Restrict access user select

app/abilities/user_ability.rb

@@ -14,11 +14,7 @@ def initialize(user)
       user.admin? || (!user.generic? && user == given_user)
     end
 
-    can :fill_user_select, User do
-      user.active_teachable_editor?
-    end
-
-    can :list_generic_users, User do
+    can [:fill_user_select, :list_generic_users], User do
       user.admin?
     end
   end

app/helpers/lectures_helper.rb

@@ -135,4 +135,16 @@ def editors_preselection(lecture)
                          [editor.info, editor.id]
                        end, lecture.editor_ids)
   end
+
+  def teachers_preselection(lecture)
+    options_for_select(lecture.eligible_as_teachers.map do |teacher|
+                         [teacher.info, teacher.id]
+                       end, lecture.teacher_id)
+  end
+
+  def teachers_preselection_for_new_lecture(lecture)
+    options_for_select((User.teachers + [current_user]).map do |teacher|
+                         [teacher.info, teacher.id]
+                       end)
+  end
 end

app/models/lecture.rb

@@ -920,6 +920,10 @@ def eligible_as_editors
     # still given by the old system, this will not be true
   end
 
+  def eligible_as_teachers
+    (User.teachers + editors + course.editors + [teacher]).uniq
+  end
+
   def eligible_as_speakers
     (speakers + speakers_by_redemption + editors + [teacher]).uniq
     # the first one should (in the future) actually be contained in the sum of

app/views/administration/index/_my_courses.html.erb

@@ -18,12 +18,14 @@
     </div>
   </div>
   <div class="card-body scrollable">
-    <div id="new-course-area"
-         class="bg-green-lighten-4 p-3 mb-3 rounded"
-         style="display: none;">
-      <%= render partial: 'courses/new',
-                 locals: { course: Course.new } %>
-    </div>
+    <% if current_user.admin? %>
+      <div id="new-course-area"
+           class="bg-green-lighten-4 p-3 mb-3 rounded"
+           style="display: none;">
+        <%= render partial: 'courses/new',
+                   locals: { course: Course.new } %>
+      </div>
+    <% end %>
     <% if current_user.edited_courses.any? %>
       <%= render partial: 'administration/index/courses_card',
                  locals: { courses:

app/views/lectures/_new.html.erb

@@ -57,18 +57,25 @@
                     t('basics.teacher'),
                     class: "form-label" %>
         <%= helpdesk(t('admin.lecture.info.teacher'), false) %>
-        <%= f.select :teacher_id,
-                     options_for_select([[current_user.info, current_user.id]],
-                                        current_user.id),
-                     {},
-                     { class: 'selectize',
-                       data: { ajax: true,
-                               model: 'user',
-                               filled: false,
-                               placeholder: t('basics.enter_two_letters'),
-                               no_results: t('basics.no_results'),
-                               current: current_user.id,
-                               modal: modal } } %>
+        <% if current_user.admin? %>
+          <%= f.select :teacher_id,
+                       options_for_select([[current_user.info, current_user.id]],
+                                          current_user.id),
+                       {},
+                       { class: 'selectize',
+                         data: { ajax: true,
+                                 model: 'user',
+                                 filled: false,
+                                 placeholder: t('basics.enter_two_letters'),
+                                 no_results: t('basics.no_results'),
+                                 current: current_user.id,
+                                 modal: modal } } %>
+        <% else %>
+          <%= f.select :teacher_id,
+                       teachers_preselection_for_new_lecture(lecture),
+                       {},
+                       { class: 'selectize' } %>
+        <% end %>
       </div>
       <div class="col-12" id="newLectureSort"
            style="<%= term_independent ? 'display: none;' : '' %>">

app/views/lectures/edit/_people.html.erb

@@ -9,19 +9,26 @@
                   class: "form-label" %>
         <%= helpdesk(t('admin.lecture.info.teacher'), false) %>
         <div id="lecture_teacher_select" %>
-          <%= f.select :teacher_id, 
-                       options_for_select([[lecture.teacher.info,
-                       lecture.teacher.id]],
-                       lecture.teacher.id),
-                       {},
-                       { class: 'selectize',
-                         data: { ajax: true,
-                                 model: 'user',
-                                 filled: false,
-                                 placeholder:
-                                   t('basics.enter_two_letters'),
-                                 no_results:
+          <% if current_user.admin? %>
+            <%= f.select :teacher_id,
+                         options_for_select([[lecture.teacher.info,
+                         lecture.teacher.id]],
+                         lecture.teacher.id),
+                         {},
+                         { class: 'selectize',
+                           data: { ajax: true,
+                                   model: 'user',
+                                   filled: false,
+                                   placeholder:
+                                     t('basics.enter_two_letters'),
+                                   no_results:
                                    t('basics.no_results') } } %>
+          <% else %>
+            <%= f.select :teacher_id,
+                         teachers_preselection(lecture),
+                         {},
+                         { class: 'selectize' } %>
+          <% end %>
           <div class="invalid-feedback" id="lecture-teacher-error">
           </div>
         </div>