#!/usr/bin/env python3
"""将误写入的 0020_* revision 回退到 0018，以便重新执行 0019_align_legacy_schema。

用法（在 api 目录，DATABASE_URL 已配置）：

    uv run python scripts/repair_alembic_version_after_withdrawn_0020.py
    uv run python scripts/repair_alembic_version_after_withdrawn_0020.py --dry-run

启动时也会自动执行同等逻辑（见 app.core.alembic_startup）。
"""

from __future__ import annotations

import argparse
import sys
from pathlib import Path

_API_DIR = Path(__file__).resolve().parents[1]
if str(_API_DIR) not in sys.path:
    sys.path.insert(0, str(_API_DIR))

from sqlalchemy import create_engine, text

from app.core.alembic_revision_repair import (
    _WITHDRAWN_0020_REVISIONS,
    try_repair_withdrawn_0020_revision,
)
from app.core.db import _database_url


def main() -> int:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument(
        "--dry-run",
        action="store_true",
        help="只检查，不写库",
    )
    args = parser.parse_args()

    engine = create_engine(_database_url())
    with engine.connect() as conn:
        row = conn.execute(text("SELECT version_num FROM alembic_version")).fetchone()
        current = row[0] if row else None
        print(f"当前 version_num: {current!r}")

        if current is None:
            print("alembic_version 表为空，无需修复")
            return 0

        if args.dry_run:
            if current in _WITHDRAWN_0020_REVISIONS:
                print("[dry-run] 将回退到 0018_users_language_preference")
            else:
                print("无需修复")
            return 0

        if try_repair_withdrawn_0020_revision(conn):
            conn.commit()
            print("已回退到 0018_users_language_preference；请执行: uv run alembic upgrade head")
        else:
            print("无需修复")
        return 0


if __name__ == "__main__":
    raise SystemExit(main())