from rest_framework import serializers
from apps.files.models import PostFileModel


class PostFileSerializer(serializers.ModelSerializer):
    """Serializer for PostFileModel."""

    class Meta:
        model = PostFileModel
        fields = ["hash_blake3", "file_type", "file", "thumbnail"]
        # Add any other fields you need

    def to_representation(self, instance):
        """Customize the representation of the model."""
        representation = super().to_representation(instance)

        # Add file name from related model
        try:
            representation["filename"] = instance.name.first().filename
        except (AttributeError, IndexError):
            representation["filename"] = "Unknown"

        # Add URLs for different thumbnail sizes
        base_url = f"/api/files/{instance.hash_blake3}/"
        thumbnails = {}
        for size_key in THUMBNAIL_SIZES:
            thumbnails[size_key] = f"{base_url}?t={size_key}"

        representation["thumbnails"] = thumbnails
        representation["download_url"] = f"{base_url}?d=0"

        return representation