Add quiz support: parse *_quiz_solved.txt files, take and grade quizzes

Scanner indexes quiz files found next to videos ([&] questions, "- "
options, "-- Correct" markers; _notsolved twins ignored). Quizzes appear
in the folder content list interleaved with videos by filename order.
New api/quiz.php serves questions without answers and grades attempts
server-side; per-user best/last score and attempts stored in
quiz_progress. Folder/course progress now aggregates videos + quizzes
with partial credit for partial scores.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

README.md

@@ -72,6 +72,30 @@ Top-level folders become courses on the home page.
 
 5. Open the site, create an account, and watch.
 
+## Quizzes
+
+Course folders may contain quiz text files next to the videos. Files named
+`*_quiz_solved.txt` are indexed (a `*_quiz_notsolved.txt` twin is ignored —
+it's the same content without answers). Format:
+
+```
+[&] Which two are supported CLI connectivity methods? (Select two)
+- RDP
+- rlogin
+- GUI widget -- Correct
+- FortiExplorer -- Correct
+```
+
+Questions start with `[&]`, options with `- `, and correct options end with
+`-- Correct`. Questions with more than one correct option automatically render
+as checkboxes instead of radios.
+
+Quizzes are graded server-side (answers are never sent to the browser before
+submission). A question counts only if the selected set exactly matches the
+correct set. Best score, last score, and attempt count are stored per user;
+a quiz is *completed* once every question is answered correctly in one
+attempt, and quiz scores count toward folder progress alongside videos.
+
 ## How progress works
 
 - The player POSTs `{video_id, position, duration}` to `api/progress.php`

api/library.php

@@ -24,6 +24,7 @@ function videoSummary(array $v): array
     return [
         'id'        => (int)$v['id'],
         'name'      => $v['name'],
+        'filename'  => $v['filename'],
         'duration'  => $duration !== null ? (float)$duration : null,
         'position'  => $position,
         'completed' => (bool)($v['completed'] ?? false),
@@ -31,6 +32,19 @@ function videoSummary(array $v): array
     ];
 }
 
+function quizSummary(array $q): array
+{
+    return [
+        'id'         => (int)$q['id'],
+        'name'       => $q['name'],
+        'filename'   => $q['filename'],
+        'questions'  => (int)$q['num_questions'],
+        'attempts'   => (int)($q['attempts'] ?? 0),
+        'best_score' => (int)($q['best_score'] ?? 0),
+        'completed'  => (bool)($q['completed'] ?? false),
+    ];
+}
+
 function crumbList(array $folder): array
 {
     return array_map(
@@ -70,6 +84,8 @@ switch ($view) {
                                        childFolders((int)$folder['id'])),
             'videos'      => array_map('videoSummary',
                                        folderVideos((int)$folder['id'], $userId)),
+            'quizzes'     => array_map('quizSummary',
+                                       folderQuizzes((int)$folder['id'], $userId)),
         ]);
         break;
 

