"""
審計日誌歸檔批次 (5.3)
執行時間: 每月 1 日 01:00
批次名稱: archive_audit_logs

將 90 天前的審計日誌匯出為 CSV，並從主資料庫刪除
歸檔目錄: /mnt/nas/working/audit_logs/
"""
import csv
import logging
import os
from datetime import datetime, timedelta
from typing import Optional

from app.batch.base import log_batch_execution

logger = logging.getLogger(__name__)

ARCHIVE_DAYS = 90  # 保留最近 90 天，超過的歸檔
ARCHIVE_BASE_DIR = "/mnt/nas/working/audit_logs"


def _get_archive_dir() -> str:
    """取得歸檔目錄，不存在時建立"""
    os.makedirs(ARCHIVE_BASE_DIR, exist_ok=True)
    return ARCHIVE_BASE_DIR


def run_archive_audit_logs(dry_run: bool = False) -> dict:
    """
    執行審計日誌歸檔批次

    Args:
        dry_run: True 時只統計不實際刪除

    Returns:
        執行結果摘要
    """
    started_at = datetime.utcnow()
    cutoff_date = datetime.utcnow() - timedelta(days=ARCHIVE_DAYS)

    logger.info(f"=== 開始審計日誌歸檔批次 === 截止日期: {cutoff_date.strftime('%Y-%m-%d')}")
    if dry_run:
        logger.info("[DRY RUN] 不會實際刪除資料")

    from app.db.session import get_db
    from app.models.audit_log import AuditLog

    db = next(get_db())
    try:
        # 1. 查詢超過 90 天的日誌
        old_logs = db.query(AuditLog).filter(
            AuditLog.performed_at < cutoff_date
        ).order_by(AuditLog.performed_at).all()

        total_count = len(old_logs)
        logger.info(f"找到 {total_count} 筆待歸檔日誌")

        if total_count == 0:
            message = f"無需歸檔 (截止日期 {cutoff_date.strftime('%Y-%m-%d')} 前無記錄)"
            log_batch_execution(
                batch_name="archive_audit_logs",
                status="success",
                message=message,
                started_at=started_at,
            )
            return {"status": "success", "archived": 0, "message": message}

        # 2. 匯出到 CSV
        archive_month = cutoff_date.strftime("%Y%m")
        archive_dir = _get_archive_dir()
        csv_path = os.path.join(archive_dir, f"archive_{archive_month}.csv")

        fieldnames = [
            "id", "action", "resource_type", "resource_id",
            "performed_by", "ip_address",
            "details", "performed_at"
        ]

        logger.info(f"匯出至: {csv_path}")
        with open(csv_path, "w", newline="", encoding="utf-8") as f:
            writer = csv.DictWriter(f, fieldnames=fieldnames)
            writer.writeheader()
            for log in old_logs:
                writer.writerow({
                    "id": log.id,
                    "action": log.action,
                    "resource_type": log.resource_type,
                    "resource_id": log.resource_id,
                    "performed_by": getattr(log, "performed_by", ""),
                    "ip_address": getattr(log, "ip_address", ""),
                    "details": str(getattr(log, "details", "")),
                    "performed_at": str(log.performed_at),
                })

        logger.info(f"已匯出 {total_count} 筆至 {csv_path}")

        # 3. 刪除舊日誌 (非 dry_run 才執行)
        deleted_count = 0
        if not dry_run:
            for log in old_logs:
                db.delete(log)
            db.commit()
            deleted_count = total_count
            logger.info(f"已刪除 {deleted_count} 筆舊日誌")
        else:
            logger.info(f"[DRY RUN] 將刪除 {total_count} 筆 (未實際執行)")

        # 4. 記錄批次執行日誌
        finished_at = datetime.utcnow()
        message = (
            f"歸檔 {total_count} 筆到 {csv_path}"
            + (f"; 已刪除 {deleted_count} 筆" if not dry_run else " (DRY RUN)")
        )
        log_batch_execution(
            batch_name="archive_audit_logs",
            status="success",
            message=message,
            started_at=started_at,
            finished_at=finished_at,
        )

        logger.info(f"=== 審計日誌歸檔批次完成 === {message}")
        return {
            "status": "success",
            "archived": total_count,
            "deleted": deleted_count,
            "csv_path": csv_path,
        }

    except Exception as e:
        error_msg = f"審計日誌歸檔批次失敗: {str(e)}"
        logger.error(error_msg)
        try:
            db.rollback()
        except Exception:
            pass
        log_batch_execution(
            batch_name="archive_audit_logs",
            status="failed",
            message=error_msg,
            started_at=started_at,
        )
        return {"status": "failed", "error": str(e)}
    finally:
        db.close()


if __name__ == "__main__":
    import sys
    import argparse
    sys.path.insert(0, os.path.join(os.path.dirname(__file__), "../../.."))
    logging.basicConfig(level=logging.INFO)

    parser = argparse.ArgumentParser()
    parser.add_argument("--dry-run", action="store_true", help="只統計不實際刪除")
    args = parser.parse_args()

    result = run_archive_audit_logs(dry_run=args.dry_run)
    print(f"執行結果: {result}")