"""
系统日志服务
"""
import logging
from typing import Optional
from datetime import datetime
from sqlalchemy import select, func, or_
from sqlalchemy.ext.asyncio import AsyncSession

from app.models.system_log import SystemLog
from app.schemas.system_log import SystemLogCreate, SystemLogQuery

logger = logging.getLogger(__name__)


class SystemLogService:
    """系统日志服务类"""

    async def create_log(
        self,
        db: AsyncSession,
        log_data: SystemLogCreate
    ) -> SystemLog:
        """
        创建系统日志
        
        Args:
            db: 数据库会话
            log_data: 日志数据
            
        Returns:
            创建的日志对象
        """
        try:
            log = SystemLog(**log_data.model_dump())
            db.add(log)
            await db.commit()
            await db.refresh(log)
            return log
        except Exception as e:
            await db.rollback()
            logger.error(f"创建系统日志失败: {str(e)}")
            raise

    async def get_logs(
        self,
        db: AsyncSession,
        query_params: SystemLogQuery
    ) -> tuple[list[SystemLog], int]:
        """
        查询系统日志列表
        
        Args:
            db: 数据库会话
            query_params: 查询参数
            
        Returns:
            (日志列表, 总数)
        """
        try:
            # 构建基础查询
            stmt = select(SystemLog)
            count_stmt = select(func.count(SystemLog.id))

            # 应用筛选条件
            filters = []
            
            if query_params.level:
                filters.append(SystemLog.level == query_params.level)
            
            if query_params.type:
                filters.append(SystemLog.type == query_params.type)
            
            if query_params.user:
                filters.append(SystemLog.user == query_params.user)
            
            if query_params.keyword:
                filters.append(SystemLog.message.like(f"%{query_params.keyword}%"))
            
            if query_params.start_date:
                filters.append(SystemLog.created_at >= query_params.start_date)
            
            if query_params.end_date:
                filters.append(SystemLog.created_at <= query_params.end_date)

            # 应用所有筛选条件
            if filters:
                stmt = stmt.where(*filters)
                count_stmt = count_stmt.where(*filters)

            # 获取总数
            result = await db.execute(count_stmt)
            total = result.scalar_one()

            # 应用排序和分页
            stmt = stmt.order_by(SystemLog.created_at.desc())
            stmt = stmt.offset((query_params.page - 1) * query_params.page_size)
            stmt = stmt.limit(query_params.page_size)

            # 执行查询
            result = await db.execute(stmt)
            logs = result.scalars().all()

            return list(logs), total

        except Exception as e:
            logger.error(f"查询系统日志失败: {str(e)}")
            raise

    async def get_log_by_id(
        self,
        db: AsyncSession,
        log_id: int
    ) -> Optional[SystemLog]:
        """
        根据ID获取日志详情
        
        Args:
            db: 数据库会话
            log_id: 日志ID
            
        Returns:
            日志对象或None
        """
        try:
            stmt = select(SystemLog).where(SystemLog.id == log_id)
            result = await db.execute(stmt)
            return result.scalar_one_or_none()
        except Exception as e:
            logger.error(f"获取日志详情失败: {str(e)}")
            raise

    async def delete_logs_before_date(
        self,
        db: AsyncSession,
        before_date: datetime
    ) -> int:
        """
        删除指定日期之前的日志（用于日志清理）
        
        Args:
            db: 数据库会话
            before_date: 截止日期
            
        Returns:
            删除的日志数量
        """
        try:
            stmt = select(SystemLog).where(SystemLog.created_at < before_date)
            result = await db.execute(stmt)
            logs = result.scalars().all()
            
            count = len(logs)
            for log in logs:
                await db.delete(log)
            
            await db.commit()
            logger.info(f"已删除 {count} 条日志记录")
            return count
        except Exception as e:
            await db.rollback()
            logger.error(f"删除日志失败: {str(e)}")
            raise


# 创建全局服务实例
system_log_service = SystemLogService()