Codeforces: asyncify hook

youmubot-cf/src/hook.rs

@@ -1,5 +1,7 @@
+use crate::CFClient;
 use chrono::{TimeZone, Utc};
-use codeforces::{Contest, Problem};
+use codeforces::{Client, Contest, Problem};
+use dashmap::DashMap as HashMap;
 use lazy_static::lazy_static;
 use rayon::{iter::Either, prelude::*};
 use regex::{Captures, Regex};
@@ -7,7 +9,7 @@ use serenity::{
     builder::CreateEmbed, framework::standard::CommandError, model::channel::Message,
     utils::MessageBuilder,
 };
-use std::{collections::HashMap, sync::Arc};
+use std::{sync::Arc, time::Instant};
 use youmubot_prelude::*;
 
 lazy_static! {
@@ -27,95 +29,109 @@ enum ContestOrProblem {
 }
 
 /// Caches the contest list.
-#[derive(Clone, Debug, Default)]
-pub struct ContestCache(Arc<RwLock<HashMap<u64, (Contest, Option<Vec<Problem>>)>>>);
+pub struct ContestCache {
+    contests: HashMap<u64, (Contest, Option<Vec<Problem>>)>,
+    all_list: RwLock<(Vec<Contest>, Instant)>,
+    http: Arc<Client>,
+}
 
 impl TypeMapKey for ContestCache {
     type Value = ContestCache;
 }
 
 impl ContestCache {
-    fn get(
-        &self,
-        http: &<HTTPClient as TypeMapKey>::Value,
-        contest_id: u64,
-    ) -> Result<(Contest, Option<Vec<Problem>>), CommandError> {
-        let rl = self.0.read();
-        match rl.get(&contest_id) {
-            Some(r @ (_, Some(_))) => Ok(r.clone()),
-            Some((c, None)) => match Contest::standings(http, contest_id, |f| f.limit(1, 1)) {
-                Ok((c, p, _)) => Ok({
-                    drop(rl);
-                    let mut v = self.0.write();
-                    let v = v.entry(contest_id).or_insert((c, None));
-                    v.1 = Some(p);
-                    v.clone()
-                }),
-                Err(_) => Ok((c.clone(), None)),
-            },
-            None => {
-                drop(rl);
-                // Step 1: try to fetch it individually
-                match Contest::standings(http, contest_id, |f| f.limit(1, 1)) {
-                    Ok((c, p, _)) => Ok(self
-                        .0
-                        .write()
-                        .entry(contest_id)
-                        .or_insert((c, Some(p)))
-                        .clone()),
-                    Err(codeforces::Error::Codeforces(s)) if s.ends_with("has not started") => {
-                        // Fetch the entire list
-                        {
-                            let mut m = self.0.write();
-                            let contests = Contest::list(http, contest_id > 100_000)?;
-                            contests.into_iter().for_each(|c| {
-                                m.entry(c.id).or_insert((c, None));
-                            });
-                        }
-                        self.0
-                            .read()
-                            .get(&contest_id)
-                            .cloned()
-                            .ok_or("No contest found".into())
-                    }
-                    Err(e) => Err(e.into()),
-                }
-                // Step 2: try to fetch the entire list.
+    /// Creates a new, empty cache.
+    pub async fn new(http: Arc<Client>) -> Result<Self> {
+        let contests_list = Contest::list(&*http, true).await?;
+        Ok(Self {
+            contests: HashMap::new(),
+            all_list: RwLock::new((contests_list, Instant::now())),
+            http,
+        })
+    }
+
+    /// Gets a contest from the cache, fetching from upstream if possible.
+    pub async fn get(&self, contest_id: u64) -> Result<(Contest, Option<Vec<Problem>>)> {
+        if let Some(v) = self.contests.get(&contest_id) {
+            if v.1.is_some() {
+                return Ok(v.clone());
             }
         }
+        self.get_and_store_contest(contest_id).await
+    }
+
+    async fn get_and_store_contest(
+        &self,
+        contest_id: u64,
+    ) -> Result<(Contest, Option<Vec<Problem>>)> {
+        let (c, p) = match Contest::standings(&*self.http, contest_id, |f| f.limit(1, 1)).await {
+            Ok((c, p, _)) => (c, Some(p)),
+            Err(codeforces::Error::Codeforces(s)) if s.ends_with("has not started") => {
+                let c = self.get_from_list(contest_id).await?;
+                (c, None)
+            }
+            Err(v) => return Err(Error::from(v)),
+        };
+        self.contests.insert(contest_id, (c, p));
+        Ok(self.contests.get(&contest_id).unwrap().clone())
+    }
+
+    async fn get_from_list(&self, contest_id: u64) -> Result<Contest> {
+        let last_updated = self.all_list.read().await.1.clone();
+        if Instant::now() - last_updated > std::time::Duration::from_secs(60 * 60) {
+            // We update at most once an hour.
+            *self.all_list.write().await =
+                (Contest::list(&*self.http, true).await?, Instant::now());
+        }
+        self.all_list
+            .read()
+            .await
+            .0
+            .iter()
+            .find(|v| v.id == contest_id)
+            .cloned()
+            .ok_or_else(|| Error::msg("Contest not found"))
     }
 }
 
