+use sqlx::ConnectOptions;
+use std::str::FromStr;
+use thiserror::Error;
+
+//pub mod migrations;
+
+#[derive(Error, Debug)]
+pub enum MigrationError {
+    #[error("sqlite connection error: {0}")]
+    SqlxError(#[from] sqlx::Error),
+
+    #[error("refinery migration error: {0}")]
+    RefineryError(#[from] refinery::Error),
+}
+
+mod embedded {
+    use refinery::embed_migrations;
+    embed_migrations!("src/db/sqlite/migrator/migrations");
+}
+
+/// Run database migrations against the sqlite database.
+pub async fn migrate(db_path: &str) -> Result<(), MigrationError> {
+    //Create database if missing.
+    let conn = SqliteConnectOptions::from_str(&format!("sqlite://{}", db_path))?
+        .create_if_missing(true)
+        .connect()
+        .await?;
+
+    drop(conn);
+
+    let mut conn = Config::new(ConfigDbType::Sqlite).set_db_path(db_path);
+    info!("Running migrations");
+    embedded::migrations::runner().run(&mut conn)?;
+    Ok(())
+}

dicebot/src/db/sqlite/mod.rs

@@ -0,0 +1,51 @@
+use crate::db::errors::DataError;
+use sqlx::sqlite::{SqliteConnectOptions, SqlitePool, SqlitePoolOptions};
+use sqlx::ConnectOptions;
+use std::clone::Clone;
+use std::str::FromStr;
+
+pub mod migrator;
+pub mod rooms;
+pub mod state;
+pub mod users;
+pub mod variables;
+
+pub struct Database {
+    conn: SqlitePool,
+}
+
+impl Database {
+    fn new_db(conn: SqlitePool) -> Result<Database, DataError> {
+        let database = Database { conn: conn.clone() };
+        Ok(database)
+    }
+
+    pub async fn new(path: &str) -> Result<Database, DataError> {
+        //Create database if missing.
+        let conn = SqliteConnectOptions::from_str(path)?
+            .create_if_missing(true)
+            .connect()
+            .await?;
+
+        drop(conn);
+
+        //Migrate database.
+        migrator::migrate(&path).await?;
+
+        //Return actual conncetion pool.
+        let conn = SqlitePoolOptions::new()
+            .max_connections(5)
+            .connect(path)
+            .await?;
+
+        Self::new_db(conn)
+    }
+}
+
+impl Clone for Database {
+    fn clone(&self) -> Self {
+        Database {
+            conn: self.conn.clone(),
+        }
+    }
+}

dicebot/src/db/sqlite/rooms.rs

@@ -0,0 +1,93 @@
+use super::Database;
+use crate::db::{errors::DataError, Rooms};
+use async_trait::async_trait;
+use sqlx::SqlitePool;
+use std::time::{SystemTime, UNIX_EPOCH};
+
+async fn record_event(conn: &SqlitePool, room_id: &str, event_id: &str) -> Result<(), DataError> {
+    use std::convert::TryFrom;
+    let now: i64 = i64::try_from(
+        SystemTime::now()
+            .duration_since(UNIX_EPOCH)
+            .expect("Clock has gone backwards")
+            .as_secs(),
+    )?;
+
+    sqlx::query(
+        r#"INSERT INTO room_events
+                      (room_id, event_id, event_timestamp)
+                      VALUES (?, ?, ?)"#,
+    )
+    .bind(room_id)
+    .bind(event_id)
+    .bind(now)
+    .execute(conn)
+    .await?;
+
+    Ok(())
+}
+
+#[async_trait]
+impl Rooms for Database {
+    async fn should_process(&self, room_id: &str, event_id: &str) -> Result<bool, DataError> {
+        let row = sqlx::query!(
+            r#"SELECT event_id FROM room_events
+               WHERE room_id = ? AND event_id = ?"#,
+            room_id,
+            event_id
+        )
+        .fetch_optional(&self.conn)
+        .await?;
+
+        match row {
+            Some(_) => Ok(false),
+            None => {
+                record_event(&self.conn, room_id, event_id).await?;
+                Ok(true)
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::db::sqlite::Database;
+    use crate::db::Rooms;
+    use std::future::Future;
+
+    async fn with_db<Fut>(f: impl FnOnce(Database) -> Fut)
+    where
+        Fut: Future<Output = ()>,
+    {
+        let db_path = tempfile::NamedTempFile::new_in(".").unwrap();
+        crate::db::sqlite::migrator::migrate(db_path.path().to_str().unwrap())
+            .await
+            .unwrap();
+
+        let db = Database::new(db_path.path().to_str().unwrap())
+            .await
+            .unwrap();
+
+        f(db).await;
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn should_process_test() {
+        with_db(|db| async move {
+            let first_check = db
+                .should_process("myroom", "myeventid")
+                .await
+                .expect("should_process failed in first insert");
+
+            assert_eq!(first_check, true);
+
+            let second_check = db
+                .should_process("myroom", "myeventid")
+                .await
+                .expect("should_process failed in first insert");
+
+            assert_eq!(second_check, false);
+        })
+        .await;
+    }
+}

dicebot/src/db/sqlite/state.rs

@@ -0,0 +1,100 @@
+use super::Database;
+use crate::db::{errors::DataError, DbState};
+use async_trait::async_trait;
+
+#[async_trait]
+impl DbState for Database {
+    async fn get_device_id(&self) -> Result<Option<String>, DataError> {
+        let state = sqlx::query!(r#"SELECT device_id FROM bot_state limit 1"#)
+            .fetch_optional(&self.conn)
+            .await?;
+
+        Ok(state.map(|s| s.device_id))
+    }
+
+    async fn set_device_id(&self, device_id: &str) -> Result<(), DataError> {
+        // This will have to be updated if we ever add another column
+        // to this table!
+        sqlx::query("DELETE FROM bot_state")
+            .execute(&self.conn)
+            .await
+            .ok();
+
+        sqlx::query(
+            r#"INSERT INTO bot_state
+                      (device_id)
+                      VALUES (?)"#,
+        )
+        .bind(device_id)
+        .execute(&self.conn)
+        .await?;
+
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::db::sqlite::Database;
+    use crate::db::DbState;
+    use std::future::Future;
+
+    async fn with_db<Fut>(f: impl FnOnce(Database) -> Fut)
+    where
+        Fut: Future<Output = ()>,
+    {
+        let db_path = tempfile::NamedTempFile::new_in(".").unwrap();
+        crate::db::sqlite::migrator::migrate(db_path.path().to_str().unwrap())
+            .await
+            .unwrap();
+
+        let db = Database::new(db_path.path().to_str().unwrap())
+            .await
+            .unwrap();
+
+        f(db).await;
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn set_and_get_device_id() {
+        with_db(|db| async move {
+            db.set_device_id("device_id")
+                .await
+                .expect("Could not set device ID");
+
+            let device_id = db.get_device_id().await.expect("Could not get device ID");
+
+            assert!(device_id.is_some());
+            assert_eq!(device_id.unwrap(), "device_id");
+        })
+        .await;
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn no_device_id_set_returns_none() {
+        with_db(|db| async move {
+            let device_id = db.get_device_id().await.expect("Could not get device ID");
+            assert!(device_id.is_none());
+        })
+        .await;
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn can_update_device_id() {
+        with_db(|db| async move {
+            db.set_device_id("device_id")
+                .await
+                .expect("Could not set device ID");
+
+            db.set_device_id("device_id2")
+                .await
+                .expect("Could not set device ID");
+
+            let device_id = db.get_device_id().await.expect("Could not get device ID");
+
+            assert!(device_id.is_some());
+            assert_eq!(device_id.unwrap(), "device_id2");
+        })
+        .await;
+    }
+}

dicebot/src/db/sqlite/users.rs

@@ -0,0 +1,361 @@
+use super::Database;
+use crate::db::{errors::DataError, Users};
+use crate::error::BotError;
+use crate::models::User;
+use async_trait::async_trait;
+
+#[async_trait]
+impl Users for Database {
+    async fn upsert_user(&self, user: &User) -> Result<(), DataError> {
+        let mut tx = self.conn.begin().await?;
+
+        sqlx::query!(
+            r#"INSERT INTO accounts (user_id, password, account_status)
+               VALUES (?, ?, ?)
+               ON CONFLICT(user_id) DO
+               UPDATE SET password = ?, account_status = ?"#,
+            user.username,
+            user.password,
+            user.account_status,
+            user.password,
+            user.account_status
+        )
+        .execute(&mut tx)
+        .await?;
+
+        sqlx::query!(
+            r#"INSERT INTO user_state (user_id, active_room)
+               VALUES (?, ?)
+               ON CONFLICT(user_id) DO
+               UPDATE SET active_room = ?"#,
+            user.username,
+            user.active_room,
+            user.active_room
+        )
+        .execute(&mut tx)
+        .await?;
+
+        tx.commit().await?;
+        Ok(())
+    }
+
+    async fn delete_user(&self, username: &str) -> Result<(), DataError> {
+        let mut tx = self.conn.begin().await?;
+
+        sqlx::query!(r#"DELETE FROM accounts WHERE user_id = ?"#, username)
+            .execute(&mut tx)
+            .await?;
+
+        sqlx::query!(r#"DELETE FROM user_state WHERE user_id = ?"#, username)
+            .execute(&mut tx)
+            .await?;
+
+        tx.commit().await?;
+
+        Ok(())
+    }
+
+    async fn get_user(&self, username: &str) -> Result<Option<User>, DataError> {
+        // Should be query_as! macro, but the left join breaks it with a
+        // non existing error message.
+        let user_row: Option<User> = sqlx::query_as(
+            r#"SELECT
+               a.user_id as "username",
+               a.password,
+               s.active_room,
+               COALESCE(a.account_status, 'not_registered') as "account_status"
+               FROM accounts a
+               LEFT JOIN user_state s on a.user_id = s.user_id
+               WHERE a.user_id = ?"#,
+        )
+        .bind(username)
+        .fetch_optional(&self.conn)
+        .await?;
+
+        Ok(user_row)
+    }
+
+    async fn authenticate_user(
+        &self,
+        username: &str,
+        raw_password: &str,
+    ) -> Result<Option<User>, BotError> {
+        let user = self.get_user(username).await?;
+        Ok(user.filter(|u| u.verify_password(raw_password)))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::db::sqlite::Database;
+    use crate::db::Users;
+    use crate::models::AccountStatus;
+    use std::future::Future;
+
+    async fn with_db<Fut>(f: impl FnOnce(Database) -> Fut)
+    where
+        Fut: Future<Output = ()>,
+    {
+        let db_path = tempfile::NamedTempFile::new_in(".").unwrap();
+        crate::db::sqlite::migrator::migrate(db_path.path().to_str().unwrap())
+            .await
+            .unwrap();
+
+        let db = Database::new(db_path.path().to_str().unwrap())
+            .await
+            .unwrap();
+
+        f(db).await;
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn create_and_get_full_user_test() {
+        with_db(|db| async move {
+            let insert_result = db
+                .upsert_user(&User {
+                    username: "myuser".to_string(),
+                    password: Some("abc".to_string()),
+                    account_status: AccountStatus::Registered,
+                    active_room: Some("myroom".to_string()),
+                })
+                .await;
+
+            assert!(insert_result.is_ok());
+
+            let user = db
+                .get_user("myuser")
+                .await
+                .expect("User retrieval query failed");
+
+            assert!(user.is_some());
+            let user = user.unwrap();
+            assert_eq!(user.username, "myuser");
+            assert_eq!(user.password, Some("abc".to_string()));
+            assert_eq!(user.account_status, AccountStatus::Registered);
+            assert_eq!(user.active_room, Some("myroom".to_string()));
+        })
+        .await;
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn can_get_user_with_no_state_record() {
+        with_db(|db| async move {
+            let insert_result = db
+                .upsert_user(&User {
+                    username: "myuser".to_string(),
+                    password: Some("abc".to_string()),
+                    account_status: AccountStatus::AwaitingActivation,
+                    active_room: Some("myroom".to_string()),
+                })
+                .await;
+
+            assert!(insert_result.is_ok());
+
+            sqlx::query("DELETE FROM user_state")
+                .execute(&db.conn)
+                .await
+                .expect("Could not delete from user_state table.");
+
+            let user = db
+                .get_user("myuser")
+                .await
+                .expect("User retrieval query failed");
+
+            assert!(user.is_some());
+            let user = user.unwrap();
+            assert_eq!(user.username, "myuser");
+            assert_eq!(user.password, Some("abc".to_string()));
+            assert_eq!(user.account_status, AccountStatus::AwaitingActivation);
+
+            //These should be default values because the state record is missing.
+            assert_eq!(user.active_room, None);
+        })
+        .await;
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn can_insert_without_password() {
+        with_db(|db| async move {
+            let insert_result = db
+                .upsert_user(&User {
+                    username: "myuser".to_string(),
+                    password: None,
+                    ..Default::default()
+                })
+                .await;
+
+            assert!(insert_result.is_ok());
+
+            let user = db
+                .get_user("myuser")
+                .await
+                .expect("User retrieval query failed");
+
+            assert!(user.is_some());
+            let user = user.unwrap();
+            assert_eq!(user.username, "myuser");
+            assert_eq!(user.password, None);
+        })
+        .await;
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn can_insert_without_active_room() {
+        with_db(|db| async move {
+            let insert_result = db
+                .upsert_user(&User {
+                    username: "myuser".to_string(),
+                    active_room: None,
+                    ..Default::default()
+                })
+                .await;
+
+            assert!(insert_result.is_ok());
+
+            let user = db
+                .get_user("myuser")
+                .await
+                .expect("User retrieval query failed");
+
+            assert!(user.is_some());
+            let user = user.unwrap();
+            assert_eq!(user.username, "myuser");
+            assert_eq!(user.active_room, None);
+        })
+        .await;
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn can_update_user() {
+        with_db(|db| async move {
+            let insert_result1 = db
+                .upsert_user(&User {
+                    username: "myuser".to_string(),
+                    password: Some("abc".to_string()),
+                    ..Default::default()
+                })
+                .await;
+
+            assert!(insert_result1.is_ok());
+
+            let insert_result2 = db
+                .upsert_user(&User {
+                    username: "myuser".to_string(),
+                    password: Some("123".to_string()),
+                    active_room: Some("room".to_string()),
+                    account_status: AccountStatus::AwaitingActivation,
+                })
+                .await;
+
+            assert!(insert_result2.is_ok());
+
+            let user = db
+                .get_user("myuser")
+                .await
+                .expect("User retrieval query failed");
+
+            assert!(user.is_some());
+            let user = user.unwrap();
+            assert_eq!(user.username, "myuser");
+
+            //From second upsert
+            assert_eq!(user.password, Some("123".to_string()));
+            assert_eq!(user.active_room, Some("room".to_string()));
+            assert_eq!(user.account_status, AccountStatus::AwaitingActivation);
+        })
+        .await;
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn can_delete_user() {
+        with_db(|db| async move {
+            let insert_result = db
+                .upsert_user(&User {
+                    username: "myuser".to_string(),
+                    password: Some("abc".to_string()),
+                    ..Default::default()
+                })
+                .await;
+
+            assert!(insert_result.is_ok());
+
+            db.delete_user("myuser")
+                .await
+                .expect("User deletion query failed");
+
+            let user = db
+                .get_user("myuser")
+                .await
+                .expect("User retrieval query failed");
+
+            assert!(user.is_none());
+        })
+        .await;
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn username_not_in_db_returns_none() {
+        with_db(|db| async move {
+            let user = db
+                .get_user("does not exist")
+                .await
+                .expect("Get user query failure");
+
+            assert!(user.is_none());
+        })
+        .await;
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn authenticate_user_is_some_with_valid_password() {
+        with_db(|db| async move {
+            let insert_result = db
+                .upsert_user(&User {
+                    username: "myuser".to_string(),
+                    password: Some(
+                        crate::logic::hash_password("abc").expect("password hash error!"),
+                    ),
+                    ..Default::default()
+                })
+                .await;
+
+            assert!(insert_result.is_ok());
+
+            let user = db
+                .authenticate_user("myuser", "abc")
+                .await
+                .expect("User retrieval query failed");
+
+            assert!(user.is_some());
+            let user = user.unwrap();
+            assert_eq!(user.username, "myuser");
+        })
+        .await;
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn authenticate_user_is_none_with_wrong_password() {
+        with_db(|db| async move {
+            let insert_result = db
+                .upsert_user(&User {
+                    username: "myuser".to_string(),
+                    password: Some(
+                        crate::logic::hash_password("abc").expect("password hash error!"),
+                    ),
+                    ..Default::default()
+                })
+                .await;
+
+            assert!(insert_result.is_ok());
+
+            let user = db
+                .authenticate_user("myuser", "wrong-password")
+                .await
+                .expect("User retrieval query failed");
+
+            assert!(user.is_none());
+        })
+        .await;
+    }
+}

