from lavalink import LoadResult, LoadType, Source, DeferredAudioTrack, PlaylistInfo


class LoadError(Exception):  # We'll raise this if we have trouble loading our track.
    pass


class CustomAudioTrack(DeferredAudioTrack):
    # A DeferredAudioTrack allows us to load metadata now, and a playback URL later.
    # This makes the DeferredAudioTrack highly efficient, particularly in cases
    # where large playlists are loaded.

    async def load(self, client):  # Load our 'actual' playback track using the metadata from this one.
        result: LoadResult = await client.get_tracks('ytsearch:{0.title} {0.author} audio'.format(self))  # Search for our track on YouTube.

        if result.load_type != LoadType.SEARCH or not result.tracks:  # We're expecting a 'SEARCH' due to our 'ytsearch' prefix above.
            raise LoadError

        first_track = result.tracks[0]  # Grab the first track from the results.
        base64 = first_track.track  # Extract the base64 string from the track.
        self.track = base64  # We'll store this for later, as it allows us to save making network requests
        # if this track is re-used (e.g. repeat).

        return base64


class CustomSource(Source):
    def __init__(self):
        super().__init__(name='custom')  # Initialising our custom source with the name 'custom'.

    async def load_item(self, user, metadata):
        track = CustomAudioTrack({  # Create an instance of our CustomAudioTrack.
            'identifier': metadata['id'],  # Fill it with metadata that we've obtained from our source's provider.
            'isSeekable': True,
            'author': metadata['artists'][0]['name'],
            'length': metadata['duration_ms'],
            'isStream': False,
            'title': metadata['name'],
            'uri': metadata['external_urls']['spotify'],
            'duration': metadata['duration_ms'],
            }, requester=user, extra=metadata['album']['images'][0]['url'])
        return LoadResult(LoadType.TRACK, [track], playlist_info=PlaylistInfo.none())

    async def load_album(self, user, metadata):
        tracks = []
        for track in metadata['tracks']['items']:  # Loop through each track in the album.
            tracks.append(CustomAudioTrack({  # Create an instance of our CustomAudioTrack.
                'identifier': track['id'],  # Fill it with metadata that we've obtained from our source's provider.
                'isSeekable': True,
                'author': track['artists'][0]['name'],
                'length': track['duration_ms'],
                'isStream': False,
                'title': track['name'],
                'uri': track['external_urls']['spotify'],
                'duration': track['duration_ms'],
                }, requester=user, extra=metadata['images'][0]['url']))

        return LoadResult(LoadType.PLAYLIST, tracks, playlist_info=PlaylistInfo.none())

    async def load_playlist(self, user, metadata):
        tracks = []
        for track in metadata['tracks']['items']:  # Loop through each track in the playlist.
            tracks.append(CustomAudioTrack({  # Create an instance of our CustomAudioTrack.
                'identifier': track['track']['id'],  # Fill it with metadata that we've obtained from our source's provider.
                'isSeekable': True,
                'author': track['track']['artists'][0]['name'],
                'length': track['track']['duration_ms'],
                'isStream': False,
                'title': track['track']['name'],
                'uri': track['track']['external_urls']['spotify'],
                'duration': track['track']['duration_ms'],
                }, requster=user, extra=track['track']['album']['images'][0]['url']))

        return LoadResult(LoadType.PLAYLIST, tracks, playlist_info=PlaylistInfo.none())