import os
import pathlib
import re
import subprocess
import tempfile

from datetime import datetime
from concurrent.futures import ThreadPoolExecutor, as_completed
from functools import partial

from twitchdl import twitch
from twitchdl.download import download_file
from twitchdl.output import print_out
from twitchdl.utils import slugify


def read_int(msg, min, max, default):
    msg = msg + " [default {}]: ".format(default)

    while True:
        try:
            val = input(msg)
            if not val:
                return default
            if min <= int(val) <= max:
                return int(val)
        except ValueError:
            pass


def format_size(bytes_):
    if bytes_ < 1024:
        return str(bytes_)

    kilo = bytes_ / 1024
    if kilo < 1024:
        return "{:.1f}K".format(kilo)

    mega = kilo / 1024
    if mega < 1024:
        return "{:.1f}M".format(mega)

    return "{:.1f}G".format(mega / 1024)


def format_duration(total_seconds):
    total_seconds = int(total_seconds)
    hours = total_seconds // 3600
    remainder = total_seconds % 3600
    minutes = remainder // 60
    seconds = total_seconds % 60

    if hours:
        return "{} h {} min".format(hours, minutes)

    if minutes:
        return "{} min {} sec".format(minutes, seconds)

    return "{} sec".format(seconds)


def _print_video(video):
    published_at = video['published_at'].replace('T', ' @ ').replace('Z', '')
    length = format_duration(video['length'])
    name = video['channel']['display_name']

    print_out("\n<bold>{}</bold>".format(video['_id'][1:]))
    print_out("<green>{}</green>".format(video["title"]))
    print_out("<cyan>{}</cyan> playing <cyan>{}</cyan>".format(name, video['game']))
    print_out("Published <cyan>{}</cyan>  Length: <cyan>{}</cyan> ".format(published_at, length))


def videos(channel_name, **kwargs):
    videos = twitch.get_channel_videos(channel_name)

    print("Found {} videos".format(videos["_total"]))

    for video in videos['videos']:
        _print_video(video)


def _select_quality(playlists):
    print("\nAvailable qualities:")
    for no, v in playlists.items():
        print("{}) {}".format(no, v[0]))

    keys = list(playlists.keys())
    no = read_int("Choose quality", min=min(keys), max=max(keys), default=keys[0])

    return playlists[no]


def _print_progress(futures):
    counter = 1
    total = len(futures)
    total_size = 0
    start_time = datetime.now()

    for future in as_completed(futures):
        size = future.result()
        percentage = 100 * counter // total
        total_size += size
        duration = (datetime.now() - start_time).seconds
        speed = total_size // duration if duration else 0
        remaining = (total - counter) * duration / counter

        msg = "Downloaded VOD {}/{} ({}%) total <cyan>{}B</cyan> at <cyan>{}B/s</cyan> remaining <cyan>{}</cyan>".format(
            counter, total, percentage, format_size(total_size), format_size(speed), format_duration(remaining))

        print_out("\r" + msg.ljust(80), end='')
        counter += 1


def _download_files(base_url, directory, filenames, max_workers):
    urls = [base_url.format(f) for f in filenames]
    paths = ["/".join([directory, f]) for f in filenames]
    partials = (partial(download_file, url, path) for url, path in zip(urls, paths))

    with ThreadPoolExecutor(max_workers=max_workers) as executor:
        futures = [executor.submit(fn) for fn in partials]
        _print_progress(futures)

    return paths


def _join_vods(directory, paths, target):
    input_path = "{}/files.txt".format(directory)

    with open(input_path, 'w') as f:
        for path in paths:
            f.write('file {}\n'.format(os.path.basename(path)))

    result = subprocess.run([
        "ffmpeg",
        "-f", "concat",
        "-i", input_path,
        "-c", "copy",
        target,
        "-stats",
        "-loglevel", "warning",
    ])

    result.check_returncode()


def _video_target_filename(video, format):
    match = re.search(r"^(\d{4})-(\d{2})-(\d{2})T", video['published_at'])
    date = "".join(match.groups())

    name = "_".join([
        date,
        video['_id'][1:],
        video['channel']['name'],
        slugify(video['title']),
    ])

    return name + "." + format


def download(video_id, max_workers, format='mkv', **kwargs):
    print("Looking up video...")
    video = twitch.get_video(video_id)

    print("Fetching access token...")
    access_token = twitch.get_access_token(video_id)

    print("Fetching playlists...")
    playlists = twitch.get_playlists(video_id, access_token)
    quality, playlist_url = _select_quality(playlists)

    print("\nFetching playlist...")
    base_url, filenames = twitch.get_playlist_urls(playlist_url)

    # Create a temp dir to store downloads if it doesn't exist
    directory = '{}/twitch-dl/{}/{}'.format(tempfile.gettempdir(), video_id, quality)
    pathlib.Path(directory).mkdir(parents=True, exist_ok=True)
    print("Download dir: {}".format(directory))

    print("Downloading VODs with {} workers...".format(max_workers))
    paths = _download_files(base_url, directory, filenames, max_workers)

    print("\n\nJoining files...")
    target = _video_target_filename(video, format)
    _join_vods(directory, paths, target)

    print("\nDeleting vods...")
    for path in paths:
        os.unlink(path)

    print("\nDownloaded: {}".format(target))