exports.up = async (knex) => knex.raw(`
	CREATE FUNCTION entities_scene_tags(entity entities, selectable_tags text[]) RETURNS SETOF tags AS $$
		SELECT tags.*
		FROM releases
		LEFT JOIN
			releases_tags ON releases_tags.release_id = releases.id
		LEFT JOIN
			tags ON tags.id = releases_tags.tag_id
		WHERE
			releases.entity_id = entity.id
		AND
			CASE WHEN array_length(selectable_tags, 1) IS NOT NULL
			THEN tags.slug = ANY(selectable_tags)
			ELSE true
			END
		GROUP BY tags.id
		ORDER BY tags.name;
	$$ LANGUAGE SQL STABLE;
`);

exports.down = async (knex) => knex.raw(`
	DROP FUNCTION IF EXISTS entities_scene_tags;
`);