from rest_framework.permissions import IsAuthenticated # 判斷用戶是否登錄
from rest_framework_jwt.authentication import JSONWebTokenAuthentication # jwt用戶認證
class UserFavViewset(mixins.CreateModelMixin, mixins.ListModelMixin, mixins.RetrieveModelMixin,
      mixins.DestroyModelMixin, viewsets.GenericViewSet):
 """
 list:
  獲取用戶收藏列表
 retrieve:
  判斷某個商品是否已經收藏
 create:
  收藏商品
 delete:
  取消收藏
 """
 # 權限判斷：IsAuthenticated表示是否已經登錄，IsOwnerOrReadOnly表示數據是不是屬于當前登錄用戶
 permission_classes = (IsAuthenticated, IsOwnerOrReadOnly)
 # 用戶認證：方式一：JSONWebTokenAuthentication；方式二：SessionAuthentication
 authentication_classes = (JSONWebTokenAuthentication, SessionAuthentication)
 # 定義通過哪個參數來定位實例
 lookup_field = "goods_id" # 在詳細頁面時，搜索goods_id來確認該商品有沒有被收藏，是在當前用戶下進行搜索的

 def get_queryset(self):
  """獲取當前登錄用戶的收藏信息"""
  return UserFav.objects.filter(user=self.request.user)

 # 方法一：修改商品收藏數
 # def perform_create(self, serializer):
 #  """修改商品收藏數"""
 #  instance = serializer.save()
 #  goods = instance.goods
 #  goods.fav_num += 1
 #  goods.save()

 # 動態(tài)設置序列化類
 def get_serializer_class(self):
  if self.action == "list":
   return UserFavDetailSerializer
  elif self.action == "create":
   return UserFavSerializer

  return UserFavSerializer

from rest_framework import permissions

# 權限判斷：數據是不是屬于當前登錄用戶
class IsOwnerOrReadOnly(permissions.BasePermission):
 """
 Object-level permission to only allow owners of an object to edit it.
 Assumes the model instance has an `owner` attribute.
 """

 def has_object_permission(self, request, view, obj):
  # 1 只讀
  # Read permissions are allowed to any request,
  # so we'll always allow GET, HEAD or OPTIONS requests.
  if request.method in permissions.SAFE_METHODS: # 是不是安全的訪問方法
   return True
 # 2 寫權限
  # Instance must have an attribute named `owner`.
  # return (obj.publisher if obj.publisher else self.fans )== request.user
  return obj.user== request.user # 判斷當前數據是不是登錄用戶的數據

class UserFavViewset(mixins.CreateModelMixin, mixins.ListModelMixin, mixins.RetrieveModelMixin,
      mixins.DestroyModelMixin, viewsets.GenericViewSet):
 """
 list:
  獲取用戶收藏列表
 retrieve:
  判斷某個商品是否已經收藏
 create:
  收藏商品
  delete:
   取消收藏
 """
 # 權限判斷：IsAuthenticated表示是否已經登錄，IsOwnerOrReadOnly表示數據是不是屬于當前登錄用戶
 permission_classes = (IsAuthenticated, IsOwnerOrReadOnly)
 # 用戶認證：方式一：JSONWebTokenAuthentication；方式二：SessionAuthentication
 authentication_classes = (JSONWebTokenAuthentication, SessionAuthentication)
 # 設置
 lookup_field = "goods_id" # 在詳細頁面時，搜索goods_id來確認該商品有沒有被收藏，是在當前用戶下進行搜索的

 def get_queryset(self):
  """獲取當前登錄用戶的收藏信息"""
  return UserFav.objects.filter(user=self.request.user)

from rest_framework import permissions

class IsOwnerOrReadOnly(permissions.BasePermission):
  '''
  常規(guī)的授權是 只有擁有者才能編輯它
  '''

  def has_object_permission(self, request, view, obj):
    # 讀權限 向所有請求開放
    # 所以我們總是允許get, head or options requests.
    if request.method in permissions.SAFE_METHODS:
      return True

    # 寫權限 只給擁有者
    return obj.owner == request.user

'''基于泛型類的視圖'''
from snippets.models import Snippet
from snippets.serializers import SnippetSerializer, UserSerializer
from rest_framework import generics
from snippets.permissions import IsOwnerOrReadOnly
from django.contrib.auth.models import User

class UserList(generics.ListAPIView):
  '''
  User表的列表api視圖 查 增 操作
  '''
  queryset = User.objects.all()
  serializer_class = UserSerializer

class UserDetail(generics.RetrieveDestroyAPIView):
  '''
  User表的詳情api視圖 查 改 刪操作
  '''
  queryset = User.objects.all()
  serializer_class = UserSerializer



class SnippetList(generics.ListCreateAPIView):
  permission_classes = [permissions.IsAuthenticatedOrReadOnly]
  queryset = Snippet.objects.all()
  serializer_class = SnippetSerializer

  def perform_create(self, serializer):
    serializer.save(owner=self.request.user)


class SnippetDetail(generics.RetrieveDestroyAPIView):
  # detail 所有人都能讀，但是只有擁有者可以更改

  # permissions.IsAuthenticatedOrReadOnly 表示沒有認證的人有讀的權限，認證的人有所有權限
  # IsOwnerOrReadOnly 通過了前面的授權之后，還要通過這個授權
  # 當所有的授權都通過的時候 所有的對象實例都返回true 表示授權通過
  permission_classes = [permissions.IsAuthenticatedOrReadOnly, IsOwnerOrReadOnly]
  queryset = Snippet.objects.all()
  serializer_class = SnippetSerializer