7 files changed, 160 insertions, 1 deletions
diff --git a/actionmailer/lib/action_mailer.rb b/actionmailer/lib/action_mailer.rb
index 83969d4074..49a380419f 100644
--- a/actionmailer/lib/action_mailer.rb
+++ b/actionmailer/lib/action_mailer.rb
@@ -45,4 +45,5 @@ module ActionMailer
   autoload :Previews, 'action_mailer/preview'
   autoload :TestCase
   autoload :TestHelper
+  autoload :DeliverLater
 end
diff --git a/actionmailer/lib/action_mailer/base.rb b/actionmailer/lib/action_mailer/base.rb
index bc540aece0..df0c945434 100644
--- a/actionmailer/lib/action_mailer/base.rb
+++ b/actionmailer/lib/action_mailer/base.rb
@@ -549,7 +549,11 @@ module ActionMailer
 
       def method_missing(method_name, *args) # :nodoc:
         if respond_to?(method_name)
-          new(method_name, *args).message
+          if defined?(::ActiveJob) && action_methods.include?(method_name.to_s)
+            DeliverLater::MailMessageWrapper.new(self, method_name, *args)
+          else
+            new(method_name, *args).message
+          end
         else
           super
         end
diff --git a/actionmailer/lib/action_mailer/deliver_later.rb b/actionmailer/lib/action_mailer/deliver_later.rb
new file mode 100644
index 0000000000..5609e35d01
--- /dev/null
+++ b/actionmailer/lib/action_mailer/deliver_later.rb
@@ -0,0 +1,9 @@
+require 'active_job'
+
+module ActionMailer
+  module DeliverLater
+    extend ActiveSupport::Autoload
+    autoload :Job
+    autoload :MailMessageWrapper
+  end
+end
+\ No newline at end of file
diff --git a/actionmailer/lib/action_mailer/deliver_later/job.rb b/actionmailer/lib/action_mailer/deliver_later/job.rb
new file mode 100644
index 0000000000..fda3b626b2
--- /dev/null
+++ b/actionmailer/lib/action_mailer/deliver_later/job.rb
@@ -0,0 +1,11 @@
+module ActionMailer
+  module DeliverLater
+    class Job < ActiveJob::Base
+      queue_as :mailers
+
+      def perform(mailer, mail_method, delivery_method, *args)
+        mailer.constantize.send(mail_method, *args).send(delivery_method)
+      end
+    end
+  end
+end
diff --git a/actionmailer/lib/action_mailer/deliver_later/mail_message_wrapper.rb b/actionmailer/lib/action_mailer/deliver_later/mail_message_wrapper.rb
new file mode 100644
index 0000000000..5c0a5304d4
--- /dev/null
+++ b/actionmailer/lib/action_mailer/deliver_later/mail_message_wrapper.rb
@@ -0,0 +1,46 @@
+module ActionMailer
+  module DeliverLater
+    class MailMessageWrapper < Delegator
+      def initialize(mailer, mail_method, *args)
+        @mailer      = mailer
+        @mail_method = mail_method
+        @args        = args
+        __getobj__
+      end
+
+      def __getobj__
+        @obj ||= @mailer.send(:new, @mail_method, *@args).message
+      end
+
+      def __setobj__(obj)
+        @obj = obj
+      end
+
+      def deliver_later!(options={})
+        enqueue_delivery :deliver!, options
+      end
+
+      def deliver_later(options={})
+        enqueue_delivery :deliver, options
+      end
+
+      def method_missing(m, *args, &block)
+        __getobj__.__send__(m, *args, &block)
+      end
+
+      private
+      def enqueue_delivery(delivery_method, options={})
+        args = @mailer.name, @mail_method.to_s, delivery_method.to_s, *@args
+        enqueue_method = :enqueue
+        if options[:at]
+          enqueue_method = :enqueue_at
+          args.unshift options[:at]
+        elsif options[:in]
