added overlay function for tarot cards

app/quiz-calendars.js

@@ -3,79 +3,21 @@
 (function () {
   "use strict";
 
-  // ----- shared utilities (mirrored from ui-quiz.js since they aren't exported) -----
+  const quizPluginHelpers = window.QuizPluginHelpers || {};
+  const {
+    normalizeOption,
+    normalizeKey,
+    toUniqueOptionList,
+    makeTemplate
+  } = quizPluginHelpers;
 
-  function normalizeOption(value) {
-    return String(value || "").trim();
-  }
-
-  function normalizeKey(value) {
-    return normalizeOption(value).toLowerCase();
-  }
-
-  function toUniqueOptionList(values) {
-    const seen = new Set();
-    const unique = [];
-    (values || []).forEach((value) => {
-      const formatted = normalizeOption(value);
-      if (!formatted) return;
-      const key = normalizeKey(formatted);
-      if (seen.has(key)) return;
-      seen.add(key);
-      unique.push(formatted);
-    });
-    return unique;
-  }
-
-  function shuffle(list) {
-    const clone = list.slice();
-    for (let i = clone.length - 1; i > 0; i -= 1) {
-      const j = Math.floor(Math.random() * (i + 1));
-      [clone[i], clone[j]] = [clone[j], clone[i]];
-    }
-    return clone;
-  }
-
-  function buildOptions(correctValue, poolValues) {
-    const correct = normalizeOption(correctValue);
-    if (!correct) return null;
-    const uniquePool = toUniqueOptionList(poolValues || []);
-    if (!uniquePool.some((v) => normalizeKey(v) === normalizeKey(correct))) {
-      uniquePool.push(correct);
-    }
-    const distractors = uniquePool.filter((v) => normalizeKey(v) !== normalizeKey(correct));
-    if (distractors.length < 3) return null;
-    const selected = shuffle(distractors).slice(0, 3);
-    const options = shuffle([correct, ...selected]);
-    const correctIndex = options.findIndex((v) => normalizeKey(v) === normalizeKey(correct));
-    if (correctIndex < 0 || options.length < 4) return null;
-    return { options, correctIndex };
-  }
-
-  /**
-   * Build a validated quiz question template.
-   * Returns null if there aren't enough distractors for a 4-choice question.
-   */
-  function makeTemplate(key, categoryId, category, prompt, answer, pool) {
-    const correctStr = normalizeOption(answer);
-    const promptStr = normalizeOption(prompt);
-    if (!key || !categoryId || !promptStr || !correctStr) return null;
-
-    const uniquePool = toUniqueOptionList(pool || []);
-    if (!uniquePool.some((v) => normalizeKey(v) === normalizeKey(correctStr))) {
-      uniquePool.push(correctStr);
-    }
-    const distractorCount = uniquePool.filter((v) => normalizeKey(v) !== normalizeKey(correctStr)).length;
-    if (distractorCount < 3) return null;
-
-    return {
-      key,
-      categoryId,
-      category,
-      promptByDifficulty: promptStr,
-      answerByDifficulty: correctStr,
-      poolByDifficulty: uniquePool
-    };
+  if (
+    typeof normalizeOption !== "function"
+    || typeof normalizeKey !== "function"
+    || typeof toUniqueOptionList !== "function"
+    || typeof makeTemplate !== "function"
+  ) {
+    throw new Error("QuizPluginHelpers must load before quiz-calendars.js");
   }
 
   function ordinal(n) {