ER-815 Service Unavailable Page (#941)

* add redirect to service unavailable page

* rubocop

* update specs

* update service unavailable redirect

* add maintencance? method to application config

* update spec

* rename maintenance page and update spec

.env.example

@@ -81,3 +81,6 @@ E2E=true
 
 # Deployment environment
 ENVIRONMENT=
+
+# DISPLAY SERVICE_UNAVAILABLE PAGE
+MAINTENANCE = true

app/controllers/application_controller.rb

@@ -6,10 +6,11 @@ class ApplicationController < ActionController::Base
                 :set_hotjar_site_id,
                 :prepare_cms
 
+  before_action :maintenance_page, if: :maintenance?
+
   helper_method :current_user,
                 :timeout_timer,
                 :debug?
-
   default_form_builder(EarlyYearsRecoveryFormBuilder)
 
   include Tracking
@@ -67,6 +68,15 @@ def timeout_timer
 
 private
 
+  # @return [Boolean]
+  def maintenance?
+    Rails.application.maintenance? && request.path != '/maintenance'
+  end
+
+  def maintenance_page
+    redirect_to static_path('maintenance')
+  end
+
   def set_time_zone(&block)
     Time.use_zone(ENV['TZ'], &block)
   end

config/application.rb

@@ -105,6 +105,11 @@ def debug?
       Types::Params::Bool[ENV.fetch('DEBUG', false)]
     end
 
+    # @return [Boolean]
+    def maintenance?
+      Types::Params::Bool[ENV.fetch('MAINTENANCE', false)]
+    end
+
     # @return [ActiveSupport::TimeWithZone]
     def public_beta_launch_date
       Time.zone.local(2023, 2, 9, 15, 0, 0)

spec/system/maintenance_spec.rb

@@ -0,0 +1,38 @@
+require 'rails_helper'
+
+RSpec.shared_examples 'displays service unavailable page' do
+  it 'displays the service unavailable message and title' do
+    expect(page).to have_css('h1', text: 'Sorry, the service is unavailable')
+    expect(page).to have_title('Early years child development training : Sorry, the service is unavailable')
+  end
+end
+
+RSpec.describe 'Service Unavailable' do
+  before do
+    allow(Rails.application).to receive(:maintenance?).and_return(true)
+  end
+
+  context 'when the service is unavailable and user navigates to home' do
+    before do
+      visit '/'
+    end
+
+    it_behaves_like 'displays service unavailable page'
+  end
+
+  context 'when the service is unavailable and user navigates to my modules page' do
+    before do
+      visit my_modules_path
+    end
+
+    it_behaves_like 'displays service unavailable page'
+  end
+
+  context 'when the service is unavailable and user is already on the service unavailable page' do
+    before do
+      visit '/maintenance'
+    end
+
+    it_behaves_like 'displays service unavailable page'
+  end
+end