dicebot/src/db/sqlite/variables.rs

@@ -0,0 +1,257 @@
+use super::Database;
+use crate::db::{errors::DataError, Variables};
+use async_trait::async_trait;
+use std::collections::HashMap;
+
+#[async_trait]
+impl Variables for Database {
+    async fn get_user_variables(
+        &self,
+        user: &str,
+        room_id: &str,
+    ) -> Result<HashMap<String, i32>, DataError> {
+        let rows = sqlx::query!(
+            r#"SELECT key, value as "value: i32" FROM user_variables
+               WHERE room_id = ? AND user_id = ?"#,
+            room_id,
+            user
+        )
+        .fetch_all(&self.conn)
+        .await?;
+
+        Ok(rows.into_iter().map(|row| (row.key, row.value)).collect())
+    }
+
+    async fn get_variable_count(&self, user: &str, room_id: &str) -> Result<i32, DataError> {
+        let row = sqlx::query!(
+            r#"SELECT count(*) as "count: i32" FROM user_variables
+               WHERE room_id = ? and user_id = ?"#,
+            room_id,
+            user
+        )
+        .fetch_optional(&self.conn)
+        .await?;
+
+        Ok(row.map(|r| r.count).unwrap_or(0))
+    }
+
+    async fn get_user_variable(
+        &self,
+        user: &str,
+        room_id: &str,
+        variable_name: &str,
+    ) -> Result<i32, DataError> {
+        let row = sqlx::query!(
+            r#"SELECT value as "value: i32" FROM user_variables
+               WHERE user_id = ? AND room_id = ? AND key = ?"#,
+            user,
+            room_id,
+            variable_name
+        )
+        .fetch_optional(&self.conn)
+        .await?;
+
+        row.map(|r| r.value)
+            .ok_or_else(|| DataError::KeyDoesNotExist(variable_name.to_string()))
+    }
+
+    async fn set_user_variable(
+        &self,
+        user: &str,
+        room_id: &str,
+        variable_name: &str,
+        value: i32,
+    ) -> Result<(), DataError> {
+        sqlx::query(
+            "INSERT INTO user_variables
+                    (user_id, room_id, key, value)
+                    values (?, ?, ?, ?)",
+        )
+        .bind(user)
+        .bind(room_id)
+        .bind(variable_name)
+        .bind(value)
+        .execute(&self.conn)
+        .await?;
+
+        Ok(())
+    }
+
+    async fn delete_user_variable(
+        &self,
+        user: &str,
+        room_id: &str,
+        variable_name: &str,
+    ) -> Result<(), DataError> {
+        sqlx::query(
+            "DELETE FROM user_variables
+             WHERE user_id = ? AND room_id = ? AND key = ?",
+        )
+        .bind(user)
+        .bind(room_id)
+        .bind(variable_name)
+        .execute(&self.conn)
+        .await?;
+
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::db::sqlite::Database;
+    use crate::db::Variables;
+    use std::future::Future;
+
+    async fn with_db<Fut>(f: impl FnOnce(Database) -> Fut)
+    where
+        Fut: Future<Output = ()>,
+    {
+        let db_path = tempfile::NamedTempFile::new_in(".").unwrap();
+        crate::db::sqlite::migrator::migrate(db_path.path().to_str().unwrap())
+            .await
+            .unwrap();
+
+        let db = Database::new(db_path.path().to_str().unwrap())
+            .await
+            .unwrap();
+
+        f(db).await;
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn set_and_get_variable_test() {
+        with_db(|db| async move {
+            db.set_user_variable("myuser", "myroom", "myvariable", 1)
+                .await
+                .expect("Could not set variable");
+
+            let value = db
+                .get_user_variable("myuser", "myroom", "myvariable")
+                .await
+                .expect("Could not get variable");
+
+            assert_eq!(value, 1);
+        })
+        .await;
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn get_missing_variable_test() {
+        with_db(|db| async move {
+            let value = db.get_user_variable("myuser", "myroom", "myvariable").await;
+
+            assert!(value.is_err());
+            assert!(matches!(
+                value.err().unwrap(),
+                DataError::KeyDoesNotExist(_)
+            ));
+        })
+        .await;
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn get_other_user_variable_test() {
+        with_db(|db| async move {
+            db.set_user_variable("myuser1", "myroom", "myvariable", 1)
+                .await
+                .expect("Could not set variable");
+
+            let value = db
+                .get_user_variable("myuser2", "myroom", "myvariable")
+                .await;
+
+            assert!(value.is_err());
+            assert!(matches!(
+                value.err().unwrap(),
+                DataError::KeyDoesNotExist(_)
+            ));
+        })
+        .await;
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn count_variables_test() {
+        with_db(|db| async move {
+            for variable_name in &["var1", "var2", "var3"] {
+                db.set_user_variable("myuser", "myroom", variable_name, 1)
+                    .await
+                    .expect("Could not set variable");
+            }
+
+            let count = db
+                .get_variable_count("myuser", "myroom")
+                .await
+                .expect("Could not get count.");
+
+            assert_eq!(count, 3);
+        })
+        .await;
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn count_variables_respects_user_id() {
+        with_db(|db| async move {
+            for variable_name in &["var1", "var2", "var3"] {
+                db.set_user_variable("different-user", "myroom", variable_name, 1)
+                    .await
+                    .expect("Could not set variable");
+            }
+
+            let count = db
+                .get_variable_count("myuser", "myroom")
+                .await
+                .expect("Could not get count.");
+
+            assert_eq!(count, 0);
+        })
+        .await;
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn count_variables_respects_room_id() {
+        with_db(|db| async move {
+            for variable_name in &["var1", "var2", "var3"] {
+                db.set_user_variable("myuser", "different-room", variable_name, 1)
+                    .await
+                    .expect("Could not set variable");
+            }
+
+            let count = db
+                .get_variable_count("myuser", "myroom")
+                .await
+                .expect("Could not get count.");
+
+            assert_eq!(count, 0);
+        })
+        .await;
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn delete_variable_test() {
+        with_db(|db| async move {
+            for variable_name in &["var1", "var2", "var3"] {
+                db.set_user_variable("myuser", "myroom", variable_name, 1)
+                    .await
+                    .expect("Could not set variable");
+            }
+
+            db.delete_user_variable("myuser", "myroom", "var1")
+                .await
+                .expect("Could not delete variable.");
+
+            let count = db
+                .get_variable_count("myuser", "myroom")
+                .await
+                .expect("Could not get count");
+
+            assert_eq!(count, 2);
+
+            let var1 = db.get_user_variable("myuser", "myroom", "var1").await;
+            assert!(var1.is_err());
+            assert!(matches!(var1.err().unwrap(), DataError::KeyDoesNotExist(_)));
+        })
+        .await;
+    }
+}

dicebot/src/error.rs

@@ -0,0 +1,126 @@
+use std::net::AddrParseError;
+
+use crate::commands::CommandError;
+use crate::config::ConfigError;
+use crate::db::errors::DataError;
+use thiserror::Error;
+use tonic::metadata::errors::InvalidMetadataValue;
+
+#[derive(Error, Debug)]
+pub enum BotError {
+    #[error("configuration error: {0}")]
+    ConfigurationError(#[from] ConfigError),
+
+    /// Sync token couldn't be found.
+    #[error("the sync token could not be retrieved")]
+    SyncTokenRequired,
+
+    #[error("could not retrieve device id")]
+    NoDeviceIdFound,
+
+    #[error("could not build client: {0}")]
+    ClientBuildError(#[from] matrix_sdk::ClientBuildError),
+
+    #[error("could not open matrix store: {0}")]
+    OpenStoreError(#[from] matrix_sdk::store::OpenStoreError),
+
+    #[error("command error: {0}")]
+    CommandError(#[from] CommandError),
+
+    #[error("database error: {0}")]
+    DataError(#[from] DataError),
+
+    #[error("the message should not be processed because it failed validation")]
+    ShouldNotProcessError,
+
+    #[error("no cache directory found")]
+    NoCacheDirectoryError,
+
+    #[error("could not parse URL")]
+    UrlParseError(#[from] url::ParseError),
+
+    #[error("could not parse ID")]
+    IdParseError(#[from] matrix_sdk::ruma::IdParseError),
+
+    #[error("error in matrix state store: {0}")]
+    MatrixStateStoreError(#[from] matrix_sdk::StoreError),
+
+    #[error("uncategorized matrix SDK error: {0}")]
+    MatrixError(#[from] matrix_sdk::Error),
+
+    #[error("future canceled")]
+    FutureCanceledError,
+
+    //de = deserialization
+    #[error("toml parsing error")]
+    TomlParsingError(#[from] toml::de::Error),
+
+    #[error("i/o error: {0}")]
+    IoError(#[from] std::io::Error),
+
+    #[error("dice parsing error: {0}")]
+    DiceParsingError(#[from] crate::parser::dice::DiceParsingError),
+
+    #[error("command parsing error: {0}")]
+    CommandParsingError(#[from] crate::commands::parser::CommandParsingError),
+
+    #[error("dice rolling error: {0}")]
+    DiceRollingError(#[from] DiceRollingError),
+
+    #[error("variable parsing error: {0}")]
+    VariableParsingError(#[from] crate::parser::variables::VariableParsingError),
+
+    #[error("legacy parsing error")]
+    NomParserError(nom::error::ErrorKind),
+
+    #[error("legacy parsing error: not enough data")]
+    NomParserIncomplete,
+
+    #[error("variables not yet supported")]
+    VariablesNotSupported,
+
+    #[error("too many commands or message was too large")]
+    MessageTooLarge,
+
+    #[error("could not convert to proper integer type")]
+    TryFromIntError(#[from] std::num::TryFromIntError),
+
+    // #[error("identifier error: {0}")]
+    // IdentifierError(#[from] matrix_sdk::ruma::Error),
+
+    #[error("password creation error: {0}")]
+    PasswordCreationError(argon2::Error),
+
+    #[error("account does not exist, or password incorrect")]
+    AuthenticationError,
+
+    #[error("user account does not exist, try registering")]
+    AccountDoesNotExist,
+
+    #[error("user account already exists")]
+    AccountAlreadyExists,
+
+    #[error("room name or id does not exist")]
+    RoomDoesNotExist,
+
+    #[error("tonic transport error: {0}")]
+    TonicTransportError(#[from] tonic::transport::Error),
+
+    #[error("address parsing error: {0}")]
+    AddressParseError(#[from] AddrParseError),
+
+    #[error("invalid metadata value: {0}")]
+    TonicInvalidMetadata(#[from] InvalidMetadataValue),
+}
+
+#[derive(Error, Debug)]
+pub enum DiceRollingError {
+    #[error("variable not found: {0}")]
+    VariableNotFound(String),
+
+    #[error("invalid amount")]
+    InvalidAmount,
+
+    #[error("dice pool expression too large")]
+    ExpressionTooLarge,
+}

