Instead of using an Arc Mutex for state management embedded directly
into the bot, utilize actor pattern, with the idea that this will be
much more useful than simply logging a message once in the future.
This also refactors the bot code so that instead of a single run_bot
function, the DiceBot struct now has a run() method attached to it.
This also necessitated changes and cleanup to the dicebot main, which
is for the better anyhow.
The error and config types are also now in their own files, and
implemented for more in-depth use cases.
This commit lays the groundwork for a stateful dicebot, instead of one
that only responds to commands. It now maintains a simple state
machine, used to store the current state of the bot. Currently, it
only cares about whether or not the message about skipping old
messages was logged.
This makes the oldest message age setting optional, in additon to the
entire bot config (for now). If the oldest message age is not
specified (or if the entire bot config is missing), it will default to
15 minutes.
This behavior became broken again after switching away from the
macro-based command parsing. The bot would return any non !command
message as an error, which would cause it to read more messages, and
return those as errors, until finally the matrix SDK would throw up.
Command parser now more properly handles empty messages and
non-commands, but we also simply abort processing if the incoming
message doesn't start with an exclamation point.
By using the alpha1 function in complete mode, we are able to handle
arbitrary single-word commands (e.g. "!help") and proprly map the
remaining input to an empty string.
This gives us many things for free, like automated state management,
no need to declare special API structs and use HTTP requests directly,
and most importantly: ENCRYPTION!