diff --git a/src/arcaea_offline/database.py b/src/arcaea_offline/database.py
index c9e9164..73e22ce 100644
--- a/src/arcaea_offline/database.py
+++ b/src/arcaea_offline/database.py
@@ -4,6 +4,7 @@ from typing import Optional, Union
 from sqlalchemy import Engine, func, inspect, select
 from sqlalchemy.orm import sessionmaker
 
+from .external.arcsong.arcsong_json import ArcSongJsonBuilder
 from .models.config import *
 from .models.scores import *
 from .models.songs import *
@@ -165,3 +166,8 @@ class Database(metaclass=Singleton):
         with self.sessionmaker() as session:
             result = session.scalar(stmt)
         return result
+
+    def generate_arcsong(self):
+        with self.sessionmaker() as session:
+            arcsong = ArcSongJsonBuilder(session).generate_arcsong_json()
+        return arcsong
diff --git a/src/arcaea_offline/external/arcsong/arcsong_json.py b/src/arcaea_offline/external/arcsong/arcsong_json.py
new file mode 100644
index 0000000..61d941d
--- /dev/null
+++ b/src/arcaea_offline/external/arcsong/arcsong_json.py
@@ -0,0 +1,155 @@
+import logging
+import re
+from typing import List, Optional, TypedDict
+
+from sqlalchemy import func, select
+from sqlalchemy.orm import Session
+
+from ...models import (
+    ChartInfo,
+    Difficulty,
+    DifficultyLocalized,
+    Pack,
+    Song,
+    SongLocalized,
+)
+
+logger = logging.getLogger(__name__)
+
+
+class TArcSongJsonDifficultyItem(TypedDict):
+    name_en: str
+    name_jp: str
+    artist: str
+    bpm: str
+    bpm_base: float
+    set: str
+    set_friendly: str
+    time: int
+    side: int
+    world_unlock: bool
+    remote_download: bool
+    bg: str
+    date: int
+    version: str
+    difficulty: int
+    rating: int
+    note: int
+    chart_designer: str
+    jacket_designer: str
+    jacket_override: bool
+    audio_override: bool
+
+
+class TArcSongJsonSongItem(TypedDict):
+    song_id: str
+    difficulties: List[TArcSongJsonDifficultyItem]
+    alias: List[str]
+
+
+class TArcSongJson(TypedDict):
+    songs: List[TArcSongJsonSongItem]
+
+
+class ArcSongJsonBuilder:
+    def __init__(self, session: Session):
+        self.session = session
+
+    def get_difficulty_item(
+        self,
+        difficulty: Difficulty,
+        song: Song,
+        pack: Pack,
+        song_localized: Optional[SongLocalized],
+    ) -> TArcSongJsonDifficultyItem:
+        if "_append_" in pack.id:
+            base_pack = self.session.scalar(
+                select(Pack).where(Pack.id == re.sub(r"_append_.*$", "", pack.id))
+            )
+        else:
+            base_pack = None
+
+        difficulty_localized = self.session.scalar(
+            select(DifficultyLocalized).where(
+                (DifficultyLocalized.song_id == difficulty.song_id)
+                & (DifficultyLocalized.rating_class == difficulty.rating_class)
+            )
+        )
+        chart_info = self.session.scalar(
+            select(ChartInfo).where(
+                (ChartInfo.song_id == difficulty.song_id)
+                & (ChartInfo.rating_class == difficulty.rating_class)
+            )
+        )
+
+        if difficulty_localized:
+            name_jp = difficulty_localized.title_ja or ""
+        elif song_localized:
+            name_jp = song_localized.title_ja or ""
+        else:
+            name_jp = ""
+
+        return {
+            "name_en": difficulty.title or song.title,
+            "name_jp": name_jp,
+            "artist": difficulty.artist or song.artist,
+            "bpm": difficulty.bpm or song.bpm or "",
+            "bpm_base": difficulty.bpm_base or song.bpm_base or 0.0,
+            "set": song.set,
+            "set_friendly": f"{base_pack.name} - {pack.name}"
+            if base_pack
+            else pack.name,
+            "time": 0,
+            "side": song.side or 0,
+            "world_unlock": False,
+            "remote_download": False,
+            "bg": difficulty.bg or song.bg or "",
+            "date": difficulty.date or song.date or 0,
+            "version": difficulty.version or song.version or "",
+            "difficulty": difficulty.rating * 2 + int(difficulty.rating_plus),
+            "rating": chart_info.constant or 0 if chart_info else 0,
+            "note": chart_info.note or 0 if chart_info else 0,
+            "chart_designer": difficulty.chart_designer or "",
+            "jacket_designer": difficulty.jacket_desginer or "",
+            "jacket_override": difficulty.jacket_override,
+            "audio_override": difficulty.audio_override,
+        }
+
+    def get_song_item(self, song: Song) -> TArcSongJsonSongItem:
+        difficulties = self.session.scalars(
+            select(Difficulty).where(Difficulty.song_id == song.id)
+        )
+
+        pack = self.session.scalar(select(Pack).where(Pack.id == song.set))
+        if not pack:
+            logger.warning(f'Cannot find pack "{song.set}", using placeholder instead.')
+            pack = Pack(id="unknown", name="Unknown", description="__PLACEHOLDER__")
+        song_localized = self.session.scalar(
+            select(SongLocalized).where(SongLocalized.id == song.id)
+        )
+
+        return {
+            "song_id": song.id,
+            "difficulties": [
+                self.get_difficulty_item(difficulty, song, pack, song_localized)
+                for difficulty in difficulties
+            ],
+            "alias": [],
+        }
+
+    def generate_arcsong_json(self) -> TArcSongJson:
+        songs = self.session.scalars(select(Song))
+        arcsong_songs = []
+        for song in songs:
+            proceed = self.session.scalar(
+                select(func.count(Difficulty.rating_class)).where(
+                    Difficulty.song_id == song.id
+                )
+            )
+
+            if not proceed:
+                continue
+
+            arcsong_songs.append(self.get_song_item(song))
+
+        return {"songs": arcsong_songs}