api/quiz.php

@@ -0,0 +1,122 @@
+<?php
+// GET  api/quiz.php?id=N   -> quiz questions + options (no answers) + user's results
+// POST api/quiz.php        -> grade an attempt, save the result
+//      JSON body: {quiz_id, answers: [[optIdx,...], ...]}  (one array per question)
+//      Response includes the correct options so the UI can mark the attempt.
+require_once __DIR__ . '/../includes/auth.php';
+require_once __DIR__ . '/../includes/functions.php';
+
+header('Content-Type: application/json');
+$userId = requireLoginApi();
+
+function quizProgressRow(int $userId, int $quizId): array
+{
+    $stmt = db()->prepare(
+        'SELECT best_score, last_score, total_questions, attempts, completed
+         FROM quiz_progress WHERE user_id = ? AND quiz_id = ?'
+    );
+    $stmt->execute([$userId, $quizId]);
+    return $stmt->fetch()
+        ?: ['best_score' => 0, 'last_score' => 0, 'total_questions' => 0,
+            'attempts' => 0, 'completed' => 0];
+}
+
+if ($_SERVER['REQUEST_METHOD'] === 'GET') {
+    $quiz = getQuiz((int)($_GET['id'] ?? 0));
+    if (!$quiz) {
+        http_response_code(404);
+        echo json_encode(['error' => 'Quiz not found']);
+        exit;
+    }
+    $file = quizFilePath($quiz);
+    $questions = $file ? parseQuizFile($file) : [];
+    if (!$questions) {
+        http_response_code(404);
+        echo json_encode(['error' => 'Quiz file is missing — rescan the library']);
+        exit;
+    }
+    $folder = getFolder((int)$quiz['folder_id']);
+    $p = quizProgressRow($userId, (int)$quiz['id']);
+    echo json_encode([
+        'quiz'        => ['id' => (int)$quiz['id'], 'name' => $quiz['name']],
+        'folder'      => ['id' => (int)$folder['id'], 'name' => $folder['name']],
+        'breadcrumbs' => array_map(
+            fn($c) => ['id' => (int)$c['id'], 'name' => $c['name']],
+            folderBreadcrumbs($folder)
+        ),
+        'questions'   => array_map(fn($q) => [
+            'text'    => $q['text'],
+            'multi'   => $q['multi'],
+            'options' => $q['options'],
+        ], $questions),
+        'progress'    => [
+            'attempts'   => (int)$p['attempts'],
+            'best_score' => (int)$p['best_score'],
+            'last_score' => (int)$p['last_score'],
+            'total'      => count($questions),
+            'completed'  => (bool)$p['completed'],
+        ],
+    ]);
+    exit;
+}
+
+if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
+    http_response_code(405);
+    echo json_encode(['error' => 'Method not allowed']);
+    exit;
+}
+
+$data = json_decode(file_get_contents('php://input'), true) ?: [];
+$quiz = getQuiz((int)($data['quiz_id'] ?? 0));
+$answers = $data['answers'] ?? null;
+if (!$quiz || !is_array($answers)) {
+    http_response_code(400);
+    echo json_encode(['error' => 'Bad request']);
+    exit;
+}
+
+$file = quizFilePath($quiz);
+$questions = $file ? parseQuizFile($file) : [];
+if (!$questions) {
+    http_response_code(404);
+    echo json_encode(['error' => 'Quiz file is missing — rescan the library']);
+    exit;
+}
+
+$score   = 0;
+$results = [];
+foreach ($questions as $i => $q) {
+    $selected = array_values(array_unique(array_map('intval', (array)($answers[$i] ?? []))));
+    sort($selected);
+    $correct = $q['correct'];
+    sort($correct);
+    $isCorrect = $selected === $correct;
+    if ($isCorrect) $score++;
+    $results[] = [
+        'correct'         => $isCorrect,
+        'correct_options' => $correct,
+        'selected'        => $selected,
+    ];
+}
+
+$total     = count($questions);
+$completed = ($score === $total) ? 1 : 0;
+
+db()->prepare(
+    'INSERT INTO quiz_progress
+        (user_id, quiz_id, best_score, last_score, total_questions, attempts, completed)
+     VALUES (?, ?, ?, ?, ?, 1, ?)
+     ON DUPLICATE KEY UPDATE
+        last_score      = VALUES(last_score),
+        best_score      = GREATEST(best_score, VALUES(best_score)),
+        total_questions = VALUES(total_questions),
+        attempts        = attempts + 1,
+        completed       = GREATEST(completed, VALUES(completed))'
+)->execute([$userId, (int)$quiz['id'], $score, $score, $total, $completed]);
+
+echo json_encode([
+    'score'     => $score,
+    'total'     => $total,
+    'completed' => (bool)$completed,
+    'results'   => $results,
+]);

assets/app.js

@@ -173,7 +173,7 @@
             </div>
             ${progressBar(c.progress.percent)}
             <div class="small text-secondary mt-1">
-              ${c.progress.completed} / ${c.progress.total} videos completed · ${c.progress.percent}%
+              ${c.progress.completed} / ${c.progress.total} completed · ${c.progress.percent}%
             </div>
           </div>
         </a>
@@ -206,23 +206,44 @@
           </a>`).join('')}
       </div>` : '';
 
