import apiclient.discovery
import datetime

import helpers

class VideoNotFound(Exception):
    pass

class Video:
    def __init__(self, snippet):
        self.id = snippet['id']

        snippet = snippet['snippet']
        self.title = snippet['title'] or '[untitled]'
        self.description = snippet['description']
        self.author_id = snippet['channelId']
        self.author_name = snippet['channelTitle']
        # Something like '2016-10-01T21:00:01'
        self.published_string = snippet['publishedAt']
        published = snippet['publishedAt']
        published = published.split('.')[0]
        published = datetime.datetime.strptime(published, '%Y-%m-%dT%H:%M:%S')
        self.published = published.timestamp()

        thumbnails = snippet['thumbnails']
        best_thumbnail = max(thumbnails, key=lambda x: thumbnails[x]['width'] * thumbnails[x]['height'])
        self.thumbnail = thumbnails[best_thumbnail]

    def __str__(self):
        return 'Video:%s' % self.id


class Youtube:
    def __init__(self, key):
        youtube = apiclient.discovery.build(
            developerKey=key,
            serviceName='youtube',
            version='v3',
        )
        self.youtube = youtube

    def get_user_id(self, username):
        user = self.youtube.channels().list(part='snippet', forUsername=username).execute()
        return user['items'][0]['id']

    def get_user_name(self, uid):
        user = self.youtube.channels().list(part='snippet', id=uid).execute()
        return user['items'][0]['snippet']['title']

    def get_user_videos(self, username=None, uid=None):
        if username:
            user = self.youtube.channels().list(part='contentDetails', forUsername=username).execute()
        else:
            user = self.youtube.channels().list(part='contentDetails', id=uid).execute()
        upload_playlist = user['items'][0]['contentDetails']['relatedPlaylists']['uploads']
        page_token = None
        while True:
            items = self.youtube.playlistItems().list(
                maxResults=50,
                pageToken=page_token,
                part='contentDetails',
                playlistId=upload_playlist,
            ).execute()
            page_token = items.get('nextPageToken', None)
            new = [item['contentDetails']['videoId'] for item in items['items']]
            count = len(new)
            new = self.get_video(new)
            new.sort(key=lambda x: x.published, reverse=True)
            yield from new
            #print('Found %d more, %d total' % (count, len(videos)))
            if page_token is None or count < 50:
                break

    def get_related_videos(self, video_id, part='id,snippet', count=50):
        if isinstance(video_id, Video):
            video_id = video_id.id

        results = self.youtube.search().list(
            part=part,
            relatedToVideoId=video_id,
            type='video',
            maxResults=count,
        ).execute()
        videos = []
        for related in results['items']:
            related['id'] = related['id']['videoId']
            video = Video(related)
            videos.append(video)
        return videos

    def get_video(self, video_ids):
        if isinstance(video_ids, str):
            singular = True
            video_ids = [video_ids]
        else:
            singular = False

        results = []
        chunks = helpers.chunk_sequence(video_ids, 50)
        for chunk in chunks:
            chunk = ','.join(chunk)
            data = self.youtube.videos().list(part='snippet', id=chunk).execute()
            items = data['items']
            results.extend(items)
        results = [Video(snippet) for snippet in results]
        if singular:
            if len(results) == 1:
                return results[0]
            elif len(results) == 0:
                raise VideoNotFound(video_ids[0])
        return results