diff --git a/src/arcaea_offline/external/__init__.py b/src/arcaea_offline/external/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/src/arcaea_offline/external/scores/__init__.py b/src/arcaea_offline/external/scores/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/src/arcaea_offline/external/scores/common.py b/src/arcaea_offline/external/scores/common.py
new file mode 100644
index 0000000..bea5ff0
--- /dev/null
+++ b/src/arcaea_offline/external/scores/common.py
@@ -0,0 +1,20 @@
+import dataclasses
+from typing import List
+
+
+@dataclasses.dataclass
+class ExternalScoreItem:
+    song_id: str
+    rating_class: int
+    score: int
+    pure: int = -1
+    far: int = -1
+    lost: int = -1
+    max_recall: int = -1
+    clear_type: int = -1
+    time: int = -1
+
+
+class ExternalScoreSource:
+    def get_score_items(self) -> List[ExternalScoreItem]:
+        ...
diff --git a/src/arcaea_offline/external.py b/src/arcaea_offline/external/scores/st3.py
similarity index 80%
rename from src/arcaea_offline/external.py
rename to src/arcaea_offline/external/scores/st3.py
index 9cc1c90..a17d889 100644
--- a/src/arcaea_offline/external.py
+++ b/src/arcaea_offline/external/scores/st3.py
@@ -1,24 +1,7 @@
-import dataclasses
 import sqlite3
-from typing import List, Union
+from typing import Union
 
-
-@dataclasses.dataclass
-class ExternalScoreItem:
-    song_id: str
-    rating_class: int
-    score: int
-    pure: int = -1
-    far: int = -1
-    lost: int = -1
-    max_recall: int = -1
-    clear_type: int = -1
-    time: int = -1
-
-
-class ExternalScoreSource:
-    def get_score_items(self) -> List[ExternalScoreItem]:
-        ...
+from .common import ExternalScoreItem, ExternalScoreSource
 
 
 class St3ScoreSource(ExternalScoreSource):
diff --git a/src/arcaea_offline/init_sqls.py b/src/arcaea_offline/init_sqls.py
deleted file mode 100644
index d69540b..0000000
--- a/src/arcaea_offline/init_sqls.py
+++ /dev/null
@@ -1,148 +0,0 @@
-from typing import Dict, List, TypedDict
-
-
-class VersionSqls(TypedDict):
-    init: List[str]
-    update: List[str]
-
-
-INIT_SQLS: Dict[int, VersionSqls] = {
-    1: {
-        "init": [
-            # region CREATE
-            """
-            CREATE TABLE IF NOT EXISTS charts (
-                song_id          TEXT    NOT NULL,
-                rating_class     INTEGER NOT NULL,
-                name_en          TEXT    NOT NULL,
-                name_jp          TEXT,
-                artist           TEXT    NOT NULL,
-                bpm              TEXT    NOT NULL,
-                bpm_base         REAL    NOT NULL,
-                package_id       TEXT    NOT NULL,
-                time             INTEGER,
-                side             INTEGER NOT NULL,
-                world_unlock     BOOLEAN NOT NULL,
-                remote_download  BOOLEAN,
-                bg               TEXT    NOT NULL,
-                date             INTEGER NOT NULL,
-                version          TEXT    NOT NULL,
-                difficulty       INTEGER NOT NULL,
-                rating           INTEGER NOT NULL,
-                note             INTEGER NOT NULL,
-                chart_designer   TEXT,
-                jacket_designer  TEXT,
-                jacket_override  BOOLEAN NOT NULL,
-                audio_override   BOOLEAN NOT NULL,
-
-                PRIMARY KEY (song_id, rating_class)
-            )
-            """,
-            """
-            CREATE TABLE IF NOT EXISTS aliases (
-                song_id  TEXT NOT NULL,
-                alias    TEXT NOT NULL
-            )
-            """,
-            """
-            CREATE TABLE IF NOT EXISTS packages (
-                package_id  TEXT NOT NULL,
-                name        TEXT NOT NULL
-            )
-            """,
-            """
-            CREATE TABLE IF NOT EXISTS scores (
-                id                 INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
-                song_id            TEXT NOT NULL,
-                rating_class       INTEGER NOT NULL,
-                score              INTEGER NOT NULL,
-                pure               INTEGER,
-                far                INTEGER,
-                lost               INTEGER,
-                time               INTEGER NOT NULL,
-                max_recall         INTEGER,
-                clear_type         INTEGER,
-
-                FOREIGN KEY (song_id, rating_class) REFERENCES charts(song_id, rating_class) ON UPDATE CASCADE ON DELETE NO ACTION
-            )
-            """,
-            """
-            CREATE TABLE IF NOT EXISTS properties (
-                key    TEXT NOT NULL UNIQUE,
-                value  TEXT NOT NULL
-            )
-            """,
-            """
-            CREATE VIEW IF NOT EXISTS calculated AS
-            SELECT
-                scores.id,
-                scores.song_id,
