import os
import argparse
import shutil
import sys
from pathlib import Path
from PIL import Image
from caption import caption_images


def is_image_file(filename):
    """Check if a file is an allowed image type."""
    allowed_extensions = ['.png', '.jpg', '.jpeg', '.webp']
    return any(filename.lower().endswith(ext) for ext in allowed_extensions)


def is_unsupported_image(filename):
    """Check if a file is an image but not of an allowed type."""
    unsupported_extensions = ['.bmp', '.gif', '.tiff', '.tif', '.ico', '.svg']
    return any(filename.lower().endswith(ext) for ext in unsupported_extensions)


def is_text_file(filename):
    """Check if a file is a text file."""
    return filename.lower().endswith('.txt')


def validate_input_directory(input_dir):
    """Validate that the input directory only contains allowed image formats."""
    input_path = Path(input_dir)

    unsupported_files = []
    text_files = []

    for file_path in input_path.iterdir():
        if file_path.is_file():
            if is_unsupported_image(file_path.name):
                unsupported_files.append(file_path.name)
            elif is_text_file(file_path.name):
                text_files.append(file_path.name)

    if unsupported_files:
        print("Error: Unsupported image formats detected.")
        print("Only .png, .jpg, .jpeg, and .webp files are allowed.")
        print("The following files are not supported:")
        for file in unsupported_files:
            print(f"  - {file}")
        sys.exit(1)

    if text_files:
        print("Warning: Text files detected in the input directory.")
        print("The following text files will be overwritten:")
        for file in text_files:
            print(f"  - {file}")


def collect_images_by_category(input_path):
    """Collect all valid images and group them by category."""
    images_by_category = {}
    image_paths_by_category = {}

    for file_path in input_path.iterdir():
        if file_path.is_file() and is_image_file(file_path.name):
            try:
                image = Image.open(file_path).convert("RGB")

                # Determine the category from the filename
                category = file_path.stem.rsplit('_', 1)[0]

                # Add image to the appropriate category
                if category not in images_by_category:
                    images_by_category[category] = []
                    image_paths_by_category[category] = []

                images_by_category[category].append(image)
                image_paths_by_category[category].append(file_path)
            except Exception as e:
                print(f"Error loading {file_path.name}: {e}")

    return images_by_category, image_paths_by_category


def process_by_category(images_by_category, image_paths_by_category, input_path, output_path):
    """Process images in batches by category."""
    processed_count = 0
    for category, images in images_by_category.items():
        image_paths = image_paths_by_category[category]
        try:
            # Generate captions for the entire category using batch mode
            captions = caption_images(images, category=category, batch_mode=True)
            write_captions(image_paths, captions, input_path, output_path)
            processed_count += len(images)
        except Exception as e:
            print(f"Error generating captions for category '{category}': {e}")
    return processed_count


def process_all_at_once(images_by_category, image_paths_by_category, input_path, output_path):
    """Process all images at once."""
    all_images = [img for imgs in images_by_category.values() for img in imgs]
    all_image_paths = [path for paths in image_paths_by_category.values() for path in paths]
    processed_count = 0
    try:
        captions = caption_images(all_images, batch_mode=False)
        write_captions(all_image_paths, captions, input_path, output_path)
        processed_count += len(all_images)
    except Exception as e:
        print(f"Error generating captions: {e}")
    return processed_count


def process_images(input_dir, output_dir, batch_images=False):
    """Process all images in the input directory and generate captions."""
    input_path = Path(input_dir)
    output_path = Path(output_dir) if output_dir else input_path

    validate_input_directory(input_dir)
    os.makedirs(output_path, exist_ok=True)

    # Collect images by category
    images_by_category, image_paths_by_category = collect_images_by_category(input_path)

    # Log the number of images found
    total_images = sum(len(images) for images in images_by_category.values())
    print(f"Found {total_images} images to process.")

    if not total_images:
        print("No valid images found to process.")
        return

    if batch_images:
        processed_count = process_by_category(images_by_category, image_paths_by_category, input_path, output_path)
    else:
        processed_count = process_all_at_once(images_by_category, image_paths_by_category, input_path, output_path)

    print(f"\nProcessing complete. {processed_count} images were captioned.")


def write_captions(image_paths, captions, input_path, output_path):
    """Helper function to write captions to files."""
    for file_path, caption in zip(image_paths, captions):
        try:
            # Create caption file path (same name but with .txt extension)
            caption_filename = file_path.stem + ".txt"
            caption_path = input_path / caption_filename

            with open(caption_path, 'w', encoding='utf-8') as f:
                f.write(caption)

            # If output directory is different from input, copy files
            if output_path != input_path:
                shutil.copy2(file_path, output_path / file_path.name)
                shutil.copy2(caption_path, output_path / caption_filename)
            print(f"Processed {file_path.name} → {caption_filename}")
        except Exception as e:
            print(f"Error processing {file_path.name}: {e}")


def main():
    parser = argparse.ArgumentParser(description='Generate captions for images using GPT-4o.')
    parser.add_argument('--input', type=str, required=True, help='Directory containing images')
    parser.add_argument('--output', type=str, help='Directory to save images and captions (defaults to input directory)')
    parser.add_argument('--batch_images', action='store_true', help='Flag to indicate if images should be processed in batches')

    args = parser.parse_args()

    if not os.path.isdir(args.input):
        print(f"Error: Input directory '{args.input}' does not exist.")
        return

    process_images(args.input, args.output, args.batch_images)


if __name__ == "__main__":
    main()