-    const videos = data.videos.length ? `
+    const items = [
-      <h2 class="h6 text-secondary text-uppercase">Videos</h2>
+      ...data.videos.map((v) => ({ ...v, kind: 'video' })),
+      ...data.quizzes.map((q) => ({ ...q, kind: 'quiz' })),
+    ].sort((a, b) => a.filename.localeCompare(b.filename, undefined,
+                                              { numeric: true, sensitivity: 'base' }));
+
+    const content = items.length ? `
+      <h2 class="h6 text-secondary text-uppercase">Content</h2>
       <div class="list-group">
-        ${data.videos.map((v) => {
+        ${items.map((it) => {
-          const icon = v.completed
+          if (it.kind === 'quiz') {
+            const icon = it.completed
+              ? '<i class="bi bi-check-circle-fill text-success fs-4"></i>'
+              : '<i class="bi bi-patch-question-fill text-info fs-4"></i>';
+            return `
+            <a href="#/quiz/${it.id}" class="list-group-item list-group-item-action d-flex align-items-center gap-3">
+              ${icon}
+              <div class="flex-grow-1 min-w-0">
+                <div class="text-truncate">${esc(it.name)}</div>
+              </div>
+              ${it.attempts ? `<span class="badge ${it.completed ? 'text-bg-success' : 'text-bg-secondary'}">
+                 ${it.best_score}/${it.questions}</span>` : ''}
+              <span class="text-secondary small">Quiz · ${it.questions} questions</span>
+            </a>`;
+          }
+          const icon = it.completed
             ? '<i class="bi bi-check-circle-fill text-success fs-4"></i>'
-            : (v.position > 5
+            : (it.position > 5
                ? '<i class="bi bi-play-circle-fill text-primary fs-4"></i>'
                : '<i class="bi bi-circle text-secondary fs-4"></i>');
           return `
-          <a href="#/watch/${v.id}" class="list-group-item list-group-item-action d-flex align-items-center gap-3">
+          <a href="#/watch/${it.id}" class="list-group-item list-group-item-action d-flex align-items-center gap-3">
             ${icon}
             <div class="flex-grow-1 min-w-0">
-              <div class="text-truncate">${esc(v.name)}</div>
+              <div class="text-truncate">${esc(it.name)}</div>
-              ${!v.completed && v.percent > 0 ? `<div class="mt-1">${progressBar(v.percent, '')}</div>` : ''}
+              ${!it.completed && it.percent > 0 ? `<div class="mt-1">${progressBar(it.percent, '')}</div>` : ''}
             </div>
-            <span class="text-secondary small">${fmt(v.duration)}</span>
+            <span class="text-secondary small">${fmt(it.duration)}</span>
           </a>`;
         }).join('')}
       </div>` : (!data.subfolders.length ? '<div class="alert alert-secondary">This folder is empty.</div>' : '');
@@ -231,10 +252,100 @@
       ${breadcrumbs(data.breadcrumbs)}
       <div class="d-flex align-items-center justify-content-between flex-wrap gap-2 mb-3">
         <h1 class="h4 mb-0"><i class="bi bi-folder2-open text-warning me-2"></i>${esc(data.folder.name)}</h1>
-        <div class="text-secondary small">${data.progress.completed} / ${data.progress.total} videos completed</div>
+        <div class="text-secondary small">${data.progress.completed} / ${data.progress.total} completed</div>
       </div>
       <div class="mb-4">${progressBar(data.progress.percent)}</div>
-      ${subfolders}${videos}`;
+      ${subfolders}${content}`;
+  }
+
+  async function renderQuiz(id) {
+    spinner();
+    const data = await api(`api/quiz.php?id=${id}`);
+
+    const qHtml = data.questions.map((q, qi) => `
+      <div class="card mb-3" data-qi="${qi}">
+        <div class="card-body">
+          <div class="fw-semibold mb-2">
+            ${qi + 1}. ${esc(q.text)}
+            ${q.multi ? '<span class="badge text-bg-info ms-1">multiple answers</span>' : ''}
