feat: add redo functionality for failed exam questions and update translations

.gitignore

@@ -7,3 +7,4 @@ backend/db/brainwave.db-wal
 node_modules/.vite/vitest/da39a3ee5e6b4b0d3255bfef95601890afd80709/results.json
 brainwave.db-shm
 brainwave.db-wal
+node_modules/

frontend/src/App.tsx

@@ -129,7 +129,7 @@ function AppInner() {
     setExamState(withNotes(state));
   };
 
-  const loadExam = (data: Exam, saveToWorkspace = false, examId?: number | null) => {
+  const loadExam = (data: Exam, saveToWorkspace = false, examId?: number | null, isRedo = false) => {
     if (saveToWorkspace && user && isAuthenticated()) {
       examApi.createExam(data)
         .then((res) => {
@@ -156,6 +156,7 @@ function AppInner() {
         revealed: {},
         startedAt: Date.now(),
         feedbackMode: fm,
+        isRedo,
       });
     });
     navigate(`/exam/${getExamUrlId(data)}/q1`);
@@ -195,33 +196,60 @@ function AppInner() {
       state: { ...examState, completedAt },
     };
 
-    if (user && isAuthenticated()) {
-      void resultApi.submitResult({
-        exam_id: savedExamIdRef.current,
-        title: entry.title,
-        score_points: entry.scorePoints,
-        total_points: entry.totalPoints,
-        correct_count: entry.correctCount,
-        graded_count: entry.gradedCount,
-        passing_score: entry.passingScore,
-        elapsed_ms: entry.elapsedMs,
-        state: entry.state as unknown,
-        exam: entry.exam as unknown,
-      }).then((data) => {
-        sessionStorage.setItem('brainwave.pendingResultId', String(data.id));
-      }).catch(() => {
+    // Skip saving to history / API when this is a redo session
+    if (!examState.isRedo) {
+      if (user && isAuthenticated()) {
+        void resultApi.submitResult({
+          exam_id: savedExamIdRef.current,
+          title: entry.title,
+          score_points: entry.scorePoints,
+          total_points: entry.totalPoints,
+          correct_count: entry.correctCount,
+          graded_count: entry.gradedCount,
+          passing_score: entry.passingScore,
+          elapsed_ms: entry.elapsedMs,
+          state: entry.state as unknown,
+          exam: entry.exam as unknown,
+        }).then((data) => {
+          sessionStorage.setItem('brainwave.pendingResultId', String(data.id));
+        }).catch(() => {
+          appendHistory(entry);
+        });
+      } else {
         appendHistory(entry);
-      });
-    } else {
-      appendHistory(entry);
+      }
+
+      setHistory((prev) => [entry, ...prev]);
     }
 
-    setHistory((prev) => [entry, ...prev]);
     clearState();
     setExamState((s) => (s ? { ...s, completedAt } : s));
     navigate("/results");
   }, [exam, examState, user, navigate]);
 
+  const redoFailed = useCallback(() => {
+    if (!exam || !examState) return;
+    const graded = exam.questions.map((q) =>
+      gradeQuestion(q, examState.answers[q.id]),
+    );
+    const failedQuestions = exam.questions
+      .map((q, i) => ({ q, result: graded[i] }))
+      .filter(({ result }) => !result.correct)
+      .map(({ q }) => q);
+
+    if (failedQuestions.length === 0) return;
+
+    // Shuffle failed questions using Fisher-Yates
+    const shuffled = [...failedQuestions];
+    for (let i = shuffled.length - 1; i > 0; i--) {
+      const j = Math.floor(Math.random() * (i + 1));
+      [shuffled[i], shuffled[j]] = [shuffled[j], shuffled[i]];
+    }
+
+    const redoExam: Exam = { ...exam, questions: shuffled };
+    loadExam(redoExam, false, savedExamIdRef.current, true);
+  }, [exam, examState]);
+
   const exit = () => {
     setExam(null);
     setExamState(null);
@@ -461,6 +489,7 @@ function AppInner() {
                 state={examState}
                 onRestart={restart}
                 onExit={exit}
+                onRedoFailed={redoFailed}
                 reviewOnly={false}
               />
             ) : user && isAuthenticated() ? (

frontend/src/components/Results.tsx

@@ -12,10 +12,11 @@ interface Props {
   state: ExamState
   onRestart: () => void
   onExit: () => void
+  onRedoFailed?: () => void
   reviewOnly?: boolean
 }
 
