Add: Backup notification (#3225)

* Formatting updates

* Add: backup completion notification

* Fix: comment for backup

* Add: backup size units to notification

* Add: failed backup notification

* Add: calls to failed backup notification

* Update: notification OpenAPI spec

* Update notifications to first check if any are active for an event, update JS docs

---------

Co-authored-by: advplyr <advplyr@protonmail.com>

server/managers/BackupManager.js

@@ -16,9 +16,11 @@ const { getFileSize } = require('../utils/fileUtils')
 const Backup = require('../objects/Backup')
 
 class BackupManager {
-  constructor() {
+  constructor(notificationManager) {
     this.ItemsMetadataPath = Path.join(global.MetadataPath, 'items')
     this.AuthorsMetadataPath = Path.join(global.MetadataPath, 'authors')
+    /** @type {import('./NotificationManager')} */
+    this.notificationManager = notificationManager
 
     this.scheduleTask = null
 
@@ -294,6 +296,8 @@ class BackupManager {
     // Create backup sqlite file
     const sqliteBackupPath = await this.backupSqliteDb(newBackup).catch((error) => {
       Logger.error(`[BackupManager] Failed to backup sqlite db`, error)
+      const errorMsg = error?.message || error || 'Unknown Error'
+      this.notificationManager.onBackupFailed(errorMsg)
       return false
     })
 
@@ -304,6 +308,8 @@ class BackupManager {
     // Zip sqlite file, /metadata/items, and /metadata/authors folders
     const zipResult = await this.zipBackup(sqliteBackupPath, newBackup).catch((error) => {
       Logger.error(`[BackupManager] Backup Failed ${error}`)
+      const errorMsg = error?.message || error || 'Unknown Error'
+      this.notificationManager.onBackupFailed(errorMsg)
       return false
     })
 
@@ -324,13 +330,18 @@ class BackupManager {
     }
 
     // Check remove oldest backup
-    if (this.backups.length > this.backupsToKeep) {
+    const removeOldest = this.backups.length > this.backupsToKeep
+    if (removeOldest) {
       this.backups.sort((a, b) => a.createdAt - b.createdAt)
 
       const oldBackup = this.backups.shift()
       Logger.debug(`[BackupManager] Removing old backup ${oldBackup.id}`)
       this.removeBackup(oldBackup)
     }
+
+    // Notification for backup successfully completed
+    this.notificationManager.onBackupCompleted(newBackup, this.backups.length, removeOldest)
+
     return true
   }
 
@@ -348,7 +359,6 @@ class BackupManager {
   /**
    * @see https://github.com/TryGhost/node-sqlite3/pull/1116
    * @param {Backup} backup
-   * @promise
    */
   backupSqliteDb(backup) {
     const db = new sqlite3.Database(Database.dbPath)