import os
import shutil

# Image extensions we attempt to load (PIL-decodable raster formats).
IMAGE_EXTENSIONS = ('.jpg', '.jpeg', '.png', '.bmp', '.tif', '.tiff', '.webp')


def list_image_files(image_dir, allowed_extensions=IMAGE_EXTENSIONS, recursive=False):
    """
    List image file paths in a directory with allowed extensions.

    Args:
        image_dir (str): Path to the directory containing images.
        allowed_extensions (tuple, optional): Allowed file extensions (lowercase,
            leading dot). Defaults to IMAGE_EXTENSIONS.
        recursive (bool, optional): Recurse into subdirectories. Defaults to False.

    Returns:
        list: Sorted list of full file paths for images with allowed extensions.
    """
    if recursive:
        paths = [
            os.path.join(root, f)
            for root, _, files in os.walk(image_dir)
            for f in files
            if f.lower().endswith(allowed_extensions)
        ]
    else:
        paths = [
            os.path.join(image_dir, f)
            for f in os.listdir(image_dir)
            if f.lower().endswith(allowed_extensions)
        ]
    return sorted(paths)
    
def copy_image(row, repartition_dir):
    """
    Copy an image file to a cluster-specific subdirectory.

    Args:
        row (dict): A dictionary containing at least 'cluster' (cluster ID) and 'image_path' (source image path).
        repartition_dir (str): The root directory where cluster subfolders will be created.

    Returns:
        dict or None: A dictionary with keys 'abs_path', 'file_name', and 'cluster' if successful; None if an error occurs.
    """
    cluster_id = row['cluster']
    src_img_path = row['image_path']
    cluster_folder = os.path.join(repartition_dir, f"cluster_{cluster_id}")
    os.makedirs(cluster_folder, exist_ok=True)
    dst_img_path = os.path.join(cluster_folder, os.path.basename(src_img_path))
    try:
        shutil.copy2(src_img_path, dst_img_path)
        return {
            "abs_path": os.path.abspath(dst_img_path),
            "file_name": os.path.basename(src_img_path),
            "cluster": cluster_id
        }
    except Exception as e:
        return None  # Optionally log error