import {NachklangFeedbackDB} from '../Feedback.db';

export const addSong = async (eventId: number, title: string, composer: string | null): Promise<number> => {
	let conn = await NachklangFeedbackDB.getConnection();
	try {
		await conn.beginTransaction();
		const posRows = await conn.query('SELECT COALESCE(MAX(position), -1) + 1 as next_position FROM songs WHERE event_id = ?', [eventId]);
		const position = posRows[0].next_position;
		const res = await conn.query(
			'INSERT INTO songs (event_id, title, composer, position) VALUES (?,?,?,?) RETURNING song_id',
			[eventId, title, composer, position]
		);
		await conn.commit();
		return res[0].song_id;
	} catch (err) {
		await conn.rollback();
		throw err;
	} finally {
		await conn.end();
	}
};

export const updateSong = async (songId: number, title: string, composer: string | null): Promise<boolean> => {
	let conn = await NachklangFeedbackDB.getConnection();
	try {
		await conn.beginTransaction();
		const res = await conn.query('UPDATE songs SET title = ?, composer = ? WHERE song_id = ?', [title, composer, songId]);
		await conn.commit();
		return res.affectedRows > 0;
	} catch (err) {
		await conn.rollback();
		throw err;
	} finally {
		await conn.end();
	}
};

/**
 * Removes a song. submission_answers rows referencing it keep their
 * song_title_snapshot (song_id is set to NULL via ON DELETE SET NULL) -
 * past answers still say what song was rated, even after the song is gone.
 */
export const deleteSong = async (songId: number): Promise<boolean> => {
	let conn = await NachklangFeedbackDB.getConnection();
	try {
		await conn.beginTransaction();
		const res = await conn.query('DELETE FROM songs WHERE song_id = ?', [songId]);
		await conn.commit();
		return res.affectedRows > 0;
	} catch (err) {
		await conn.rollback();
		throw err;
	} finally {
		await conn.end();
	}
};