Allow multiple reminder dates for a single chat group

src/main.rs

@@ -14,13 +14,15 @@ use bot::fetch_and_announce_appointment;
 use chrono::{DateTime, Days, NaiveTime, TimeZone, Utc};
 use chrono_tz::Europe;
 use db::ChatInfo;
-use diesel::result::Error::NotFound;
-use diesel::{Connection, RunQueryDsl, SqliteConnection};
+use diesel::result::Error::{self, NotFound};
+use diesel::{
+	BelongingToDsl, Connection, GroupedBy, RunQueryDsl, SelectableHelper, SqliteConnection,
+};
 use diesel::{ExpressionMethods, QueryDsl};
 use diesel_migrations::{embed_migrations, EmbeddedMigrations, MigrationHarness};
 use error::ConfigLoadError;
 use log::*;
-use serde::{de::Error, Deserialize, Deserializer};
+use serde::{Deserialize, Deserializer};
 use teloxide::adaptors::Throttle;
 use teloxide::prelude::RequesterExt;
 use teloxide::requests::Requester;
@@ -29,7 +31,7 @@ use teloxide::{adaptors::throttle::Limits, Bot};
 use tokio::time::sleep;
 
 use crate::bot::Command;
-use crate::db::DbChat;
+use crate::db::{DbChat, DbReminder};
 
 #[macro_use]
 extern crate rust_i18n;
@@ -49,7 +51,7 @@ pub struct Config {
 
 fn deserialize_time<'de, D: Deserializer<'de>>(deserializer: D) -> Result<NaiveTime, D::Error> {
 	let s: String = Deserialize::deserialize(deserializer)?;
-	NaiveTime::parse_from_str(&s, "%H:%M").map_err(D::Error::custom)
+	NaiveTime::parse_from_str(&s, "%H:%M").map_err(serde::de::Error::custom)
 }
 
 impl Config {
@@ -146,15 +148,29 @@ struct Reminder<Tz: TimeZone> {
 // Checks if the date of the next appointment has changed (and announces if so)
 // Additionally, checks if it is time for a reminder and sends that reminder if necessary
 async fn check_task(bot: &Throttle<Bot>, config: &Config, db: &Database) -> Result<()> {
-	let chats = db.lock().await.transaction(|db| {
+	let chats = db.lock().await.transaction::<_, Error, _>(|db| {
 		use schema::chat::dsl::*;
-		chat.load::<DbChat>(db)
+		use schema::reminder::dsl::*;
+		let chats = chat.load::<DbChat>(db)?;
+
+		let reminders: Vec<DbReminder> = DbReminder::belonging_to(&chats)
+			.select(DbReminder::as_select())
+			.order(days_ahead.asc())
+			.load(db)?;
+
+		let reminders_per_chat = reminders
+			.grouped_by(&chats)
+			.into_iter()
+			.zip(chats)
+			.collect::<Vec<_>>();
+
+		Ok(reminders_per_chat)
 	})?;
 
 	let now = Utc::now().with_timezone(&Europe::Berlin);
 
-	for chat in chats {
-		let mut chat_info = ChatInfo::from(chat);
+	for (reminders, chat) in chats {
+		let mut chat_info = ChatInfo::from_db(chat, reminders);
 		fetch_and_announce_appointment(bot, &mut chat_info, db).await?;
 
 		let appointment = match chat_info.next_appointment {
@@ -170,17 +186,24 @@ async fn check_task(bot: &Throttle<Bot>, config: &Config, db: &Database) -> Resu
 				text: t!("messages.starting_now", locale = &chat_info.locale),
 			});
 		} else {
-			let reminder_day =
-				appointment.start.date_naive() - Days::new(chat_info.remind_days_ahead);
-			let reminder_date_time = if chat_info.remind_days_ahead == 0 {
-				reminder_day.and_time(config.reminder_time)
-			} else {
-				reminder_day.and_time(config.preceeding_day_reminder_time)
-			};
-			let reminder_date_time = reminder_date_time
-				.and_local_timezone(now.timezone())
-				.unwrap();
-			if now >= reminder_date_time {
+			// This assumes that remind_days_ahead is sorted in ascending order
+			let most_recent_active_reminder = chat_info
+				.remind_days_ahead
+				.iter()
+				.map(|days_ahead| {
+					let reminder_day = appointment.start.date_naive() - Days::new(*days_ahead);
+					let reminder_date_time = if *days_ahead == 0 {
+						reminder_day.and_time(config.reminder_time)
+					} else {
+						reminder_day.and_time(config.preceeding_day_reminder_time)
+					};
+					reminder_date_time
+						.and_local_timezone(now.timezone())
+						.unwrap()
+				})
+				.find(|reminder_datetime| now >= *reminder_datetime);
+
+			if let Some(reminder_date_time) = most_recent_active_reminder {
 				// TODO This can have weird effects if it's happenig around midnight, since it's not timezone aware (and may even mix multiple timezones)
 				let remaining_time = appointment.start.date_naive() - now.date_naive();
 				let remaining_days = remaining_time.num_days();
@@ -203,7 +226,7 @@ async fn check_task(bot: &Throttle<Bot>, config: &Config, db: &Database) -> Resu
 				reminder = Some(Reminder {
 					time: reminder_date_time,
 					text: reminder_text,
-				})
+				});
 			}
 		}