"""V2 历史数据归档清理(2026-06-12 拍板:归档后删)。

把生产库 content_agent_* 全部 21 张表中 created_at < cutoff 的 V2 时代行
导出为 JSON 档案后删除,并删掉 decode 时代的 7 个旧列 + rule_decisions 的
画像列(B1 已砍画像链)。生产库只有一台(.env CONTENT_SUPPLY_DB_*),只跑一次。

    python scripts/archive_v2_db_rows.py                 # dry-run(默认,零写入)
    python scripts/archive_v2_db_rows.py --execute       # 归档→对账→删行→删列
    python scripts/archive_v2_db_rows.py --restore <dir> # 从档案回灌(删行回滚通道)

任一对账断言失败:回滚当前表、立即退出,绝不进入删列 DDL。
DDL 前 SHOW COLUMNS 探测,列已不存在则跳过——重跑幂等。
"""

from __future__ import annotations

import argparse
import datetime as dt
import decimal
import json
import sys
from pathlib import Path

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

from content_agent.integrations.database_runtime import ContentSupplyDbConfig
from scripts.validate_content_agent_db import EXPECTED_TABLES

DEFAULT_CUTOFF = "2026-06-12 00:00:00"
ARCHIVE_ROOT = ROOT / "archive" / "v2_db_archive"

# 与 sql/content_agent_schema.sql、database_runtime.TABLE_COLUMNS 的收窄保持一致。
DDL_STATEMENTS = [
    (
        "content_agent_pattern_recall_evidence",
        ["decode_status", "decode_task_id", "matched_terms", "matched_category_paths",
         "decode_elements", "match_paths_request", "match_paths_response"],
        # 旧索引含 decode_status,显式重建为单列,不留给 MySQL 隐式收缩。
        "ALTER TABLE content_agent_pattern_recall_evidence "
        "DROP INDEX idx_content_agent_pattern_recall_status, "
        "ADD INDEX idx_content_agent_pattern_recall_status (recall_status), "
        + ", ".join(
            f"DROP COLUMN {col}"
            for col in ["decode_status", "decode_task_id", "matched_terms",
                        "matched_category_paths", "decode_elements",
                        "match_paths_request", "match_paths_response"]
        ),
    ),
    (
        "content_agent_rule_decisions",
        ["age_50_plus_level"],
        "ALTER TABLE content_agent_rule_decisions DROP COLUMN age_50_plus_level",
    ),
]


def _json_default(value):
    if isinstance(value, (dt.datetime, dt.date)):
        return value.isoformat()
    if isinstance(value, decimal.Decimal):
        return str(value)
    if isinstance(value, bytes):
        return value.decode("utf-8", errors="replace")
    raise TypeError(f"unserializable: {type(value)}")


def _table_columns(cursor, table: str) -> list[str]:
    cursor.execute(f"SHOW COLUMNS FROM {table}")
    return [row["Field"] for row in cursor.fetchall()]


def dry_run(conn, cutoff: str) -> int:
    total = 0
    with conn.cursor() as cursor:
        for table in EXPECTED_TABLES:
            cursor.execute(
                f"SELECT COUNT(*) AS n, MIN(created_at) AS a, MAX(created_at) AS b "
                f"FROM {table} WHERE created_at < %s",
                (cutoff,),
            )
            row = cursor.fetchone()
            count = row["n"]
            total += count
            run_ids = ""
            if count and "run_id" in _table_columns(cursor, table):
                cursor.execute(
                    f"SELECT DISTINCT run_id FROM {table} WHERE created_at < %s LIMIT 20",
                    (cutoff,),
                )
                run_ids = " runs=" + ",".join(r["run_id"] for r in cursor.fetchall())
            span = f" [{row['a']} → {row['b']}]" if count else ""
            print(f"  {table}: {count} 行{span}{run_ids}")
    print(f"\ndry-run 合计 {total} 行将被归档删除(cutoff={cutoff});未做任何写入。")
    return 0


def execute(conn, cutoff: str) -> int:
    stamp = dt.datetime.now(dt.timezone.utc).strftime("%Y%m%dT%H%M%SZ")
    out_dir = ARCHIVE_ROOT / stamp
    out_dir.mkdir(parents=True, exist_ok=True)
    manifest: dict = {"cutoff": cutoff, "executed_at": stamp, "tables": {}, "ddl_applied": False}