+          </div>
+          ${q.options.map((o, oi) => `
+            <div class="form-check" data-oi="${oi}">
+              <input class="form-check-input" type="${q.multi ? 'checkbox' : 'radio'}"
+                     name="q${qi}" id="q${qi}o${oi}" value="${oi}">
+              <label class="form-check-label" for="q${qi}o${oi}">${esc(o)}</label>
+              <span class="ms-1 quiz-mark"></span>
+            </div>`).join('')}
+          <div class="small mt-2 quiz-feedback"></div>
+        </div>
+      </div>`).join('');
+
+    const best = data.progress.attempts
+      ? `Best score: ${data.progress.best_score}/${data.progress.total}` +
+        (data.progress.completed ? ' <i class="bi bi-check-circle-fill text-success"></i>' : '')
+      : 'Not attempted yet';
+
+    app.innerHTML = `
+      ${breadcrumbs(data.breadcrumbs, data.quiz.name)}
+      <div class="d-flex align-items-center justify-content-between flex-wrap gap-2 mb-3">
+        <h1 class="h4 mb-0"><i class="bi bi-patch-question-fill text-info me-2"></i>${esc(data.quiz.name)}</h1>
+        <div class="text-secondary small">${best}</div>
+      </div>
+      <form id="quiz-form">
+        ${qHtml}
+        <div class="d-flex gap-2 align-items-center flex-wrap">
+          <button class="btn btn-primary" type="submit" id="quiz-submit">
+            <i class="bi bi-send me-1"></i>Submit answers
+          </button>
+          <a class="btn btn-outline-secondary" href="#/folder/${data.folder.id}">
+            Back to ${esc(data.folder.name)}
+          </a>
+          <span id="quiz-score" class="fw-semibold"></span>
+        </div>
+      </form>`;
+
+    const form = document.getElementById('quiz-form');
+    let graded = false;
+
+    form.addEventListener('submit', async (e) => {
+      e.preventDefault();
+      if (graded) { renderQuiz(id); return; }   // "Try again" re-renders fresh
+
+      const answers = data.questions.map((q, qi) =>
+        [...form.querySelectorAll(`input[name="q${qi}"]:checked`)].map((i) => +i.value));
+
+      const res = await api('api/quiz.php', { json: { quiz_id: id, answers } });
+      graded = true;
+
+      res.results.forEach((r, qi) => {
+        const card = form.querySelector(`[data-qi="${qi}"]`);
+        r.correct_options.forEach((oi) => {
+          const row = card.querySelector(`[data-oi="${oi}"]`);
+          row.querySelector('label').classList.add('text-success', 'fw-semibold');
+          row.querySelector('.quiz-mark').innerHTML = '<i class="bi bi-check-lg text-success"></i>';
+        });
+        r.selected.filter((oi) => !r.correct_options.includes(oi)).forEach((oi) => {
+          const row = card.querySelector(`[data-oi="${oi}"]`);
+          row.querySelector('label').classList.add('text-danger');
+          row.querySelector('.quiz-mark').innerHTML = '<i class="bi bi-x-lg text-danger"></i>';
+        });
+        const fb = card.querySelector('.quiz-feedback');
+        fb.innerHTML = r.correct
+          ? '<span class="text-success"><i class="bi bi-check-circle-fill me-1"></i>Correct</span>'
+          : '<span class="text-danger"><i class="bi bi-x-circle-fill me-1"></i>Incorrect</span>';
+        card.classList.add('border', r.correct ? 'border-success' : 'border-danger');
+      });
+
+      form.querySelectorAll('input').forEach((i) => { i.disabled = true; });
+      document.getElementById('quiz-score').textContent = `Score: ${res.score}/${res.total}`;
+      const btn = document.getElementById('quiz-submit');
+      btn.innerHTML = '<i class="bi bi-arrow-repeat me-1"></i>Try again';
+      btn.classList.replace('btn-primary', 'btn-outline-primary');
+      toast(res.completed
+        ? `Perfect score — ${res.score}/${res.total}!`
+        : `Scored ${res.score}/${res.total}.`,
+        res.completed ? 'success' : 'secondary');
+    });
   }
 
