Allow notifications to be sent days ahead of time

src/main.rs

@@ -10,7 +10,7 @@ use std::{env, fs::File, io::BufReader, sync::Arc};
 use anyhow::Result;
 use async_mutex::Mutex;
 use bot::fetch_and_announce_appointment;
-use chrono::{DateTime, NaiveTime, TimeZone, Utc};
+use chrono::{DateTime, Days, NaiveTime, TimeZone, Utc};
 use chrono_tz::Europe;
 use db::ChatInfo;
 use diesel::result::Error::NotFound;
@@ -41,6 +41,8 @@ pub struct Config {
 	poll_interval: u64,
 	#[serde(deserialize_with = "deserialize_time")]
 	reminder_time: NaiveTime,
+	#[serde(deserialize_with = "deserialize_time")]
+	preceeding_day_reminder_time: NaiveTime,
 }
 
 fn deserialize_time<'de, D: Deserializer<'de>>(deserializer: D) -> Result<NaiveTime, D::Error> {
@@ -79,7 +81,7 @@ async fn main() {
 	db.run_pending_migrations(MIGRATIONS).unwrap();
 	let db = Arc::new(Mutex::new(db));
 
-	let bot = Bot::new(config.token).throttle(Limits::default());
+	let bot = Bot::new(&config.token).throttle(Limits::default());
 
 	{
 		let db = db.clone();
@@ -104,16 +106,18 @@ async fn main() {
 					Err(e) => Err(e).unwrap(),
 				};
 
+				let next_appointment =
+					next_appointment.map(|timestamp| Utc.timestamp_opt(timestamp, 0).unwrap());
+
 				let sleep_duration = next_appointment
-					.map(|timestamp| Utc.timestamp_opt(timestamp, 0).unwrap())
-					.map(|date_time| date_time - now)
+					.map(|next_appointment| next_appointment - now)
 					.map(|duration| duration.to_std().unwrap())
 					.filter(|duration| *duration < poll_duration)
 					.unwrap_or(poll_duration);
 
 				sleep(sleep_duration).await;
 
-				let result = check_task(&bot, config.reminder_time, &db).await;
+				let result = check_task(&bot, &config, &db).await;
 				if let Err(e) = result {
 					error!("{}\nBacktrace:\n{}", e, e.backtrace());
 				}
@@ -131,14 +135,15 @@ struct Reminder<Tz: TimeZone> {
 	text: String,
 }
 
-async fn check_task(bot: &Throttle<Bot>, reminder_time: NaiveTime, db: &Database) -> Result<()> {
+// 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| {
 		use schema::chat::dsl::*;
 		chat.load::<DbChat>(db)
 	})?;
 
 	let now = Utc::now().with_timezone(&Europe::Berlin);
-	let today = now.date_naive();
 
 	for chat in chats {
 		let mut chat_info = ChatInfo::from(chat);
@@ -150,10 +155,6 @@ async fn check_task(bot: &Throttle<Bot>, reminder_time: NaiveTime, db: &Database
 		};
 		let appointment = appointment.with_timezone(&Europe::Berlin);
 
-		if appointment.start.date_naive() != today {
-			continue;
-		}
-
 		let mut reminder = None;
 		if now >= appointment.start {
 			reminder = Some(Reminder {
@@ -161,24 +162,39 @@ async fn check_task(bot: &Throttle<Bot>, reminder_time: NaiveTime, db: &Database
 				text: t!("messages.starting_now", locale = &chat_info.locale),
 			});
 		} else {
-			let reminder_date_time = now
-				.date_naive()
-				.and_time(reminder_time)
+			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 {
+				// 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();
+				let message_id = match remaining_days {
+					0 => "messages.appointment_today",
+					1 => "messages.appointment_tomorrow",
+					_ => "messages.appointment_soon",
+				};
+				let reminder_text = t!(
+					message_id,
+					locale = &chat_info.locale,
+					no_days = remaining_days,
+					start_time = &appointment.start.format("%H:%M").to_string(),
+					uk_time = &appointment
+						.start
+						.with_timezone(&Europe::London)
+						.format("%H:%M")
+						.to_string()
+				);
 				reminder = Some(Reminder {
 					time: reminder_date_time,
-					text: t!(
-						"messages.appointment_today",
-						locale = &chat_info.locale,
-						start_time = &appointment.start.format("%H:%M").to_string(),
-						uk_time = &appointment
-							.start
-							.with_timezone(&Europe::London)
-							.format("%H:%M")
-							.to_string()
-					),
+					text: reminder_text,
 				})
 			}
 		}