Use the last contest rating change id, instead of rating change time

youmubot-cf/src/announcer.rs

@@ -1,6 +1,6 @@
 use crate::db::{CfSavedUsers, CfUser};
 use announcer::MemberToChannels;
-use chrono::{DateTime, Utc};
+use chrono::Utc;
 use codeforces::{RatingChange, User};
 use serenity::{
     framework::standard::{CommandError, CommandResult},
@@ -53,7 +53,7 @@ fn update_user(
     };
 
     let mut channels_list: Option<Vec<ChannelId>> = None;
-    let last_update = std::mem::replace(&mut cfu.last_update, Utc::now());
+    cfu.last_update = Utc::now();
     // Update the rating
     cfu.rating = info.rating;
 
@@ -81,16 +81,24 @@ fn update_user(
         Ok(())
     };
 
+    let rating_changes = match cfu.last_contest_id {
+        None => rating_changes,
+        Some(v) => rating_changes
+            .into_iter()
+            .take_while(|rc| rc.contest_id != v)
+            .collect(),
+    };
+
+    cfu.last_contest_id = rating_changes
+        .iter()
+        .last()
+        .map(|v| v.contest_id)
+        .or(cfu.last_contest_id);
+
     // Check for any good announcements to make
     for rc in rating_changes {
-        let date: DateTime<Utc> = DateTime::from_utc(
-            chrono::NaiveDateTime::from_timestamp(rc.rating_update_time_seconds as i64, 0),
-            Utc,
-        );
-        if &date > &last_update {
-            if let Err(v) = send_message(rc) {
-                dbg!(v);
-            }
+        if let Err(v) = send_message(rc) {
+            dbg!(v);
         }
     }
     after.recv().ok();

youmubot-cf/src/db.rs

@@ -1,5 +1,5 @@
 use chrono::{DateTime, Utc};
-use codeforces::User;
+use codeforces::{RatingChange, User};
 use serenity::model::id::UserId;
 use std::collections::HashMap;
 use youmubot_db::DB;
@@ -12,24 +12,19 @@ pub type CfSavedUsers = DB<HashMap<UserId, CfUser>>;
 pub struct CfUser {
     pub handle: String,
     pub last_update: DateTime<Utc>,
+    #[serde(default)]
+    pub last_contest_id: Option<u64>,
     pub rating: Option<i64>,
 }
 
-impl Default for CfUser {
-    fn default() -> Self {
-        Self {
-            handle: "".to_owned(),
-            last_update: Utc::now(),
-            rating: None,
-        }
-    }
-}
-
-impl From<User> for CfUser {
-    fn from(u: User) -> Self {
+impl CfUser {
+    /// Save a new user as an internal CFUser.
+    /// Requires a vector of rating changes because we must rely on the Codeforces rating_changes API's return order to properly announce.
+    pub(crate) fn save(u: User, rc: Vec<RatingChange>) -> Self {
         Self {
             handle: u.handle,
             last_update: Utc::now(),
+            last_contest_id: rc.into_iter().last().map(|v| v.contest_id),
             rating: u.rating,
         }
     }

youmubot-cf/src/lib.rs

@@ -16,7 +16,7 @@ mod hook;
 /// Live-commentating a Codeforces round.
 mod live;
 
-use db::CfSavedUsers;
+use db::{CfSavedUsers, CfUser};
 
 pub use hook::codeforces_info_hook;
 
@@ -97,13 +97,15 @@ pub fn save(ctx: &mut Context, m: &Message, mut args: Args) -> CommandResult {
             m.reply(&ctx, "cannot find an account with such handle")?;
         }
         Some(acc) => {
+            // Collect rating changes data.
+            let rating_changes = acc.rating_changes(&http)?;
             let db = CfSavedUsers::open(&*ctx.data.read());
             let mut db = db.borrow_mut()?;
             m.reply(
                 &ctx,
                 format!("account `{}` has been linked to your account.", &acc.handle),
             )?;
-            db.insert(m.author.id, acc.into());
+            db.insert(m.author.id, CfUser::save(acc, rating_changes));
         }
     }