   async function renderWatch(id) {
@@ -374,6 +485,7 @@
     try {
       if ((m = hash.match(/^#\/folder\/(\d+)$/)))     await renderFolder(+m[1]);
       else if ((m = hash.match(/^#\/watch\/(\d+)$/))) await renderWatch(+m[1]);
+      else if ((m = hash.match(/^#\/quiz\/(\d+)$/)))  await renderQuiz(+m[1]);
       else                                            await renderHome();
     } catch (err) {
       if (state.user) {
@@ -399,7 +511,8 @@
     btn.innerHTML = '<span class="spinner-border spinner-border-sm me-1"></span>Scanning…';
     try {
       const res = await api('api/scan.php', { method: 'POST' });
-      toast(`Scan complete: ${res.stats.folders} folders, ${res.stats.videos} videos indexed.`);
+      toast(`Scan complete: ${res.stats.folders} folders, ${res.stats.videos} videos, `
+          + `${res.stats.quizzes} quizzes indexed.`);
       route();                      // refresh current view with new data
     } catch (err) {
       toast(err.message, 'danger');

includes/functions.php

@@ -6,11 +6,53 @@ function h(?string $s): string
     return htmlspecialchars($s ?? '', ENT_QUOTES, 'UTF-8');
 }
 
+/* ---------------------------------------------------------------------------
+ * Quiz file parser
+ * Format ("*_quiz_solved.txt"):
+ *   [&] Question text (Select two)
+ *   - wrong option
+ *   - right option -- Correct
+ * Returns [['text', 'options' => [...], 'correct' => [optIndex,...], 'multi'], ...]
+ * ------------------------------------------------------------------------- */
+function parseQuizFile(string $absPath): array
+{
+    $raw = @file_get_contents($absPath);
+    if ($raw === false) return [];
+
+    $questions = [];
+    $cur = null;
+    foreach (preg_split('/\r\n|\r|\n/', $raw) as $line) {
+        $line = trim($line);
+        if ($line === '') continue;
+
+        if (str_starts_with($line, '[&]')) {
+            if ($cur && $cur['options']) $questions[] = $cur;
+            $cur = ['text' => trim(substr($line, 3)), 'options' => [], 'correct' => []];
+        } elseif (str_starts_with($line, '-') && $cur !== null) {
+            $opt = trim(substr($line, 1));
+            if (preg_match('/\s*--\s*correct\s*$/i', $opt)) {
+                $opt = trim(preg_replace('/\s*--\s*correct\s*$/i', '', $opt));
+                $cur['correct'][] = count($cur['options']);
+            }
+            $cur['options'][] = $opt;
+        } elseif ($cur !== null && !$cur['options']) {
+            $cur['text'] .= ' ' . $line;   // wrapped question text
+        }
+    }
+    if ($cur && $cur['options']) $questions[] = $cur;
+
+    foreach ($questions as &$q) {
+        $q['multi'] = count($q['correct']) > 1;
+    }
+    return $questions;
+}
+
 /* ---------------------------------------------------------------------------
  * Library scanner
- * Walks VIDEOS_ROOT recursively, upserts every directory into `folders` and
+ * Walks VIDEOS_ROOT recursively, upserts every directory into `folders`,
- * every *.mp4 into `videos` (keyed by relative path so IDs stay stable across
+ * every *.mp4 into `videos`, and every *_quiz_solved.txt into `quizzes`
- * rescans), then flags rows whose files disappeared as is_missing.
+ * (keyed by relative path so IDs stay stable across rescans), then flags
+ * rows whose files disappeared as is_missing.
  * ------------------------------------------------------------------------- */
 function scanLibrary(): array
 {
@@ -20,9 +62,11 @@ function scanLibrary(): array
     }
 
