const BaseService = require('lib/services/BaseService').default;
const Migration = require('lib/models/Migration');

class MigrationService extends BaseService {
	constructor() {
		super();
	}

	static instance() {
		if (this.instance_) return this.instance_;
		this.instance_ = new MigrationService();
		return this.instance_;
	}

	async runScript(num) {
		const script = Migration.script(num);
		await script.exec();
	}

	async run() {
		const migrations = await Migration.migrationsToDo();

		for (const migration of migrations) {
			this.logger().info(`Running migration: ${migration.number}`);

			try {
				await this.runScript(migration.number);
				await Migration.delete(migration.id);
			} catch (error) {
				this.logger().error(`Cannot run migration: ${migration.number}`, error);
				break;
			}
		}
	}
}

module.exports = MigrationService;