config.js

const _ = require('lodash');
const utils = require('./server/utils');

// load environment variables
require('dotenv').config();

/**
 * Allows alternative keys to be used for environment variables.
 * This lets Slotty use the key name it wants while allowing it to accept different key names for the same setting in different environments.
 * @readonly
 * @type {Object}
 */
const aliases = {
  DATABASE: 'DB_PROD',
  POSTGRES: 'DB_PROD',
  DATABASE_URL: 'DB_PROD',
  POSTGRES_URL: 'DB_PROD',
};

/**
 * Define the default options and types of the configuration.
 * Note: If you want to change these values, a better option is to create a .env file.
 *       All environment variables that match config options will get used instead.
 * @readonly
 * @type {Object}
 */
const config = {
  /**
   * Defines the name of the app that is used for any dynamic operations.
   * In particular, this is the name used when sending notifications.
   * @readonly
   * @constant
   * @type {String}
   */
  appName: 'Slotty',

  /**
   * Provides a wrapper around the app environment.
   * @readonly
   * @constant
   * @type {Boolean}
   */
  isDev: process.env.NODE_ENV === 'development',

  /**
   * Defines the URL of the webadvisor-api that will be used to perform course lookups.
   * @readonly
   * @constant
   * @type {String}
   */
  webadvisorApi: 'https://webadvisor-api.herokuapp.com/graphql',

  /**
   * Defines the base URL prefix to use for API routes.
   * @readonly
   * @constant
   * @type {String}
   */
  apiBaseUrl: '/api',

  /**
   * Defines the format to tell morgan to use when logging requests.
   * @see https://github.com/expressjs/morgan#readme
   * @readonly
   * @constant
   * @type {String}
   */
  logFormat: 'common',

  /**
   * Defines the port that Slotty will bind its web and API server to by default.
   * If the environment variable "PORT" has been set, it will override this value.
   * @readonly
   * @constant
   * @type {Number}
   */
  port: 3001,

  /**
   * Defines the interval, in seconds, between each slot check that is performed.
   * Each slot check will make a large number of HTTP requests (GraphQL queries) to webadvisor-api.
   * Note: Do not set this value too low or you may get rate limited, on the other hand, if you set it to high, you may miss open slots.
   * @readonly
   * @constant
   * @type {Number}
   */
  workerInterval: 15 /* seconds */,

  /**
   * Defines the time, in seconds, that results from slot checks will be considered valid for.
   * If this value is less than the workerInterval, all notifications will be checked on every worker run.
   * Otherwise, if this value is larger than worker interval, notifications will end up being checked in chunks.
   * @readonly
   * @constant
   * @type {Number}
   */
  slotDataTtl: 60 /* seconds */,

  /**
   * Defines what server should be used as the database for Slotty. Must be a PostgreSQL database.
   * Supply a PostgreSQL connection string for each environment.
   * While developing, you can use `yarn pg` to quickly spin up a PostgreSQL server in docker and `yarn stop` to kill it.
   * Generally this value should be overridden through the use of environment variables to ensure you don't commit secrets.
   * @readonly
   * @constant
   * @type {{ dev: String, prod: String }}
   */
  db: {
    dev: 'postgresql://postgres:docker@localhost:5432/postgres',
    prod: 'postgresql://postgres:docker@localhost:5432/postgres',
  },

  /**
   * Defines the account credentials used to connect to Twilio (SMS provider).
   * These must be set to valid values if you wish to send SMS notifications.
   * @readonly
   * @constant
   * @type {{ accountSid: String, authToken: String, fromNumber: String }}
   */
  twilio: {
    accountSid: 'ACfake',
    authToken: 'fake',
    fromNumber: '',
  },

