import argparse
from pathlib import Path
import os


SAFETY = 'jellyfin'

def get_args():
    parser = argparse.ArgumentParser()
    parser.add_argument('source', type=Path)
    parser.add_argument('dest', type=Path)
    parser.add_argument('--dry', help='Only output changes', action="store_true")
    return parser.parse_args()


def main(source: Path, dest: Path, dry: bool):
    remove_deleted_files(source, dest, dry)
    create_new_links(source, dest, dry)

def remove_deleted_files(source: Path, dest: Path, dry: bool):
    for file in dest.iterdir():
        if file.is_dir():
            original_dir = source / file.name

            if original_dir.is_dir():
                remove_deleted_files(original_dir, file, dry)
            else:
                remove_deleted_files(original_dir, file, dry)
                if dry:
                    print(f"Remove directory: {file}")
                else:
                    file.rmdir() # will fail if files have since been created
        elif file.is_file():
            original_file = source / file.name

            if not original_file.exists() or original_file.is_dir():
                if SAFETY not in str(file):
                    raise Exception("Deletion path does not include jellyfin")
                if dry:
                    print(f"Remove file: {file}")
                else:
                    file.unlink()

def create_new_links(source: Path, dest: Path, dry: bool):
    for file in source.iterdir():
        if file.is_dir():
            new_dest = dest / file.name

            if not new_dest.exists():
                if dry:
                    print(f"Create directory: {new_dest}")
                else:
                    new_dest.mkdir()
            elif new_dest.exists() and not new_dest.is_dir():
                raise Exception("Directory expected")

            create_new_links(file, new_dest, dry)

        elif file.is_file():
            new_file = dest / file.name

            if not new_file.exists():
                if dry:
                    print(f"Create file: {new_file}")
                else:
                    try:
                        file.copy(new_file)
                    except AttributeError:
                        os.system(f'cp --reflink "{file}" "{new_file}"')

if __name__ == '__main__':
    args = get_args()
    source_directory = args.source
    destination_directory = args.dest
    dryrun = args.dry

    if len(source_directory.parts) < 3 or len(destination_directory.parts) < 3:
        raise Exception("Paths too short")

    if dryrun:
        print("Dry run - no changes will be made")

    main(source_directory, destination_directory, dryrun)

    if dryrun:
        print("Dry run - no changes have been made")