Implement BeatmapCache and Oppai interface

youmubot-osu/Cargo.toml

@@ -15,6 +15,8 @@ bitflags = "1"
 rayon = "1.1"
 lazy_static = "1"
 regex = "1"
+oppai-rs = "0.2.0"
+dashmap = "3.11.4"
 
 youmubot-db = { path = "../youmubot-db" }
 youmubot-prelude = { path = "../youmubot-prelude" }

youmubot-osu/src/discord/mod.rs

@@ -20,6 +20,7 @@ mod cache;
 mod db;
 pub(crate) mod embeds;
 mod hook;
+mod oppai_cache;
 mod server_rank;
 
 use db::OsuUser;
@@ -58,9 +59,10 @@ pub fn setup(
     // API client
     let http_client = data.get_cloned::<HTTPClient>();
     data.insert::<OsuClient>(OsuHttpClient::new(
-        http_client,
+        http_client.clone(),
         std::env::var("OSU_API_KEY").expect("Please set OSU_API_KEY as osu! api key."),
     ));
+    data.insert::<oppai_cache::BeatmapCache>(oppai_cache::BeatmapCache::new(http_client));
 
     // Announcer
     announcers.add(announcer::ANNOUNCER_KEY, announcer::updates);

youmubot-osu/src/discord/oppai_cache.rs

@@ -0,0 +1,90 @@
+use serenity::framework::standard::CommandError;
+use std::{ffi::CString, sync::Arc};
+use youmubot_prelude::TypeMapKey;
+
+/// the information collected from a download/Oppai request.
+#[derive(Clone, Debug)]
+pub struct BeatmapContent {
+    id: u64,
+    content: Arc<CString>,
+}
+
+/// the output of "one" oppai run.
+#[derive(Clone, Copy, Debug)]
+pub struct BeatmapInfo {
+    stars: f32,
+    pp: [f32; 4], // 95, 98, 99, 100
+}
+
+impl BeatmapContent {
+    /// Get pp given the combo and accuracy.
+    pub fn get_pp_from(
+        &self,
+        combo: oppai_rs::Combo,
+        accuracy: f32,
+        mods: impl Into<oppai_rs::Mods>,
+    ) -> Result<f32, CommandError> {
+        Ok(oppai_rs::Oppai::new_from_content(&self.content[..])?
+            .combo(combo)?
+            .accuracy(accuracy)?
+            .mods(mods.into())
+            .pp())
+    }
+
+    /// Get info given mods.
+    pub fn get_info_with(
+        &self,
+        mods: impl Into<oppai_rs::Mods>,
+    ) -> Result<BeatmapInfo, CommandError> {
+        let mut oppai = oppai_rs::Oppai::new_from_content(&self.content[..])?;
+        oppai.mods(mods.into()).combo(oppai_rs::Combo::PERFECT)?;
+        let pp = [
+            oppai.accuracy(95.0)?.pp(),
+            oppai.accuracy(98.0)?.pp(),
+            oppai.accuracy(99.0)?.pp(),
+            oppai.accuracy(100.0)?.pp(),
+        ];
+        let stars = oppai.stars();
+        Ok(BeatmapInfo { stars, pp })
+    }
+}
+
+/// A central cache for the beatmaps.
+pub struct BeatmapCache {
+    client: reqwest::blocking::Client,
+    cache: Arc<dashmap::DashMap<u64, BeatmapContent>>,
+}
+
+impl BeatmapCache {
+    /// Create a new cache.
+    pub fn new(client: reqwest::blocking::Client) -> Self {
+        BeatmapCache {
+            client,
+            cache: Arc::new(dashmap::DashMap::new()),
+        }
+    }
+
+    fn download_beatmap(&self, id: u64) -> Result<BeatmapContent, CommandError> {
+        let content = self
+            .client
+            .get(&format!("https://osu.ppy.sh/u/{}", id))
+            .send()?
+            .bytes()?;
+        Ok(BeatmapContent {
+            id,
+            content: Arc::new(CString::new(content.into_iter().collect::<Vec<_>>())?),
+        })
+    }
+
+    /// Get a beatmap from the cache.
+    pub fn get_beatmap(&self, id: u64) -> Result<BeatmapContent, CommandError> {
+        self.cache
+            .entry(id)
+            .or_try_insert_with(|| self.download_beatmap(id))
+            .map(|v| v.clone())
+    }
+}
+
+impl TypeMapKey for BeatmapCache {
+    type Value = BeatmapCache;
+}