"""
ADR-073 Phase 2-5: 回填 incidents.alertname 欄位
2026-04-12 ogt: 舊資料 signals JSONB 用 alert_name key (非 alertname alias)
                新資料 (Phase 2-1 修復後) 已有 alertname alias

執行方式:
    kubectl exec -n awoooi-prod <api-pod> -- python3 scripts/backfill_alertname.py
"""
import asyncio
import sys
sys.path.insert(0, "/app")

from sqlalchemy import text

from src.db.base import get_db_context


async def main() -> None:
    async with get_db_context() as db:
        # 先查有多少需要回填
        count_r = await db.execute(
            text("SELECT COUNT(*) FROM incidents WHERE alertname IS NULL")
        )
        total = count_r.scalar()
        print(f"待回填: {total} 筆")

        # 優先用 signals->0->>'alertname' (Phase 2-1 修復後的新寫法)
        # fallback: signals->0->>'alert_name' (舊寫法)
        result = await db.execute(
            text("""
                UPDATE incidents
                SET alertname = COALESCE(
                    signals->0->>'alertname',
                    signals->0->>'alert_name'
                )
                WHERE alertname IS NULL
                  AND (
                    signals->0->>'alertname' IS NOT NULL
                    OR signals->0->>'alert_name' IS NOT NULL
                  )
            """)
        )
        await db.commit()
        print(f"已回填: {result.rowcount} 筆")

        # 剩餘無法回填的
        remain_r = await db.execute(
            text("SELECT COUNT(*) FROM incidents WHERE alertname IS NULL")
        )
        remain = remain_r.scalar()
        print(f"仍為 NULL: {remain} 筆 (signals 無 alert_name 欄位，無法回填)")


if __name__ == "__main__":
    asyncio.run(main())