Add active_language controller and cookie storage

app/controllers/active_language_controller.rb

@@ -0,0 +1,10 @@
+class ActiveLanguageController < ApplicationController
+
+  def set_active_language
+    if Language.find_by_id(params[:active_language_id]) != nil
+      cookies[:active_language_id] = params[:active_language_id]
+    else
+      redirect_to root_path, status: :unprocessable_entity
+    end
+  end
+end

app/helpers/active_language_helper.rb

@@ -0,0 +1,8 @@
+module ActiveLanguageHelper
+
+  def active_language_select_tag
+    languages = Language.all.to_a.delete_if {|language| language.name == "English" }
+    options = options_from_collection_for_select(languages, "id", "name", cookies[:active_language_id] || 1)
+    select_tag "active_language_id", options
+  end
+end

app/views/layouts/application.html.erb

@@ -18,6 +18,11 @@
           <% if user_signed_in? %>
             <pre style="display: inline;">|</pre>
             <%= link_to "Languages", admin_languages_path %>
+            <pre style="display: inline;">|</pre>
+            <%= form_tag '/set_active_language', class: "d-inline" do %>
+              <%= active_language_select_tag %>
+              <%= submit_tag "Switch Language" %>
+            <% end %>
           <% end %>
         </div>
         <div class="ms-auto p-2">

config/routes.rb

@@ -3,6 +3,9 @@ Rails.application.routes.draw do
   #get 'dictionary/index'
   resources :dictionary, only: [:index, :show, :create]
   resources :words, only: [:index, :show]
+
+  post '/set_active_language', action: :set_active_language, controller: :active_language
+
   namespace :admin do
     resources :languages
   end

spec/factories/languages.rb

@@ -1,5 +1,9 @@
 FactoryBot.define do
   factory :language do
-    name { "MyString" }
+    sequence(:name) { |n| "MyString#{n.to_s}" }
+  end
+
+  factory :language_english, class: :language do
+    name { "English" }
   end
 end

spec/helpers/active_language_helper_spec.rb

@@ -0,0 +1,31 @@
+require 'rails_helper'
+
+# Specs in this file have access to a helper object that includes
+# the ActiveLanguageHelper. For example:
+#
+# describe ActiveLanguageHelper do
+#   describe "string concat" do
+#     it "concats two strings with spaces" do
+#       expect(helper.concat_strings("this","that")).to eq("this that")
+#     end
+#   end
+# end
+RSpec.describe ActiveLanguageHelper, type: :helper do
+
+  describe "active_language_helper_tag" do
+    before :each do
+      english = FactoryBot.create(:language_english)
+      2.times { FactoryBot.create(:language) }
+      @tag = active_language_select_tag
+    end
+
+    it "should return a select tag" do
+      expect(@tag).to have_selector(%(select))
+    end
+
+    it "should not contain an English option" do
+      expect(@tag).to_not include("English")
+      
+    end
+  end
+end

spec/requests/active_language_spec.rb

@@ -0,0 +1,20 @@
+require 'rails_helper'
+
+RSpec.describe "ActiveLanguages", type: :request do
+
+  describe "POST :set_active_language" do
+    
+    it "should set the cookie" do
+      language = FactoryBot.create(:language)
+      post "/set_active_language/", params: { active_language_id: language.id }
+      expect(cookies[:active_language_id]).to_not be_nil
+    end
+
+    it "should not set the cookie if language does not exist" do
+      language = FactoryBot.create(:language)
+      id = language.id + 1
+      post "/set_active_language/", params: { active_language_id: id }
+      expect(response).to have_http_status(:unprocessable_entity)
+    end
+  end
+end

spec/requests/root_spec.rb

@@ -39,5 +39,12 @@ RSpec.describe "Root path", type: :request do
       get root_path
       expect(response.body).to include(user.username)
     end
+
+    it "should have a language drop-down" do
+      user = FactoryBot.create(:user)
+      sign_in user
+      get root_path
+      expect(response.body).to have_field("active_language_id")
+    end
   end
 end