import logging
from pathlib import Path
import time
import tempfile
from typing import Optional

import libtorrent


def magnet2torrent(magnet: str, output: Path):
    log = logging.getLogger()

    if not output.parent.is_dir():
        raise Exception("Invalid output file: directory does not exist")

    with tempfile.TemporaryDirectory() as tmp_dir:
        session = libtorrent.session()
        #params = {
        #    "save_path": tmp_dir,
        #    "storage_mode": libtorrent.storage_mode_t(2),
        #    "paused": False,
        #    "auto_managed": True,
        #    "duplicate_is_error": True,
        #}
        #handle = libtorrent.add_magnet_uri(session, magnet, params)

        params = libtorrent.parse_magnet_uri(magnet)
        handle = session.add_torrent(params)
        log.info("Downloading metadata")
        while not handle.has_metadata():
            try:
                time.sleep(1)
            except KeyboardInterrupt:
                log.info("Cleaning up")
                session.pause()
                raise
        session.pause()
        log.info("Done")

        info = handle.get_torrent_info()
        torrent_file = libtorrent.create_torrent(info)
        torrent_path = Path(info.name() + ".torrent").absolute()

        if output.is_dir():
            output = output / torrent_path.name

        log.info("Writing to %s", output)
        content = libtorrent.bencode(torrent_file.generate())
        output.write_bytes(content)
        session.remove_torrent(handle)