import time
import os
from os.path import join, exists
import argparse
from urllib.parse import urlparse
import logging
import json
import multiprocessing

from splinter import Browser

log = logging.getLogger(__name__)


def visit_track(b, url):
    log.debug('Visiting track %s' % url)
    b.visit(url)
    b.find_by_css('.playbutton').first.click()
    artist = b.find_by_xpath('//span[@itemprop="byArtist"]').first.value
    album = b.find_by_xpath('//span[@itemprop="inAlbum"]').first.value
    title = b.find_by_css('#name-section h2.trackTitle').first.value
    time.sleep(0.2)  # how nice!
    b.find_by_css('.playbutton').first.click()
    return dict(
        artist=artist,
        album=album,
        title=title,
        url=b.find_by_css('audio').first['src']
    )


def visit_album(b, url):
    log.debug('Visiting album %s' % url)
    b.visit(url)
    track_urls = [link['href'] for link in
                  b.find_by_css('.track_row_view.linked .title a')
                  if link['href'] and '/track/' in link['href']]
    for track_url in track_urls:
        yield visit_track(b, track_url)


def download_track(track):
    log.debug('Downloading "%s"' % track['title'])
    fdir = join(track['artist'], track['album']).replace(' ', '_')
    fname = track['title'].replace(' ', '_') + '.mp3'
    fpath = join(args.download_base, fdir, fname)
    os.makedirs(join(args.download_base, fdir), exist_ok=True)
    if exists(fpath):
        log.info('file %s exists, skipping' % fpath)
    log.debug('download in ' + fpath)
    resp = requests.get(track['url'], stream=True)
    if not resp.ok:
        log.error('Error downloading track ', track['title'])
        return
    with open(fpath, 'wb') as buf:
        log.debug('writing ' + fname)
        for block in resp.iter_content():
            buf.write(block)
    audio = mutagen.mp3.EasyMP3(fpath)  # TODO: is it always mp3?
    audio['title'] = track['title']
    audio['artist'] = track['artist']
    audio['album'] = track['album']
    audio.save()
    log.info('track %(title)s downloaded' % track)
    return fpath


def get_parser():
    p = argparse.ArgumentParser(
        description='Download tracks from bandcamp, sharing is caring!',
        formatter_class=argparse.ArgumentDefaultsHelpFormatter)
    p.add_argument('url')
    p.add_argument('--loglevel', default='INFO', help='Log level',
                   choices=['DEBUG', 'INFO', 'WARNING', 'ERROR'])
    info = p.add_argument_group('fetch track info')
    info.add_argument('--driver', default='firefox',
                      help='Internal splinter option',
                      choices=['firefox', 'chrome'])
    info.add_argument('--mode', default=None,
                      choices=['album', 'track', 'artist'])
    do = p.add_argument_group('what to do with fetched urls')
    do.add_argument('--do', default='print',
                    help='What to do with retrieved informations',
                    choices=['print', 'wgetprint', 'download'])
    do.add_argument('--download-base', default='.',
                    help='Only applies to wget')
    do.add_argument('-j', '--jobs', default=3, type=int,
                    help='Parallel downloads')

    return p


def get_mode(url):
    path = urlparse(url).path
    if path.startswith('/track/'):
        return 'track'
    if path.startswith('/album/'):
        return 'album'
    raise ValueError('unsupported url')


args = get_parser().parse_args()
logging.basicConfig(level=args.loglevel)
logging.getLogger('selenium.webdriver').setLevel(logging.WARNING)
logging.getLogger('requests').setLevel(logging.WARNING)
if args.do == 'download':
    try:
        import requests
        import mutagen.mp3
    except ImportError:
        log.critical('--do=download requires requests and download libraries')
        raise

if args.mode is None:
    args.mode = get_mode(args.url)
    log.info('Going in %s mode' % args.mode)

prefs = {
    'dom.audiochannel.mutedByDefault': True
}
with Browser(args.driver, profile_preferences=prefs) as br:
    # get track info
    if args.mode == 'track':
        tracks = visit_track(br, args.url)
    elif args.mode == 'album':
        tracks = visit_album(br, args.url)
    else:
        raise NotImplementedError('info retrieval ' + args.mode)

    # do something
    if args.do == 'print':
        for track in tracks:
            print(json.dumps(track))
    elif args.do == 'wgetprint':
        for track in tracks:
            cmd = ['wget', '-nv', "'%s'" % track['url'],
                   '-O', "'%s'" %
                   join(args.download_base,
                        '-'.join((track['artist'], track['album'],
                                  track['title']))).replace(' ', '_')
                   ]
            print(' '.join(cmd))
    elif args.do == 'download':
        pool = multiprocessing.Pool(processes=args.jobs)
        for res in pool.imap_unordered(download_track, tracks):
            print('R', res)
        pool.close()
        pool.join()
    else:
        raise NotImplementedError('action ' + args.do)