Add student and admin frontends

static/admin.js

@@ -1,2 +1,212 @@
 const app = document.querySelector("#admin-app");
-app.textContent = "Loading admin...";
+
+let quizzes = [];
+let sessions = [];
+let activeSid = null;
+let ws = null;
+let leaderboard = [];
+let roster = [];
+let liveHistogram = null;
+let currentState = null;
+
+const samplePool = {
+  title: "Week 9 Recap: Computer Organization",
+  score_fn: "linear_decay",
+  time_limit_default: 60,
+  questions: [
+    {id: "q1", text: "Which unit sequences control signals in a multi-cycle datapath?", options: {A: "ALU", B: "Control unit", C: "Register file", D: "Instruction memory"}, correct: "B"}
+  ]
+};
+
+function escapeText(value) {
+  return String(value ?? "").replace(/[&<>"']/g, (char) => ({
+    "&": "&amp;",
+    "<": "&lt;",
+    ">": "&gt;",
+    '"': "&quot;",
+    "'": "&#039;",
+  })[char]);
+}
+
+async function api(path, options = {}) {
+  const response = await fetch(path, {
+    credentials: "same-origin",
+    headers: {"Content-Type": "application/json", ...(options.headers || {})},
+    ...options,
+  });
+  if (!response.ok) throw new Error(await response.text());
+  const contentType = response.headers.get("content-type") || "";
+  return contentType.includes("json") ? response.json() : response.text();
+}
+
+async function boot() {
+  try {
+    await refresh();
+    render();
+  } catch {
+    renderLogin();
+  }
+}
+
+function renderLogin(error = "") {
+  app.innerHTML = `<section class="shell"><div class="panel narrow">
+    <h1>Admin Login</h1>
+    <form id="login-form" class="stack">
+      <label>Password <input name="password" type="password" required></label>
+      ${error ? `<p class="error">${escapeText(error)}</p>` : ""}
+      <button class="primary">Log in</button>
+    </form>
+  </div></section>`;
+  document.querySelector("#login-form").addEventListener("submit", async (event) => {
+    event.preventDefault();
+    const form = new FormData(event.currentTarget);
+    try {
+      await api("/admin/login", {method: "POST", body: JSON.stringify({password: form.get("password")})});
+      await refresh();
+      render();
+    } catch {
+      renderLogin("Login failed.");
+    }
+  });
+}
+
+async function refresh() {
+  quizzes = (await api("/admin/api/quizzes")).quizzes;
+  sessions = (await api("/admin/api/sessions")).sessions;
+}
+
+function render() {
+  app.innerHTML = `<section class="admin-layout">
+    <aside class="sidebar">
+      <h1>Quiz Admin</h1>
+      <button id="new-quiz" class="secondary">Add Pool</button>
+      <button id="new-session" class="primary" ${quizzes.length ? "" : "disabled"}>Create Session</button>
+      <h2>Quizzes</h2>
+      <div class="list">${quizzes.map((quiz) => `<button data-quiz="${quiz.id}">${escapeText(quiz.title)}</button>`).join("") || "<p>No quizzes yet.</p>"}</div>
+      <h2>Sessions</h2>
+      <div class="list">${sessions.map((session) => `<button data-session="${session.sid}">${session.sid} ${escapeText(session.state)}</button>`).join("") || "<p>No sessions yet.</p>"}</div>
+    </aside>
+    <main class="workspace">${renderSession()}</main>
+  </section>`;
+  document.querySelector("#new-quiz").addEventListener("click", renderQuizModal);
+  document.querySelector("#new-session").addEventListener("click", renderSessionModal);
+  document.querySelectorAll("[data-session]").forEach((button) => {
+    button.addEventListener("click", () => connectSession(button.dataset.session));
+  });
+  bindControls();
+}
+