+          enqueue_method = :enqueue_in
+          args.unshift options[:in]
+        end
+        ActionMailer::DeliverLater::Job.send enqueue_method, *args
+      end
+    end
+  end
+end
diff --git a/actionmailer/test/deliver_later_test.rb b/actionmailer/test/deliver_later_test.rb
new file mode 100644
index 0000000000..829c96872f
--- /dev/null
+++ b/actionmailer/test/deliver_later_test.rb
@@ -0,0 +1,82 @@
+# encoding: utf-8
+gem 'activejob'
+require 'action_mailer/deliver_later'
+require 'abstract_unit'
+require 'minitest/mock'
+require_relative 'mailers/delayed_mailer'
+
+class MailerTest < ActiveSupport::TestCase
+
+  setup do
+    @previous_logger = ActiveJob::Base.logger
+    @previous_delivery_method = ActionMailer::Base.delivery_method
+    ActionMailer::Base.delivery_method = :test
+    ActiveJob::Base.logger = Logger.new('/dev/null')
+    @mail = DelayedMailer.test_message(1, 2, 3)
+    ActionMailer::Base.deliveries.clear
+  end
+
+  teardown do
+    ActiveJob::Base.logger = @previous_logger
+    ActionMailer::Base.delivery_method = @previous_delivery_method
+  end
+
+  test 'should be a MailMessageWrapper' do
+    assert_equal @mail.class, ActionMailer::DeliverLater::MailMessageWrapper
+  end
+
+  test 'its object should be a Mail::Message' do
+    assert_equal @mail.__getobj__.class, Mail::Message
+  end
+
+  test 'should respond to .deliver' do
+    assert_respond_to @mail, :deliver
+  end
+
+  test 'should respond to .deliver!' do
+    assert_respond_to @mail, :deliver!
+  end
+
+  test 'should respond to .deliver_later' do
+    assert_respond_to @mail, :deliver_later
+  end
+
+  test 'should respond to .deliver_later!' do
+    assert_respond_to @mail, :deliver_later!
+  end
+
+  test 'should enqueue and run correctly in activejob' do
+    @mail.deliver_later!
+    assert_equal ActionMailer::Base.deliveries.size, 1
+  end
+
+  test 'should enqueue the email with :deliver delivery method' do
+    ret = ActionMailer::DeliverLater::Job.stub :enqueue, ->(*args){ args } do
+      @mail.deliver_later
+    end
+    assert_equal ret, ["DelayedMailer", "test_message", "deliver", 1, 2, 3]
+  end
+
+  test 'should enqueue the email with :deliver! delivery method' do
+    ret = ActionMailer::DeliverLater::Job.stub :enqueue, ->(*args){ args } do
+      @mail.deliver_later!
+    end
+    assert_equal ret, ["DelayedMailer", "test_message", "deliver!", 1, 2, 3]
+  end
+
+  test 'should enqueue a delivery with a delay' do
+    ret = ActionMailer::DeliverLater::Job.stub :enqueue_in, ->(*args){ args } do
+      @mail.deliver_later in: 600
+    end
+    assert_equal ret, [600, "DelayedMailer", "test_message", "deliver", 1, 2, 3]
+  end
+
+  test 'should enqueue a delivery at a specific time' do
+    later_time = Time.now.to_i + 3600
+    ret = ActionMailer::DeliverLater::Job.stub :enqueue_at, ->(*args){ args } do
+      @mail.deliver_later at: later_time
+    end
+    assert_equal ret, [later_time, "DelayedMailer", "test_message", "deliver", 1, 2, 3]
+  end
+
+end
diff --git a/actionmailer/test/mailers/delayed_mailer.rb b/actionmailer/test/mailers/delayed_mailer.rb
new file mode 100644
index 0000000000..62d4baa434
--- /dev/null
+++ b/actionmailer/test/mailers/delayed_mailer.rb
@@ -0,0 +1,6 @@
+class DelayedMailer < ActionMailer::Base
+
+  def test_message(*)
+    mail(from: 'test-sender@test.com', to: 'test-receiver@test.com', subject: 'Test Subject', body: 'Test Body')
+  end
+end