dicebot/src/help.rs

@@ -0,0 +1,156 @@
+use indoc::indoc;
+
+pub fn parse_help_topic(input: &str) -> Option<HelpTopic> {
+    match input {
+        "cofd" => Some(HelpTopic::ChroniclesOfDarkness),
+        "dicepool" => Some(HelpTopic::DicePool),
+        "dice" => Some(HelpTopic::RollingDice),
+        "cthulhu" => Some(HelpTopic::Cthulhu),
+        "variables" => Some(HelpTopic::Variables),
+        "var" => Some(HelpTopic::Variables),
+        "variable" => Some(HelpTopic::Variables),
+        "" => Some(HelpTopic::General),
+        _ => None,
+    }
+}
+
+pub enum HelpTopic {
+    ChroniclesOfDarkness,
+    DicePool,
+    Cthulhu,
+    RollingDice,
+    Variables,
+    General,
+}
+
+const COFD_HELP: &'static str = indoc! {"
+Chronicles of Darkness
+
+Commands available:
+ !pool, !rp: roll a dice pool
+ !chance: roll a chance die
+
+See also:
+ !help dicepool
+"};
+
+const DICE_HELP: &'static str = indoc! {"
+Rolling basic dice
+
+Command: !roll, !r
+
+Syntax !roll <dice-expression>
+
+Dice expression can be a basic die (e.g. 1d4), with a bonus (1d4+3),
+or a more complex series of dice rolls or arbitrary numbers.
+Parentheses are not supported.
+
+Examples:
+ !roll 1d4
+ !roll 1d4+5
+ !roll 2d6+8
+ !roll 2d8 + 4d6 - 3
+"};
+
+const DICEPOOL_HELP: &'static str = indoc! {"
+Rolling dice pools
+
+Command: !pool, !rp
+
+Syntax: !pool <modifiers>:<expression>
+
+Short syntax: !pool <expression>
+
+Expression Syntax: <num|variable> [+/- <expression> ...]
+
+Modifiers:
+ n = nine-again
+ e = eight-again
+ r = rote quality
+ x = do not re-roll 10s
+ s<num> = number of successes for exceptional
+
+Examples:
+ !pool 8 (roll a regular pool of 8 dice)
+ !pool n:5 (roll dice pool of 5, nine-again)
+ !pool rs3:6 (roll dice pool of 6, rote quality, 3 successes for exceptional)
+ !pool 10 + 3 (roll dice pool of 10 + 3, which is 13)
+ !pool myskill - 4 (roll pool of the value of myskill - 4).
+ !pool n:myskill - 5 (roll pool of myskill - 5, with nine-again)
+"};
+
+const CTHULHU_HELP: &'static str = indoc! {"
+Rolling Call of Cthlhu dice
+
+Commands: !cthroll (regular rolls), !cthadv (advancement rolls)
+
+Regular roll syntax: !cthroll <modifiers>:<num|variable>
+
+Advancement roll syntax: !cthadv <num|variable>
+
+Modifiers:
+ b = one bonus die
+ bb = two bonus dice
+ p = one penalty die
+ pp = two penalty dice
+
+Examples:
+  !cthroll 60 (make a roll against a skill of 60)
+  !cthroll spothidden (make a roll against variable spothidden)
+  !cthroll bb:30 (make a roll against skill of 30 with two bonus dice)
+  !cthadv 50 (make an advancement roll against a skill of 50)
+  !cthadv spothidden (make an advancement roll against the number in spothidden)
+
+Note: If !cthadv is given a variable, and the roll is successful, it will
+update the variable with the new skill.
+"};
+
+const VARIABLES_HELP: &'static str = indoc! {"
+Variables
+
+Commands: !get, !set, !variables
+
+Manage variables that can be substituted into roll commands.
+
+Examples: !get myvar, !set myvar 10
+
+!get <variable> = show variable of the given name
+!set <variable> <num> = set a variable to a number
+
+The !variables command will list all variables for the room. The
+variables command cna be used in a secure room to avoid spamming the
+actual room that the variable is set in.
+
+Variable names can be used in all types of dice rolls:
+
+!pool myvar + 3
+!roll myvar
+
+There are some limitations on variables: they cannot themselves be
+dice expressions (i.e. can only be numbers), and they must be uniquely
+parseable in an expression (i.e 'myvard6' does not work for the !roll
+command).
+
+"};
+
+const GENERAL_HELP: &'static str = indoc! {"
+General Help
+
+Try these help commands:
+  !help cofd
+  !help dice
+  !help cthulhu
+"};
+
+impl HelpTopic {
+    pub fn message(&self) -> &str {
+        match self {
+            HelpTopic::ChroniclesOfDarkness => COFD_HELP,
+            HelpTopic::DicePool => DICEPOOL_HELP,
+            HelpTopic::Cthulhu => CTHULHU_HELP,
+            HelpTopic::RollingDice => DICE_HELP,
+            HelpTopic::Variables => VARIABLES_HELP,
+            HelpTopic::General => GENERAL_HELP,
+        }
+    }
+}

dicebot/src/lib.rs

@@ -0,0 +1,17 @@
+pub mod basic;
+pub mod bot;
+pub mod cofd;
+pub mod commands;
+pub mod config;
+pub mod context;
+pub mod cthulhu;
+pub mod db;
+pub mod error;
+mod help;
+pub mod logic;
+pub mod matrix;
+pub mod models;
+mod parser;
+pub mod rpc;
+pub mod state;
+pub mod systems;

dicebot/src/logic.rs

@@ -0,0 +1,131 @@
+use crate::error::{BotError, DiceRollingError};
+use crate::parser::dice::{Amount, Element};
+use crate::{context::Context, models::Account};
+use crate::{
+    db::{sqlite::Database, Users, Variables},
+    models::TransientUser,
+};
+use argon2::{self, Config, Error as ArgonError};
+use futures::stream::{self, StreamExt, TryStreamExt};
+use rand::Rng;
+use std::slice;
+
+/// Calculate the amount of dice to roll by consulting the database
+/// and replacing variables with corresponding the amount. Errors out
+/// if it cannot find a variable defined, or if the database errors.
+pub async fn calculate_single_die_amount(
+    amount: &Amount,
+    ctx: &Context<'_>,
+) -> Result<i32, BotError> {
+    calculate_dice_amount(slice::from_ref(amount), ctx).await
+}
+
+/// Calculate the amount of dice to roll by consulting the database
+/// and replacing variables with corresponding amounts. Errors out if
+/// it cannot find a variable defined, or if the database errors.
+pub async fn calculate_dice_amount(amounts: &[Amount], ctx: &Context<'_>) -> Result<i32, BotError> {
+    let stream = stream::iter(amounts);
+    let variables = &ctx
+        .db
+        .get_user_variables(&ctx.username, ctx.active_room_id().as_str())
+        .await?;
+
+    use DiceRollingError::VariableNotFound;
+    let dice_amount: i32 = stream
+        .then(|amount| async move {
+            match &amount.element {
+                Element::Number(num_dice) => Ok(num_dice * amount.operator.mult()),
+                Element::Variable(variable) => variables
+                    .get(variable)
+                    .ok_or_else(|| VariableNotFound(variable.clone()))
+                    .map(|i| *i),
+            }
+        })
+        .try_fold(0, |total, num_dice| async move { Ok(total + num_dice) })
+        .await?;
+
+    Ok(dice_amount)
+}
+
+/// Hash a password using the argon2 algorithm with a 16 byte salt.
+pub(crate) fn hash_password(raw_password: &str) -> Result<String, ArgonError> {
+    let salt = rand::thread_rng().gen::<[u8; 16]>();
+    let config = Config::default();
+    argon2::hash_encoded(raw_password.as_bytes(), &salt, &config)
+}
+
+pub(crate) async fn get_account(db: &Database, username: &str) -> Result<Account, BotError> {
+    Ok(db
+        .get_user(username)
+        .await?
+        .map(|user| Account::Registered(user))
+        .unwrap_or_else(|| {
+            Account::Transient(TransientUser {
+                username: username.to_owned(),
+            })
+        }))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::db::Users;
+    use crate::models::{AccountStatus, User};
+    use std::future::Future;
+
+    async fn with_db<Fut>(f: impl FnOnce(Database) -> Fut)
+    where
+        Fut: Future<Output = ()>,
+    {
+        let db_path = tempfile::NamedTempFile::new_in(".").unwrap();
+        crate::db::sqlite::migrator::migrate(db_path.path().to_str().unwrap())
+            .await
+            .unwrap();
+
+        let db = Database::new(db_path.path().to_str().unwrap())
+            .await
+            .unwrap();
+
+        f(db).await;
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn get_account_no_user_exists() {
+        with_db(|db| async move {
+            let account = get_account(&db, "@test:example.com")
+                .await
+                .expect("Account retrieval didn't work");
+
+            assert!(matches!(account, Account::Transient(_)));
+
+            let user = account.transient_user().unwrap();
+            assert_eq!(user.username, "@test:example.com");
+        })
+        .await;
+    }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+    async fn get_or_create_user_when_user_exists() {
+        with_db(|db| async move {
+            let user = User {
+                username: "myuser".to_string(),
+                password: Some("abc".to_string()),
+                account_status: AccountStatus::Registered,
+                active_room: Some("myroom".to_string()),
+            };
+
+            let insert_result = db.upsert_user(&user).await;
+            assert!(insert_result.is_ok());
+
+            let account = get_account(&db, "myuser")
+                .await
+                .expect("Account retrieval did not work");
+
+            assert!(matches!(account, Account::Registered(_)));
+
+            let user_again = account.registered_user().unwrap();
+            assert_eq!(user, *user_again);
+        })
+        .await;
+    }
+}

dicebot/src/matrix.rs

@@ -0,0 +1,113 @@
+use std::path::PathBuf;
+
+use futures::stream::{self, StreamExt, TryStreamExt};
+use log::error;
+use matrix_sdk::ruma::events::room::message::{InReplyTo, RoomMessageEventContent, Relation};
+use matrix_sdk::ruma::events::AnyMessageLikeEventContent;
+use matrix_sdk::ruma::{RoomId, OwnedEventId, OwnedUserId};
+use matrix_sdk::Client;
+use matrix_sdk::Error as MatrixError;
+use matrix_sdk::room::Joined;
+use url::Url;
+
+use crate::{config::Config, error::BotError};
+
+fn cache_dir() -> Result<PathBuf, BotError> {
+    let mut dir = dirs::cache_dir().ok_or(BotError::NoCacheDirectoryError)?;
+    dir.push("matrix-dicebot");
+    Ok(dir)
+}
+
+/// Extracts more detailed error messages out of a matrix SDK error.
+fn extract_error_message(error: MatrixError) -> String {
+    use matrix_sdk::{Error::Http, HttpError};
+    if let Http(HttpError::Api(ruma_err)) = error {
+        ruma_err.to_string()
+    } else {
+        error.to_string()
+    }
+}
+
+/// Creates the matrix client.
+pub async fn create_client(config: &Config) -> Result<Client, BotError> {
+    let cache_dir = cache_dir()?;
+    let homeserver_url = Url::parse(&config.matrix_homeserver())?;
+
+    let client = Client::builder()
+        .sled_store(cache_dir, None)?
+        .homeserver_url(homeserver_url).build()
+        .await?;
+
+    Ok(client)
+}
+
+/// Retrieve a list of users in a given room.
+pub async fn get_users_in_room(
+    client: &Client,
+    room_id: &RoomId,
+) -> Result<Vec<String>, MatrixError> {
+    if let Some(joined_room) = client.get_joined_room(room_id) {
+        let members = joined_room.joined_members().await?;
+
+        Ok(members
+            .into_iter()
+            .map(|member| member.user_id().to_string())
+            .collect())
+    } else {
+        Ok(vec![])
+    }
+}
+
+pub async fn get_rooms_for_user(
+    client: &Client,
+    user: &OwnedUserId,
+) -> Result<Vec<Joined>, MatrixError> {
+    // Carries errors through, in case we cannot load joined user IDs
+    // from the room for some reason.
+    let user_is_in_room = |room: Joined| async move {
+        match room.joined_user_ids().await {
+            Ok(users) => match users.contains(user) {
+                true => Some(Ok(room)),
+                false => None,
+            },
+            Err(e) => Some(Err(e)),
+        }
+    };
+
+    let rooms_for_user: Vec<Joined> = stream::iter(client.joined_rooms())
+        .filter_map(user_is_in_room)
+        .try_collect()
+        .await?;
+
+    Ok(rooms_for_user)
+}
+
+/// Send a message. The message is a tuple of HTML and plain text
+/// responses.
+pub async fn send_message(
+    client: &Client,
+    room_id: &RoomId,
+    message: (&str, &str),
+    reply_to: Option<OwnedEventId>,
+) {
+    let (html, plain) = message;
+    let room = match client.get_joined_room(room_id) {
+        Some(room) => room,
+        _ => return,
+    };
+
+    let mut content = RoomMessageEventContent::notice_html(plain.trim(), html);
+
+    content.relates_to = reply_to.map(|event_id| Relation::Reply {
+        in_reply_to: InReplyTo::new(event_id)
+    });
+
+    let content = AnyMessageLikeEventContent::RoomMessage(content);
+
+    let result = room.send(content, None).await;
+
+    if let Err(e) = result {
+        let html = extract_error_message(e);
+        error!("Error sending html: {}", html);
+    };
+}