+function renderSession() {
+  if (!activeSid) return `<div class="panel"><h1>No active session</h1><p>Create or select a session.</p></div>`;
+  const session = sessions.find((item) => item.sid === activeSid);
+  return `<div class="panel">
+    <div class="topline"><h1>${escapeText(session?.title || activeSid)}</h1><span>${escapeText(currentState?.state || session?.state || "")}</span></div>
+    <p>Session ID: <strong>${activeSid}</strong></p>
+    <div class="toolbar">
+      <button data-command="open_question" class="primary">Open</button>
+      <button data-command="close_question">Close &amp; Reveal</button>
+      <button data-command="next">Next</button>
+      <button data-command="end_session" class="danger">End</button>
+      <a class="button" href="/admin/api/sessions/${activeSid}/csv">Download CSV</a>
+    </div>
+    <label>Question index <input id="question-idx" type="number" min="0" value="${currentState?.current_question_idx ?? 0}"></label>
+    <label>Time limit <input id="time-limit" type="number" min="1" value="60"></label>
+    <h2>Roster (${roster.length})</h2>
+    <div class="roster">${roster.map((p) => `<span>${escapeText(p.student_id)} ${escapeText(p.name)}</span>`).join("") || "No students yet."}</div>
+    <h2>Live Histogram</h2>
+    ${renderHistogram(liveHistogram?.histogram)}
+    <h2>Leaderboard</h2>
+    ${renderLeaderboard(leaderboard)}
+  </div>`;
+}
+
+function renderHistogram(histogram) {
+  const data = histogram || {A: 0, B: 0, C: 0, D: 0, missed: 0, pending: 0};
+  return `<div class="histogram">${Object.entries(data).map(([key, value]) => (
+    `<div class="hist-row"><span>${key}</span><meter min="0" max="50" value="${value}"></meter><b>${value}</b></div>`
+  )).join("")}</div>`;
+}
+
+function renderLeaderboard(rows) {
+  return `<ol class="leaderboard">${(rows || []).map((row) => (
+    `<li><span>${row.rank}. ${escapeText(row.name)} ${row.student_id ? `(${escapeText(row.student_id)})` : ""}</span><strong>${row.score}</strong></li>`
+  )).join("") || "<li>No scores yet.</li>"}</ol>`;
+}
+
+function bindControls() {
+  document.querySelectorAll("[data-command]").forEach((button) => {
+    button.addEventListener("click", () => {
+      if (!ws || ws.readyState !== WebSocket.OPEN) return;
+      const command = button.dataset.command;
+      if (command === "open_question") {
+        ws.send(JSON.stringify({
+          type: command,
+          question_idx: Number(document.querySelector("#question-idx").value || 0),
+          time_limit: Number(document.querySelector("#time-limit").value || 60),
+        }));
+      } else {
+        ws.send(JSON.stringify({type: command}));
+      }
+    });
+  });
+}
+
+function renderQuizModal() {
+  app.innerHTML = `<section class="shell"><div class="panel">
+    <h1>Add Pool</h1>
+    <form id="quiz-form" class="stack">
+      <label>Pool JSON <textarea name="pool" rows="18">${escapeText(JSON.stringify(samplePool, null, 2))}</textarea></label>
+      <button class="primary">Create Quiz</button>
+      <button type="button" id="cancel">Cancel</button>
+    </form>
+  </div></section>`;
+  document.querySelector("#cancel").addEventListener("click", render);
+  document.querySelector("#quiz-form").addEventListener("submit", async (event) => {
+    event.preventDefault();
+    const pool = JSON.parse(new FormData(event.currentTarget).get("pool"));
+    await api("/admin/api/quizzes", {method: "POST", body: JSON.stringify({pool_json: pool})});
+    await refresh();
+    render();
