from api.models import *
from rest_framework import serializers


class CourseSerializer(serializers.ModelSerializer):
    level = serializers.CharField(source="get_level_display")

    class Meta:
        model = Course
        fields = ‘__all__‘


class CourseDetailSerializer(serializers.ModelSerializer):
    # one2one/fk/choice字段可以直接取出数据，m2m字段会返回一个queryset列表
    title = serializers.CharField(source="course.title")    # source引用本model字段的外键值作为新增"fields"的值
    img = serializers.CharField(source="course.course_img")
    level = serializers.CharField(source="course.get_level_display") # 获取choice的对应值，需要使用get_field_display()方法
                                                                    # restframework源码内部会判断"()"是否该添加

    # m2m字段取数据，需要自定义方法，这里使用SerializerMethodField，方法名称get_field()，这里定义get_recommends()方法。
    # class Meta中的fields需要明确字段值，字段值必须与通过这里使用SerializerMethodField()生成的实例对象名相等。
    recommends = serializers.SerializerMethodField()
    chapter = serializers.SerializerMethodField()

    class Meta:
        model = CourseDetail
        fields = ["course","title","img","level","slogon","why","recommends","chapter"]
        # depth = 2 # 定义返回数据的深度，可以将外键数据库中对应的值全部返回。

    # m2m字段取数据
    def get_recommends(self, obj):
        queryset = obj.recommend_course.all()
        return [{"id":row.id, "title":row.title} for row in queryset]

    # 字段为外键，并且需要反向查找取数据
    def get_chapter(self, obj):
        queryset = obj.course.chapter_set.all()
        return [{"id":row.id, "name":row.name} for row in queryset]

from rest_framework.views import APIView
from rest_framework.response import Response

from api import models
from api.serializers import CourseSerializer,CourseDetailSerializer

class CourseView(APIView):
    # renderer_classes = [JSONRenderer,]
    def get(self, request, *args, **kwargs):
        ret = {"code":1000, "data":None}
        try:
            pk = kwargs.get("pk")
            if pk:
                obj = models.Course.objects.filter(pk=pk).first()
                ser = CourseSerializer(instance=obj, many=False)
            else:
                queryset = models.Course.objects.all()
                ser = CourseSerializer(instance=queryset, many=True)
            ret["data"] = ser.data
        except Exception as e:
            ret["code"] = 1001
            ret["error"] = "获取课程失败"
        return Response(ret)

from api.views import course

urlpatterns = [
    path("course/", course.CourseView.as_view()),
    re_path("course/(?P<pk>\d+)", course.CourseView.as_view()),
]

urlpatterns = [
    path("course/", course.CourseView.as_view({"get":"list"})),
    re_path("course/(?P<pk>\d+)", course.CourseView.as_view({"get":"retrieve"})),
]

from rest_framework.viewsets import ViewSetMixin

class CourseView(ViewSetMixin, APIView):
    def list(self, request, *args, **kwargs):
        ret = {"code": 1000, "data": None}
        try:
            queryset = models.Course.objects.all()
            ser = CourseSerializer(instance=queryset, many=True)
            ret["data"] = ser.data
        except Exception as e:
            ret["code"] = 1001
            ret["error"] = "获取课程失败"
        return Response(ret)

    def retrieve(self, request, *args, **kwargs):
        ret = {"code": 1000, "data": None}
        try:
            pk = kwargs.get("pk")
            queryset = models.CourseDetail.objects.filter(course_id=pk)
            ser = CourseDetailSerializer(instance=queryset, many=True)
            ret["data"] = ser.data
        except Exception as e:
            ret["code"] = 1001
            ret["error"] = "获取课程详细信息失败"
        return Response(ret)

# one2one/fk/choice字段可以直接取出数据，m2m字段会返回一个queryset列表
    title = serializers.CharField(source="course.title")    # source引用本model字段的外键值作为新增"fields"的值
    img = serializers.CharField(source="course.course_img")
    level = serializers.CharField(source="course.get_level_display") # 获取choice的对应值，需要使用get_field_display()方法
                                                                    # restframework源码内部会判断"()"是否该添加

# m2m字段取数据，需要自定义方法，这里使用SerializerMethodField，方法名称get_field()，这里定义get_recommends()方法。
    # class Meta中的fields需要明确字段值，字段值必须与通过这里使用SerializerMethodField()生成的实例对象名相等。
    recommends = serializers.SerializerMethodField()

def get_recommends(self, obj):
    queryset = obj.recommend_course.all()
    return [{"id":row.id, "title":row.title} for row in queryset]

# 二者与class Meta同级，直接定义在class下

chapter = serializers.SerializerMethodField()

def get_chapter(self, obj):
        queryset = obj.course.chapter_set.all()
        return [{"id":row.id, "name":row.name} for row in queryset]

# 二者与class Meta同级，直接定义在class下