dicebot/src/models.rs

@@ -0,0 +1,157 @@
+use serde::{Deserialize, Serialize};
+
+/// RoomInfo has basic metadata about a room: its name, ID, etc.
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq)]
+pub struct RoomInfo {
+    pub room_id: String,
+    pub room_name: String,
+}
+
+#[derive(Eq, PartialEq, Clone, Copy, Debug, sqlx::Type)]
+#[sqlx(rename_all = "snake_case")]
+pub enum AccountStatus {
+    /// Account is not registered, which means a transient "account"
+    /// with limited information exists only for the duration of the
+    /// command request.
+    NotRegistered,
+
+    /// User account is fully registered, either via Matrix directly,
+    /// or a web UI sign-up.
+    Registered,
+
+    /// Account is awaiting activation with a registration
+    /// code. Account cannot do privileged actions yet.
+    AwaitingActivation,
+}
+
+impl Default for AccountStatus {
+    fn default() -> Self {
+        AccountStatus::NotRegistered
+    }
+}
+
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub enum Account {
+    /// A registered user account, stored in the database.
+    Registered(User),
+
+    /// A transient account. Not stored in the database. Represents a
+    /// user in a public channel that has not registered directly with
+    /// the bot yet.
+    Transient(TransientUser),
+}
+
+impl Account {
+    /// Whether or not this account is a registered user account.
+    pub fn is_registered(&self) -> bool {
+        matches!(self, Self::Registered(_))
+    }
+
+    /// Gets the account status. For registered users, this is their
+    /// actual account status (fully registered or awaiting
+    /// activation). For transient users, this is
+    /// AccountStatus::NotRegistered.
+    pub fn account_status(&self) -> AccountStatus {
+        match self {
+            Self::Registered(user) => user.account_status,
+            Self::Transient(_) => AccountStatus::NotRegistered,
+        }
+    }
+
+    /// Consume self into an Option<User> instance, which will be Some
+    /// if this account has a registered user, and None otherwise.
+    pub fn registered_user(&self) -> Option<&User> {
+        match self {
+            Self::Registered(ref user) => Some(user),
+            _ => None,
+        }
+    }
+
+    /// Consume self into an Option<TransientUser> instance, which
+    /// will be Some if this account has a non-registered user, and
+    /// None otherwise.
+    pub fn transient_user(self) -> Option<TransientUser> {
+        match self {
+            Self::Transient(user) => Some(user),
+            _ => None,
+        }
+    }
+}
+
+impl Default for Account {
+    fn default() -> Self {
+        Account::Transient(TransientUser {
+            username: "".to_string(),
+        })
+    }
+}
+
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub struct TransientUser {
+    pub username: String,
+}
+
+#[derive(Eq, PartialEq, Clone, Debug, Default, sqlx::FromRow)]
+pub struct User {
+    pub username: String,
+    pub password: Option<String>,
+    pub active_room: Option<String>,
+    pub account_status: AccountStatus,
+}
+
+impl User {
+    /// Create a new unregistered skeleton marker account for a
+    /// username.
+    pub fn unregistered(username: &str) -> User {
+        User {
+            username: username.to_owned(),
+            ..Default::default()
+        }
+    }
+
+    pub fn verify_password(&self, raw_password: &str) -> bool {
+        self.password
+            .as_ref()
+            .and_then(|p| argon2::verify_encoded(p, raw_password.as_bytes()).ok())
+            .unwrap_or(false)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn verify_password_passes_with_correct_password() {
+        let user = User {
+            password: Some(
+                crate::logic::hash_password("mypassword").expect("Password hashing error!"),
+            ),
+            ..Default::default()
+        };
+
+        assert_eq!(user.verify_password("mypassword"), true);
+    }
+
+    #[test]
+    fn verify_password_fails_with_wrong_password() {
+        let user = User {
+            password: Some(
+                crate::logic::hash_password("mypassword").expect("Password hashing error!"),
+            ),
+            ..Default::default()
+        };
+
+        assert_eq!(user.verify_password("wrong-password"), false);
+    }
+
+    #[test]
+    fn verify_password_fails_with_no_password() {
+        let user = User {
+            password: None,
+            ..Default::default()
+        };
+
+        assert_eq!(user.verify_password("wrong-password"), false);
+    }
+}

dicebot/src/parser/dice.rs

@@ -0,0 +1,318 @@
+use combine::error::ParseError;
+use combine::parser::char::{digit, letter, spaces};
+use combine::stream::Stream;
+use combine::{many, many1, one_of, Parser};
+use thiserror::Error;
+
+/// Errors for dice parsing.
+#[derive(Debug, Clone, PartialEq, Copy, Error)]
+pub enum DiceParsingError {
+    #[error("invalid amount")]
+    InvalidAmount,
+
+    #[error("modifiers not specified properly")]
+    InvalidModifiers,
+
+    #[error("extraneous input detected")]
+    UnconsumedInput,
+
+    #[error("{0}")]
+    InternalParseError(#[from] combine::error::StringStreamError),
+
+    #[error("number parsing error (too large?)")]
+    ConversionError,
+
+    #[error("unexpected element in expression")]
+    WrongElementType,
+}
+
+impl From<std::num::ParseIntError> for DiceParsingError {
+    fn from(_: std::num::ParseIntError) -> Self {
+        DiceParsingError::ConversionError
+    }
+}
+
+type ParseResult<T> = Result<T, DiceParsingError>;
+
+/// A parsed operator for a number. Whether to add or remove it from
+/// the total amount of dice rolled.
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
+pub enum Operator {
+    Plus,
+    Minus,
+}
+
+impl Operator {
+    /// Calculate multiplier for how to convert the number. Returns 1
+    /// for positive, and -1 for negative.
+    pub fn mult(&self) -> i32 {
+        match self {
+            Operator::Plus => 1,
+            Operator::Minus => -1,
+        }
+    }
+}
+
+/// One part of the dice amount in an expression. Can be a number or a
+/// variable name.
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub enum Element {
+    /// This element in the expression is a variable, which will be
+    /// resolved to a number by consulting the dtaabase.
+    Variable(String),
+
+    /// This element is a simple number, and will be added or
+    /// subtracted from the total dice amount depending on its
+    /// corresponding Operator.
+    Number(i32),
+}
+
+/// One part of the parsed dice rolling expression. Combines an
+/// operator and an element into one struct. Examples of Amounts would
+/// be "+4" or "- myvariable", which translate to Operator::Plus and
+/// Element::Number(4), and Operator::Minus and
+/// Element::Variable("myvariable"), respectively.
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub struct Amount {
+    pub operator: Operator,
+    pub element: Element,
+}
+
+/// Parser that attempt to convert the text at the start of the dice
+/// parsing into an Amount instance.
+fn first_amount_parser<Input>() -> impl Parser<Input, Output = ParseResult<Amount>>
+where
+    Input: Stream<Token = char>,
+    Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
+{
+    let map_first_amount = |value: String| {
+        if value.chars().all(char::is_numeric) {
+            let num = value.parse::<i32>()?;
+            Ok(Amount {
+                operator: Operator::Plus,
+                element: Element::Number(num),
+            })
+        } else {
+            Ok(Amount {
+                operator: Operator::Plus,
+                element: Element::Variable(value),
+            })
+        }
+    };
+
+    many1(letter())
+        .or(many1(digit()))
+        .skip(spaces().silent()) //Consume any space after first amount
+        .map(map_first_amount)
+}
+
+/// Attempt to convert some text in the middle or end of the dice roll
+/// string into an Amount.
+fn amount_parser<Input>() -> impl Parser<Input, Output = ParseResult<Amount>>
+where
+    Input: Stream<Token = char>,
+    Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
+{
+    let plus_or_minus = one_of("+-".chars());
+    let parse_operator = plus_or_minus.map(|sign: char| match sign {
+        '+' => Operator::Plus,
+        '-' => Operator::Minus,
+        _ => Operator::Plus,
+    });
+
+    // Element must either be a proper i32, or a variable name.
+    let map_element = |value: String| -> ParseResult<Element> {
+        if value.chars().all(char::is_numeric) {
+            let num = value.parse::<i32>()?;
+            Ok(Element::Number(num))
+        } else {
+            Ok(Element::Variable(value))
+        }
+    };
+
+    let parse_element = many1(letter()).or(many1(digit())).map(map_element);
+
+    let element_parser = parse_operator
+        .skip(spaces().silent())
+        .and(parse_element)
+        .skip(spaces().silent());
+
+    let convert_to_amount = |(operator, element_result)| match element_result {
+        Ok(element) => Ok(Amount { operator, element }),
+        Err(e) => Err(e),
+    };
+
+    element_parser.map(convert_to_amount)
+}
+
+/// Parse an expression of numbers and/or variables into elements
+/// coupled with operators, where an operator is "+" or "-", and an
+/// element is either a number or variable name. The first element
+/// should not have an operator, but every one after that should.
+/// Accepts expressions like "8", "10 + variablename", "variablename -
+/// 3", etc. This function is currently common to systems that don't
+/// deal with XdY rolls. Support for that will be added later. Returns
+/// parsed amounts and unconsumed input (e.g. roll modifiers).
+pub fn parse_amounts(input: &str) -> ParseResult<(Vec<Amount>, &str)> {
+    let input = input.trim();
+
+    let remaining_amounts = many(amount_parser()).map(|amounts: Vec<ParseResult<Amount>>| amounts);
+    let mut parser = first_amount_parser().and(remaining_amounts);
+
+    // Collapses first amount + remaining amounts into a single Vec,
+    // while collecting extraneous input.
+    type ParsedAmountExpr = (ParseResult<Amount>, Vec<ParseResult<Amount>>);
+    let (results, rest) = parser
+        .parse(input)
+        .map(|mut results: (ParsedAmountExpr, &str)| {
+            let mut amounts = vec![(results.0).0];
+            amounts.append(&mut (results.0).1);
+            (amounts, results.1)
+        })?;
+
+    // Any ParseResult errors will short-circuit the collect.
+    let results: Vec<Amount> = results.into_iter().collect::<ParseResult<_>>()?;
+    Ok((results, rest))
+}
+
+/// Parse an expression that expects a single number or variable. No
+/// operators are allowed. This function is common to systems that
+/// don't deal with XdY rolls. Currently. this function does not
+/// support parsing negative numbers. Returns the parsed amount and
+/// any unconsumed input (useful for dice roll modifiers).
+pub fn parse_single_amount(input: &str) -> ParseResult<(Amount, &str)> {
+    // TODO add support for negative numbers, as technically they
+    // should be allowed.
+    let input = input.trim();
+    let mut parser = first_amount_parser().map(|amount: ParseResult<Amount>| amount);
+    let (result, rest) = parser.parse(input)?;
+    Ok((result?, rest))
+}
+
+#[cfg(test)]
+mod parse_single_amount_tests {
+    use super::*;
+
+    #[test]
+    fn parse_single_variable_test() {
+        let result = parse_single_amount("abc");
+        assert!(result.is_ok());
+        assert_eq!(
+            result.unwrap(),
+            (
+                Amount {
+                    operator: Operator::Plus,
+                    element: Element::Variable("abc".to_string())
+                },
+                ""
+            )
+        )
+    }
+
+    // TODO add support for negative numbers in parse_single_amount
+    // #[test]
+    // fn parse_single_negative_number_test() {
+    //     let result = parse_single_amount("-1");
+    //     assert!(result.is_ok());
+    //     assert_eq!(
+    //         result.unwrap(),
+    //         Amount {
+    //             operator: Operator::Minus,
+    //             element: Element::Number(1)
+    //         }
+    //     )
+    // }
+
+    #[test]
+    fn parse_single_number_test() {
+        let result = parse_single_amount("1");
+        assert!(result.is_ok());
+        assert_eq!(
+            result.unwrap(),
+            (
+                Amount {
+                    operator: Operator::Plus,
+                    element: Element::Number(1)
+                },
+                ""
+            )
+        )
+    }
+}
+
+#[cfg(test)]
+mod parse_many_amounts_tests {
+    use super::*;
+
+    #[test]
+    fn parse_single_number_amount_test() {
+        let result = parse_amounts("1");
+        assert!(result.is_ok());
+        assert_eq!(
+            result.unwrap(),
+            (
+                vec![Amount {
+                    operator: Operator::Plus,
+                    element: Element::Number(1)
+                }],
+                ""
+            )
+        );
+
+        let result = parse_amounts("10");
+        assert!(result.is_ok());
+        assert_eq!(
+            result.unwrap(),
+            (
+                vec![Amount {
+                    operator: Operator::Plus,
+                    element: Element::Number(10)
+                }],
+                ""
+            )
+        );
+    }
+
+    #[test]
+    fn parsing_huge_number_should_error() {
+        // A number outside the bounds of i32 should not be a valid
+        // parse.
+        let result = parse_amounts("159875294375198734982379875392");
+        assert!(result.is_err());
+        assert!(result.unwrap_err() == DiceParsingError::ConversionError);
+    }
+
+    #[test]
+    fn parse_single_variable_amount_test() {
+        let result = parse_amounts("asdf");
+        assert!(result.is_ok());
+        assert_eq!(
+            result.unwrap(),
+            (
+                vec![Amount {
+                    operator: Operator::Plus,
+                    element: Element::Variable("asdf".to_string())
+                }],
+                ""
+            )
+        );
+
+        let result = parse_amounts("nosis");
+        assert!(result.is_ok());
+        assert_eq!(
+            result.unwrap(),
+            (
+                vec![Amount {
+                    operator: Operator::Plus,
+                    element: Element::Variable("nosis".to_string())
+                }],
+                ""
+            )
+        );
+    }
+
+    #[test]
+    fn parse_complex_amount_expression() {
+        assert!(parse_amounts("1 + myvariable - 2").is_ok());
+    }
+}