+  });
+}
+
+async function renderSessionModal() {
+  const options = quizzes.map((quiz) => `<option value="${quiz.id}">${escapeText(quiz.title)}</option>`).join("");
+  app.innerHTML = `<section class="shell"><div class="panel narrow">
+    <h1>Create Session</h1>
+    <form id="session-form" class="stack">
+      <label>Quiz <select name="quiz_id">${options}</select></label>
+      <button class="primary">Create</button>
+      <button type="button" id="cancel">Cancel</button>
+    </form>
+    <div id="session-result"></div>
+  </div></section>`;
+  document.querySelector("#cancel").addEventListener("click", render);
+  document.querySelector("#session-form").addEventListener("submit", async (event) => {
+    event.preventDefault();
+    const quizId = Number(new FormData(event.currentTarget).get("quiz_id"));
+    const result = await api("/admin/api/sessions", {method: "POST", body: JSON.stringify({quiz_id: quizId})});
+    document.querySelector("#session-result").innerHTML = `<h2>${result.sid}</h2><p><a href="${result.join_url}">${result.join_url}</a></p><img class="qr" src="${result.qr_url}" alt="QR code">`;
+    await refresh();
+    connectSession(result.sid);
+  });
+}
+
+function connectSession(sid) {
+  activeSid = sid;
+  if (ws) ws.close();
+  const protocol = window.location.protocol === "https:" ? "wss" : "ws";
+  ws = new WebSocket(`${protocol}://${window.location.host}/ws/instructor/${sid}`);
+  ws.addEventListener("message", (event) => {
+    const message = JSON.parse(event.data);
+    if (message.type === "state") currentState = message;
+    if (message.type === "lobby_update") roster = message.participants;
+    if (message.type === "live_histogram") liveHistogram = message;
+    if (message.type === "full_leaderboard") leaderboard = message.leaderboard;
+    if (message.type === "question_closed") liveHistogram = {histogram: message.histogram};
+    render();
+  });
+  render();
+}
+
+boot();

static/quiz.js

@@ -1,2 +1,223 @@
 const app = document.querySelector("#app");
-app.textContent = "Loading quiz...";
+const params = new URLSearchParams(window.location.search);
+const sid = params.get("sid");
+
+let ws = null;
+let me = null;
+let activeQuestion = null;
+let submitted = null;
+let countdownTimer = null;
+
+function html(strings, ...values) {
+  return strings.map((part, index) => part + (values[index] ?? "")).join("");
+}
+
+function escapeText(value) {
+  return String(value ?? "").replace(/[&<>"']/g, (char) => ({
+    "&": "&amp;",
+    "<": "&lt;",
+    ">": "&gt;",
+    '"': "&quot;",
+    "'": "&#039;",
+  })[char]);
+}
+
+function setView(markup) {
+  app.innerHTML = `<section class="shell">${markup}</section>`;
+}
+
+function askForLink() {
+  setView(html`<div class="panel center">
+    <h1>Ask your instructor for the link</h1>
+    <p>This quiz link is missing or no longer valid.</p>
+  </div>`);
+}
+
+async function api(path, options = {}) {
+  const response = await fetch(path, {
+    credentials: "same-origin",
+    headers: {"Content-Type": "application/json", ...(options.headers || {})},
+    ...options,
+  });
+  if (!response.ok) throw new Error(await response.text());
+  return response.json();
+}
+
+async function boot() {
+  if (!sid) {
+    askForLink();
+    return;
+  }
+  try {
+    await api(`/api/session/${sid}`);
+  } catch {
+    askForLink();
+    return;
+  }
+  try {
+    me = await api(`/api/session/${sid}/me`);
+    connect();
+  } catch {
+    renderJoin();
+  }
+}
+
+function renderJoin(error = "") {
