import os
import sys
import argparse
import tarfile
from constants import *
import concurrent.futures

def compress_chunk(chunk, chunk_index, output_dir):
    with tarfile.open(os.path.join(output_dir, f"chunk_{chunk_index}.tar"), "w") as tar:
        for image_path in chunk:
            tags_path = os.path.splitext(image_path)[0] + ".txt"
            if not os.path.isfile(tags_path):
                continue
            tar.add(image_path, arcname=os.path.basename(image_path))
            tar.add(tags_path, arcname=os.path.basename(tags_path))

def parse_args():
    parser = argparse.ArgumentParser(description="Group images into uncompressed tar files.")
    parser.add_argument("-i", "--input-dir", default=IMAGE_DIR, help="Input directory for the images to chunk into tars")
    parser.add_argument("-o", "--output-dir", default=COMPRESSED_DIR, help="Output directory for chunked tars")
    parser.add_argument("-n", "--num-images-per-chunk", type=int, default=1024, help="Number of images per chunk, default to 1024")
    args = parser.parse_args()
    if args.num_images_per_chunk < 1:
        print("Number of images per chunk needs to be a positive integer!")
        sys.exit(1)
    return args

def main():
    args = parse_args()
    if not os.path.isdir(args.input_dir):
        print(f"Your input dir \"{args.input_dir}\" doesn't exist or isn't a directory!")
        sys.exit(1)
    image_files = [os.path.join(args.input_dir, f) for f in os.listdir(args.input_dir) if not f.endswith(".txt")]
    image_files.sort()
    os.makedirs(args.output_dir, exist_ok=True)
    with concurrent.futures.ThreadPoolExecutor(max_workers=os.cpu_count()) as executor:
        futures = []
        for i in range(0, len(image_files), args.num_images_per_chunk):
            chunk = image_files[i:i + args.num_images_per_chunk]
            chunk_index = i // args.num_images_per_chunk
            future = executor.submit(compress_chunk, chunk, chunk_index, args.output_dir)
            futures.append(future)
        concurrent.futures.wait(futures)

if __name__ == "__main__":
    try:
        main()
    except KeyboardInterrupt:
        print("\nScript interrupted by user, exiting...")
        sys.exit(1)