from datetime import datetime
from functools import wraps
from typing import Any, Callable, Optional

from fastapi import Request
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from app.models.audit_log import AuditAction, AuditLog
from app.schemas.audit_log import AuditLogCreate, AuditLogQuery


class AuditService:
    """审计日志服务"""

    @staticmethod
    async def log_action(
        db: AsyncSession,
        company_id: int,
        action: str,
        resource_type: str,
        user_id: Optional[int] = None,
        resource_id: Optional[str] = None,
        details: Optional[dict[str, Any]] = None,
        ip_address: Optional[str] = None,
        user_agent: Optional[str] = None,
    ) -> AuditLog:
        """
        记录审计日志
        
        Args:
            db: 数据库会话
            company_id: 企业 ID
            action: 操作类型
            resource_type: 资源类型
            user_id: 用户 ID
            resource_id: 资源 ID
            details: 操作详情
            ip_address: IP 地址
            user_agent: User-Agent
            
        Returns:
            创建的审计日志对象
        """
        log_data = AuditLogCreate(
            company_id=company_id,
            user_id=user_id,
            action=action,
            resource_type=resource_type,
            resource_id=resource_id,
            details=details,
            ip_address=ip_address,
            user_agent=user_agent,
        )
        
        audit_log = AuditLog(**log_data.model_dump())
        db.add(audit_log)
        await db.commit()
        await db.refresh(audit_log)
        return audit_log

    @staticmethod
    async def get_logs(
        db: AsyncSession,
        query_params: AuditLogQuery,
    ) -> list[AuditLog]:
        """
        查询审计日志
        
        Args:
            db: 数据库会话
            query_params: 查询参数
            
        Returns:
            审计日志列表
        """
        stmt = select(AuditLog)
        
        # 添加过滤条件
        if query_params.company_id:
            stmt = stmt.where(AuditLog.company_id == query_params.company_id)
        if query_params.user_id:
            stmt = stmt.where(AuditLog.user_id == query_params.user_id)
        if query_params.action:
            stmt = stmt.where(AuditLog.action == query_params.action)
        if query_params.resource_type:
            stmt = stmt.where(AuditLog.resource_type == query_params.resource_type)
        if query_params.resource_id:
            stmt = stmt.where(AuditLog.resource_id == query_params.resource_id)
        if query_params.start_date:
            stmt = stmt.where(AuditLog.created_at >= query_params.start_date)
        if query_params.end_date:
            stmt = stmt.where(AuditLog.created_at <= query_params.end_date)
        
        # 排序和分页
        stmt = stmt.order_by(AuditLog.created_at.desc())
        stmt = stmt.offset(query_params.skip).limit(query_params.limit)
        
        result = await db.execute(stmt)
        return list(result.scalars().all())

    @staticmethod
    async def log_from_request(
        db: AsyncSession,
        request: Request,
        company_id: int,
        action: str,
        resource_type: str,
        user_id: Optional[int] = None,
        resource_id: Optional[str] = None,
        details: Optional[dict[str, Any]] = None,
    ) -> AuditLog:
        """
        从 Request 对象中提取信息并记录审计日志
        
        Args:
            db: 数据库会话
            request: FastAPI 请求对象
            company_id: 企业 ID
            action: 操作类型
            resource_type: 资源类型
            user_id: 用户 ID
            resource_id: 资源 ID
            details: 操作详情
            
        Returns:
            创建的审计日志对象
        """
        # 提取 IP 地址
        ip_address = request.client.host if request.client else None
        
        # 提取 User-Agent
        user_agent = request.headers.get("user-agent")
        
        return await AuditService.log_action(
            db=db,
            company_id=company_id,
            action=action,
            resource_type=resource_type,
            user_id=user_id,
            resource_id=resource_id,
            details=details,
            ip_address=ip_address,
            user_agent=user_agent,
        )


# 单例实例
audit_service = AuditService()


def audit_log(
    action: str,
    resource_type: str,
    get_resource_id: Optional[Callable] = None,
):
    """
    审计日志装饰器
    
    Args:
        action: 操作类型
        resource_type: 资源类型
        get_resource_id: 从函数返回值中获取 resource_id 的函数
        
    Example:
        @audit_log(action=AuditAction.CREATE, resource_type="company")
        async def create_company(...):
            ...
    """
    def decorator(func: Callable):
        @wraps(func)
        async def wrapper(*args, **kwargs):
            result = await func(*args, **kwargs)
            
            # TODO: 在实现认证后，从上下文获取 company_id 和 user_id
            # 目前暂时跳过实际记录
            
            return result
        return wrapper
    return decorator