import logging
import os
import pprint

from pelican import signals
from PIL import Image

log = logging.getLogger(__name__)

THUMBNAIL_MAX_SIZE = 448

def generator_finalized(generator):
    """
    Generates thumbnails for images specified in article metadata.
    """
    output_path = generator.settings['OUTPUT_PATH']
    content_path = generator.settings['PATH']
    media_path = os.path.join(content_path, 'media')
    thumb_dir = os.path.join(output_path, 'media', 'thumbnails')

    if not os.path.exists(thumb_dir):
        try:
            os.makedirs(thumb_dir)
            log.info(f"Created thumbnail directory: {thumb_dir}")
        except OSError as e:
            log.error(f"Could not create thumbnail directory {thumb_dir}: {e}")
            return

    for article in generator.articles:
        if hasattr(article, 'image'):
            image_path_rel_to_content = article.image
            # image_path_rel_to_content is often like 'media/imagename.jpg'
            # or just 'imagename.jpg' if it's directly in 'content/media/'
            # and STATIC_PATHS includes 'media'.
            # We assume article.image is a path relative to the 'content' folder.
            
            source_image_full_path = os.path.join(media_path, image_path_rel_to_content)

            if not os.path.exists(source_image_full_path):
                log.warning(f"Source image not found for article '{article.slug}': {source_image_full_path}")
                continue

            image_filename = os.path.basename(image_path_rel_to_content)
            thumb_path = os.path.join(thumb_dir, image_filename)

            _, ext = os.path.splitext(image_filename)
            ext_lower = ext.lower()
            if ext_lower not in ['.jpg', '.jpeg', '.png']:
                log.info(f"Skipping non-JPG/PNG image for article '{article.slug}': {image_filename}")
                continue

            try:
                log.debug(f"Processing image: {source_image_full_path}")
                img = Image.open(source_image_full_path)
                
                # Preserve original format, handle potential conversion issues for some modes
                original_format = img.format
                if img.mode == 'P' and 'transparency' in img.info: # Palette mode with transparency
                    img = img.convert('RGBA')
                elif img.mode not in ('RGB', 'RGBA', 'L'): # L is grayscale
                    log.info(f"Converting image {image_filename} from mode {img.mode} to RGB for thumbnailing.")
                    img = img.convert('RGB')

                img.thumbnail((THUMBNAIL_MAX_SIZE, THUMBNAIL_MAX_SIZE))
                
                save_kwargs = {}
                if original_format:
                    save_kwargs['format'] = original_format
                if original_format == 'JPEG':
                    save_kwargs['quality'] = 95 # Adjust quality for JPEGs
                    save_kwargs['optimize'] = True
                elif original_format == 'PNG':
                    save_kwargs['optimize'] = True

                img.save(thumb_path, **save_kwargs)
                log.info(f"Generated thumbnail for '{article.slug}': {thumb_path}")
                
                # Optionally, add thumbnail URL to article metadata if needed by templates
                # This depends on how SITEURL and paths are structured.
                # For now, just creating the file.
                # article.thumbnail_url = f"{generator.settings.get('SITEURL', '')}/media/thumbs/{image_filename}"

            except FileNotFoundError:
                log.error(f"Image file not found: {source_image_full_path}")
            except IOError as e:
                log.error(f"Could not open or process image {source_image_full_path}: {e}")
            except Exception as e:
                log.error(f"An unexpected error occurred while processing {source_image_full_path}: {e}")


def register():
    signals.article_generator_finalized.connect(generator_finalized)