import os
from io import BytesIO
from PIL import Image
from django.db import models
from django.core.files.base import ContentFile
import logging

logger = logging.getLogger(__name__)


class WebPImageField(models.ImageField):
    """
    A custom ImageField that converts uploaded images to WebP automatically.

    Inherits from models.ImageField (description: "Image").
    Accepts the same arguments:
        verbose_name, name, upload_to, storage,
        width_field, height_field, **kwargs
    """

    def pre_save(self, model_instance, add):
        file_obj = getattr(model_instance, self.attname)

        if file_obj and not file_obj._committed:
            self._convert_to_webp(file_obj)

        return super().pre_save(model_instance, add)

    def _convert_to_webp(self, file_obj):
        try:
            file_obj.open()
            image = Image.open(file_obj)

            if image.format == 'WEBP':
                image.close()
                return

            if image.mode == 'P':
                image = image.convert('RGBA')
            elif image.mode not in ('RGBA', 'LA'):
                image = image.convert('RGB')

            image_io = BytesIO()
            image.save(image_io, format='WEBP', quality=85, optimize=True)
            image.close()

            new_filename = os.path.splitext(file_obj.name)[0] + '.webp'
            file_obj.save(new_filename, ContentFile(image_io.getvalue()), save=False)

        except Exception as e:
            logger.error(f"WebP conversion failed: {e}")