+  setView(html`<div class="panel narrow">
+    <h1>Join Quiz</h1>
+    <form id="join-form" class="stack">
+      <label>Student ID <input name="student_id" autocomplete="username" required></label>
+      <label>Name <input name="name" autocomplete="name" required></label>
+      ${error ? `<p class="error">${escapeText(error)}</p>` : ""}
+      <button class="primary" type="submit">Join</button>
+    </form>
+  </div>`);
+  document.querySelector("#join-form").addEventListener("submit", async (event) => {
+    event.preventDefault();
+    const form = new FormData(event.currentTarget);
+    try {
+      await api(`/api/session/${sid}/join`, {
+        method: "POST",
+        body: JSON.stringify({
+          student_id: form.get("student_id"),
+          name: form.get("name"),
+        }),
+      });
+      me = await api(`/api/session/${sid}/me`);
+      connect();
+    } catch {
+      renderJoin("Could not join this session.");
+    }
+  });
+}
+
+function connect() {
+  const protocol = window.location.protocol === "https:" ? "wss" : "ws";
+  ws = new WebSocket(`${protocol}://${window.location.host}/ws/student/${sid}`);
+  ws.addEventListener("message", (event) => handleMessage(JSON.parse(event.data)));
+  ws.addEventListener("close", () => {
+    clearInterval(countdownTimer);
+    setView(html`<div class="panel center"><h1>Connection closed</h1><p>Refresh the page to reconnect.</p></div>`);
+  });
+}
+
+function handleMessage(message) {
+  if (message.type === "state") renderState(message);
+  if (message.type === "question_open") renderQuestion(message);
+  if (message.type === "submit_ack") renderSubmitted(message);
+  if (message.type === "question_closed") renderReveal(message);
+  if (message.type === "between_questions") renderBetween(message);
+  if (message.type === "session_ended") renderFinished(message);
+  if (message.type === "error") renderError(message.message);
+}
+
+function renderState(message) {
+  activeQuestion = null;
+  submitted = null;
+  clearInterval(countdownTimer);
+  if (message.state === "lobby") {
+    setView(html`<div class="panel center">
+      <h1>${escapeText(message.title)}</h1>
+      <p class="status">You are in. Waiting for instructor to start.</p>
+      <p>${escapeText(me?.name || "")}</p>
+      <div class="spinner"></div>
+    </div>`);
+  }
+}
+
+function renderQuestion(message) {
+  activeQuestion = message;
+  submitted = null;
+  const buttons = Object.entries(message.options).map(([key, value]) => (
+    `<button class="answer" data-answer="${key}"><strong>${key}</strong><span>${escapeText(value)}</span></button>`
+  )).join("");
+  setView(html`<article class="panel quiz-panel">
+    <div class="topline"><span>Question ${message.question_idx + 1}</span><span id="timer"></span></div>
+    <div class="bar"><span id="bar-fill"></span></div>
+    <h1>${escapeText(message.text)}</h1>
+    <div class="answers">${buttons}</div>
+  </article>`);
+  document.querySelectorAll("[data-answer]").forEach((button) => {
+    button.addEventListener("click", () => submitAnswer(button.dataset.answer));
+  });
+  startCountdown(message);
+}
+
+function startCountdown(message) {
+  clearInterval(countdownTimer);
+  const endAt = Date.now() + message.remaining_ms;
+  const total = message.time_limit * 1000;
+  const tick = () => {
+    const remaining = Math.max(0, endAt - Date.now());
+    const timer = document.querySelector("#timer");
+    const fill = document.querySelector("#bar-fill");
