import mysql from 'mysql';
import semver from 'semver';
import { fatal, getVersion } from './utils';

const DATABASE = 'chronos';

export default class Database {
	constructor(options) {
		this.connection = mysql.createConnection(options);
		this.connection.connect();

		this.checkAndMigrate();
	}

	query(query, values) {
		console.log('QUERY:', query.replace(/[\n\t]+/g, ' ').replace(/^ /g, '').replace(/ $/g, ''));
		return new Promise((resolve, reject) => {
			this.connection.query(query, values, (err, results, fields) => {
				if (err) {
					reject(err);
				}
				resolve(results, fields);
			});
		});
	}

	async checkAndMigrate() {
		return this.query(`CREATE DATABASE IF NOT EXISTS ${DATABASE}`)
		.then(() => this.query(`USE ${DATABASE}`))
		.then(() => this.query('SELECT * FROM options WHERE option = ?', ['VERSION'])
			.then(result => this.migrate(result[0] ? result[0].value : null))
			.catch(() => this.migrate()))
		.catch(err => fatal(err));
	}

	async migrate(oldVersion) {
		if (semver.satisfies(oldVersion, '~1')) {
			// database is up-to-date
			return true;
		} else if (semver.satisfies(oldVersion, '~0')) { // lmao forces database migration
			// database needs to be updated
			return this.query(`DROP DATABASE ${DATABASE}`)
				.then(() => this.checkAndMigrate());
		}
		// database does not exist

		// create tables
		const tables = [
			`CREATE TABLE options (
				option		VARCHAR(12) NOT NULL,
				value		VARCHAR(64) NOT NULL,
				PRIMARY KEY (option)
			)`,
			`CREATE TABLE school (
				id			INT NOT NULL AUTO_INCREMENT,
				name		VARCHAR(64) NOT NULL,
				domain		VARCHAR(32),
				PRIMARY KEY (id)
			)`,
			`CREATE TABLE auth (
				school		INT NOT NULL,
				id			INT NOT NULL,
				type		CHAR(3) NOT NULL,
				oid_meta	VARCHAR(128),
				oid_cid		VARCHAR(64),
				oid_csecret	VARCHAR(64),
				PRIMARY KEY (school, id),
				FOREIGN KEY (school) REFERENCES school(id) ON DELETE CASCADE ON UPDATE CASCADE
			)`,
			`CREATE TABLE holiday (
				id			INT NOT NULL AUTO_INCREMENT,
				name		VARCHAR(64)	NOT NULL,
				start		DATETIME NOT NULL,
				end			DATETIME NOT NULL,
				PRIMARY KEY (id)
			)`,
			`CREATE TABLE observes (
				school		INT NOT NULL,
				holiday		INT NOT NULL,
				FOREIGN KEY (school) REFERENCES school(id) ON DELETE CASCADE ON UPDATE CASCADE,
				FOREIGN KEY (holiday) REFERENCES holiday(id) ON DELETE CASCADE ON UPDATE CASCADE
			)`,
			`CREATE TABLE user (
				school		INT NOT NULL,
				id			INT	AUTO_INCREMENT NOT NULL,
				name		VARCHAR(64),
				email		VARCHAR(64),
				oid_id		VARCHAR(64),
				pwd_hash	VARCHAR(64),
				role		CHAR(3),
				PRIMARY KEY (id),
				FOREIGN KEY (school) REFERENCES school(id) ON DELETE CASCADE ON UPDATE CASCADE
			)`,
			`CREATE TABLE group_ (
				id			INT	AUTO_INCREMENT NOT NULL,
				name		VARCHAR(64) NOT NULL,
				type		CHAR(3),
				PRIMARY KEY (id)
			)`,
			`CREATE TABLE group_mentor (
				id			INT	NOT NULL,
				level		TINYINT NOT NULL,
				year		YEAR NOT NULL,
				PRIMARY KEY (id),
				FOREIGN KEY (id) REFERENCES group_(id) ON DELETE CASCADE ON UPDATE CASCADE
			)`,
			`CREATE TABLE member (
				user		INT NOT NULL,
				group_		INT NOT NULL,
				FOREIGN KEY (user) REFERENCES user(id) ON DELETE CASCADE ON UPDATE CASCADE,
				FOREIGN KEY (group_) REFERENCES group_(id) ON DELETE CASCADE ON UPDATE CASCADE
			)`,
			`CREATE TABLE event_once (
				group_		INT NOT NULL,
				id			INT	AUTO_INCREMENT NOT NULL,
				name		VARCHAR(64) NOT NULL,
				start		DATETIME NOT NULL,
				end			DATETIME NOT NULL,
				PRIMARY KEY (id),
				FOREIGN KEY (group_) REFERENCES group_(id) ON DELETE CASCADE ON UPDATE CASCADE
			)`,
			`CREATE TABLE attachment (
				event_once	INT NOT NULL,
				id			INT NOT NULL,
				PRIMARY KEY (event_once, id),
				FOREIGN KEY (event_once) REFERENCES event_once(id) ON DELETE CASCADE ON UPDATE CASCADE
			)`,
			`CREATE TABLE event_weekly (
				group_		INT NOT NULL,
				id			INT	AUTO_INCREMENT NOT NULL,
				name		VARCHAR(64) NOT NULL,
				day			TINYINT NOT NULL,
				starttime	TIME NOT NULL,
				endtime		TIME NOT NULL,
				PRIMARY KEY (id),
				FOREIGN KEY (group_) REFERENCES group_(id) ON DELETE CASCADE ON UPDATE CASCADE
			)`,
			`CREATE TABLE ignored (	
				user		INT NOT NULL,
				event_weekly	INT NOT NULL,
				FOREIGN KEY (user) REFERENCES user(id) ON DELETE CASCADE ON UPDATE CASCADE,
				FOREIGN KEY (event_weekly) REFERENCES event_weekly(id) ON DELETE CASCADE ON UPDATE CASCADE
			)`,
		];
		for (let i = 0; i < tables.length; i += 1) {
			// eslint-disable-next-line no-await-in-loop
			await this.query(tables[i]);
		}

		// set version number
		await this.query(`
			INSERT INTO options (option, value)
			VALUES ('version', '${getVersion()}')
		`);

		// add first school
		await this.query(`
			INSERT INTO school (name, domain)
			VALUES (?, ?)
		`, ['NUS High School', 'nushigh.edu.sg']);

		return true;
	}
}