"""
AI Box Sophon Adapter — 告警记录清理

当告警记录超过配置的 max_records 时，自动清理最早的记录及其关联的视频文件。
"""
import logging
import os
import shutil

from sqlalchemy import select, func, asc

from .models.orm import AlarmRecord

logger = logging.getLogger(__name__)


async def trim_alarm_records(db_session, upload_root: str, max_records: int) -> int:
    """
    裁剪告警记录，保留最新的 max_records 条

    删除超出限制的最早记录，同时清理关联的视频文件目录。

    Args:
        db_session: SQLAlchemy 异步 session
        upload_root: 上传文件根目录（如 ./data/uploads）
        max_records: 最大保留条数，<= 0 表示不限制

    Returns:
        实际删除的记录数
    """
    if max_records <= 0:
        return 0

    # 查询当前总记录数
    count_result = await db_session.execute(
        select(func.count()).select_from(AlarmRecord)
    )
    total = count_result.scalar() or 0

    if total <= max_records:
        return 0

    # 超出数量
    overflow = total - max_records

    # 查询最早的 overflow 条记录（按 created_at 升序）
    stmt = (
        select(AlarmRecord)
        .order_by(asc(AlarmRecord.created_at)) # type: ignore
        .limit(overflow)
    )
    result = await db_session.execute(stmt)
    old_records = result.scalars().all()

    deleted_count = 0
    for record in old_records:
        # 清理关联的视频文件目录
        if record.video_file:
            _delete_video_dir(upload_root, record.video_file)

        await db_session.delete(record)
        deleted_count += 1

    await db_session.commit()

    if deleted_count > 0:
        logger.info(
            f"[AlarmTrim] 已清理 {deleted_count} 条告警记录 "
            f"（保留最新 {max_records} 条，原共 {total} 条）"
        )

    return deleted_count


def _delete_video_dir(upload_root: str, video_id: str) -> None:
    """
    删除告警关联的视频文件目录

    视频存储路径: {upload_root}/aibox_sophon_adapter/{video_id}/

    Args:
        upload_root: 上传根目录
        video_id: 视频唯一标识（VideoId）
    """
    video_dir = os.path.join(upload_root, "aibox_sophon_adapter", video_id)

    if not os.path.isdir(video_dir):
        return

    try:
        shutil.rmtree(video_dir)
        logger.debug(f"[AlarmTrim] 已删除视频目录: {video_dir}")
    except OSError as e:
        logger.warning(f"[AlarmTrim] 删除视频目录失败 [{video_dir}]: {e}")