const nconf = module.exports = require('nconf');
const path = require('path');

nconf
// 1. Command-line arguments
    .argv()
    // 2. Environment variables
    .env([
        'DATA_BACKEND',
        'GCLOUD_PROJECT',
        'MYSQL_USER',
        'MYSQL_PASSWORD',
        'MYSQL_HOST',
        'PORT',
        'INSTANCE_CONNECTION_NAME',
        'NODE_ENV'
    ])
    // 3. Config file
    .file({ file: path.join(__dirname, 'config.json') })
    // 4. Defaults
    .defaults({
        // dataBackend can be 'datastore', 'cloudsql', or 'mongodb'. Be sure to
        // configure the appropriate settings for each storage engine below.
        // If you are unsure, use datastore as it requires no additional
        // configuration.
        DATA_BACKEND: 'cloudsql',
        // This is the id of your project in the Google Cloud Developers Console.
        GCLOUD_PROJECT: 'bookingsystem2',
        MYSQL_USER: 'my user',
        MYSQL_PASSWORD: 'my password',
        MYSQL_HOST: 'sql ip address',
        PORT: 3306,
        INSTANCE_CONNECTION_NAME: 'my ICN',
        NODE_ENV: 'production'
    });


// Check for required settings
checkConfig('GCLOUD_PROJECT');


if (nconf.get('DATA_BACKEND') === 'cloudsql') {
    checkConfig('MYSQL_USER');
    checkConfig('MYSQL_PASSWORD');
    if (nconf.get('NODE_ENV') === 'production') {
        checkConfig('INSTANCE_CONNECTION_NAME');
    }
}

function checkConfig (setting) {
    if (!nconf.get(setting)) {
        throw new Error('You must set ' + setting + ' as an environment variable or in config.json!');
    }
}