tenebrous-dicebot/src/dice.rs

47 lines
1.7 KiB
Rust
Raw Normal View History

use crate::context::Context;
use crate::db::sqlite::Variables;
use crate::db::variables::UserAndRoom;
use crate::error::BotError;
use crate::error::DiceRollingError;
use crate::parser::Amount;
use crate::parser::Element as NewElement;
use futures::stream::{self, StreamExt, TryStreamExt};
2021-05-13 20:24:17 +00:00
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
}
2020-04-20 17:19:50 +00:00
/// 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.room_id().as_str())
.await?;
use DiceRollingError::VariableNotFound;
let dice_amount: i32 = stream
.then(|amount| async move {
match &amount.element {
NewElement::Number(num_dice) => Ok(num_dice * amount.operator.mult()),
NewElement::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)
}