#!/usr/bin/env node

const logger = require('./logger').global;

async function appStart () {
	// Create config file db settings if environment variables have been set
	await createDbConfigFromEnvironment();

	const migrate             = require('./migrate');
	const setup               = require('./setup');
	const app                 = require('./app');
	const apiValidator        = require('./lib/validator/api');
	const internalCertificate = require('./internal/certificate');
	const internalIpRanges    = require('./internal/ip_ranges');

	return migrate.latest()
		.then(setup)
		.then(() => {
			return apiValidator.loadSchemas;
		})
		.then(internalIpRanges.fetch)
		.then(() => {

			internalCertificate.initTimer();
			internalIpRanges.initTimer();

			const server = app.listen(3000, () => {
				logger.info('Backend PID ' + process.pid + ' listening on port 3000 ...');

				process.on('SIGTERM', () => {
					logger.info('PID ' + process.pid + ' received SIGTERM');
					server.close(() => {
						logger.info('Stopping.');
						process.exit(0);
					});
				});
			});
		})
		.catch((err) => {
			logger.error(err.message);
			setTimeout(appStart, 1000);
		});
}

async function createDbConfigFromEnvironment() {
	return new Promise((resolve, reject) => {
		const envMysqlHost  = process.env.DB_MYSQL_HOST || null;
		const envMysqlPort  = process.env.DB_MYSQL_PORT || null;
		const envMysqlUser  = process.env.DB_MYSQL_USER || null;
		const envMysqlName  = process.env.DB_MYSQL_NAME || null;
		const envSqliteFile = process.env.DB_SQLITE_FILE || null;

		if ((envMysqlHost && envMysqlPort && envMysqlUser && envMysqlName) || envSqliteFile) {
			const fs       = require('fs');
			const filename = (process.env.NODE_CONFIG_DIR || './config') + '/' + (process.env.NODE_ENV || 'default') + '.json';
			let configData = {};

			try {
				configData = require(filename);
			} catch (err) {
				// do nothing
			}

			if (configData.database && configData.database.engine && !configData.database.fromEnv) {
				logger.info('Manual db configuration already exists, skipping config creation from environment variables');
				resolve();
				return;
			}

			if (envMysqlHost && envMysqlPort && envMysqlUser && envMysqlName) {
				const newConfig = {
					fromEnv:  true,
					engine:   'mysql',
					host:     envMysqlHost,
					port:     envMysqlPort,
					user:     envMysqlUser,
					password: process.env.DB_MYSQL_PASSWORD,
					name:     envMysqlName,
				};

				if (JSON.stringify(configData.database) === JSON.stringify(newConfig)) {
					// Config is unchanged, skip overwrite
					resolve();
					return;
				}

				logger.info('Generating MySQL db configuration from environment variables');
				configData.database = newConfig;

			} else {
				const newConfig = {
					fromEnv: true,
					engine:  'knex-native',
					knex:    {
						client:     'sqlite3',
						connection: {
							filename: envSqliteFile
						}
					}
				};
				if (JSON.stringify(configData.database) === JSON.stringify(newConfig)) {
					// Config is unchanged, skip overwrite
					resolve();
					return;
				}

				logger.info('Generating Sqlite db configuration from environment variables');
				configData.database = newConfig;
			}

			// Write config
			fs.writeFile(filename, JSON.stringify(configData, null, 2), (err) => {
				if (err) {
					logger.error('Could not write db config to config file: ' + filename);
					reject(err);
				} else {
					logger.info('Wrote db configuration to config file: ' + filename);
					resolve();
				}
			});
		} else {
			resolve();
		}
	});
}

try {
	appStart();
} catch (err) {
	logger.error(err.message, err);
	process.exit(1);
}