dicebot/src/parser/mod.rs

@@ -0,0 +1,2 @@
+pub mod dice;
+pub mod variables;

dicebot/src/parser/variables.rs

@@ -0,0 +1,70 @@
+use combine::parser::char::{char, digit, letter, spaces};
+use combine::{many1, optional, Parser};
+use thiserror::Error;
+
+enum ParsedValue {
+    Valid(i32),
+    Invalid,
+}
+
+#[derive(Error, Debug)]
+pub enum VariableParsingError {
+    #[error("invalid variable value, must be a number")]
+    InvalidValue,
+
+    #[error("unconsumed input")]
+    UnconsumedInput,
+
+    #[error("parser error: {0}")]
+    InternalParseError(#[from] combine::error::StringStreamError),
+}
+
+pub fn parse_set_variable(input: &str) -> Result<(String, i32), VariableParsingError> {
+    let name = many1(letter()).map(|value: String| value);
+
+    let maybe_minus = optional(char('-')).map(|value: Option<char>| match value {
+        Some(minus_sign) => String::from(minus_sign),
+        _ => "".to_owned(),
+    });
+
+    let value = maybe_minus
+        .and(many1(digit()))
+        .map(|value: (String, String)| {
+            let number = format!("{}{}", value.0, value.1);
+            match number.parse::<i32>() {
+                Ok(num) => ParsedValue::Valid(num),
+                _ => ParsedValue::Invalid,
+            }
+        });
+
+    let mut parser = name.skip(spaces().silent()).and(value);
+    let (result, rest) = parser.parse(input)?;
+
+    if rest.len() == 0 {
+        match result {
+            (variable_name, ParsedValue::Valid(value)) => Ok((variable_name, value)),
+            _ => Err(VariableParsingError::InvalidValue),
+        }
+    } else {
+        Err(VariableParsingError::UnconsumedInput)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn parse_postive_number() {
+        let result = parse_set_variable("myvar 5");
+        assert!(result.is_ok());
+        assert_eq!(("myvar".to_string(), 5), result.unwrap());
+    }
+
+    #[test]
+    fn parse_negative_number() {
+        let result = parse_set_variable("myvar -5");
+        assert!(result.is_ok());
+        assert_eq!(("myvar".to_string(), -5), result.unwrap());
+    }
+}

dicebot/src/rpc/mod.rs

@@ -0,0 +1,50 @@
+use crate::error::BotError;
+use crate::{config::Config, db::sqlite::Database};
+use log::{info, warn};
+use matrix_sdk::Client;
+use service::DicebotRpcService;
+use std::sync::Arc;
+use tenebrous_rpc::protos::dicebot::dicebot_server::DicebotServer;
+use tonic::{metadata::MetadataValue, transport::Server, Request, Status};
+
+pub(crate) mod service;
+
+pub async fn serve_grpc(
+    config: &Arc<Config>,
+    db: &Database,
+    client: &Client,
+) -> Result<(), BotError> {
+    match config.rpc_addr().zip(config.rpc_key()) {
+        Some((addr, rpc_key)) => {
+            let expected_bearer = MetadataValue::from_str(&format!("Bearer {}", rpc_key))?;
+            let addr = addr.parse()?;
+
+            let rpc_service = DicebotRpcService {
+                db: db.clone(),
+                config: config.clone(),
+                client: client.clone(),
+            };
+
+            info!("Serving Dicebot gRPC service on {}", addr);
+
+            let interceptor = move |req: Request<()>| match req.metadata().get("authorization") {
+                Some(bearer) if bearer == expected_bearer => Ok(req),
+                _ => Err(Status::unauthenticated("No valid auth token")),
+            };
+
+            let server = DicebotServer::with_interceptor(rpc_service, interceptor);
+
+            Server::builder()
+                .add_service(server)
+                .serve(addr)
+                .await
+                .map_err(|e| e.into())
+        }
+        _ => noop().await,
+    }
+}
+
+pub async fn noop() -> Result<(), BotError> {
+    warn!("RPC address or shared secret not specified. Not enabling gRPC.");
+    Ok(())
+}

dicebot/src/rpc/service.rs

@@ -0,0 +1,117 @@
+use crate::db::{errors::DataError, Variables};
+use crate::error::BotError;
+use crate::matrix;
+use crate::{config::Config, db::sqlite::Database};
+use futures::stream;
+use futures::{StreamExt, TryFutureExt, TryStreamExt};
+use matrix_sdk::ruma::OwnedUserId;
+use matrix_sdk::{room::Joined, Client};
+use std::convert::TryFrom;
+use std::sync::Arc;
+use tenebrous_rpc::protos::dicebot::{
+    dicebot_server::Dicebot, rooms_list_reply::Room, GetAllVariablesReply, GetAllVariablesRequest,
+    RoomsListReply, SetVariableReply, SetVariableRequest, UserIdRequest,
+};
+use tenebrous_rpc::protos::dicebot::{GetVariableReply, GetVariableRequest};
+use tonic::{Code, Request, Response, Status};
+
+impl From<BotError> for Status {
+    fn from(error: BotError) -> Status {
+        Status::new(Code::Internal, error.to_string())
+    }
+}
+
+impl From<DataError> for Status {
+    fn from(error: DataError) -> Status {
+        Status::new(Code::Internal, error.to_string())
+    }
+}
+
+#[derive(Clone)]
+pub(super) struct DicebotRpcService {
+    pub(super) config: Arc<Config>,
+    pub(super) db: Database,
+    pub(super) client: Client,
+}
+
+#[tonic::async_trait]
+impl Dicebot for DicebotRpcService {
+    async fn set_variable(
+        &self,
+        request: Request<SetVariableRequest>,
+    ) -> Result<Response<SetVariableReply>, Status> {
+        let SetVariableRequest {
+            user_id,
+            room_id,
+            variable_name,
+            value,
+        } = request.into_inner();
+
+        self.db
+            .set_user_variable(&user_id, &room_id, &variable_name, value)
+            .await?;
+
+        Ok(Response::new(SetVariableReply { success: true }))
+    }
+
+    async fn get_variable(
+        &self,
+        request: Request<GetVariableRequest>,
+    ) -> Result<Response<GetVariableReply>, Status> {
+        let request = request.into_inner();
+        let value = self
+            .db
+            .get_user_variable(&request.user_id, &request.room_id, &request.variable_name)
+            .await?;
+
+        Ok(Response::new(GetVariableReply { value }))
+    }
+
+    async fn get_all_variables(
+        &self,
+        request: Request<GetAllVariablesRequest>,
+    ) -> Result<Response<GetAllVariablesReply>, Status> {
+        let request = request.into_inner();
+        let variables = self
+            .db
+            .get_user_variables(&request.user_id, &request.room_id)
+            .await?;
+
+        Ok(Response::new(GetAllVariablesReply { variables }))
+    }
+
+    async fn rooms_for_user(
+        &self,
+        request: Request<UserIdRequest>,
+    ) -> Result<Response<RoomsListReply>, Status> {
+        let UserIdRequest { user_id } = request.into_inner();
+        let user_id = OwnedUserId::try_from(user_id).map_err(BotError::from)?;
+
+        let rooms_for_user = matrix::get_rooms_for_user(&self.client, &user_id)
+            .err_into::<BotError>()
+            .await?;
+
+        let mut rooms: Vec<Room> = stream::iter(rooms_for_user)
+            .filter_map(|room: Joined| async move {
+                let room: Result<Room, _> = room.display_name().await.map(|room_name| Room {
+                    room_id: room.room_id().to_string(),
+                    display_name: room_name.to_string(),
+                });
+
+                Some(room)
+            })
+            .err_into::<BotError>()
+            .try_collect()
+            .await?;
+
+        let sort = |r1: &Room, r2: &Room| {
+            r1.display_name
+                .to_lowercase()
+                .cmp(&r2.display_name.to_lowercase())
+        };
+
+        rooms.sort_by(sort);
+
+        Ok(Response::new(RoomsListReply { rooms }))
+    }
+}

dicebot/src/state.rs

@@ -0,0 +1,36 @@
+use crate::config::*;
+use log::info;
+use std::sync::Arc;
+
+/// Holds state of the dice bot, for anything requiring mutable
+/// transitions. This is a simple mutable trait whose values represent
+/// the current state of the dicebot. It provides mutable methods to
+/// change state.
+pub struct DiceBotState {
+    logged_skipped_old_messages: bool,
+    _config: Arc<Config>,
+}
+
+impl DiceBotState {
+    /// Create initial dice bot state.
+    pub fn new(config: &Arc<Config>) -> DiceBotState {
+        DiceBotState {
+            logged_skipped_old_messages: false,
+            _config: config.clone(),
+        }
+    }
+
+    pub fn logged_skipped_old_messages(&self) -> bool {
+        self.logged_skipped_old_messages
+    }
+
+    /// Log and record that we have skipped some old messages. This
+    /// method will log once, and then no-op from that point on.
+    pub fn skipped_old_messages(&mut self) {
+        if !self.logged_skipped_old_messages {
+            info!("Skipped some messages received while offline because they are too old.");
+        }
+
+        self.logged_skipped_old_messages = true;
+    }
+}

dicebot/src/systems/mod.rs

@@ -0,0 +1,21 @@
+use strum::{AsRefStr, Display, EnumIter, EnumString};
+
+#[derive(EnumString, EnumIter, AsRefStr, Display)]
+pub(crate) enum GameSystem {
+    ChroniclesOfDarkness,
+    Changeling,
+    MageTheAwakening,
+    WerewolfTheForsaken,
+    DeviantTheRenegades,
+    MummyTheCurse,
+    PrometheanTheCreated,
+    CallOfCthulhu,
+    DungeonsAndDragons5e,
+    DungeonsAndDragons4e,
+    DungeonsAndDragons35e,
+    DungeonsAndDragons2e,
+    DungeonsAndDragons1e,
+    None,
+}
+
+impl GameSystem {}

rpc/Cargo.toml

@@ -0,0 +1,18 @@
+[package]
+name = "tenebrous-rpc"
+version = "0.1.0"
+authors = ["projectmoon <projectmoon@agnos.is>"]
+edition = "2018"
+description = "gRPC protobuf models for Tenebrous."
+homepage = "https://git.agnos.is/projectmoon/tenebrous-dicebot"
+repository = "https://git.agnos.is/projectmoon/tenebrous-dicebot"
+license = "AGPL-3.0-or-later"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[build-dependencies]
+tonic-build = "0.4"
+
+[dependencies]
+tonic = "0.4"
+prost = "0.7"

rpc/build.rs

@@ -0,0 +1,4 @@
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    tonic_build::compile_protos("protos/dicebot.proto")?;
+    Ok(())
+}

rpc/protos/dicebot.proto

@@ -0,0 +1,52 @@
+syntax = "proto3";
+package dicebot;
+
+service Dicebot {
+  rpc GetVariable(GetVariableRequest) returns (GetVariableReply);
+  rpc GetAllVariables(GetAllVariablesRequest) returns (GetAllVariablesReply);
+  rpc SetVariable(SetVariableRequest) returns (SetVariableReply);
+  rpc RoomsForUser(UserIdRequest) returns (RoomsListReply);
+}
+
+message GetVariableRequest {
+  string user_id = 1;
+  string room_id = 2;
+  string variable_name = 3;
+}
+
+message GetVariableReply {
+  int32 value = 1;
+}
+
+message GetAllVariablesRequest {
+  string user_id = 1;
+  string room_id = 2;
+}
+
+message GetAllVariablesReply {
+  map<string, int32> variables = 1;
+}
+
+message SetVariableRequest {
+  string user_id = 1;
+  string room_id = 2;
+  string variable_name = 3;
+  int32 value = 4;
+}
+
+message SetVariableReply {
+  bool success = 1;
+}
+
+message UserIdRequest {
+  string user_id = 1;
+}
+
+message RoomsListReply {
+  message Room {
+    string room_id = 1;
+    string display_name = 2;
+  }
+
+  repeated Room rooms = 1;
+}

