MOBILE-1362 participants: Check if the Participants option must be di…

www/addons/participants/services/courses_nav_handler.js

@@ -21,7 +21,7 @@ angular.module('mm.addons.participants')
  * @ngdoc service
  * @name $mmaParticipantsCoursesNavHandler
  */
-.factory('$mmaParticipantsCoursesNavHandler', function(mmCoursesAccessMethods) {
+.factory('$mmaParticipantsCoursesNavHandler', function($mmaParticipants, mmCoursesAccessMethods) {
     return {
 
         /**
@@ -38,13 +38,14 @@ angular.module('mm.addons.participants')
          *
          * @param {Number} courseId   Course ID.
          * @param {Object} accessData Type of access to the course: default, guest, ...
-         * @return {Boolean}          True if handler is enabled, false otherwise.
+         * @return {Boolean|Promise}  Promise resolved  with true if handler is enabled,
+         *                            false or promise rejected or resolved with false otherwise.
          */
         isEnabledForCourse: function(courseId, accessData) {
             if (accessData && accessData.type == mmCoursesAccessMethods.guest) {
                 return false; // Not enabled for guests.
             }
-            return true;
+            return $mmaParticipants.isPluginEnabledForCourse(courseId);
         },
 
         /**

www/addons/participants/services/participants.js

@@ -117,5 +117,27 @@ angular.module('mm.addons.participants')
         return $mmSite.invalidateWsCacheForKey(getParticipantsListCacheKey(courseid));
     };
 
+    /**
+     * Returns whether or not the participants addon is enabled for a certain course.
+     *
+     * @module mm.addons.participants
+     * @ngdoc method
+     * @name $mmaParticipants#isPluginEnabledForCourse
+     * @param {Number} courseId Course ID.
+     * @return {Promise}        Promise resolved with true if plugin is enabled, rejected or resolved with false otherwise.
+     */
+    self.isPluginEnabledForCourse = function(courseId) {
+        if (!courseId) {
+            return $q.reject();
+        }
+
+        // Retrieving one participant will fail if browsing users is disabled by capabilities.
+        return self.getParticipants(courseId, 0, 1).then(function(parcitipants) {
+            return true;
+        }).catch(function(error) {
+            return false;
+        });
+    };
+
     return self;
 });