Add admin-only empty playlist display

app/assets/stylesheets/playlists.css.scss.erb

@@ -591,3 +591,23 @@ span.private_item {
     margin-top: 8px;
   }
 }
+
+#empty-playlists td {
+    padding: 5px;
+    border: 1px black solid; 
+}
+
+#empty-playlists {
+  width: 1050px;
+  .url {
+      width: 110px;
+  }
+  .user {
+      width: 110px;
+  }
+  .title {
+      width: 210px;
+  }
+  .description {
+  }
+}

app/controllers/playlists_controller.rb

@@ -46,6 +46,11 @@ def index
     common_index Playlist
   end
 
+  def empty
+    sql = "select p.* from playlists p left join playlist_items pi ON p.id = pi.playlist_id where pi.id is null order by p.id desc"
+    @playlists = Playlist.find_by_sql(sql).paginate(:page => params[:page], :per_page => 75)
+  end
+
   def show
     return if redirect_bad_format
 

app/models/ability.rb

@@ -73,7 +73,7 @@ def initialize(user)
 
       can :access, :rails_admin
       can :dashboard, :all
-      can [:import, :submit_import], :playlists
+      can [:import, :submit_import, :empty], :playlists
       can [:index, :show, :export, :export_as, :export_unique, :bulk_delete, :destroy, :view_in_app, :edit_in_app, :edit,
            :update, :position_update, :update_notes, :delete_inherited_annotations, :save_readable_state],
         :all

app/views/playlists/empty.html.erb

@@ -0,0 +1,36 @@
+<h1>Playlists with Zero Playlist Items - 1</h1>
+
+<br>
+<br>
+<%= will_paginate @playlists, container: false, :previous_label => 'Previous', :next_label => 'Next' %>
+
+<table id="empty-playlists">
+  <!-- playlist URL, playlist ID, title and description field. -->
+  <tr>
+    <th>ID</th><th>User</th><th>Title</th><th>Description</th><th></th><th></th>
+  </tr>
+
+<% @playlists.each do |playlist| %>
+  <tr>
+    <td class="url">
+      <%= link_to playlist_path(playlist), playlist_path(playlist), target: '_blank' %>
+    </td>
+    <td class="user">
+      <%= link_to(
+          raw("#{user_path(playlist.user)}<br>#{playlist.user.email_address}"),
+          user_path(playlist.user),
+          target: '_blank'
+          )%>
+    </td>
+    <td class="title">
+      <%= playlist.name %>
+    </td>
+    <td class="description">
+      <%= playlist.description %>
+    </td>
+  </tr>
+<% end %>
+</table>
+
+<%= will_paginate @playlists, container: false, :previous_label => 'Previous', :next_label => 'Next' %>
+

config/initializers/rails_admin.rb

@@ -150,7 +150,8 @@ class EditInApp < RailsAdmin::Config::Actions::Base
 
 RailsAdmin.config do |config|
   config.navigation_static_links = {
-    'Playlist Importer' => '/playlists/import'
+    'Playlist Importer' => '/playlists/import',
+    'Empty Playlists' => '/playlists/empty',
   }
   config.current_user_method do
     current_user

config/routes.rb

@@ -87,6 +87,7 @@
       get 'playlist_lookup'
       get 'import'
       post 'submit_import'
+      get 'empty'
     end
   end
   resources :playlist_items do