rpc/src/lib.rs

@@ -0,0 +1,5 @@
+pub mod protos {
+    pub mod dicebot {
+        tonic::include_proto!("dicebot");
+    }
+}

src/bin/dicebot-cmd.rs

@@ -1,12 +0,0 @@
-use chronicle_dicebot::commands::parse_command;
-
-fn main() -> Result<(), String> {
-    let command = std::env::args().skip(1).collect::<Vec<String>>().join(" ");
-    let command = match parse_command(&command) {
-        Ok(Some(command)) => command,
-        Ok(None) => return Err("Command not recognized".into()),
-        Err(e) => return Err(format!("Error parsing command: {}", e)),
-    };
-    println!("{}", command.execute().plain());
-    Ok(())
-}

src/bin/dicebot.rs

@@ -1,27 +0,0 @@
-use chronicle_dicebot::bot::run_bot;
-use chronicle_dicebot::bot::Config;
-use std::fs;
-use std::path::PathBuf;
-
-fn read_config<P: Into<PathBuf>>(config_path: P) -> Result<Config, Box<dyn std::error::Error>> {
-    let config_path = config_path.into();
-    let config = {
-        let contents = fs::read_to_string(&config_path)?;
-        toml::from_str(&contents)?
-    };
-
-    Ok(config)
-}
-
-#[tokio::main]
-async fn main() -> Result<(), Box<dyn std::error::Error>> {
-    let config_path = std::env::args()
-        .skip(1)
-        .next()
-        .expect("Need a config as an argument");
-
-    let cfg = read_config(config_path)?;
-
-    run_bot(cfg.matrix).await?;
-    Ok(())
-}

src/bot.rs

@@ -1,183 +0,0 @@
-use crate::commands::parse_command;
-use dirs;
-use matrix_sdk::{
-    self,
-    events::{
-        room::member::MemberEventContent,
-        room::message::{MessageEventContent, NoticeMessageEventContent, TextMessageEventContent},
-        AnyMessageEventContent, StrippedStateEvent, SyncMessageEvent,
-    },
-    Client, ClientConfig, EventEmitter, JsonStore, SyncRoom, SyncSettings,
-};
-use matrix_sdk_common_macros::async_trait;
-use serde::{self, Deserialize, Serialize};
-use thiserror::Error;
-use url::Url;
-
-//TODO move the config structs and read_config into their own file.
-
-/// The "matrix" section of the config, which gives home server, login information, and etc.
-#[derive(Serialize, Deserialize, Debug)]
-pub struct MatrixConfig {
-    /// Your homeserver of choice, as an FQDN without scheme or path
-    pub home_server: String,
-
-    /// Username to login as. Only the localpart.
-    pub username: String,
-
-    /// Bot account password.
-    pub password: String,
-}
-
-/// Represents the toml config file for the dicebot.
-#[derive(Serialize, Deserialize, Debug)]
-pub struct Config {
-    pub matrix: MatrixConfig,
-}
-
-/// The DiceBot struct itself is the core of the program, essentially the entrypoint
-/// to the bot.
-pub struct DiceBot {
-    client: Client,
-}
-
-impl DiceBot {
-    /// Create a new dicebot with the given Matrix client.
-    pub fn new(client: Client) -> Self {
-        DiceBot { client }
-    }
-}
-
-/// This event emitter listens for messages with dice rolling commands.
-/// Originally adapted from the matrix-rust-sdk  examples.
-#[async_trait]
-impl EventEmitter for DiceBot {
-    async fn on_stripped_state_member(
-        &self,
-        room: SyncRoom,
-        room_member: &StrippedStateEvent<MemberEventContent>,
-        _: Option<MemberEventContent>,
-    ) {
-        if let SyncRoom::Invited(room) = room {
-            if let Some(user_id) = self.client.user_id().await {
-                if room_member.state_key != user_id {
-                    return;
-                }
-            }
-
-            let room = room.read().await;
-            println!("Autojoining room {}", room.display_name());
-
-            match self.client.join_room_by_id(&room.room_id).await {
-                Err(e) => println!("Could not join room: {}", e.to_string()),
-                _ => (),
-            }
-        }
-    }
-
-    async fn on_room_message(&self, room: SyncRoom, event: &SyncMessageEvent<MessageEventContent>) {
-        if let SyncRoom::Joined(room) = room {
-            let (msg_body, sender_username) = if let SyncMessageEvent {
-                content: MessageEventContent::Text(TextMessageEventContent { body, .. }),
-                sender,
-                ..
-            } = event
-            {
-                (
-                    body.clone(),
-                    format!("@{}:{}", sender.localpart(), sender.server_name()),
-                )
-            } else {
-                (String::new(), String::new())
-            };
-
-            let (plain, html) = match parse_command(&msg_body) {
-                Ok(Some(command)) => {
-                    let command = command.execute();
-                    (command.plain().into(), command.html().into())
-                }
-                Ok(None) => return,
-                Err(e) => {
-                    let message = format!("Error parsing command: {}", e);
-                    let html_message = format!("<p><strong>{}</strong></p>", message);
-                    (message, html_message)
-                }
-            };
-
-            let plain = format!("{}\n{}", sender_username, plain);
-            let html = format!("<p>{}</p>\n{}", sender_username, html);
-            let content = AnyMessageEventContent::RoomMessage(MessageEventContent::Notice(
-                NoticeMessageEventContent::html(plain, html),
-            ));
-
-            //we clone here to hold the lock for as little time as possible.
-            let room_id = room.read().await.room_id.clone();
-            let result = self.client.room_send(&room_id, content, None).await;
-
-            match result {
-                Err(e) => println!("Error sending message: {}", e.to_string()),
-                Ok(_) => (),
-            }
-        }
-    }
-}
-
-#[derive(Error, Debug)]
-pub enum BotError {
-    /// Sync token couldn't be found.
-    #[error("the sync token could not be retrieved")]
-    SyncTokenRequired,
-}
-
-/// Run the matrix dice bot until program terminated, or a panic occurs.
-/// Originally adapted from the matrix-rust-sdk command bot example.
-pub async fn run_bot(config: MatrixConfig) -> Result<(), Box<dyn std::error::Error>> {
-    let homeserver_url = config.home_server;
-    let username = config.username;
-    let password = config.password;
-
-    let mut cache_dir = dirs::cache_dir().expect("no cache directory found");
-    cache_dir.push("matrix-dicebot");
-
-    //If the local json store has not been created yet, we need to do a single initial sync.
-    //It stores data under username's localpart.
-    let should_sync = {
-        let mut cache = cache_dir.clone();
-        cache.push(username.clone());
-        !cache.exists()
-    };
-
-    let store = JsonStore::open(&cache_dir)?;
-    let client_config = ClientConfig::new().state_store(Box::new(store));
-
-    let homeserver_url = Url::parse(&homeserver_url).expect("Couldn't parse the homeserver URL");
-    let mut client = Client::new_with_config(homeserver_url, client_config).unwrap();
-
-    client
-        .login(&username, &password, None, Some("matrix dice bot"))
-        .await?;
-
-    println!("Logged in as {}", username);
-
-    if should_sync {
-        println!("Performing initial sync");
-        client.sync(SyncSettings::default()).await?;
-    }
-
-    //Attach event handler.
-    client
-        .add_event_emitter(Box::new(DiceBot::new(client.clone())))
-        .await;
-
-    let token = client
-        .sync_token()
-        .await
-        .ok_or(BotError::SyncTokenRequired)?;
-    let settings = SyncSettings::default().token(token);
-
-    //this keeps state from the server streaming in to the dice bot via the EventEmitter trait
-    println!("Listening for commands");
-    client.sync_forever(settings, |_| async {}).await;
-
-    Ok(())
-}

