Add system_notification sending email feature

app/mailers/app_mailer.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class AppMailer < Devise::Mailer
   helper :application, :mailer, :input_sanitize
   include Devise::Controllers::UrlHelpers
@@ -20,4 +22,17 @@ class AppMailer < Devise::Mailer
     }.merge(opts)
     mail(headers)
   end
+
+  def system_notification(user, system_notification)
+    @user = user
+    @system_notification = system_notification
+
+    headers = {
+      to: @user.email,
+      subject: "[#{t('system_notifications.emails.title')}] "\
+               "#{@system_notification.title}"
+    }
+
+    mail(headers)
+  end
 end

app/models/user_system_notification.rb

@@ -6,8 +6,15 @@ class UserSystemNotification < ApplicationRecord
 
   scope :unseen, -> { where(seen_at: nil) }
 
-  def self.mark_as_seen(notifications_id)
-    where(system_notification_id: notifications_id)
+  def send_email
+    if user.system_message_email_notification
+      AppMailer
+        .system_notification(user, system_notification)
+    end
+  end
+
+  def self.mark_as_seen(notifications)
+    where(system_notification_id: notifications)
       .update_all(seen_at: Time.now)
   end
 

app/views/users/mailer/system_notification.html.erb

@@ -0,0 +1,10 @@
+<p>
+  <%= I18n.t("system_notifications.emails.intro_paragraph", user_name: @user.name) %>
+</p>
+<p>
+  <%= link_to @system_notification.title.html_safe, system_notifications_url %>
+</p>
+
+<p>
+  <%= @system_notification.description.html_safe %>
+</p>

config/environments/development.rb

@@ -57,6 +57,8 @@ Rails.application.configure do
   # Print deprecation notices to the Rails logger.
   config.active_support.deprecation = :log
 
+  config.action_mailer.preview_path = "#{Rails.root}/test/mailers/previews"
+
   # Raise an error on page load if there are pending migrations.
   config.active_record.migration_error = :page_load
 

config/environments/test.rb

@@ -56,7 +56,7 @@ Rails.application.configure do
   config.action_mailer.default_url_options = { host: Rails.application.secrets.mail_server_url }
   config.action_mailer.default_options = { from: Rails.application.secrets.mail_from }
   config.action_mailer.raise_delivery_errors = false
-  config.action_mailer.delivery_method = :smtp
+  # config.action_mailer.delivery_method = :smtp
 
   config.action_mailer.smtp_settings = {
     address: Rails.application.secrets.mailer_address,

config/locales/en.yml

@@ -1292,6 +1292,9 @@ en:
     create:
       success_flash: "Successfully added sample group <strong>%{sample_group}</strong> to team <strong>%{team}</strong>."
   system_notifications:
+    emails:
+      title: "What's new notification"
+      intro_paragraph: "Hello %{user_name}, you received new What's new notification!"
     index:
       whats_new: "What's New"
       more_notifications: "More system notifications"

spec/models/user_system_notification_spec.rb

@@ -15,6 +15,25 @@ describe UserSystemNotification do
     it { is_expected.to belong_to(:system_notification) }
   end
 
+  describe '.send_email' do
+    context 'when user has enabled notifications' do
+      it 'delivers new email' do
+        allow(user_system_notification.user)
+          .to receive(:system_message_email_notification).and_return(true)
+
+        expect { user_system_notification.send_email&.deliver_now }
+          .to change { ActionMailer::Base.deliveries.count }.by(1)
+      end
+    end
+
+    context 'when user has disabled notifications' do
+      it 'doesn\'t deliver new email' do
+        expect { user_system_notification.send_email&.deliver_now }
+          .not_to(change { ActionMailer::Base.deliveries.count })
+      end
+    end
+  end
+
   describe 'Methods' do
     let(:notifcation_one) { create :system_notification }
     let(:notifcation_two) { create :system_notification }

test/mailers/previews/app_mailer_preview.rb

@@ -82,6 +82,12 @@ class AppMailerPreview < ActionMailer::Preview
     )
   end
 
+  def system_notification
+    sn = FactoryBot.build(:system_notification)
+    user = FactoryBot.build(:user)
+    AppMailer.system_notification(user, sn)
+  end
+
   private
 
   def fake_user