 /// Prints info whenever a problem or contest (or more) is sent on a channel.
-pub fn codeforces_info_hook(ctx: &mut Context, m: &Message) {
-    if m.author.bot {
-        return;
+pub struct InfoHook;
+
+#[async_trait]
+impl Hook for InfoHook {
+    async fn call(&mut self, ctx: &Context, m: &Message) -> Result<()> {
+        if m.author.bot {
+            return Ok(());
+        }
+        let data = ctx.data.read().await;
+        let http = data.get::<CFClient>().unwrap();
+        let contest_cache = data.get::<ContestCache>().unwrap();
+        let matches = parse(&m.content[..], contest_cache)
+            .collect::<Vec<_>>()
+            .await;
+        if !matches.is_empty() {
+            m.channel_id
+                .send_message(&ctx, |c| {
+                    c.content("Here are the info of the given Codeforces links!")
+                        .embed(|e| print_info_message(&matches[..], e))
+                })
+                .await?;
+        }
+        Ok(())
     }
-    let http = ctx.data.get_cloned::<HTTPClient>();
-    let contest_cache = ctx.data.get_cloned::<ContestCache>();
+}
+
+fn parse<'a>(
+    content: &'a str,
+    contest_cache: &'a ContestCache,
+) -> impl stream::Stream<Item = (ContestOrProblem, &'a str)> + 'a {
     let matches = CONTEST_LINK
-        .captures_iter(&m.content)
-        .chain(PROBLEMSET_LINK.captures_iter(&m.content))
-        // .collect::<Vec<_>>()
-        // .into_par_iter()
-        .filter_map(
-            |v| match parse_capture(http.clone(), contest_cache.clone(), v) {
-                Ok(v) => Some(v),
-                Err(e) => {
-                    dbg!(e);
-                    None
-                }
-            },
-        )
-        .collect::<Vec<_>>();
-    if !matches.is_empty() {
-        m.channel_id
-            .send_message(&ctx, |c| {
-                c.content("Here are the info of the given Codeforces links!")
-                    .embed(|e| print_info_message(&matches[..], e))
-            })
-            .ok();
-    }
+        .captures_iter(content)
+        .chain(PROBLEMSET_LINK.captures_iter(content))
+        .map(|v| parse_capture(contest_cache, v))
+        .collect::<stream::FuturesUnordered<_>>()
+        .filter_map(|v| future::ready(v.ok()));
+    matches
 }
 
 fn print_info_message<'a>(
@@ -190,9 +206,8 @@ fn print_info_message<'a>(
     e.description(m.build())
 }
 
-fn parse_capture<'a>(
-    http: <HTTPClient as TypeMapKey>::Value,
-    contest_cache: ContestCache,
+async fn parse_capture<'a>(
+    contest_cache: &ContestCache,
     cap: Captures<'a>,
 ) -> Result<(ContestOrProblem, &'a str), CommandError> {
     let contest_id: u64 = cap
@@ -200,7 +215,7 @@ fn parse_capture<'a>(
         .ok_or(CommandError::from("Contest not captured"))?
         .as_str()
         .parse()?;
-    let (contest, problems) = contest_cache.get(&http, contest_id)?;
+    let (contest, problems) = contest_cache.get(contest_id).await?;
     match cap.name("problem") {
         Some(p) => {
             for problem in problems.ok_or(CommandError::from("Contest hasn't started"))? {

youmubot-cf/src/lib.rs

@@ -7,7 +7,7 @@ use serenity::{
     model::channel::Message,
     utils::MessageBuilder,
 };
-use std::{collections::HashMap, time::Duration};
+use std::{collections::HashMap, sync::Arc, time::Duration};
 use youmubot_prelude::*;
 
 mod announcer;
@@ -18,15 +18,25 @@ mod hook;
 /// Live-commentating a Codeforces round.
 mod live;
 
+/// The TypeMapKey holding the Client.
+struct CFClient;
+
+impl TypeMapKey for CFClient {
+    type Value = Arc<codeforces::Client>;
+}
+
 use db::{CfSavedUsers, CfUser};
 
 pub use hook::codeforces_info_hook;
 
 /// Sets up the CF databases.
-pub fn setup(path: &std::path::Path, data: &mut ShareMap, announcers: &mut AnnouncerHandler) {
+pub async fn setup(path: &std::path::Path, data: &mut TypeMap, announcers: &mut AnnouncerHandler) {
     CfSavedUsers::insert_into(data, path.join("cf_saved_users.yaml"))
         .expect("Must be able to set up DB");
-    data.insert::<hook::ContestCache>(hook::ContestCache::default());
+    let http = data.get::<HTTPClient>().unwrap();
+    let client = Arc::new(codeforces::Client::new(http.clone()));
+    data.insert::<hook::ContestCache>(hook::ContestCache::new(client.clone()).await.unwrap());
+    data.insert::<CFClient>(client);
     announcers.add("codeforces", announcer::updates);
 }