src/cofd.rs

@@ -1,360 +0,0 @@
-use crate::roll::{Roll, Rolled};
-use itertools::Itertools;
-use std::convert::TryFrom;
-use std::fmt;
-
-pub mod parser;
-
-#[derive(Debug, PartialEq, Eq, Clone, Copy)]
-pub enum DicePoolQuality {
-    TenAgain,
-    NineAgain,
-    EightAgain,
-    Rote,
-    ChanceDie,
-}
-
-impl fmt::Display for DicePoolQuality {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        match self {
-            DicePoolQuality::TenAgain => write!(f, "ten-again"),
-            DicePoolQuality::NineAgain => write!(f, "nine-again"),
-            DicePoolQuality::EightAgain => write!(f, "eight-again"),
-            DicePoolQuality::Rote => write!(f, "rote quality"),
-            DicePoolQuality::ChanceDie => write!(f, "chance die"),
-        }
-    }
-}
-
-#[derive(Debug, PartialEq, Eq, Clone)]
-pub struct DicePool {
-    pub(crate) count: u32,
-    pub(crate) sides: u32,
-    pub(crate) success_on: u32,
-    pub(crate) exceptional_success: u32,
-    pub(crate) quality: DicePoolQuality,
-}
-
-impl fmt::Display for DicePool {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(
-            f,
-            "{} dice ({}, exceptional on {} successes)",
-            self.count, self.quality, self.exceptional_success
-        )
-    }
-}
-
-impl DicePool {
-    fn new(count: u32, successes_for_exceptional: u32, quality: DicePoolQuality) -> DicePool {
-        DicePool {
-            count: count,
-            sides: 10,     //TODO make configurable
-            success_on: 8, //TODO make configurable
-            exceptional_success: successes_for_exceptional,
-            quality: quality,
-        }
-    }
-
-    pub fn chance_die() -> DicePool {
-        DicePool {
-            count: 1,
-            sides: 10,
-            success_on: 10,
-            exceptional_success: 5,
-            quality: DicePoolQuality::ChanceDie,
-        }
-    }
-}
-
-///Store all rolls of the dice pool dice into one struct.
-#[derive(Debug, PartialEq, Eq, Clone)]
-pub struct DicePoolRoll {
-    quality: DicePoolQuality,
-    success_on: u32,
-    exceptional_on: u32,
-    rolls: Vec<u32>,
-}
-
-fn fmt_for_failure(pool: &DicePoolRoll) -> String {
-    match pool.quality {
-        //There should only be 1 die in a chance die roll.
-        DicePoolQuality::ChanceDie if pool.rolls().first() == Some(&1) => {
-            String::from("dramatic failure!")
-        }
-        _ => String::from("failure!"),
-    }
-}
-
-impl DicePoolRoll {
-    pub fn rolls(&self) -> &[u32] {
-        &self.rolls
-    }
-
-    pub fn successes(&self) -> i32 {
-        let successes = self
-            .rolls
-            .iter()
-            .cloned()
-            .filter(|&roll| roll >= self.success_on)
-            .count();
-        i32::try_from(successes).unwrap_or(0)
-    }
-
-    pub fn is_exceptional(&self) -> bool {
-        self.successes() >= (self.exceptional_on as i32)
-    }
-}
-
-impl Roll for DicePool {
-    type Output = DicePoolRoll;
-
-    fn roll(&self) -> DicePoolRoll {
-        roll_dice(self)
-    }
-}
-
-impl Rolled for DicePoolRoll {
-    fn rolled_value(&self) -> i32 {
-        self.successes()
-    }
-}
-
-impl fmt::Display for DicePoolRoll {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        let successes = self.successes();
-        if successes > 0 {
-            let success_msg = if self.is_exceptional() {
-                format!("{} successes (exceptional!)", successes)
-            } else {
-                format!("{} successes", successes)
-            };
-
-            write!(f, "{} ({})", success_msg, self.rolls().iter().join(", "))?;
-        } else {
-            write!(
-                f,
-                "{} ({})",
-                fmt_for_failure(&self),
-                self.rolls().iter().join(", ")
-            )?;
-        }
-
-        Ok(())
-    }
-}
-
-trait DieRoller {
-    fn roll_number(&mut self, sides: u32) -> u32;
-}
-
-///A version of DieRoller that uses a rand::Rng to roll numbers.
-struct RngDieRoller<R: rand::Rng>(R);
-
-impl<R: rand::Rng> DieRoller for RngDieRoller<R> {
-    fn roll_number(&mut self, sides: u32) -> u32 {
-        self.0.gen_range(1, sides + 1)
-    }
-}
-
-///Roll a die in the pool, that "explodes" on a given number or higher. Dice will keep
-///being rolled until the result is lower than the explode number, which is normally 10.
-///Statistically speaking, usually one result will be returned from this function.
-fn roll_exploding_die<R: DieRoller>(
-    roller: &mut R,
-    sides: u32,
-    explode_on_or_higher: u32,
-) -> Vec<u32> {
-    let mut results = vec![];
-    loop {
-        let roll = roller.roll_number(sides);
-        results.push(roll);
-        if roll < explode_on_or_higher {
-            break;
-        }
-    }
-    results
-}
-
-///A die with the rote quality is re-rolled once if the roll fails. Otherwise, it obeys
-///all normal rules (re-roll 10s). Re-rolled dice are appended to the result set, so we
-///can keep track of the actual dice that were rolled.
-fn roll_rote_die<R: DieRoller>(roller: &mut R, sides: u32) -> Vec<u32> {
-    let mut rolls = roll_exploding_die(roller, sides, 10);
-    if rolls.len() == 1 && rolls[0] < 8 {
-        rolls.append(&mut roll_exploding_die(roller, sides, 10));
-    }
-
-    rolls
-}
-
-///Roll a single die in the pool, potentially rolling additional dice depending on  pool
-///behavior. The default ten-again will "explode" the die if the result is 10 (repeatedly, if
-///there are multiple 10s). Nine- and eight-again will explode similarly if the result is
-///at least that number. Rote quality will re-roll a failure once, while also exploding
-///on 10. The function returns a Vec of all rolled dice (usually 1).
-fn roll_die<R: DieRoller>(roller: &mut R, sides: u32, quality: DicePoolQuality) -> Vec<u32> {
-    let mut results = vec![];
-    match quality {
-        DicePoolQuality::TenAgain => results.append(&mut roll_exploding_die(roller, sides, 10)),
-        DicePoolQuality::NineAgain => results.append(&mut roll_exploding_die(roller, sides, 9)),
-        DicePoolQuality::EightAgain => results.append(&mut roll_exploding_die(roller, sides, 8)),
-        DicePoolQuality::Rote => results.append(&mut roll_rote_die(roller, sides)),
-        DicePoolQuality::ChanceDie => results.push(roller.roll_number(sides)),
-    }
-
-    results
-}
-
-///Roll the dice in a dice pool, according to behavior documented in the various rolling
-///methods.
-fn roll_dice(pool: &DicePool) -> DicePoolRoll {
-    let mut roller = RngDieRoller(rand::thread_rng());
-
-    let rolls: Vec<u32> = (0..pool.count)
-        .flat_map(|_| roll_die(&mut roller, pool.sides, pool.quality))
-        .collect();
-
-    DicePoolRoll {
-        quality: pool.quality,
-        rolls: rolls,
-        exceptional_on: pool.exceptional_success,
-        success_on: pool.success_on,
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    ///Instead of being random, generate a series of numbers we have complete
-    ///control over.
-    struct SequentialDieRoller {
-        results: Vec<u32>,
-        position: usize,
-    }
-
-    impl SequentialDieRoller {
-        fn new(results: Vec<u32>) -> SequentialDieRoller {
-            SequentialDieRoller {
-                results: results,
-                position: 0,
-            }
-        }
-    }
-
-    impl DieRoller for SequentialDieRoller {
-        fn roll_number(&mut self, _sides: u32) -> u32 {
-            let roll = self.results[self.position];
-            self.position += 1;
-            roll
-        }
-    }
-
-    //Dice rolling tests.
-    #[test]
-    pub fn ten_again_test() {
-        let mut roller = SequentialDieRoller::new(vec![10, 8, 1]);
-        let rolls = roll_exploding_die(&mut roller, 10, 10);
-        assert_eq!(vec![10, 8], rolls);
-    }
-
-    #[test]
-    pub fn nine_again_test() {
-        let mut roller = SequentialDieRoller::new(vec![10, 9, 8, 1]);
-        let rolls = roll_exploding_die(&mut roller, 10, 9);
-        assert_eq!(vec![10, 9, 8], rolls);
-    }
-
-    #[test]
-    pub fn eight_again_test() {
-        let mut roller = SequentialDieRoller::new(vec![10, 9, 8, 8, 1]);
-        let rolls = roll_exploding_die(&mut roller, 10, 8);
-        assert_eq!(vec![10, 9, 8, 8, 1], rolls);
-    }
-
-    #[test]
-    pub fn rote_quality_fail_then_succeed_test() {
-        let mut roller = SequentialDieRoller::new(vec![5, 8, 1]);
-        let rolls = roll_rote_die(&mut roller, 10);
-        assert_eq!(vec![5, 8], rolls);
-    }
-
-    #[test]
-    pub fn rote_quality_fail_twice_test() {
-        let mut roller = SequentialDieRoller::new(vec![5, 6, 10]);
-        let rolls = roll_rote_die(&mut roller, 10);
-        assert_eq!(vec![5, 6], rolls);
-    }
-
-    #[test]
-    pub fn rote_quality_fail_then_explode_test() {
-        let mut roller = SequentialDieRoller::new(vec![5, 10, 8, 1]);
-        let rolls = roll_rote_die(&mut roller, 10);
-        assert_eq!(vec![5, 10, 8], rolls);
-    }
-
-    //DiceRoll tests
-    #[test]
-    fn is_successful_on_equal_test() {
-        let result = DicePoolRoll {
-            quality: DicePoolQuality::TenAgain,
-            rolls: vec![8],
-            exceptional_on: 5,
-            success_on: 8,
-        };
-
-        assert_eq!(1, result.successes());
-    }
-
-    #[test]
-    fn is_exceptional_test() {
-        let result = DicePoolRoll {
-            quality: DicePoolQuality::TenAgain,
-            rolls: vec![8, 8, 9, 10, 8],
-            exceptional_on: 5,
-            success_on: 8,
-        };
-
-        assert_eq!(5, result.successes());
-        assert_eq!(true, result.is_exceptional());
-    }
-
-    #[test]
-    fn is_not_exceptional_test() {
-        let result = DicePoolRoll {
-            quality: DicePoolQuality::TenAgain,
-            rolls: vec![8, 8, 9, 10],
-            exceptional_on: 5,
-            success_on: 8,
-        };
-
-        assert_eq!(4, result.successes());
-        assert_eq!(false, result.is_exceptional());
-    }
-
-    //Format tests
-    #[test]
-    fn formats_dramatic_failure_test() {
-        let result = DicePoolRoll {
-            quality: DicePoolQuality::ChanceDie,
-            rolls: vec![1],
-            exceptional_on: 5,
-            success_on: 10,
-        };
-
-        assert_eq!("dramatic failure!", fmt_for_failure(&result));
-    }
-
-    #[test]
-    fn formats_regular_failure_when_not_chance_die_test() {
-        let result = DicePoolRoll {
-            quality: DicePoolQuality::TenAgain,
-            rolls: vec![1],
-            exceptional_on: 5,
-            success_on: 10,
-        };
-
-        assert_eq!("failure!", fmt_for_failure(&result));
-    }
-}

src/cofd/parser.rs

@@ -1,232 +0,0 @@
-use nom::{
-    alt, bytes::complete::tag, character::complete::digit1, complete, many0, named,
-    sequence::tuple, tag, IResult,
-};
-
-use crate::cofd::{DicePool, DicePoolQuality};
-use crate::parser::eat_whitespace;
-
-#[derive(Debug, PartialEq, Eq, Clone)]
-pub enum DicePoolElement {
-    NumberOfDice(u32),
-    SuccessesForExceptional(u32),
-    DicePoolQuality(DicePoolQuality),
-}
-
-// Parse a single digit expression.  Does not eat whitespace
-fn parse_digit(input: &str) -> IResult<&str, u32> {
-    let (input, num) = digit1(input)?;
-    Ok((input, num.parse().unwrap()))
-}
-
-fn parse_quality(input: &str) -> IResult<&str, DicePoolQuality> {
-    let (input, _) = eat_whitespace(input)?;
-    named!(quality(&str) -> DicePoolQuality, alt!(
-        complete!(tag!("n")) => { |_| DicePoolQuality::NineAgain } |
-        complete!(tag!("e")) => { |_| DicePoolQuality::EightAgain } |
-        complete!(tag!("r")) => { |_| DicePoolQuality::Rote }
-    ));
-
-    let (input, dice_pool_quality) = quality(input)?;
-    Ok((input, dice_pool_quality))
-}
-
-fn parse_exceptional_requirement(input: &str) -> IResult<&str, u32> {
-    let (input, _) = eat_whitespace(input)?;
-    let (input, (_, successes)) = tuple((tag("s"), digit1))(input)?;
-    Ok((input, successes.parse().unwrap()))
-}
-
-// Parse a dice pool element expression.  Eats whitespace.
-fn parse_dice_pool_element(input: &str) -> IResult<&str, DicePoolElement> {
-    let (input, _) = eat_whitespace(input)?;
-    named!(element(&str) -> DicePoolElement, alt!(
-        parse_digit => { |num| DicePoolElement::NumberOfDice(num) } |
-        parse_quality => { |qual| DicePoolElement::DicePoolQuality(qual) } |
-        parse_exceptional_requirement => { |succ| DicePoolElement::SuccessesForExceptional(succ) }
-    ));
-
-    let (input, element) = element(input)?;
-    Ok((input, element))
-}
-
-fn find_elements(elements: Vec<DicePoolElement>) -> (Option<u32>, DicePoolQuality, u32) {
-    let mut found_quality: Option<DicePoolQuality> = None;
-    let mut found_count: Option<u32> = None;
-    let mut found_successes_required: Option<u32> = None;
-
-    for element in elements {
-        if found_quality.is_some() && found_count.is_some() && found_successes_required.is_some() {
-            break;
-        }
-
-        match element {
-            DicePoolElement::NumberOfDice(found) => {
-                if found_count.is_none() {
-                    found_count = Some(found);
-                }
-            }
-            DicePoolElement::DicePoolQuality(found) => {
-                if found_quality.is_none() {
-                    found_quality = Some(found);
-                }
-            }
-            DicePoolElement::SuccessesForExceptional(found) => {
-                if found_successes_required.is_none() {
-                    found_successes_required = Some(found);
-                }
-            }
-        };
-    }
-
-    let quality: DicePoolQuality = found_quality.unwrap_or(DicePoolQuality::TenAgain);
-    let successes_for_exceptional: u32 = found_successes_required.unwrap_or(5);
-    (found_count, quality, successes_for_exceptional)
-}
-
-fn convert_to_dice_pool(input: &str, elements: Vec<DicePoolElement>) -> IResult<&str, DicePool> {
-    let (count, quality, successes_for_exceptional) = find_elements(elements);
-
-    if count.is_some() {
-        Ok((
-            input,
-            DicePool::new(count.unwrap(), successes_for_exceptional, quality),
-        ))
-    } else {
-        use nom::error::ErrorKind;
-        use nom::Err;
-        Err(Err::Error((input, ErrorKind::Alt)))
-    }
-}
-
-pub fn parse_dice_pool(input: &str) -> IResult<&str, DicePool> {
-    named!(first_element(&str) -> DicePoolElement, alt!(
-            parse_dice_pool_element => { |e| e }
-    ));
-    let (input, first) = first_element(input)?;
-    let (input, elements) = if input.trim().is_empty() {
-        (input, vec![first])
-    } else {
-        named!(rest_elements(&str) -> Vec<DicePoolElement>, many0!(parse_dice_pool_element));
-        let (input, mut rest) = rest_elements(input)?;
-        rest.insert(0, first);
-        (input, rest)
-    };
-
-    convert_to_dice_pool(input, elements)
-}
-
-pub fn create_chance_die() -> IResult<&'static str, DicePool> {
-    Ok(("", DicePool::chance_die()))
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn parse_digit_test() {
-        use nom::error::ErrorKind;
-        use nom::Err;
-        assert_eq!(parse_digit("1"), Ok(("", 1)));
-        assert_eq!(parse_digit("10"), Ok(("", 10)));
-        assert_eq!(
-            parse_digit("adsf"),
-            Err(Err::Error(("adsf", ErrorKind::Digit)))
-        );
-    }
-
-    #[test]
-    fn quality_test() {
-        use nom::error::ErrorKind;
-        use nom::Err;
-        assert_eq!(parse_quality("n"), Ok(("", DicePoolQuality::NineAgain)));
-        assert_eq!(parse_quality("e"), Ok(("", DicePoolQuality::EightAgain)));
-        assert_eq!(parse_quality("r"), Ok(("", DicePoolQuality::Rote)));
-        assert_eq!(parse_quality("b"), Err(Err::Error(("b", ErrorKind::Alt))));
-    }
-
-    #[test]
-    fn multiple_quality_test() {
-        assert_eq!(parse_quality("ner"), Ok(("er", DicePoolQuality::NineAgain)));
-    }
-
-    #[test]
-    fn exceptional_success_test() {
-        use nom::error::ErrorKind;
-        use nom::Err;
-        assert_eq!(parse_exceptional_requirement("s3"), Ok(("", 3)));
-        assert_eq!(parse_exceptional_requirement("s10"), Ok(("", 10)));
-        assert_eq!(parse_exceptional_requirement("s20b"), Ok(("b", 20)));
-        assert_eq!(
-            parse_exceptional_requirement("sab10"),
-            Err(Err::Error(("ab10", ErrorKind::Digit)))
-        );
-    }
-
-    #[test]
-    fn dice_pool_element_expression_test() {
-        use nom::error::ErrorKind;
-        use nom::Err;
-
-        assert_eq!(
-            parse_dice_pool_element("8"),
-            Ok(("", DicePoolElement::NumberOfDice(8)))
-        );
-
-        assert_eq!(
-            parse_dice_pool_element("n"),
-            Ok((
-                "",
-                DicePoolElement::DicePoolQuality(DicePoolQuality::NineAgain)
-            ))
-        );
-
-        assert_eq!(
-            parse_dice_pool_element("s3"),
-            Ok(("", DicePoolElement::SuccessesForExceptional(3)))
-        );
-
-        assert_eq!(
-            parse_dice_pool_element("8ns3"),
-            Ok(("ns3", DicePoolElement::NumberOfDice(8)))
-        );
-
-        assert_eq!(
-            parse_dice_pool_element("totallynotvalid"),
-            Err(Err::Error(("totallynotvalid", ErrorKind::Alt)))
-        );
-    }
-
-    #[test]
-    fn dice_pool_number_only_test() {
-        assert_eq!(
-            parse_dice_pool("8"),
-            Ok(("", DicePool::new(8, 5, DicePoolQuality::TenAgain)))
-        );
-    }
-
-    #[test]
-    fn dice_pool_number_with_quality() {
-        assert_eq!(
-            parse_dice_pool("8n"),
-            Ok(("", DicePool::new(8, 5, DicePoolQuality::NineAgain)))
-        );
-    }
-
-    #[test]
-    fn dice_pool_number_with_success_change() {
-        assert_eq!(
-            parse_dice_pool("8s3"),
-            Ok(("", DicePool::new(8, 3, DicePoolQuality::TenAgain)))
-        );
-    }
-
-    #[test]
-    fn dice_pool_with_quality_and_success_change() {
-        assert_eq!(
-            parse_dice_pool("8rs3"),
-            Ok(("", DicePool::new(8, 3, DicePoolQuality::Rote)))
-        );
-    }
-}