-export default function Results({ exam, state, onRestart, onExit, reviewOnly }: Props) {
+export default function Results({ exam, state, onRestart, onExit, onRedoFailed, reviewOnly }: Props) {
   const { t } = useTranslation()
   const { answers, startedAt, completedAt } = state
   const elapsedMs = (completedAt ?? Date.now()) - startedAt
@@ -30,6 +31,7 @@ export default function Results({ exam, state, onRestart, onExit, reviewOnly }:
   const scorePoints = graded.reduce((a, g) => a + g.result.points, 0)
   const gradedCount = graded.filter((g) => g.result.status !== 'ungraded').length
   const correctCount = graded.filter((g) => g.result.correct).length
+  const failedCount = gradedCount - correctCount
   const pct = totalPoints ? Math.round((scorePoints / totalPoints) * 100) : 0
   const passing = exam.passingScore ?? 60
   const passed = pct >= passing
@@ -137,7 +139,16 @@ export default function Results({ exam, state, onRestart, onExit, reviewOnly }:
       })}
 
       <div style={{ marginTop: 48, display: 'flex', gap: 12 }}>
-        {!reviewOnly && <button className="btn btn-primary" onClick={onRestart}>{t('results.retakeExam')}</button>}
+        {!reviewOnly && (
+          <>
+            <button className="btn btn-primary" onClick={onRestart}>{t('results.retakeExam')}</button>
+            {onRedoFailed && failedCount > 0 && (
+              <button className="btn" onClick={onRedoFailed}>
+                {t('results.redoFailed')}
+              </button>
+            )}
+          </>
+        )}
         <button className="btn" onClick={onExit}>{t('results.backToHome')}</button>
       </div>
     </div>

frontend/src/i18n/en.json

@@ -124,6 +124,7 @@
     "explanation": "Explanation",
     "rubric": "Rubric (self-grade)",
     "retakeExam": "Retake exam",
+    "redoFailed": "Redo failed questions",
     "cantRetake": "Exam no longer saved in workspace",
     "backToHome": "Back to home"
   },

frontend/src/i18n/nl.json

@@ -124,6 +124,7 @@
     "explanation": "Uitleg",
     "rubric": "Rubric (zelfbeoordeling)",
     "retakeExam": "Examen opnieuw maken",
+    "redoFailed": "Foute vragen opnieuw maken",
     "cantRetake": "Examen niet meer opgeslagen in werkruimte",
     "backToHome": "Terug naar home"
   },

frontend/src/types.ts

@@ -90,6 +90,7 @@ export interface ExamState {
   startedAt: number;
   completedAt?: number;
   feedbackMode: FeedbackMode;
+  isRedo?: boolean;
 }
 
 export interface HistoryEntry {

package-lock.json

@@ -1,20 +1,28 @@
 {
   "name": "brainwave",
+  "version": "0.0.1",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
-      "dependencies": {
-        "helmet": "^8.1.0"
+      "name": "brainwave",
+      "version": "0.0.1",
+      "devDependencies": {
+        "typescript": "^6.0.3"
       }
     },
-    "node_modules/helmet": {
-      "version": "8.1.0",
-      "resolved": "https://registry.npmjs.org/helmet/-/helmet-8.1.0.tgz",
-      "integrity": "sha512-jOiHyAZsmnr8LqoPGmCjYAaiuWwjAPLgY8ZX2XrmHawt99/u1y6RgrZMTeoPfpUbV96HOalYgz1qzkRbw54Pmg==",
-      "license": "MIT",
+    "node_modules/typescript": {
+      "version": "6.0.3",
+      "resolved": "https://registry.npmjs.org/typescript/-/typescript-6.0.3.tgz",
+      "integrity": "sha512-y2TvuxSZPDyQakkFRPZHKFm+KKVqIisdg9/CZwm9ftvKXLP8NRWj38/ODjNbr43SsoXqNuAisEf1GdCxqWcdBw==",
+      "dev": true,
+      "license": "Apache-2.0",
+      "bin": {
+        "tsc": "bin/tsc",
+        "tsserver": "bin/tsserver"
+      },
       "engines": {
-        "node": ">=18.0.0"
+        "node": ">=14.17"
       }
     }
   }

package.json

@@ -1,5 +1,8 @@
 {
   "name": "brainwave",
   "private": true,
-  "version": "0.0.1"
+  "version": "0.0.1",
+  "devDependencies": {
+    "typescript": "^6.0.3"
+  }
 }