Feat: Support for Microsoft Oauth in Email Channel (#6227)

- Adds the backend APIs required for Microsoft Email Channels

Co-authored-by: Pranav Raj S <pranav@chatwoot.com>
Co-authored-by: Sojan <sojan@pepalo.com>

lib/microsoft_graph_auth.rb

@@ -0,0 +1,55 @@
+# Copyright (c) Microsoft Corporation.
+# Licensed under the MIT License.
+# frozen_string_literal: true
+
+# Refer: https://github.com/microsoftgraph/msgraph-sample-rubyrailsapp
+
+require 'omniauth-oauth2'
+
+# Implements an OmniAuth strategy to get a Microsoft Graph
+# compatible token from Azure AD
+class MicrosoftGraphAuth < OmniAuth::Strategies::OAuth2
+  option :name, :microsoft_graph_auth
+
+  DEFAULT_SCOPE = 'offline_access https://outlook.office.com/IMAP.AccessAsUser.All https://outlook.office.com/SMTP.Send'
+
+  # Configure the Microsoft identity platform endpoints
+  option :client_options,
+         site: 'https://login.microsoftonline.com',
+         authorize_url: '/common/oauth2/v2.0/authorize',
+         token_url: '/common/oauth2/v2.0/token'
+
+  option :pcke, true
+  # Send the scope parameter during authorize
+  option :authorize_options, [:scope]
+
+  # Unique ID for the user is the id field
+  uid { raw_info['id'] }
+
+  # Get additional information after token is retrieved
+  extra do
+    {
+      'raw_info' => raw_info
+    }
+  end
+
+  def raw_info
+    # Get user profile information from the /me endpoint
+    @raw_info ||= access_token.get('https://graph.microsoft.com/v1.0/me?$select=displayName').parsed
+  end
+
+  def authorize_params
+    super.tap do |params|
+      params[:scope] = request.params['scope'] if request.params['scope']
+      params[:scope] ||= DEFAULT_SCOPE
+    end
+  end
+
+  # Override callback URL
+  # OmniAuth by default passes the entire URL of the callback, including
+  # query parameters. Azure fails validation because that doesn't match the
+  # registered callback.
+  def callback_url
+    ENV.fetch('FRONTEND_URL', nil) + app_path
+  end
+end