    for table in EXPECTED_TABLES:
        with conn.cursor() as cursor:
            cursor.execute(f"SELECT COUNT(*) AS n FROM {table} WHERE created_at < %s", (cutoff,))
            count = cursor.fetchone()["n"]
            cursor.execute(f"SELECT * FROM {table} WHERE created_at < %s", (cutoff,))
            rows = cursor.fetchall()
            if len(rows) != count:
                conn.rollback()
                print(f"FAIL {table}: SELECT {len(rows)} 行 != COUNT {count},中止(已回滚,未删任何行)")
                return 1
            (out_dir / f"{table}.json").write_text(
                json.dumps(rows, ensure_ascii=False, indent=1, default=_json_default),
                encoding="utf-8",
            )
            deleted = 0
            if count:
                cursor.execute(f"DELETE FROM {table} WHERE created_at < %s", (cutoff,))
                deleted = cursor.rowcount
                if deleted != count:
                    conn.rollback()
                    print(f"FAIL {table}: DELETE {deleted} != 归档 {count},已回滚,中止")
                    return 1
                cursor.execute(
                    f"SELECT COUNT(*) AS n FROM {table} WHERE created_at < %s", (cutoff,)
                )
                if cursor.fetchone()["n"] != 0:
                    conn.rollback()
                    print(f"FAIL {table}: 删后复核仍有残留,已回滚,中止")
                    return 1
            conn.commit()
            manifest["tables"][table] = {"archived": count, "deleted": deleted}
            print(f"  {table}: 归档 {count} 行,删除 {deleted} 行 ✓")

    # 全表通过后才做 DDL。
    with conn.cursor() as cursor:
        for table, columns, ddl in DDL_STATEMENTS:
            existing = set(_table_columns(cursor, table))
            if not (set(columns) & existing):
                print(f"  {table}: 待删列均已不存在,跳过 DDL(幂等重跑)")
                continue
            cursor.execute(ddl)
            print(f"  {table}: 已删列 {', '.join(columns)} ✓")
    conn.commit()
    manifest["ddl_applied"] = True

    (out_dir / "manifest.json").write_text(
        json.dumps(manifest, ensure_ascii=False, indent=2), encoding="utf-8"
    )
    print(f"\n完成。档案与 manifest 写入 {out_dir.relative_to(ROOT)}/")
    return 0


def restore(conn, archive_dir: Path) -> int:
    manifest = json.loads((archive_dir / "manifest.json").read_text(encoding="utf-8"))
    for table in manifest["tables"]:
        rows = json.loads((archive_dir / f"{table}.json").read_text(encoding="utf-8"))
        if not rows:
            continue
        with conn.cursor() as cursor:
            existing = set(_table_columns(cursor, table))
            dropped = set(rows[0]) - existing
            if dropped:
                print(f"  {table}: 警告——列 {sorted(dropped)} 已被 DROP,这些值只回 JSON 档案不回库")
            columns = [col for col in rows[0] if col in existing]
            placeholders = ", ".join(["%s"] * len(columns))
            sql = (
                f"INSERT IGNORE INTO {table} (" + ", ".join(f"`{c}`" for c in columns) + ")"
                f" VALUES ({placeholders})"
            )
            cursor.executemany(sql, [[row.get(c) for c in columns] for row in rows])
            print(f"  {table}: 回灌 {cursor.rowcount}/{len(rows)} 行")
        conn.commit()
    return 0


def main() -> int:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--before", default=DEFAULT_CUTOFF, help="cutoff,默认 2026-06-12 00:00:00")
    parser.add_argument("--execute", action="store_true", help="真执行:归档→对账→删行→删列")
    parser.add_argument("--restore", metavar="DIR", help="从归档目录回灌(回滚通道)")
    args = parser.parse_args()

    conn = ContentSupplyDbConfig.from_env(ROOT / ".env").connect()
    try:
        if args.restore:
            return restore(conn, Path(args.restore))
        if args.execute:
            return execute(conn, args.before)
        return dry_run(conn, args.before)
    finally:
        conn.close()


if __name__ == "__main__":
    sys.exit(main())