from channels.middleware import BaseMiddleware
from channels.db import database_sync_to_async
from django.contrib.auth.models import AnonymousUser
from rest_framework.authtoken.models import Token
from django.contrib.auth import get_user_model
import logging
import re
from django.middleware.csrf import CsrfViewMiddleware
from django.conf import settings
from django.utils.deprecation import MiddlewareMixin

logger = logging.getLogger(__name__)

User = get_user_model()  # 获取当前项目的用户模型

@database_sync_to_async
def get_user(token_key):
    """异步获取用户信息"""
    try:
        token = Token.objects.get(key=token_key)
        logger.info(f"用户认证成功: {token.user.username}")
        return token.user
    except Token.DoesNotExist:
        logger.warning(f"无效的token: {token_key}")
        return AnonymousUser()
    except Exception as e:
        logger.error(f"认证错误: {str(e)}")
        return AnonymousUser()

class TokenAuthMiddleware(BaseMiddleware):
    """Token认证中间件"""
    async def __call__(self, scope, receive, send):
        try:
            # 从请求头获取token
            headers = dict(scope['headers'])
            if b'authorization' in headers:
                token_name, token_key = headers[b'authorization'].decode().split()
                if token_name == 'Token':
                    scope['user'] = await get_user(token_key)
                    return await super().__call__(scope, receive, send)
            
            # 如果没有token或token无效
            scope['user'] = AnonymousUser()
            return await super().__call__(scope, receive, send)
            
        except Exception as e:
            logger.error(f"WebSocket认证错误: {str(e)}")
            scope['user'] = AnonymousUser()
            return await super().__call__(scope, receive, send)

class UserActivityMiddleware(MiddlewareMixin):
    """中间件用于记录用户活动"""
    
    def process_request(self, request):
        # 可以在这里记录用户活动日志
        pass

class CSRFExemptMiddleware(MiddlewareMixin):
    """为特定URL路径豁免CSRF保护的中间件"""
    
    def process_view(self, request, callback, callback_args, callback_kwargs):
        # 检查是否有CSRF豁免URL配置
        if not hasattr(settings, 'CSRF_EXEMPT_URLS'):
            return None
            
        # 获取当前请求的路径
        path = request.path_info.lstrip('/')
        
        # 检查是否匹配任何豁免模式
        for exempt_pattern in settings.CSRF_EXEMPT_URLS:
            if re.match(exempt_pattern, path):
                setattr(request, '_dont_enforce_csrf_checks', True)
                break
                
        return None