+    if (timer) timer.textContent = `${Math.ceil(remaining / 1000)}s`;
+    if (fill) fill.style.width = `${Math.max(0, Math.min(100, remaining / total * 100))}%`;
+  };
+  tick();
+  countdownTimer = setInterval(tick, 250);
+}
+
+function submitAnswer(answer) {
+  if (!ws || !activeQuestion || submitted) return;
+  ws.send(JSON.stringify({type: "submit", question_idx: activeQuestion.question_idx, answer}));
+  document.querySelectorAll("[data-answer]").forEach((button) => button.disabled = true);
+}
+
+function renderSubmitted(message) {
+  submitted = message;
+  const seconds = (message.elapsed_ms / 1000).toFixed(1);
+  setView(html`<div class="panel center">
+    <h1>Submitted</h1>
+    <p class="score">Submitted in ${seconds}s, +${message.score} pts.</p>
+    <p>Wait for the reveal.</p>
+  </div>`);
+}
+
+function renderReveal(message) {
+  clearInterval(countdownTimer);
+  const rows = Object.entries(message.histogram).map(([key, value]) => (
+    `<div class="hist-row"><span>${key}</span><meter min="0" max="50" value="${value}"></meter><b>${value}</b></div>`
+  )).join("");
+  const board = renderBoard(message.top5);
+  setView(html`<article class="panel">
+    <p class="status">Correct answer: ${escapeText(message.correct)}</p>
+    <h1>Reveal</h1>
+    <p>Your answer: ${escapeText(message.your_answer || "missed")}. Score: ${message.your_score || 0}.</p>
+    ${message.explanation ? `<p>${escapeText(message.explanation)}</p>` : ""}
+    <div class="histogram">${rows}</div>
+    ${board}
+    <p>Your rank: ${message.your_rank ?? "pending"}. Total: ${message.your_total ?? 0}.</p>
+  </article>`);
+}
+
+function renderBetween(message) {
+  setView(html`<div class="panel center">
+    <h1>Next question coming up</h1>
+    <p>Your rank: ${message.your_rank ?? "pending"}</p>
+    <p>Total: ${message.your_total ?? 0}</p>
+    ${renderBoard(message.top5)}
+  </div>`);
+}
+
+function renderFinished(message) {
+  setView(html`<div class="panel center celebration">
+    <h1>Quiz finished</h1>
+    <p>Your rank: ${message.your_rank ?? "pending"}. Total: ${message.your_total ?? 0}.</p>
+    <p>Answered ${message.questions_answered ?? 0}, correct ${message.questions_correct ?? 0}.</p>
+    ${renderBoard(message.final_top5)}
+  </div>`);
+}
+
+function renderBoard(rows = []) {
+  if (!rows.length) return "<p>No scores yet.</p>";
+  return `<ol class="leaderboard">${rows.map((row) => (
+    `<li><span>${row.rank}. ${escapeText(row.name)}</span><strong>${row.score}</strong></li>`
+  )).join("")}</ol>`;
+}
+
+function renderError(message) {
+  setView(html`<div class="panel center"><h1>Quiz message</h1><p>${escapeText(message)}</p></div>`);
+}
+
+boot();

static/style.css

@@ -1,6 +1,8 @@
 :root {
   color-scheme: light dark;
   font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
+  background: #f6f7f9;
+  color: #18212f;
 }
 
 body {
@@ -15,3 +17,283 @@ body {
   margin: 0 auto;
   padding: 24px;
 }
+
+.panel {
+  background: #ffffff;
+  border: 1px solid #d9dee7;
+  border-radius: 8px;
+  padding: 24px;
+  box-shadow: 0 10px 30px rgba(19, 33, 54, 0.08);
+}
+
+.narrow {
+  max-width: 440px;
+  margin: 8vh auto;
+}
+
+.center {
+  text-align: center;
+}
+
+.stack {
+  display: grid;
+  gap: 16px;
+}
+
+h1, h2 {
+  margin-top: 0;
+}
+
+label {
+  display: grid;
+  gap: 6px;
+  font-weight: 700;
+}
+
+input, textarea, select, button, .button {
+  font: inherit;
+}
+
+input, textarea, select {
+  border: 1px solid #b8c0cc;
+  border-radius: 8px;
+  padding: 10px 12px;
+  background: #fff;