     $db = db();
-    $stats = ['folders' => 0, 'videos' => 0, 'missing_folders' => 0, 'missing_videos' => 0];
+    $stats = ['folders' => 0, 'videos' => 0, 'quizzes' => 0,
+              'missing_folders' => 0, 'missing_videos' => 0, 'missing_quizzes' => 0];
     $seenFolderIds = [];
     $seenVideoIds  = [];
+    $seenQuizIds   = [];
 
     $upsertFolder = $db->prepare(
         'INSERT INTO folders (parent_id, name, path, depth, sort_order, is_missing)
@@ -39,9 +83,18 @@ function scanLibrary(): array
              sort_order = VALUES(sort_order), is_missing = 0,
              id = LAST_INSERT_ID(id)'
     );
+    $upsertQuiz = $db->prepare(
+        'INSERT INTO quizzes (folder_id, name, filename, path, num_questions, sort_order, is_missing)
+         VALUES (?, ?, ?, ?, ?, ?, 0)
+         ON DUPLICATE KEY UPDATE folder_id = VALUES(folder_id), name = VALUES(name),
+             filename = VALUES(filename), num_questions = VALUES(num_questions),
+             sort_order = VALUES(sort_order), is_missing = 0,
+             id = LAST_INSERT_ID(id)'
+    );
 
     $walk = function (string $dir, ?int $parentId, string $relBase, int $depth)
-        use (&$walk, $db, $upsertFolder, $upsertVideo, &$stats, &$seenFolderIds, &$seenVideoIds): void {
+        use (&$walk, $db, $upsertFolder, $upsertVideo, $upsertQuiz,
+            &$stats, &$seenFolderIds, &$seenVideoIds, &$seenQuizIds): void {
 
         $entries = scandir($dir) ?: [];
         $entries = array_values(array_filter($entries, fn($e) => $e[0] !== '.'));
@@ -49,6 +102,7 @@ function scanLibrary(): array
 
         $folderSort = 0;
         $videoSort  = 0;
+        $quizSort   = 0;
         foreach ($entries as $entry) {
             $full = $dir . '/' . $entry;
             $rel  = $relBase === '' ? $entry : $relBase . '/' . $entry;
@@ -67,6 +121,18 @@ function scanLibrary(): array
                 $upsertVideo->execute([$parentId, $name, $entry, $rel, filesize($full) ?: 0, $videoSort++]);
                 $seenVideoIds[] = (int)$db->lastInsertId();
                 $stats['videos']++;
+            } elseif (is_file($full) && preg_match('/_quiz_solved\.txt$/i', $entry)) {
+                if ($parentId === null) {
+                    continue;
+                }
+                $numQuestions = count(parseQuizFile($full));
+                if ($numQuestions === 0) {
+                    continue; // unparseable file — don't index an empty quiz
+                }
+                $name = trim(preg_replace('/_quiz_solved\.txt$/i', '', $entry));
+                $upsertQuiz->execute([$parentId, $name, $entry, $rel, $numQuestions, $quizSort++]);
+                $seenQuizIds[] = (int)$db->lastInsertId();
+                $stats['quizzes']++;
             }
         }
     };
@@ -87,6 +153,7 @@ function scanLibrary(): array
         };
         $stats['missing_folders'] = $flagMissing('folders', $seenFolderIds);
         $stats['missing_videos']  = $flagMissing('videos', $seenVideoIds);
+        $stats['missing_quizzes'] = $flagMissing('quizzes', $seenQuizIds);
 
