from rest_framework import generics
from rest_framework.decorators import api_view, permission_classes
from rest_framework.permissions import IsAuthenticated
from rest_framework.response import Response
from rest_framework.exceptions import PermissionDenied
from .models import Dictionary
from .serializers import DictionarySerializer


class DictionaryListView(generics.ListCreateAPIView):
    """
    数据字典列表和创建视图
    """
    serializer_class = DictionarySerializer
    permission_classes = [IsAuthenticated]

    def get_queryset(self):
        """
        支持按类型过滤
        """
        queryset = Dictionary.objects.all()

        # 支持按类型过滤
        dict_type = self.request.query_params.get('type')
        if dict_type:
            queryset = queryset.filter(type=dict_type)

        # 支持按名称搜索
        name = self.request.query_params.get('name')
        if name:
            queryset = queryset.filter(name__icontains=name)

        return queryset

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


class DictionaryDetailView(generics.RetrieveUpdateDestroyAPIView):
    """
    数据字典详情视图
    """
    queryset = Dictionary.objects.all()
    serializer_class = DictionarySerializer
    permission_classes = [IsAuthenticated]

    def perform_update(self, serializer):
        # 只有管理员可以更新字典
        if self.request.user.role != 'admin':
            raise PermissionDenied("只有管理员可以更新字典")
        serializer.save()

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


@api_view(['GET'])
@permission_classes([IsAuthenticated])
def dictionary_grouped(request):
    """
    获取分组的数据字典
    """
    dict_types = Dictionary.objects.values('type').distinct()

    result = []
    for dict_type in dict_types:
        type_name = dict_type['type']
        items = Dictionary.objects.filter(type=type_name)
        serializer = DictionarySerializer(items, many=True)
        result.append({
            'type': type_name,
            'items': serializer.data
        })

    return Response(result)