Limit Edits to an Authenticated Admin

app/controllers/admin/application_controller.rb

diff --git a/app/controllers/admin/application_controller.rb b/app/controllers/admin/application_controller.rb
new file mode 100644
index 0000000..b3322fe
--- /dev/null
+++ b/app/controllers/admin/application_controller.rb
@@ -0,0 +1,5 @@
+module Admin
+  class ApplicationController < ::ApplicationController
+    before_action { head :forbidden unless request.variant.admin? }
+  end
+end

app/controllers/admin/translations_controller.rb

diff --git a/app/controllers/admin/translations_controller.rb b/app/controllers/admin/translations_controller.rb
new file mode 100644
index 0000000..a360641
--- /dev/null
+++ b/app/controllers/admin/translations_controller.rb
@@ -0,0 +1,19 @@
+module Admin
+  class TranslationsController < ApplicationController
+    def create
+      translation = Translation.new(translation_params)
+
+      if translation.save
+        redirect_back fallback_location: root_url
+      else
+        head :unprocessable_entity
+      end
+    end
+
+    private
+
+    def translation_params
+      params.require(:translation).permit(:locale, :key, :value)
+    end
+  end
+end

app/controllers/application_controller.rb

diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index 09705d1..e684d65 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -1,2 +1,3 @@
 class ApplicationController < ActionController::Base
+  before_action { request.variant = :admin if cookies[:admin] }
 end

app/controllers/sessions_controller.rb

diff --git a/app/controllers/sessions_controller.rb b/app/controllers/sessions_controller.rb
new file mode 100644
index 0000000..35b3c8c
--- /dev/null
+++ b/app/controllers/sessions_controller.rb
@@ -0,0 +1,13 @@
+class SessionsController < ApplicationController
+  def create
+    cookies[:admin] = true
+
+    redirect_back fallback_location: root_url
+  end
+
+  def destroy
+    cookies.delete(:admin)
+
+    redirect_back fallback_location: root_url
+  end
+end

app/views/application/_header.html.erb

diff --git a/app/views/application/_header.html.erb b/app/views/application/_header.html.erb
index 1216183..bfb5bcc 100644
--- a/app/views/application/_header.html.erb
+++ b/app/views/application/_header.html.erb
@@ -32,11 +32,17 @@
 
       <ul class="list-reset lg:flex justify-end flex-1 items-center">
         <li class="mr-3">
-          <a
-            class="inline-block py-2 px-4 text-black font-bold no-underline"
-            href="#"
-            >Active</a
-          >
+          <% with_options class: "inline-block py-2 px-4 text-black font-bold no-underline" do |admin| %>
+            <% if request.variant.admin? %>
+              <%= admin.button_to session_path, method: :delete do %>
+                Preview
+              <% end %>
+            <% else %>
+              <%= admin.button_to sessions_path, method: :post do %>
+                Edit
+              <% end %>
+            <% end %>
+          <% end %>
         </li>
         <li class="mr-3">
           <a

app/views/translations/_translation.html+admin.erb

diff --git a/app/views/translations/_translation.html+admin.erb b/app/views/translations/_translation.html+admin.erb
new file mode 100644
index 0000000..4dd9a18
--- /dev/null
+++ b/app/views/translations/_translation.html+admin.erb
@@ -0,0 +1 @@
+<%= render "translations/form", translation: translation %>

app/views/translations/_translation.html.erb

diff --git a/app/views/translations/_translation.html.erb b/app/views/translations/_translation.html.erb
index 4dd9a18..0a71547 100644
--- a/app/views/translations/_translation.html.erb
+++ b/app/views/translations/_translation.html.erb
@@ -1 +1 @@
-<%= render "translations/form", translation: translation %>
+<%= translation %>

config/routes.rb

diff --git a/config/routes.rb b/config/routes.rb
index 9782e5e..11c457d 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -1,6 +1,11 @@
 Rails.application.routes.draw do
   # For details on the DSL available within this file, see https://guides.rubyonrails.org/routing.html
-  resources :translations, only: :create
+  scope module: :admin do
+    resources :translations, only: :create
+  end
+
+  resources :sessions, only: :create
+  resource :session, only: :destroy
 
   root to: "marketings#index"
 end

test/controllers/translations_controller_test.rb

diff --git a/test/controllers/translations_controller_test.rb b/test/controllers/admin/translations_controller_test.rb
similarity index 70%
rename from test/controllers/translations_controller_test.rb
rename to test/controllers/admin/translations_controller_test.rb
index 335dd55..8b03371 100644
--- a/test/controllers/translations_controller_test.rb
+++ b/test/controllers/admin/translations_controller_test.rb
@@ -1,8 +1,9 @@
 require "test_helper"
 
-class TranslationsControllerTest < ActionDispatch::IntegrationTest
+class Admin::TranslationsControllerTest < ActionDispatch::IntegrationTest
   test "#create with a valid Translation persists it to the I18n backend" do
     with_translations en: { key: "value" } do
+      post sessions_path
       post translations_path, params: {
         translation: { locale: :en, key: "key", value: "new value" }
       }
@@ -14,6 +15,7 @@ class TranslationsControllerTest < ActionDispatch::IntegrationTest
 
   test "#create with an valid Translation responds with an error" do
     with_translations en: {} do
+      post sessions_path
       post translations_path, params: {
         translation: { locale: :en, key: "missing", value: "" }
       }
@@ -21,4 +23,10 @@ class TranslationsControllerTest < ActionDispatch::IntegrationTest
       assert_response :unprocessable_entity
     end
   end
+
+  test "#create without authenticating responds with a Not Found status" do
+    post translations_path
+
+    assert_response :forbidden
+  end
 end

test/controllers/marketings_controller_test.rb

diff --git a/test/controllers/marketings_controller_test.rb b/test/controllers/marketings_controller_test.rb
index 6e05b54..f305cfb 100644
--- a/test/controllers/marketings_controller_test.rb
+++ b/test/controllers/marketings_controller_test.rb
@@ -3,7 +3,18 @@ require "test_helper"
 class MarketingsControllerTest < ActionDispatch::IntegrationTest
   include ActionView::Helpers::TranslationHelper
 
-  test "#index renders editors for copy" do
+  test "#index renders marketing copy" do
+    get root_path
+
+    assert_response :success
+    with_options scope: [:marketings, :index, :hero] do |i18n|
+      assert_select "title", text: i18n.translate(:title)
+      assert_select "h1", text: i18n.translate(:title)
+    end
+  end
+
+  test "#index renders editors for copy when authenticated" do
+    post sessions_path
     get root_path
 
     assert_response :success

test/system/translations_test.rb

diff --git a/test/system/translations_test.rb b/test/system/translations_test.rb
index c900990..86fa8e6 100644
--- a/test/system/translations_test.rb
+++ b/test/system/translations_test.rb
@@ -8,6 +8,7 @@ class TranslationsTest < ApplicationSystemTestCase
       translation = translate("marketings.index.hero.title")
 
       visit root_path
+      click_on "Edit"
       within "h1", text: translation do
         find(:rich_text_area).click
         fill_in_rich_text_area with: "New Hero Title"