Add new quiz generator

static/anatomy-quiz.html

@@ -3,8 +3,16 @@
   <h1>MillironX's Anatomy Quiz Generator</h1>
   <h2>Quiz material weighting</h2>
   <div id="weights"></div>
+  <hr />
+  <div>
+    <label for="num-questions">Number of questions </label>
+    <input id="num-questions" type="number" value="15" />
+  </div>
+  <hr />
+  <button onClick="generate_quiz">Generate!</button>
+  <hr />
+  <h2>Quiz</h2>
   <ul id="quiz-terms"></ul>
-  <code id="quiz"></code>
 
   <script>
     const BoldTerms = {
@@ -143,6 +151,73 @@
       weights_spinner_div.append(form_div);
     }
 
+    // Shamelessly stolen from
+    // https://github.com/trekhleb/javascript-algorithms/blob/master/src/algorithms/statistics/weighted-random/weightedRandom.js
+    function weighted_random(items, weights) {
+      const cumulativeWeights = [];
+      for (let i = 0; i < weights.length; i += 1) {
+        cumulativeWeights[i] = weights[i] + (cumulativeWeights[i - 1] || 0);
+      }
+      const maxCumulativeWeight =
+        cumulativeWeights[cumulativeWeights.length - 1];
+      const randomNumber = maxCumulativeWeight * Math.random();
+
+      for (let itemIndex = 0; itemIndex < items.length; itemIndex += 1) {
+        if (cumulativeWeights[itemIndex] >= randomNumber) {
+          return items[itemIndex];
+        }
+      }
+    }
+
+    // Shamelessly stolen from
+    // https://stackoverflow.com/a/15106541
+    function random_child(object) {
+      const keys = Object.keys(object);
+      const i = Math.floor(Math.random() * keys.length);
+      return {
+        key: keys[i],
+        object: object[keys[i]],
+      };
+    }
+
+    const terms_list = document.getElementById("quiz-terms");
+
+    function generate_quiz() {
+      let weights = [];
+      let types = [];
+
+      for (structure_type in BoldTerms) {
+        weights.push(
+          parseInt(document.getElementById(`${structure_type}-weight`).value)
+        );
+        types.push(structure_type);
+      }
+
+      const num_questions = document.getElementById("num-questions").value;
+      for (let i = 0; i <= num_questions; i += 1) {
+        // Pick the random category
+        const structure_type = weighted_random(types, weights);
+
+        // Pick a random structure from that category
+        const rand_structure = random_child(BoldTerms[structure_type]);
+
+        // Get the list of questions for that structure
+        const questions = structure_question(
+          rand_structure.key,
+          rand_structure.object
+        );
+
+        // Get a random question from that list
+        const rand_question =
+          questions[Math.floor(Math.random() * questions.length)];
+
+        // Add that structure to the list
+        let term_item = document.createElement("li");
+        term_item.innerHTML = rand_question;
+        terms_list.appendChild(term_item);
+      }
+    }
+
     const terms = [
       "scapula: glenoid cavity",
       "scapula: neck",
@@ -481,13 +556,6 @@
       "Iliopsoas"
     ];
 
-    const terms_list = document.getElementById("quiz-terms");
-
-    for (let i = 0; i < 10; i++) {
-      let rand_term = terms[Math.floor(Math.random()*terms.length)];
-      let term_item = document.createElement("li");
-      term_item.innerHTML = rand_term;
-      terms_list.appendChild(term_item);
-    }
+    generate_quiz();
   </script>
 </body>