         $db->commit();
     } catch (Throwable $e) {
@@ -101,12 +168,14 @@ function scanLibrary(): array
  * ------------------------------------------------------------------------- */
 
 /**
- * Progress for one folder's whole subtree, matched by path prefix.
+ * Progress for one folder's whole subtree (videos + quizzes), matched by
- * Returns ['total' => n, 'completed' => n, 'percent' => 0-100].
+ * path prefix. Returns ['total' => n, 'completed' => n, 'percent' => 0-100].
- * Percent gives partial credit for videos that are started but not finished.
+ * Percent gives partial credit for half-watched videos and partial scores.
  */
 function folderProgress(int $userId, string $folderPath): array
 {
+    $args = [$userId, $folderPath, likePrefix($folderPath) . '/%'];
+
     $stmt = db()->prepare(
         "SELECT COUNT(*) AS total,
                 COALESCE(SUM(vp.completed), 0) AS completed,
@@ -124,13 +193,35 @@ function folderProgress(int $userId, string $folderPath): array
          WHERE v.is_missing = 0 AND f.is_missing = 0
            AND (f.path = ? OR f.path LIKE ?)"
     );
-    $stmt->execute([$userId, $folderPath, likePrefix($folderPath) . '/%']);
+    $stmt->execute($args);
-    $row = $stmt->fetch();
+    $videos = $stmt->fetch();
-    $total = (int)$row['total'];
+
+    $stmt = db()->prepare(
+        "SELECT COUNT(*) AS total,
+                COALESCE(SUM(qp.completed), 0) AS completed,
+                COALESCE(SUM(
+                    CASE
+                        WHEN qp.completed = 1 THEN 1
+                        WHEN q.num_questions > 0
+                             THEN LEAST(COALESCE(qp.best_score, 0) / q.num_questions, 1)
+                        ELSE 0
+                    END
+                ), 0) AS credit
+         FROM quizzes q
+         JOIN folders f ON f.id = q.folder_id
+         LEFT JOIN quiz_progress qp ON qp.quiz_id = q.id AND qp.user_id = ?
+         WHERE q.is_missing = 0 AND f.is_missing = 0
+           AND (f.path = ? OR f.path LIKE ?)"
+    );
+    $stmt->execute($args);
+    $quizzes = $stmt->fetch();
+
+    $total  = (int)$videos['total'] + (int)$quizzes['total'];
+    $credit = $videos['credit'] + $quizzes['credit'];
     return [
         'total'     => $total,
-        'completed' => (int)$row['completed'],
+        'completed' => (int)$videos['completed'] + (int)$quizzes['completed'],
-        'percent'   => $total > 0 ? (int)round(100 * $row['credit'] / $total) : 0,
+        'percent'   => $total > 0 ? (int)round(100 * $credit / $total) : 0,
     ];
 }
 
@@ -182,6 +273,43 @@ function folderVideos(int $folderId, int $userId): array
     return $stmt->fetchAll();
 }
 
+function getQuiz(int $id): ?array
+{
+    $stmt = db()->prepare(
+        'SELECT q.*, f.path AS folder_path, f.name AS folder_name
+         FROM quizzes q JOIN folders f ON f.id = q.folder_id
+         WHERE q.id = ? AND q.is_missing = 0'
+    );
+    $stmt->execute([$id]);
+    return $stmt->fetch() ?: null;
+}
+
+/** Quizzes in a folder, joined with the user's results. */
+function folderQuizzes(int $folderId, int $userId): array
+{
+    $stmt = db()->prepare(
+        'SELECT q.*, qp.best_score, qp.last_score, qp.attempts, qp.completed
+         FROM quizzes q
+         LEFT JOIN quiz_progress qp ON qp.quiz_id = q.id AND qp.user_id = ?
+         WHERE q.folder_id = ? AND q.is_missing = 0
+         ORDER BY q.sort_order, q.name'
+    );
+    $stmt->execute([$userId, $folderId]);
+    return $stmt->fetchAll();
+}
+
+/** Absolute, containment-checked path of a quiz file (null if gone). */
+function quizFilePath(array $quiz): ?string
+{
+    $file = realpath(rtrim(VIDEOS_ROOT, '/') . '/' . $quiz['path']);
+    $root = realpath(VIDEOS_ROOT);
+    if ($file === false || $root === false
+        || !str_starts_with($file, $root . DIRECTORY_SEPARATOR) || !is_file($file)) {
+        return null;
+    }
+    return $file;
+}
+
 /** Breadcrumb chain root -> ... -> folder. */
 function folderBreadcrumbs(array $folder): array
 {

