from rest_framework import serializers
from ..models.rate import Rate

class RateSerializer(serializers.ModelSerializer):
    """
    Serializer for the Rate model.
    """
    class Meta:
        model = Rate
        fields = ('id', 'service', 'content_id', 'rate', 'status', 'created_at', 'updated_at')
        read_only_fields = ('id', 'created_at', 'updated_at')
    
    def validate(self, data):
        """
        Validate that the content exists in the specified service.
        """
        service = data.get('service')
        content_id = data.get('content_id')
        
        if not Rate.validate_content_exists(service, content_id):
            raise serializers.ValidationError(f"Content with ID {content_id} does not exist in {service} service.")
        
        return data
    
    def create(self, validated_data):
        """
        Create or update a rate.
        If a rate already exists for the user, service, and content_id, update it.
        """
        user = self.context['request'].user
        service = validated_data.get('service')
        content_id = validated_data.get('content_id')
        
        # Try to get an existing rate
        try:
            rate_obj = Rate.objects.get(
                user=user,
                service=service,
                content_id=content_id
            )
            # Update existing rate
            for attr, value in validated_data.items():
                setattr(rate_obj, attr, value)
            rate_obj.save()
            return rate_obj
        except Rate.DoesNotExist:
            # Create new rate
            return Rate.objects.create(user=user, **validated_data)

class RateStatusSerializer(serializers.Serializer):
    """
    Serializer for checking if a user has rated a content and getting the rate value.
    """
    service = serializers.ChoiceField(choices=Rate.ServiceChoices.choices)
    content_id = serializers.IntegerField(min_value=1)
    
    def validate(self, data):
        """
        Validate that the content exists in the specified service.
        """
        service = data.get('service')
        content_id = data.get('content_id')
        
        if not Rate.validate_content_exists(service, content_id):
            raise serializers.ValidationError(f"Content with ID {content_id} does not exist in {service} service.")
        
        return data

class AverageRateSerializer(serializers.Serializer):
    """
    Serializer for getting the average rate of a content.
    """
    service = serializers.ChoiceField(choices=Rate.ServiceChoices.choices)
    content_id = serializers.IntegerField(min_value=1)
    
    def validate(self, data):
        """
        Validate that the content exists in the specified service.
        """
        service = data.get('service')
        content_id = data.get('content_id')
        
        if not Rate.validate_content_exists(service, content_id):
            raise serializers.ValidationError(f"Content with ID {content_id} does not exist in {service} service.")
        
        return data