feat(custom-rulesets): support custom rulesets (#23)

* feat(custom_ruleset): add custom rulesets support

* feat(custom-ruleset): add version check

* feat(custom-ruleset): add LegacyIO API to get ruleset hashes

* feat(pp): add check for rulesets whose pp cannot be calculated

* docs(readme): update README to include support for custom rulesets

* fix(custom-ruleset): make `rulesets` empty instead of throw a error when version check is disabled

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* chore(custom-ruleset): apply the latest changes of generator

c891bcd159

and

e25041ad3b

* feat(calculator): add fallback performance calculation for unsupported modes

* fix(calculator): remove debug print

* fix: resolve reviews

* feat(calculator): add difficulty calculation checks

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

app/router/v2/beatmap.py

@@ -3,6 +3,7 @@ import hashlib
 import json
 from typing import Annotated
 
+from app.calculator import get_calculator
 from app.calculators.performance import ConvertError
 from app.database import Beatmap, BeatmapResp, User
 from app.database.beatmap import calculate_beatmap_attributes
@@ -147,7 +148,7 @@ async def get_beatmap_attributes(
     redis: Redis,
     fetcher: Fetcher,
     ruleset: Annotated[GameMode | None, Query(description="指定 ruleset；为空则使用谱面自身模式")] = None,
-    ruleset_id: Annotated[int | None, Query(description="以数字指定 ruleset （与 ruleset 二选一）", ge=0, le=3)] = None,
+    ruleset_id: Annotated[int | None, Query(description="以数字指定 ruleset （与 ruleset 二选一）")] = None,
 ):
     mods_ = []
     if mods and mods[0].isdigit():
@@ -170,6 +171,10 @@ async def get_beatmap_attributes(
     )
     if await redis.exists(key):
         return DifficultyAttributes.model_validate_json(await redis.get(key))  # pyright: ignore[reportArgumentType]
+
+    if await get_calculator().can_calculate_difficulty(ruleset) is False:
+        raise HTTPException(status_code=422, detail="Cannot calculate difficulty for the specified ruleset")
+
     try:
         return await calculate_beatmap_attributes(beatmap_id, ruleset, mods_, redis, fetcher)
     except HTTPStatusError: