from rest_framework import serializers
from rest_framework.exceptions import ValidationError
from drf_spectacular.utils import extend_schema_field

from users.serializers import PublicUserSerializer
from .models import Publication, Rating, Category

class CategorySerializer(serializers.ModelSerializer):
    class Meta:
        model = Category
        fields = ('pk', 'name')

class PublicationSerializer(serializers.ModelSerializer):
    category_detail = CategorySerializer(source="category", read_only=True)
    user_detail = PublicUserSerializer(source="user", read_only=True)
    average_score = serializers.SerializerMethodField(read_only=True)

    @extend_schema_field(serializers.FloatField())
    def get_average_score(self, obj):
        return getattr(obj, 'average_score', 0)
    
    def validate(self, attrs):
        content_type = attrs.get('content_type')
        image = attrs.get('image')
        video = attrs.get('video')

        errors = {}

        if content_type == 'image' and not image:
            errors['image'] = 'Required image file'

        if content_type == 'video' and not video:
            errors['video'] = 'Required video file'

        if image and video:
            errors['non_field_errors'] = 'You must upload either a video or an image, not both'

        if errors:
            raise serializers.ValidationError(errors)

        return attrs

    class Meta:
        model = Publication
        fields = ('pk', 'image', 'video', 'content_type', 'status', 'average_score', 'description', 'is_pinned', 'user', 'user_detail', 'category', 'category_detail','time_created', 'time_updated')

        read_only_fields = ('time_created', 'time_updated', 'is_pinned', 'user', 'status')

class AdminPublicationSerializer(PublicationSerializer):
    class Meta(PublicationSerializer.Meta):
        read_only_fields = ('time_created', 'time_updated', 'user')

class RatePublicationSerializer(serializers.Serializer):
    score = serializers.IntegerField()
    publication = serializers.PrimaryKeyRelatedField(queryset=Publication.objects.only_publish())

    def validate_score(self, value):
        if value > 5 or value < 1:
            raise ValidationError('Score must be between 1 and 5')
        
        return value