+  color: #18212f;
+}
+
+button, .button {
+  border: 1px solid #9aa7b8;
+  border-radius: 8px;
+  padding: 10px 14px;
+  background: #eef1f5;
+  color: #18212f;
+  cursor: pointer;
+  text-decoration: none;
+}
+
+button:disabled {
+  cursor: not-allowed;
+  opacity: 0.55;
+}
+
+.primary {
+  background: #0d6b57;
+  border-color: #0d6b57;
+  color: #fff;
+}
+
+.secondary {
+  background: #254f7a;
+  border-color: #254f7a;
+  color: #fff;
+}
+
+.danger {
+  background: #a43831;
+  border-color: #a43831;
+  color: #fff;
+}
+
+.error {
+  color: #a43831;
+  font-weight: 700;
+}
+
+.status, .score {
+  font-size: 1.2rem;
+  font-weight: 800;
+}
+
+.spinner {
+  width: 36px;
+  height: 36px;
+  margin: 20px auto 0;
+  border: 4px solid #cbd3df;
+  border-top-color: #0d6b57;
+  border-radius: 50%;
+  animation: spin 1s linear infinite;
+}
+
+@keyframes spin {
+  to { transform: rotate(360deg); }
+}
+
+.quiz-panel h1 {
+  font-size: clamp(1.5rem, 4vw, 2.5rem);
+}
+
+.topline {
+  display: flex;
+  justify-content: space-between;
+  gap: 16px;
+  align-items: center;
+  font-weight: 800;
+}
+
+.bar {
+  height: 12px;
+  background: #e0e6ef;
+  border-radius: 999px;
+  overflow: hidden;
+  margin: 12px 0 24px;
+}
+
+.bar span {
+  display: block;
+  height: 100%;
+  width: 100%;
+  background: #0d6b57;
+  transition: width 0.2s linear;
+}
+
+.answers {
+  display: grid;
+  gap: 12px;
+}
+
+.answer {
+  display: grid;
+  grid-template-columns: 42px 1fr;
+  gap: 12px;
+  min-height: 68px;
+  align-items: center;
+  text-align: left;
+  background: #fff;
+}
+
+.answer strong {
+  display: grid;
+  place-items: center;
+  width: 36px;
+  height: 36px;
+  border-radius: 50%;
+  background: #254f7a;
+  color: #fff;
+}
+
+.histogram {
+  display: grid;
+  gap: 10px;
+  margin: 16px 0;
+}
+
+.hist-row {
+  display: grid;
+  grid-template-columns: 72px 1fr 48px;
+  gap: 10px;
+  align-items: center;
+}
+
+meter {
+  width: 100%;
+}
+
+.leaderboard {
+  display: grid;
+  gap: 8px;
+  padding-left: 0;
+  list-style: none;
+}
+
+.leaderboard li {
+  display: flex;
+  justify-content: space-between;
+  gap: 16px;
+  padding: 10px 0;
+  border-bottom: 1px solid #e2e7ee;
+}
+
+.celebration {
+  outline: 6px solid #f2c94c;
+}
+
+.admin-layout {
+  display: grid;
+  grid-template-columns: 280px 1fr;
+  min-height: 100vh;
+}
+
+.sidebar {
+  padding: 20px;
+  background: #223044;
+  color: #fff;
+}
+
+.sidebar .list {
+  display: grid;
+  gap: 8px;
+  margin-bottom: 24px;
+}
+
+.sidebar button {
+  width: 100%;
+  text-align: left;
+}
+
+.workspace {
+  padding: 24px;
+}
+
+.toolbar {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 10px;
+  margin: 16px 0;
+}
+
+.roster {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 8px;
+}
+
+.roster span {
+  border: 1px solid #ccd4df;
+  border-radius: 999px;
+  padding: 6px 10px;
+}
+
+.qr {
+  width: min(280px, 100%);
+  height: auto;
+  background: #fff;
+  padding: 12px;
+}
+
+@media (max-width: 720px) {
+  .shell, .workspace {
+    padding: 14px;
+  }
+
+  .admin-layout {
+    grid-template-columns: 1fr;
+  }
+
+  .sidebar {
+    position: static;
+  }
+
+  .panel {
+    padding: 18px;
+  }
+}
+
+@media (prefers-color-scheme: dark) {
+  :root, body {
+    background: #10141b;
+    color: #edf1f7;
+  }
+
+  .panel, input, textarea, select, .answer {
+    background: #171d27;
+    color: #edf1f7;
+    border-color: #344052;
+  }
+
+  button, .button {
+    background: #263246;
+    color: #edf1f7;
+    border-color: #4a586d;
+  }
+}