Add !alert

Using !alert in a modmail thread will ping you the next time the thread
gets a new reply. Use !alert cancel to cancel.

db/migrations/20180421161550_add_alert_id_to_threads.js

@@ -0,0 +1,11 @@
+exports.up = async function (knex, Promise) {
+  await knex.schema.table('threads', table => {
+    table.string('alert_id', 20).nullable().defaultTo(null).after('scheduled_close_name');
+  });
+};
+
+exports.down = async function(knex, Promise) {
+  await knex.schema.table('threads', table => {
+    table.dropColumn('alert_id');
+  });
+};

src/data/Thread.js

@@ -19,6 +19,7 @@ const {THREAD_MESSAGE_TYPE, THREAD_STATUS} = require('./constants');
  * @property {String} scheduled_close_at
  * @property {String} scheduled_close_id
  * @property {String} scheduled_close_name
+ * @property {String} alert_id
  * @property {String} created_at
  */
 class Thread {
@@ -145,10 +146,12 @@ class Thread {
 
     if (this.scheduled_close_at) {
       await this.cancelScheduledClose();
-      await this.postSystemMessage({
-        content: `<@!${this.scheduled_close_id}> Thread that was scheduled to be closed got a new reply. Cancelling.`,
-        disableEveryone: false
-      });
+      await this.postSystemMessage(`<@!${this.scheduled_close_id}> Thread that was scheduled to be closed got a new reply. Cancelling.`);
+    }
+
+    if (this.alert_id) {
+      await this.setAlert(null);
+      await this.postSystemMessage(`<@!${this.alert_id}> New message from ${this.user_name}`);
     }
   }
 
@@ -368,6 +371,18 @@ class Thread {
       });
   }
 
+  /**
+   * @param {String} userId
+   * @returns {Promise<void>}
+   */
+  async setAlert(userId) {
+    await knex('threads')
+      .where('id', this.id)
+      .update({
+        alert_id: userId
+      });
+  }
+
   /**
    * @returns {Promise<String>}
    */

src/main.js

@@ -20,6 +20,7 @@ const typingProxy = require('./modules/typingProxy');
 const version = require('./modules/version');
 const newthread = require('./modules/newthread');
 const idModule = require('./modules/id');
+const alert = require('./modules/alert');
 
 const attachments = require("./data/attachments");
 const {ACCIDENTAL_THREAD_MESSAGES} = require('./data/constants');
@@ -183,6 +184,7 @@ module.exports = {
     await version(bot);
     await newthread(bot);
     await idModule(bot);
+    await alert(bot);
 
     // Connect to Discord
     console.log('Connecting to Discord...');

src/modules/alert.js

@@ -0,0 +1,17 @@
+const threadUtils = require('../threadUtils');
+
+module.exports = bot => {
+  const addInboxServerCommand = (...args) => threadUtils.addInboxServerCommand(bot, ...args);
+
+  addInboxServerCommand('alert', async (msg, args, thread) => {
+    if (! thread) return;
+
+    if (args[0] && args[0].startsWith('c')) {
+      await thread.setAlert(null);
+      await thread.postSystemMessage(`Cancelled new message alert`);
+    } else {
+      await thread.setAlert(msg.author.id);
+      await thread.postSystemMessage(`Pinging ${msg.author.username}#${msg.author.discriminator} when this thread gets a new reply`);
+    }
+  });
+};