"""releases module."""

from artist.connectors import mysql
from artist.models.release_artist import ReleaseArtist
from artist.models.track import Track
from artist.models.track_artist import TrackArtist
from artist.models.track_writer import TrackWriter
from artist.response import Response


def get_artists(product_id):
    """Return all artists in a release."""
    with mysql.db_session() as session:
        # Get all artists associated with this release.
        release_artists = session.query(ReleaseArtist)\
            .filter_by(release_id=product_id)\
            .all()

        # Get all artists associated with a track in this release.
        track_ids = [
            track.id
            for track in
            session.query(Track).filter_by(release_id=product_id).all()
        ]
        if track_ids:
            track_artists = session.query(TrackArtist)\
                .filter(TrackArtist.track_id.in_(track_ids))\
                .all()
            track_writers = session.query(TrackWriter)\
                .filter(TrackWriter.unique_track_id.in_(track_ids))\
                .all()
        else:
            track_artists = []
            track_writers = []

        # Build the response.
        release_artist_list = []
        for release_artist in release_artists:
            release_artist_dict = release_artist.to_dict()
            release_artist_list.append(release_artist_dict)

        track_artist_list = []
        for track_artist in track_artists:
            track_artist_dict = track_artist.to_dict()
            track_artist_list.append(track_artist_dict)

        track_writer_list = []
        for track_writer in track_writers:
            track_writer_dict = track_writer.to_dict()
            track_writer_list.append(track_writer_dict)

    return Response(message={
        'release_artists': release_artist_list,
        'track_artists': track_artist_list,
        'track_writers': track_writer_list
    })