scan.php

@@ -9,5 +9,6 @@ if (PHP_SAPI !== 'cli') {
 }
 
 $stats = scanLibrary();
-echo "Scan complete: {$stats['folders']} folders, {$stats['videos']} videos"
+echo "Scan complete: {$stats['folders']} folders, {$stats['videos']} videos, {$stats['quizzes']} quizzes"
-   . " ({$stats['missing_folders']} folders / {$stats['missing_videos']} videos flagged missing)\n";
+   . " ({$stats['missing_folders']} folders / {$stats['missing_videos']} videos"
+   . " / {$stats['missing_quizzes']} quizzes flagged missing)\n";

schema.sql

@@ -41,6 +41,41 @@ CREATE TABLE IF NOT EXISTS videos (
     INDEX idx_videos_folder (folder_id)
 ) ENGINE=InnoDB;
 
+-- One row per "*_quiz_solved.txt" file found next to the videos.
+-- Questions/options are parsed from the file on demand; only the count is
+-- cached here for progress math.
+CREATE TABLE IF NOT EXISTS quizzes (
+    id            INT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
+    folder_id     INT UNSIGNED NOT NULL,
+    name          VARCHAR(255) NOT NULL,   -- filename without the _quiz_solved.txt suffix
+    filename      VARCHAR(255) NOT NULL,
+    path          VARCHAR(700) NOT NULL UNIQUE,
+    num_questions INT UNSIGNED NOT NULL DEFAULT 0,
+    sort_order    INT UNSIGNED NOT NULL DEFAULT 0,
+    is_missing    TINYINT(1) NOT NULL DEFAULT 0,
+    created_at    TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    CONSTRAINT fk_quizzes_folder FOREIGN KEY (folder_id)
+        REFERENCES folders(id) ON DELETE CASCADE,
+    INDEX idx_quizzes_folder (folder_id)
+) ENGINE=InnoDB;
+
+-- Per-user quiz results. completed = every question answered correctly
+-- in a single attempt (sticky).
+CREATE TABLE IF NOT EXISTS quiz_progress (
+    user_id         INT UNSIGNED NOT NULL,
+    quiz_id         INT UNSIGNED NOT NULL,
+    best_score      INT UNSIGNED NOT NULL DEFAULT 0,
+    last_score      INT UNSIGNED NOT NULL DEFAULT 0,
+    total_questions INT UNSIGNED NOT NULL DEFAULT 0,
+    attempts        INT UNSIGNED NOT NULL DEFAULT 0,
+    completed       TINYINT(1) NOT NULL DEFAULT 0,
+    updated_at      TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
+        ON UPDATE CURRENT_TIMESTAMP,
+    PRIMARY KEY (user_id, quiz_id),
+    CONSTRAINT fk_qp_user FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE,
+    CONSTRAINT fk_qp_quiz FOREIGN KEY (quiz_id) REFERENCES quizzes(id) ON DELETE CASCADE
+) ENGINE=InnoDB;
+
 -- Per-user playback state: resume position + completion flag.
 CREATE TABLE IF NOT EXISTS video_progress (
     user_id          INT UNSIGNED NOT NULL,