#backend/crud_demo/serializers.py

from crud_book.models import CrudBookModel, ReadingProgress
from dvadmin.utils.serializers import CustomModelSerializer
from rest_framework import serializers
from django.conf import settings


class CrudBookModelSerializer(CustomModelSerializer):
    """
    序列化器
    """
    # 添加SerializerMethodField来处理image字段
    image = serializers.SerializerMethodField()
    location = serializers.SerializerMethodField()

    def get_image(self, obj):
        """
        获取完整的图片URL
        """
        if obj.image:
            # 检查image是否已经是完整的URL
            if obj.image.startswith(('http://', 'https://')):
                return obj.image
            # 否则添加MEDIA_URL前缀
            return settings.API_URL + obj.image
        return None

    def get_location(self, obj):
        """
        获取完整的图书URL
        """
        if obj.location:
            # 检查location是否已经是完整的URL
            if obj.location.startswith(('http://', 'https://')):
                return obj.location
            # 否则添加MEDIA_URL前缀
            return settings.API_URL + obj.location
        return None
    

#这里是进行了序列化模型及所有的字段
    class Meta:
        model = CrudBookModel
        fields = "__all__"

#这里是创建/更新时的列化器
class CrudBookModelCreateUpdateSerializer(CustomModelSerializer):
    """
    创建/更新时的列化器
    """

    class Meta:
        model = CrudBookModel
        fields = '__all__'


class ReadingProgressSerializer(CustomModelSerializer):
    """
    阅读进度序列化器
    """
    # 添加book_id字段，便于前端传递和接收
    book_id = serializers.IntegerField(write_only=True, required=True)
    
    class Meta:
        model = ReadingProgress
        fields = '__all__'
        read_only_fields = ('user', 'book')  # 将book设为只读，使用book_id进行设置
        
    def validate_book_id(self, value):
        """验证book_id对应的图书是否存在"""
        try:
            CrudBookModel.objects.get(id=value)
            return value
        except CrudBookModel.DoesNotExist:
            raise serializers.ValidationError(f'ID为{value}的图书不存在')
            
    def create(self, validated_data):
        """创建阅读进度记录"""
        # 获取book_id并删除，因为我们需要用它查找book对象
        book_id = validated_data.pop('book_id')
        
        # 查找对应的book对象
        book = CrudBookModel.objects.get(id=book_id)
        
        # 创建记录，设置user和book
        validated_data['user'] = self.context['request'].user
        validated_data['book'] = book
        
        return super().create(validated_data)
        
    def update(self, instance, validated_data):
        """更新阅读进度记录"""
        # 如果提供了book_id，则验证并更新book
        if 'book_id' in validated_data:
            book_id = validated_data.pop('book_id')
            book = CrudBookModel.objects.get(id=book_id)
            validated_data['book'] = book
            
        return super().update(instance, validated_data)