const debug = require('debug')('talk-plugin-notifications');
const path = require('path');
const linkify = require('linkifyjs/html');
const NotificationManager = require('./NotificationManager');

module.exports = connectors => {
  const {
    graph: { subscriptions: { getBroker }, Context },
    services: { Mailer, Plugins },
  } = connectors;

  // Setup the mailer. Other plugins registered before this one can replace the
  // notification template by passing the same name + format for the template
  // registration.
  Mailer.templates.register(
    path.join(__dirname, 'emails', 'notification.html.ejs'),
    'notification',
    'html'
  );
  Mailer.templates.register(
    path.join(__dirname, 'emails', 'notification.txt.ejs'),
    'notification',
    'txt'
  );

  // Register the mail helpers. You can register your own helpers by calling
  // this function in another plugin.
  Mailer.registerHelpers({ linkify });

  // Get the handle for the broker to attach to notifications.
  const broker = getBroker();

  // Create a NotificationManager to handle notifications.
  const manager = new NotificationManager(Context);

  // Get all the notification handlers. Additional plugins registered before
  // this one can expose a `notifications` hook, that contains an array of
  // notification handlers.
  //
  // A notification handler has the following form:
  //
  // {
  //   event     // the graph event to listen for
  //   handle    // the function called when the event is fired. It is called with
  //             // the (ctx, arg1, arg2, ...) where arg1, arg2 are args from the
  //             // event.
  //   category  // the name representing the notification type (like 'reply')
  //   hydrate   // returns the replacement parameters (in order!) to be used
  //             // in the translation.
  // }
  //
  const notificationHandlers = Plugins.get('server', 'notifications').reduce(
    (handlers, { plugin, notifications }) => {
      debug(
        `registered the ${
          plugin.name
        } plugin for notifications ${notifications.map(
          ({ category }) => category
        )}`
      );
      handlers.push(...notifications);
      return handlers;
    },
    []
  );

  // Attach all the notification handlers.
  manager.register(...notificationHandlers);

  // Attach the broker to the manager so it can listen for the events.
  manager.attach(broker);
};