from rest_framework import generics
from rest_framework.decorators import api_view, permission_classes
from rest_framework.permissions import AllowAny, IsAuthenticated
from rest_framework.response import Response
from rest_framework_simplejwt.views import TokenObtainPairView
from rest_framework.exceptions import PermissionDenied
from .models import User
from .serializers import UserSerializer, UserCreateSerializer, CustomTokenObtainPairSerializer


class CustomTokenObtainPairView(TokenObtainPairView):
    """
    自定义JWT令牌获取视图
    """
    serializer_class = CustomTokenObtainPairSerializer
    permission_classes = [AllowAny]


class UserListView(generics.ListCreateAPIView):
    """
    用户列表和创建视图
    """
    serializer_class = UserSerializer
    permission_classes = [IsAuthenticated]

    def get_queryset(self):
        if self.request.user.role == 'admin':
            return User.objects.all()
        return User.objects.filter(id=self.request.user.id)

    def get_serializer_class(self):
        if self.request.method == 'POST':
            return UserCreateSerializer
        return UserSerializer

    def perform_create(self, serializer):
        # 只有管理员可以创建用户
        if self.request.user.role != 'admin':
            raise PermissionDenied("只有管理员可以创建用户")
        serializer.save()


class UserDetailView(generics.RetrieveUpdateDestroyAPIView):
    """
    用户详情视图
    """
    queryset = User.objects.all()
    serializer_class = UserSerializer
    permission_classes = [IsAuthenticated]

    def perform_update(self, serializer):
        # 普通用户只能修改自己的信息
        if self.request.user.role != 'admin' and self.request.user.id != self.get_object().id:
            raise PermissionDenied("无权修改其他用户信息")

        if self.request.user.role != 'admin':
            allowed_fields = {'first_name', 'last_name', 'email', 'phone'}
            for field in list(serializer.validated_data.keys()):
                if field not in allowed_fields:
                    serializer.validated_data.pop(field)

        serializer.save()

    def perform_destroy(self, instance):
        # 只有管理员可以删除用户
        if self.request.user.role != 'admin':
            raise PermissionDenied("只有管理员可以删除用户")
        instance.delete()


@api_view(['GET'])
@permission_classes([IsAuthenticated])
def current_user(request):
    """
    获取当前用户信息
    """
    serializer = UserSerializer(request.user)
    return Response(serializer.data)