import jwt
from django.http import JsonResponse
from EduSystemServer.settings import TOKEN_KEY
from EduSystemServer.utils import ResponseUtil
from Eduadmin.models import Admin
from Student.models import Student
from teacher.models import Teacher


class JWTMiddleware:
    """
    JWT中间件，验证用户是否登录
    """
    def __init__(self, get_response):
        self.get_response = get_response

    def __call__(self, request):
        # 检查请求的路径是否是登录路由，如果是，放行
        if request.path == '/login' \
                or request.path == "/index" \
                or request.path == "/" \
                or request.path.startswith("/admin")\
                or request.path.startswith("/static"):
            response = self.get_response(request)
            return response
        # 从请求头中获取 Token
        token = request.META.get('HTTP_AUTHORIZATION', '')
        try:
            # 验证 Token
            payload = jwt.decode(token, TOKEN_KEY, algorithms=['HS256'])
            # 将解码后的 Token 数据存储在 request 中，以便视图可以访问
            if payload.get("type") == "student":
                if not Student.objects.filter(username=payload.get("username")).exists():
                    return JsonResponse(ResponseUtil.error("错误信息！"), status=401)
            if payload.get("type") == "teacher":
                if not Teacher.objects.filter(username=payload.get("username")).exists():
                    return JsonResponse(ResponseUtil.error("错误信息！"), status=401)
            if payload.get("type") == "admin":
                if not Admin.objects.filter(username=payload.get("username")).exists():
                    return JsonResponse(ResponseUtil.error("错误信息！"), status=401)
            request.jwt_payload = payload
        except jwt.ExpiredSignatureError:
            return JsonResponse(ResponseUtil.error("登录失效！"), status=401)
        except jwt.DecodeError:
            return JsonResponse(ResponseUtil.error("登录失效！"), status=401)
        # 继续处理请求
        response = self.get_response(request)
        return response