import html

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


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


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

    def get_thumbnail_url(self, thumbnails):
        for key in ('high', 'medium', 'default'):
            if key in thumbnails:
                return thumbnails[key].get('url')

    def process_items(self, items):
        result = []
        for item in items:
            id = item.get('id', '')
            kind = item.get('kind', 'youtube#').split('youtube#')[1]
            if kind == 'searchResult':
                id = item.get('id', {}).get('videoId', '')
                kind = item.get('id', {}).get('kind', 'youtube#').split('youtube#')[1]
            if kind == 'playlist':
                link = '{0}/view_play_list?p={1}'.format(BASE_URL, id)
            else:
                link = '{0}/watch?v={1}'.format(BASE_URL, id)
            result.append(dict(
                kind=kind,
                link=link,
                title=html.unescape(item.get('snippet', {}).get('title', '')),
                description=html.unescape(item.get('snippet', {}).get('description', '')),
                thumbnail_url=self.get_thumbnail_url(item.get('snippet', {}).get('thumbnails', {}))
            ))
        return result

    def get_channel(self, channel_id):
        r = self.client.channels().list(id=channel_id, maxResults=1, part='id,snippet').execute()
        channel = r.get('items', [{}]).pop()
        return dict(
            id=channel.get('id', ''),
            link='{0}/c/{1}'.format(BASE_URL, channel.get('snippet', {}).get('customUrl', '')),
            title=html.unescape(channel.get('snippet', {}).get('title', '')),
            thumbnail_url=self.get_thumbnail_url(channel.get('snippet', {}).get('thumbnails', {}))
        )

    def get_playlists(self):
        token = ''
        result = []
        while True:
            r = self.client.playlists().list(
                channelId=self.channel.get('id'),
                maxResults=50,
                part='id,snippet',
                pageToken=token
            ).execute()
            result.extend(self.process_items(r.get('items', [])))
            token = r.get('nextPageToken')
            if not token:
                break
        return result

    def search_videos(self, query, limit):
        count = limit
        token = ''
        result = []
        while True:
            r = self.client.search().list(
                channelId=self.channel.get('id'),
                q=query,
                safeSearch='none',
                type='video',
                maxResults=min(count, 50),
                part='id,snippet',
                pageToken=token
            ).execute()
            result.extend(self.process_items(r.get('items', [])))
            count -= r.get('pageInfo', {}).get('resultsPerPage', 0)
            if count <= 0:
                break
            token = r.get('nextPageToken')
            if not token:
                break
        return result

    def search(self, query):
        try:
            results = self.get_playlists()
            results.extend(self.search_videos(query, limit=5))
        except googleapiclient.errors.HttpError as e:
            raise YouTubeError(str(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.get('title') for i, r in enumerate(results)}
            descriptions = {i: r.get('description') for i, r in enumerate(results)}
            match = fuzzywuzzy.process.extractOne(token, titles,
                scorer=fuzzywuzzy.fuzz.token_set_ratio, score_cutoff=25)
            if match:
                matches.append(match)
            match = fuzzywuzzy.process.extractOne(token, descriptions,
                scorer=fuzzywuzzy.fuzz.token_set_ratio, score_cutoff=25)
            if match:
                matches.append(match)
        if not matches:
            return None
        _, _, i = sorted(matches, key=lambda m: m[1], reverse=True)[0]
        return results[i]


class YouTubeError(Exception):
    pass