paginate and sort candidates list

comletes #99

app/controllers/admin/candidate_controller.rb

@@ -3,8 +3,11 @@ module Admin
   class CandidateController < AdminController
     before_action :collect_quizzes, except: [:login, :auth]
 
+    helper_method :sort_column
+
     def index
-      @candidates = policy_scope Candidate.order(:name)
+      @candidates = policy_scope Candidate.order("#{sort_column} #{sort_direction}")
+                    .page(params[:page])
     end
 
     def new
@@ -65,5 +68,9 @@ module Admin
         CandidateMailer.welcome(candidate).deliver_later
         RecruiterMailer.candidate_created(candidate).deliver_later
       end
+
+      def sort_column
+        Candidate.column_names.include?(params[:sort]) ? params[:sort] : 'name'
+      end
   end
 end

app/controllers/admin/result_controller.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 module Admin
   class ResultController < AdminController
-    helper_method :sort_column, :sort_direction
+    helper_method :sort_column
 
     # TODO: change context from Candidate to Quiz
     # bypass pundit lockdowns until completed
@@ -30,9 +30,5 @@ module Admin
       def sort_column
         Candidate.column_names.include?(params[:sort]) ? params[:sort] : 'completed_at'
       end
-
-      def sort_direction
-        %w(asc desc).include?(params[:direction]) ? params[:direction] : 'desc'
-      end
   end
 end

app/controllers/admin_controller.rb

@@ -9,6 +9,8 @@ class AdminController < ApplicationController
   after_action :verify_authorized, except: :index
   after_action :verify_policy_scoped, only: :index
 
+  helper_method :sort_direction
+
   def current_user
     @current_user ||= User.find_by(id: session[:user]) if session[:user]
   end
@@ -16,6 +18,10 @@ class AdminController < ApplicationController
 
   private
 
+    def sort_direction
+      %w(asc desc).include?(params[:direction]) ? params[:direction] : 'desc'
+    end
+
     def authorize_user
       session[:request] = request.fullpath
       redirect_to admin_login_path unless current_user

app/views/admin/candidate/index.html.erb

@@ -9,13 +9,13 @@
 
   <table cellspacing="0" cellpadding="0">
     <tr>
-      <th>Candidate</th>
-      <th>Test ID</th>
-      <th>Email</th>
-      <th>Experience</th>
+      <th><%= sortable "name", "Candidate" %></th>
+      <th><%= sortable "test_hash", "Test ID" %></th>
+      <th><%= sortable "email" %></th>
+      <th><%= sortable "experience" %></th>
       <th>Progress</th>
-      <th>Completed</th>
-      <th>Reminded</th>
+      <th><%= sortable  "completed_at", "Completed" %></th>
+      <th><%= sortable "reminded" %></th>
       <th>Interview?</th>
     </tr>
 
@@ -36,4 +36,5 @@
       </tr>
     <% end %>
   </table>
+  <%= paginate @candidates %>
 </main>