Add functionality to create question pools

[HFP-57]

js/questionset.js

@@ -126,6 +126,9 @@ H5P.QuestionSet = function (options, contentId, contentData) {
   var endTemplate = new EJS({text: resulttemplate});
   var params = $.extend(true, {}, defaults, options);
 
+  var poolSize; // Number of questions to be pooled into a subset
+  var poolQuestions; // Questions in a pool
+  var poolOrder; // Order of questions in a pool
   var currentQuestion = 0;
   var questionInstances = [];
   var questionOrder; //Stores order of questions to allow resuming of question set
@@ -144,59 +147,7 @@ H5P.QuestionSet = function (options, contentId, contentData) {
     questionOrder = contentData.previousState.order;
   }
 
-  var $template = $(template.render(params));
+  // Create a pool of questions if necessary
-  // Set overrides for questions
-  var override;
-  if (params.override.showSolutionButton || params.override.retryButton) {
-    override = {};
-    if (params.override.showSolutionButton) {
-      // Force "Show solution" button to be on or off for all interactions
-      override.enableSolutionsButton =
-          (params.override.showSolutionButton === 'on' ? true : false);
-    }
-
-    if (params.override.retryButton) {
-      // Force "Retry" button to be on or off for all interactions
-      override.enableRetry =
-          (params.override.retryButton === 'on' ? true : false);
-    }
-  }
-
-  // Instantiate question instances
-  for (var i = 0; i < params.questions.length; i++) {
-
-    var question;
-    // If a previous order exists, use it
-    if (questionOrder !== undefined) {
-      question = params.questions[questionOrder[i]];
-    }
-    else {
-      // Use generic order when initialzing for the first time
-      question = params.questions[i];
-    }
-
-    if (override) {
-      // Extend subcontent with the overrided settings.
-      $.extend(question.params.behaviour, override);
-    }
-
-    question.params = question.params || {};
-    question.params.overrideSettings = question.params.overrideSettings || {};
-    question.params.overrideSettings.$confirmationDialogParent = $template.last();
-    question.params.overrideSettings.instance = this;
-    var hasAnswers = contentData.previousState && contentData.previousState.answers;
-    var questionInstance = H5P.newRunnable(question, contentId, undefined, undefined,
-      {
-        previousState: hasAnswers ? contentData.previousState.answers[i] : undefined,
-        parent: self
-      });
-    questionInstance.on('resize', function () {
-      up = true;
-      self.trigger('resize');
-    });
-    questionInstances.push(questionInstance);
-  }
-
   /**
    * Randomizes questions in an array and updates an array containing their order
    * @param  {array} questions
@@ -229,6 +180,104 @@ H5P.QuestionSet = function (options, contentId, contentData) {
 
   }
 
+  // Create a pool (a subset) of questions if necessary
+  if (params.poolSize) {
+
+    // If a previous pool exists, recreate it
+    if(contentData.previousState && contentData.previousState.poolOrder) {
+      poolOrder = contentData.previousState.poolOrder;
+
+      // Recreate the pool from the saved data
+      var pool = [];
+      for (var i = 0; i < poolOrder.length; i++) {
+        pool[i] = params.questions[poolOrder[i]];
+      }
+
+      // Replace original questions with just the ones in the pool
+      params.questions = pool;
+    }
+
+    // Otherwise create a new pool
+    else {
+
+      // Sanitize input
+      if (params.poolSize > params.questions.length) {
+        poolSize = params.questions.length;
+      }
+      else {
+        poolSize = params.poolSize;
+      }
+
+      // Randomize and get the results
+      var poolResult = randomizeQuestionOrdering(params.questions, poolOrder);
+      poolQuestions = poolResult.questions;
+      poolOrder = poolResult.questionOrder;
+
+      // Discard extra questions
+      poolQuestions = poolQuestions.slice(0,poolSize);
+      poolOrder = poolOrder.slice(0,poolSize);
+
+      // Replace original questions with just the ones in the pool
+      params.questions = poolQuestions;
+    }
+
+  }
+
+  // Create the html template for the question container
+  var $template = $(template.render(params));
+
+  // Set overrides for questions
+  var override;
+  if (params.override.showSolutionButton || params.override.retryButton) {
+    override = {};
+    if (params.override.showSolutionButton) {
+      // Force "Show solution" button to be on or off for all interactions
+      override.enableSolutionsButton =
+          (params.override.showSolutionButton === 'on' ? true : false);
+    }
+
+    if (params.override.retryButton) {
+      // Force "Retry" button to be on or off for all interactions
+      override.enableRetry =
+          (params.override.retryButton === 'on' ? true : false);
+    }
+  }
+
+  // Instantiate question instances
+  for (var i = 0; i < params.questions.length; i++) {
+
+    var question;
+    // If a previous order exists, use it
+    if (questionOrder !== undefined) {
+      question = params.questions[questionOrder[i]];
+    }
+    else {
+      // Use a generic order when initialzing for the first time
+      question = params.questions[i];
+    }
+
+    if (override) {
+      // Extend subcontent with the overrided settings.
+      $.extend(question.params.behaviour, override);
+    }
+
+    question.params = question.params || {};
+    question.params.overrideSettings = question.params.overrideSettings || {};
+    question.params.overrideSettings.$confirmationDialogParent = $template.last();
+    question.params.overrideSettings.instance = this;
+    var hasAnswers = contentData.previousState && contentData.previousState.answers;
+    var questionInstance = H5P.newRunnable(question, contentId, undefined, undefined,
+      {
+        previousState: hasAnswers ? contentData.previousState.answers[i] : undefined,
+        parent: self
+      });
+    questionInstance.on('resize', function () {
+      up = true;
+      self.trigger('resize');
+    });
+    questionInstances.push(questionInstance);
+  }
+
   // Randomize questions only on instantiation
   if (params.randomQuestions && contentData.previousState === undefined) {
     var result = randomizeQuestionOrdering(questionInstances,questionOrder);
@@ -1015,7 +1064,8 @@ H5P.QuestionSet = function (options, contentId, contentData) {
       answers: questionInstances.map(function (qi) {
         return qi.getCurrentState();
       }),
-      order: questionOrder
+      order: questionOrder,
+      poolOrder: poolOrder
     };
   };
 };

semantics.json

@@ -209,6 +209,13 @@
     "description": "Enable to randomize the order of questions on display.",
     "default": false
   },
+  {
+    "name": "poolSize",
+    "type": "number",
+    "label": "Number of questions to be shown:",
+    "description": "Create a randomized batch of questions from the total.",
+    "optional": true
+  },
   {
     "name": "endGame",
     "type": "group",