src/commands.rs

@@ -1,96 +0,0 @@
-use crate::cofd::DicePool;
-use crate::dice::ElementExpression;
-use crate::roll::Roll;
-
-pub mod parser;
-
-pub struct Execution {
-    plain: String,
-    html: String,
-}
-
-impl Execution {
-    pub fn plain(&self) -> &str {
-        &self.plain
-    }
-
-    pub fn html(&self) -> &str {
-        &self.html
-    }
-}
-
-pub trait Command {
-    fn execute(&self) -> Execution;
-    fn name(&self) -> &'static str;
-}
-
-pub struct RollCommand(ElementExpression);
-
-impl Command for RollCommand {
-    fn name(&self) -> &'static str {
-        "roll regular dice"
-    }
-
-    fn execute(&self) -> Execution {
-        let roll = self.0.roll();
-        let plain = format!("Dice: {}\nResult: {}", self.0, roll);
-        let html = format!(
-            "<p><strong>Dice:</strong> {}</p><p><strong>Result</strong>: {}</p>",
-            self.0, roll
-        );
-        Execution { plain, html }
-    }
-}
-
-pub struct PoolRollCommand(DicePool);
-
-impl Command for PoolRollCommand {
-    fn name(&self) -> &'static str {
-        "roll dice pool"
-    }
-
-    fn execute(&self) -> Execution {
-        let roll = self.0.roll();
-        let plain = format!("Pool: {}\nResult: {}", self.0, roll);
-        let html = format!(
-            "<p><strong>Pool:</strong> {}</p><p><strong>Result</strong>: {}</p>",
-            self.0, roll
-        );
-        Execution { plain, html }
-    }
-}
-
-/// Parse a command string into a dynamic command execution trait object.
-/// Returns an error if a command was recognized but not parsed correctly.  Returns None if no
-/// command was recognized.
-pub fn parse_command(s: &str) -> Result<Option<Box<dyn Command>>, String> {
-    match parser::parse_command(s) {
-        //The first clause prevents bot from spamming messages to itself
-        //after executing a previous command.
-        Ok((input, result)) => match (input, &result) {
-            ("", Some(_)) | (_, None) => Ok(result),
-            _ => Err(format!("{}: malformed dice expression", s)),
-        },
-        Err(err) => Err(err.to_string()),
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn chance_die_is_not_malformed() {
-        assert!(parse_command("!chance").is_ok());
-    }
-
-    #[test]
-    fn roll_malformed_expression_test() {
-        assert!(parse_command("!roll 1d20asdlfkj").is_err());
-    }
-
-    #[test]
-    fn roll_dice_pool_expression_test() {
-        assert!(parse_command("!pool 8abc").is_err());
-    }
-}

src/commands/parser.rs

@@ -1,53 +0,0 @@
-use nom::{alt, complete, named, tag, take_while, tuple, IResult};
-
-use crate::cofd::parser::{create_chance_die, parse_dice_pool};
-use crate::commands::{Command, PoolRollCommand, RollCommand};
-use crate::dice::parser::parse_element_expression;
-use crate::parser::eat_whitespace;
-
-// Parse a roll expression.
-fn parse_roll(input: &str) -> IResult<&str, Box<dyn Command>> {
-    let (input, _) = eat_whitespace(input)?;
-    let (input, expression) = parse_element_expression(input)?;
-    Ok((input, Box::new(RollCommand(expression))))
-}
-
-fn parse_pool_roll(input: &str) -> IResult<&str, Box<dyn Command>> {
-    let (input, _) = eat_whitespace(input)?;
-    let (input, pool) = parse_dice_pool(input)?;
-    Ok((input, Box::new(PoolRollCommand(pool))))
-}
-
-fn chance_die() -> IResult<&'static str, Box<dyn Command>> {
-    let (input, pool) = create_chance_die()?;
-    Ok((input, Box::new(PoolRollCommand(pool))))
-}
-
-/// Potentially parse a command expression.  If we recognize the command, an error should be raised
-/// if the command is misparsed.  If we don't recognize the command, ignore it and return none
-pub fn parse_command(original_input: &str) -> IResult<&str, Option<Box<dyn Command>>> {
-    let (input, _) = eat_whitespace(original_input)?;
-
-    //Parser understands either specific !commands with no input, or any !command with extra input.
-    named!(command(&str) -> (&str, &str), tuple!(
-        complete!(tag!("!")),
-        alt!(
-            complete!(tag!("chance")) | //TODO figure out how to just have it read single commands.
-            complete!(take_while!(char::is_alphabetic))
-        )
-    ));
-
-    let (input, command) = match command(input) {
-        // Strip the exclamation mark
-        Ok((input, (_, result))) => (input, result),
-        Err(_e) => return Ok((original_input, None)),
-    };
-
-    match command {
-        "r" | "roll" => parse_roll(input).map(|(input, command)| (input, Some(command))),
-        "rp" | "pool" => parse_pool_roll(input).map(|(input, command)| (input, Some(command))),
-        "chance" => chance_die().map(|(input, command)| (input, Some(command))),
-        // No recognized command, ignore this.
-        _ => Ok((original_input, None)),
-    }
-}

src/dice/parser.rs

@@ -1,170 +0,0 @@
-use nom::{
-    alt, bytes::complete::tag, character::complete::digit1, complete, many0, named,
-    sequence::tuple, tag, IResult,
-};
-
-use crate::dice::{Dice, Element, ElementExpression, SignedElement};
-use crate::parser::eat_whitespace;
-
-#[derive(Debug, PartialEq, Eq, Clone, Copy)]
-enum Sign {
-    Plus,
-    Minus,
-}
-
-// Parse a dice expression.  Does not eat whitespace
-fn parse_dice(input: &str) -> IResult<&str, Dice> {
-    let (input, (count, _, sides)) = tuple((digit1, tag("d"), digit1))(input)?;
-    Ok((
-        input,
-        Dice::new(count.parse().unwrap(), sides.parse().unwrap()),
-    ))
-}
-
-// Parse a single digit expression.  Does not eat whitespace
-fn parse_bonus(input: &str) -> IResult<&str, u32> {
-    let (input, bonus) = digit1(input)?;
-    Ok((input, bonus.parse().unwrap()))
-}
-
-// Parse a sign expression.  Eats whitespace.
-fn parse_sign(input: &str) -> IResult<&str, Sign> {
-    let (input, _) = eat_whitespace(input)?;
-    named!(sign(&str) -> Sign, alt!(
-            complete!(tag!("+")) => { |_| Sign::Plus } |
-            complete!(tag!("-")) => { |_| Sign::Minus }
-    ));
-
-    let (input, sign) = sign(input)?;
-    Ok((input, sign))
-}
-
-// Parse an element expression.  Eats whitespace.
-fn parse_element(input: &str) -> IResult<&str, Element> {
-    let (input, _) = eat_whitespace(input)?;
-    named!(element(&str) -> Element, alt!(
-            parse_dice => { |d| Element::Dice(d) } |
-            parse_bonus => { |b| Element::Bonus(b) }
-    ));
-
-    let (input, element) = element(input)?;
-    Ok((input, element))
-}
-
-// Parse a signed element expression.  Eats whitespace.
-fn parse_signed_element(input: &str) -> IResult<&str, SignedElement> {
-    let (input, _) = eat_whitespace(input)?;
-    let (input, sign) = parse_sign(input)?;
-    let (input, _) = eat_whitespace(input)?;
-
-    let (input, element) = parse_element(input)?;
-    let element = match sign {
-        Sign::Plus => SignedElement::Positive(element),
-        Sign::Minus => SignedElement::Negative(element),
-    };
-    Ok((input, element))
-}
-
-// Parse a full element expression.  Eats whitespace.
-pub fn parse_element_expression(input: &str) -> IResult<&str, ElementExpression> {
-    named!(first_element(&str) -> SignedElement, alt!(
-            parse_signed_element => { |e| e } |
-            parse_element => { |e| SignedElement::Positive(e) }
-    ));
-    let (input, first) = first_element(input)?;
-    let (input, rest) = if input.trim().is_empty() {
-        (input, vec![first])
-    } else {
-        named!(rest_elements(&str) -> Vec<SignedElement>, many0!(parse_signed_element));
-        let (input, mut rest) = rest_elements(input)?;
-        rest.insert(0, first);
-        (input, rest)
-    };
-
-    Ok((input, ElementExpression(rest)))
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    #[test]
-    fn dice_test() {
-        assert_eq!(parse_dice("2d4"), Ok(("", Dice::new(2, 4))));
-        assert_eq!(parse_dice("20d40"), Ok(("", Dice::new(20, 40))));
-        assert_eq!(parse_dice("8d7"), Ok(("", Dice::new(8, 7))));
-    }
-
-    #[test]
-    fn element_test() {
-        assert_eq!(
-            parse_element("  \t\n\r\n 8d7 \n"),
-            Ok((" \n", Element::Dice(Dice::new(8, 7))))
-        );
-        assert_eq!(
-            parse_element("  \t\n\r\n 8 \n"),
-            Ok((" \n", Element::Bonus(8)))
-        );
-    }
-
-    #[test]
-    fn signed_element_test() {
-        assert_eq!(
-            parse_signed_element("+ 7"),
-            Ok(("", SignedElement::Positive(Element::Bonus(7))))
-        );
-        assert_eq!(
-            parse_signed_element("  \t\n\r\n- 8 \n"),
-            Ok((" \n", SignedElement::Negative(Element::Bonus(8))))
-        );
-        assert_eq!(
-            parse_signed_element("  \t\n\r\n- 8d4 \n"),
-            Ok((
-                " \n",
-                SignedElement::Negative(Element::Dice(Dice::new(8, 4)))
-            ))
-        );
-        assert_eq!(
-            parse_signed_element("  \t\n\r\n+ 8d4 \n"),
-            Ok((
-                " \n",
-                SignedElement::Positive(Element::Dice(Dice::new(8, 4)))
-            ))
-        );
-    }
-
-    #[test]
-    fn element_expression_test() {
-        assert_eq!(
-            parse_element_expression("8d4"),
-            Ok((
-                "",
-                ElementExpression(vec![SignedElement::Positive(Element::Dice(Dice::new(
-                    8, 4
-                )))])
-            ))
-        );
-        assert_eq!(
-            parse_element_expression(" -  8d4 \n "),
-            Ok((
-                " \n ",
-                ElementExpression(vec![SignedElement::Negative(Element::Dice(Dice::new(
-                    8, 4
-                )))])
-            ))
-        );
-        assert_eq!(
-            parse_element_expression("\t3d4 + 7 - 5 - 6d12 + 1d1 + 53 1d5 "),
-            Ok((
-                " 1d5 ",
-                ElementExpression(vec![
-                    SignedElement::Positive(Element::Dice(Dice::new(3, 4))),
-                    SignedElement::Positive(Element::Bonus(7)),
-                    SignedElement::Negative(Element::Bonus(5)),
-                    SignedElement::Negative(Element::Dice(Dice::new(6, 12))),
-                    SignedElement::Positive(Element::Dice(Dice::new(1, 1))),
-                    SignedElement::Positive(Element::Bonus(53)),
-                ])
-            ))
-        );
-    }
-}

src/lib.rs

@@ -1,6 +0,0 @@
-pub mod bot;
-pub mod cofd;
-pub mod commands;
-pub mod dice;
-mod parser;
-pub mod roll;

src/parser.rs

@@ -1,11 +0,0 @@
-use nom::{bytes::complete::take_while, IResult};
-
-fn is_whitespace(input: char) -> bool {
-    input == ' ' || input == '\n' || input == '\t' || input == '\r'
-}
-
-/// Eat whitespace, returning it
-pub fn eat_whitespace(input: &str) -> IResult<&str, &str> {
-    let (input, whitespace) = take_while(is_whitespace)(input)?;
-    Ok((input, whitespace))
-}