import html

import fuzzywuzzy.fuzz
import fuzzywuzzy.process
import googleapiclient
import googleapiclient.discovery


BASE_URL = 'https://www.youtube.com'


class YoutubeError(Exception):
    pass


class Youtube(object):
    def __init__(self, api_key):
        self.client = googleapiclient.discovery.build('youtube', 'v3', developerKey=api_key)

    def _search(self, channel_id, query, playlists, limit):
        def get_thumbnail_url(thumbnails):
            for key in ['high', 'medium', 'default']:
                if key in thumbnails:
                    return thumbnails[key]['url']
        resp = self.client.channels().list(
            id=channel_id,
            maxResults=1,
            part='snippet').execute()
        channel = resp['items'][0]
        result = []
        count = limit
        token = ''
        while True:
            resp = self.client.search().list(
                channelId=channel_id,
                q=query,
                safeSearch='none',
                type='playlist' if playlists else 'video',
                maxResults=min(count, 50),
                part='id,snippet',
                pageToken=token).execute()
            for item in resp.get('items', []):
                kind = item['id']['kind'].split('youtube#')[1]
                if kind == 'playlist':
                    url = '{0}/view_play_list?p={1}'.format(BASE_URL, item['id']['playlistId'])
                else:
                    url = '{0}/watch?v={1}'.format(BASE_URL, item['id']['videoId'])
                result.append(dict(
                    kind=kind,
                    url=url,
                    title=html.unescape(item['snippet']['title']),
                    description=html.unescape(item['snippet']['description']),
                    thumbnail_url=get_thumbnail_url(item['snippet']['thumbnails']),
                    channel_title=html.unescape(channel['snippet']['title']),
                    channel_url='{0}/c/{1}'.format(BASE_URL, channel['snippet']['customUrl']),
                    channel_thumbnail_url=get_thumbnail_url(channel['snippet']['thumbnails'])))
            count -= resp['pageInfo']['resultsPerPage']
            if count <= 0:
                break
            token = resp.get('nextPageToken')
            if not token:
                break
        return result

    def search(self, channel_id, query, playlists=True, limit=None):
        try:
            return self._search(channel_id, query, playlists, limit)
        except googleapiclient.errors.HttpError as e:
            raise YoutubeError('Failed to query Youtube API: {0}'.format(e))

    def find_best_match(self, channel_ids, query):
        results = []
        for channel_id in channel_ids:
            try:
                results.extend(self._search(channel_id, query, playlists=True, limit=1))
                results.extend(self._search(channel_id, query, playlists=False, limit=1))
            except googleapiclient.errors.HttpError as e:
                raise YoutubeError('Failed to query Youtube API: {0}'.format(e))
        if not results:
            return None
        tokens = [t for t in query.split('|') if not t.strip().startswith('-')] or ['']
        matches = []
        for token in tokens:
            titles = {i: r['title'] for i, r in enumerate(results)}
            descriptions = {i: r['description'] for i, r in enumerate(results)}
            matches.append(fuzzywuzzy.process.extractOne(token, titles,
                scorer=fuzzywuzzy.fuzz.token_sort_ratio))
            matches.append(fuzzywuzzy.process.extractOne(token, descriptions,
                scorer=fuzzywuzzy.fuzz.token_sort_ratio))
        _, _, i = sorted(matches, key=lambda m: m[1], reverse=True)[0]
        return results[i]