refactor: music-db crate

music_db/src/lib.rs

@@ -0,0 +1,156 @@
+use std::{fs::OpenOptions, io::BufReader, sync::LazyLock};
+
+use rust_decimal::{Decimal, dec, serde::DecimalFromString};
+use rustc_hash::FxHashMap;
+use serde::Deserialize;
+
+#[derive(Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct MusicInfo {
+    pub id: u32,
+    pub name: String,
+    pub version: i64,
+    pub levels: Vec<Level>,
+}
+
+#[derive(Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct Level {
+    /// 0, 1, 2, 3, 4, 5
+    pub level: u32,
+    /// for example: "13.7"
+    pub difficulty: DecimalFromString,
+}
+
+type MusicDB = FxHashMap<u32, MusicInfo>;
+
+pub fn preload_db() {
+    _ = &*MUSIC_DB;
+}
+
+pub fn query_music(music_id: u32) -> Option<&'static MusicInfo> {
+    MUSIC_DB.as_ref()?.get(&music_id)
+}
+pub fn query_music_level(music_id: u32, level: u32) -> Option<&'static Level> {
+    MUSIC_DB
+        .as_ref()?
+        .get(&music_id)?
+        .levels
+        .iter()
+        .find(|d| d.level == level)
+}
+
+pub static MUSIC_DB: LazyLock<Option<MusicDB>> = LazyLock::new(|| {
+    let json = OpenOptions::new()
+        .read(true)
+        .create(false)
+        .open("musicDB.json")
+        .inspect_err(|_e| {
+            #[cfg(feature = "log")]
+            spdlog::warn!("failed to load musicDB: {_e}")
+        })
+        .ok()?;
+    let buf_reader = BufReader::new(json);
+
+    let db: Vec<MusicInfo> = serde_json::from_reader(buf_reader)
+        .inspect_err(|_e| {
+            #[cfg(feature = "log")]
+            spdlog::warn!("failed to load musicDB: {_e}")
+        })
+        .ok()?;
+
+    Some(db.into_iter().map(|entry| (entry.id, entry)).collect())
+});
+
+impl Level {
+    /// achievement: xxx.xxxx% * 10000
+    ///
+    /// This will **NOT** ignore utage level, you can calculate a in-theory DX Rating.
+    ///
+    /// On invalid input, it returns 0.
+    pub fn dx_rating(&self, achievement: i32) -> u32 {
+        let achievement = Decimal::new(achievement as _, 4);
+        let difficulty_rank: Decimal = self.difficulty.value;
+
+        let factor = match () {
+            // larger than best achievement
+            _ if achievement > dec!(101.0) => return 0,
+
+            _ if achievement >= SSS_PLUS_THRESHOLD => SSS_PLUS_FACTOR,
+            _ if achievement >= SSS_PRO_THRESHOLD => SSS_PRO_FACTOR,
+            _ if achievement >= SSS_THRESHOLD => SSS_FACTOR,
+            _ if achievement >= SS_PLUS_PRO_THRESHOLD => SS_PLUS_PRO_FACTOR,
+            _ if achievement >= SS_PLUS_THRESHOLD => SS_PLUS_FACTOR,
+            _ if achievement >= SS_THRESHOLD => SS_FACTOR,
+            _ if achievement >= S_PLUS_PRO_THRESHOLD => S_PLUS_PRO_FACTOR,
+            _ if achievement >= S_PLUS_THRESHOLD => S_PLUS_FACTOR,
+            _ if achievement >= S_THRESHOLD => S_FACTOR,
+            _ if achievement >= AAA_PRO_THRESHOLD => AAA_PRO_FACTOR,
+            _ if achievement >= AAA_THRESHOLD => AAA_FACTOR,
+            _ if achievement >= AA_THRESHOLD => AA_FACTOR,
+            _ if achievement >= A_THRESHOLD => A_FACTOR,
+
+            // lower than A rank, does not get rating.
+            _ => return 0,
+        };
+
+        // when ach > 100.5%, calculate as 100.5%
+        (factor * difficulty_rank * achievement.min(Decimal::new(1005, 1)))
+            .floor()
+            .try_into()
+            .unwrap_or_default()
+    }
+}
+
+const SSS_PLUS_THRESHOLD: Decimal = dec!(100.5);
+const SSS_PLUS_FACTOR: Decimal = dec!(0.224);
+
+const SSS_PRO_THRESHOLD: Decimal = dec!(100.4999);
+const SSS_PRO_FACTOR: Decimal = dec!(0.222);
+
+const SSS_THRESHOLD: Decimal = dec!(100);
+const SSS_FACTOR: Decimal = dec!(0.216);
+
+const SS_PLUS_PRO_THRESHOLD: Decimal = dec!(99.9999);
+const SS_PLUS_PRO_FACTOR: Decimal = dec!(0.214);
+
+const SS_PLUS_THRESHOLD: Decimal = dec!(99.5);
+const SS_PLUS_FACTOR: Decimal = dec!(0.211);
+
+const SS_THRESHOLD: Decimal = dec!(99);
+const SS_FACTOR: Decimal = dec!(0.208);
+
+const S_PLUS_PRO_THRESHOLD: Decimal = dec!(98.9999);
+const S_PLUS_PRO_FACTOR: Decimal = dec!(0.206);
+
+const S_PLUS_THRESHOLD: Decimal = dec!(98);
+const S_PLUS_FACTOR: Decimal = dec!(0.203);
+
+const S_THRESHOLD: Decimal = dec!(97);
+const S_FACTOR: Decimal = dec!(0.2);
+
+const AAA_PRO_THRESHOLD: Decimal = dec!(96.9999);
+const AAA_PRO_FACTOR: Decimal = dec!(0.176);
+
+const AAA_THRESHOLD: Decimal = dec!(94);
+const AAA_FACTOR: Decimal = dec!(0.168);
+
+const AA_THRESHOLD: Decimal = dec!(90);
+const AA_FACTOR: Decimal = dec!(0.152);
+
+const A_THRESHOLD: Decimal = dec!(80);
+const A_FACTOR: Decimal = dec!(0.136);
+
+/*
+TODO: calculate (below) BBB dx rating
+  [0, 0, 'd'],
+  [10, 1.6, 'd'],
+  [20, 3.2, 'd'],
+  [30, 4.8, 'd'],
+  [40, 6.4, 'd'],
+  [50, 8, 'c'],
+  [60, 9.6, 'b'],
+  [70, 11.2, 'bb'],
+  [75, 12.0, 'bbb'],
+  [79.9999, 12.8, 'bbb'],
+*/