Hide interface if no submissions are available and encode submissions for later use in javascript

app/views/exercises/external_users/statistics.html.slim

@@ -1,9 +1,11 @@
 h1 = "#{@exercise} (external user #{@external_user})"
-- submissions = Submission.where("user_id = ?  AND exercise_id = ?", @external_user.id, @exercise.id).to_a
-- current_index = submissions.length - 1
-- current_submission = submissions[current_index]
+- submissions = Submission.where("user_id = ?  AND exercise_id = ?", @external_user.id, @exercise.id)
+- current_submission = submissions.last
+- if current_submission
     - files = current_submission.files.to_a
 
+    .hidden data-submissions=ActiveSupport::JSON.encode(submissions)
+
     #editor.row data-exercise-id=@exercise.id data-message-depleted=t('exercises.editor.depleted') data-user-id=@external_user.id
       div class=(@exercise.hide_file_tree ? 'hidden col-sm-3' : 'col-sm-3') id='files' data-entries=FileTree.new(files).to_js_tree
       div id='frames' class=(@exercise.hide_file_tree ? 'col-sm-12' : 'col-sm-9')
@@ -11,7 +13,7 @@ h1 = "#{@exercise} (external user #{@external_user})"
           = render('editor_frame', exercise: @exercise, file: file)
 
     #slider
-    input type='range' orient='horizontal' list='datapoints' min=0 max=submissions.length-1 value=current_index
+        input type='range' orient='horizontal' list='datapoints' min=0 max=submissions.length-1 value=0
         datalist#datapoints
             - index=0
             - submissions.each do |submission|
@@ -20,3 +22,5 @@ h1 = "#{@exercise} (external user #{@external_user})"
                 - index += 1
 
     #timeline
+- else
+    p = t('.no_data_available')

config/locales/de.yml

@@ -253,6 +253,9 @@ de:
       external_user: Externe Nutzer
     submit:
       failure: Beim Übermitteln Ihrer Punktzahl ist ein Fehler aufgetreten. Bitte versuchen Sie es später erneut.
+    external_users:
+      statistics:
+        no_data_available: Keine Daten verfügbar.
   files:
     roles:
       main_file: Hauptdatei

config/locales/en.yml

@@ -253,6 +253,9 @@ en:
       external_users: External Users
     submit:
       failure: An error occured while transmitting your score. Please try again later.
+    external_users:
+      statistics:
+        no_data_available: No data available.
   files:
     roles:
       main_file: Main File