-                scores.rating_class,
-                scores.score,
-                scores.pure,
-                scores.far,
-                scores.lost,
-                scores.time,
-                charts.rating,
-                charts.note,
-                score - FLOOR(( pure * 10000000.0 / note ) + ( far * 0.5 * 10000000.0 / note )) AS pure_small,
-                CASE
-                    WHEN score >= 10000000 THEN
-                    rating / 10.0 + 2
-                    WHEN score >= 9800000 THEN
-                    rating / 10.0 + 1 + ( score - 9800000 ) / 200000.0
-                    ELSE MAX(( rating / 10.0 ) + ( score - 9500000 ) / 300000.0, 0)
-                END AS potential
-            FROM
-                scores
-                LEFT JOIN charts ON scores.rating_class = charts.rating_class
-                AND scores.song_id = charts.song_id
-            GROUP BY
-                scores.id
-            """,
-            """
-            CREATE VIEW IF NOT EXISTS bests AS
-            SELECT
-                c.song_id,
-                c.rating_class,
-                MAX(c.potential) AS potential
-            FROM
-                calculated c
-            GROUP BY
-                c.song_id,
-                c.rating_class
-            ORDER BY
-                potential DESC
-            """,
-            """
-            CREATE VIEW IF NOT EXISTS calculated_potential AS
-            SELECT
-                AVG(b30_ptt) AS b30
-            FROM
-                ( SELECT potential AS b30_ptt FROM bests ORDER BY potential DESC LIMIT 30 )
-            """,
-            """
-            CREATE VIEW IF NOT EXISTS song_id_names AS
-            SELECT song_id, name
-            FROM (
-                SELECT song_id, alias AS name FROM aliases
-                UNION ALL
-                SELECT song_id, song_id AS name FROM charts
-                UNION ALL
-                SELECT song_id, name_en AS name FROM charts
-                UNION ALL
-                SELECT song_id, name_jp AS name FROM charts
-            ) AS subquery
-            WHERE name IS NOT NULL AND name <> ''
-            GROUP BY song_id, name
-            """,
-            # endregion
-            # region INSERT
-            """
-            INSERT INTO properties VALUES ('db_version', '1')
-            """
-            # endregion
-        ],
-        "update": [],
-    }
-}
diff --git a/src/arcaea_offline/utils/__init__.py b/src/arcaea_offline/utils/__init__.py
deleted file mode 100644
index a63aa70..0000000
--- a/src/arcaea_offline/utils/__init__.py
+++ /dev/null
@@ -1,52 +0,0 @@
-from typing import Any, Optional, Sequence
-
-RATING_CLASS_TEXT_MAP = {
-    0: "Past",
-    1: "Present",
-    2: "Future",
-    3: "Beyond",
-}
-
-RATING_CLASS_SHORT_TEXT_MAP = {
-    0: "PST",
-    1: "PRS",
-    2: "FTR",
-    3: "BYD",
-}
-
-
-def rating_class_to_text(rating_class: int) -> Optional[str]:
-    return RATING_CLASS_TEXT_MAP.get(rating_class)
-
-
-def rating_class_to_short_text(rating_class: int) -> Optional[str]:
-    return RATING_CLASS_SHORT_TEXT_MAP.get(rating_class)
-
-
-SCORE_GRADE_FLOOR = [9900000, 9800000, 9500000, 9200000, 8900000, 8600000, 0]
-SCORE_GRADE_TEXTS = ["EX+", "EX", "AA", "A", "B", "C", "D"]
-
-
-def zip_score_grade(score: int, __seq: Sequence, default: Any = "__PRESERVE__"):
-    """
-    zip_score_grade is a simple wrapper that equals to:
-    ```py
-    for score_floor, val in zip(SCORE_GRADE_FLOOR, __seq):
-        if score >= score_floor:
-            return val
-    return seq[-1] if default == "__PRESERVE__" else default
-    ```
-    Could be useful in specific cases.
-    """
-    return next(
-        (
-            val
-            for score_floor, val in zip(SCORE_GRADE_FLOOR, __seq)
-            if score >= score_floor
-        ),
-        __seq[-1] if default == "__PRESERVE__" else default,
-    )
-
-
-def score_to_grade_text(score: int) -> str:
-    return zip_score_grade(score, SCORE_GRADE_TEXTS)
diff --git a/src/arcaea_offline/utils/singleton.py b/src/arcaea_offline/utils/singleton.py
deleted file mode 100644
index 6776678..0000000
--- a/src/arcaea_offline/utils/singleton.py
+++ /dev/null
@@ -1,12 +0,0 @@
-from typing import Generic, TypeVar
-
-T = TypeVar("T")
-
-
-class Singleton(type, Generic[T]):
-    _instance = None
-
-    def __call__(cls, *args, **kwargs) -> T:
-        if cls._instance is None:
-            cls._instance = super().__call__(*args, **kwargs)
-        return cls._instance
diff --git a/src/arcaea_offline/utils/types.py b/src/arcaea_offline/utils/types.py
deleted file mode 100644
index ef27e08..0000000
--- a/src/arcaea_offline/utils/types.py
+++ /dev/null
@@ -1,8 +0,0 @@
-from typing import Any, ClassVar, Dict, Protocol
-
-
-class TDataclass(Protocol):
-    __dataclass_fields__: ClassVar[Dict]
-
-    def __call__(self, *args: Any, **kwds: Any) -> Any:
-        ...