  /**
   * Defines the message that will be sent as a notification.
   * A simple replace will be ran over this string to inject a select few variables using a '$' prefix to denote variables.
   * @example
   * Variables:
   *  - $app: Extracts the name of the app as a string (e.g. "Slotty").
   *  - $time: A datetime string generated at the time of building the message.
   *  - $accessKey: The value of notification.accessKey.
   *  - $availableSlots: The current number of available slots.
   *  - $totalSlots: The current total number of slots.
   *  - $institutionKey: The value of notification.institutionKey.
   *  - $courseKey: The value of notification.courseKey.
   *  - $sectionKey: The value of notification.sectionKey.
   *  - $termKey: The value of notification.termKey.
   *  - $contact: The value of notification.contact.
   * @readonly
   * @constant
   * @type {String}
   */
  notificationMessageTemplate: `
Hello, this is an automated message from $app in relation to the notification with the following access key: "$accessKey".
Some open slots ($availableSlots/$totalSlots) have been detected for $courseKey/$sectionKey ($institutionKey - $termKey) as of $time.
We wish you luck, register fast!
(Visit $app to disable this notification using the above access key.)
`.trim(),

  /**
   * Defines the message that will be sent as a verification for a notification.
   * As above, a simple replace will be ran over this string to inject some variables using the '$' prefix.
   * @example
   * Variables:
   *  - $app: Extracts the name of the app as a string (e.g. "Slotty").
   *  - $action: The type of action triggering this message (e.g. "modified" or "created").
   *  - $accessKey: The value of notification.accessKey.
   *  - $contact: The value of notification.contact.
   * @readonly
   * @constant
   * @type {String}
   */
  verificationMessageTemplate: `
Hello, this is an automated message from $app. A notification has been $action using your phone number, $contact, with the following access key: "$accessKey".
To verify and enable this notification, please reply with a message containing the access key exactly.
If you do not wish to receive messages from $app, please ignore this message.
`.trim(),

  /**
   * Defines the message that will be sent once a notification has been verified.
   * As above, a simple replace will be ran over this string to inject some variables using the '$' prefix.
   * @example
   * Variables:
   *  - $app: Extracts the name of the app as a string (e.g. "Slotty").
   *  - $accessKey: The access key of the notification that was verified.
   * @readonly
   * @constant
   * @type {String}
   */
  verifiedMessageTemplate: `
Your notification is now verified! Your notification has the following access key: "$accessKey".
$app recommends that you write down the access key so you can edit the notification in the future!
`.trim(),

  /**
   * Defines the message that will be sent when a user fails to verify a notification.
   * As above, a simple replace will be ran over this string to inject some variables using the '$' prefix.
   * @example
   * Variables:
   *  - $app: Extracts the name of the app as a string (e.g. "Slotty").
   *  - $accessKey: The access key of the notification that was verified.
   * @readonly
   * @constant
   * @type {String}
   */
  notVerifiedMessageTemplate: `
$app is unable to verify the notification with the following access key: "$accessKey".
Please ensure you are verifying this notification from the correct contact number and that a notification with that access key does exist.
`.trim(),
};

/** EVERYTHING BELOW THIS POINT IS FOR CONFIG SETUP, DO NOT CHANGE. */

// apply the aliases to the process env
Object.keys(aliases)
  // only include aliases that are used in the current env
  .filter(alias => process.env.hasOwnProperty(alias))
  // don't override values set by their primary key
  .filter(alias => !process.env.hasOwnProperty(aliases[alias]))
  // apply each valid alias
  .forEach(alias => (process.env[aliases[alias]] = process.env[alias]));

/**
 * Defines all custom user set values that override the config defaults.
 * These are passed in as environment variables. Use SCREAMING_SNAKE_CASE.
 * To access config values that are subitems, simply use an underscore.
 * @readonly
 * @type {Object}
 */
const overrideConfig = utils
  .getPrimitiveKeys(config)
  .map(configKey => ({
    configKey,
    envKey: utils.snakeCase(configKey.split('.'), true),
  }))
  .filter(({ envKey }) => process.env.hasOwnProperty(envKey))
  .reduce((obj, { configKey, envKey }) => {
    let value = process.env[envKey];

    // parse the value correctly depending on type
    switch (typeof _.get(config, configKey)) {
      case 'number':
        value = parseFloat(value);
        break;
      case 'boolean':
        value = value.trim().toLowerCase() === 'true';
        break;
    }

    // add the override value that we just parsed
    return _.set(obj, configKey, value);
  }, {});

// merge the custom overrides into the base config and export that
module.exports = Object.freeze(_.merge({}, config, overrideConfig));