js/viewer.js

// Dataset browser (adapted from anon-submission-2026/docs/viewer.js)
// Wrapped in lazy-init so it only loads when the Dataset Browser tab is opened.

let _viewerInitialized = false;

// Base URL for images hosted in the HF dataset repo
const IMAGE_BASE_URL = "https://huggingface.co/datasets/launch/LudoBench/resolve/main/images";

// -----------------------
// Manifest loader
// -----------------------
async function loadManifest() {
  const res = await fetch("manifest.json");
  if (!res.ok) throw new Error("Failed to load manifest: " + res.status);
  const manifest = await res.json();
  return manifest.files;
}

// -----------------------
// Folder handling
// -----------------------
function buildFolderIndex(files) {
  const set = new Set();
  for (const f of files) set.add(f.folder);
  return Array.from(set).sort();
}

function populateFolderSelect(folders) {
  const sel = document.getElementById("folderSelect");
  sel.innerHTML = "";
  for (const f of folders) {
    const opt = document.createElement("option");
    opt.textContent = f;
    opt.value = f;
    sel.appendChild(opt);
  }
}

function filterFiles(files, folder) {
  return files.filter(f => f.folder === folder);
}

function populateFileSelect(files) {
  const sel = document.getElementById("fileSelect");
  sel.innerHTML = "";
  for (const f of files) {
    const opt = document.createElement("option");
    opt.value = f.json_path;
    opt.textContent = f.name;
    sel.appendChild(opt);
  }
}

// -----------------------
// Load one JSON annotation
// -----------------------
async function loadJson(path) {
  const res = await fetch(path);
  if (!res.ok) throw new Error("Error loading " + path);
  return await res.json();
}

// -----------------------
// Rendering question + answer
// -----------------------
function normalizedAnswers(raw) {
  return new Set(
    String(raw || "")
      .split(/,|\/|\bor\b/i)
      .map(s => s.trim().toLowerCase())
      .filter(Boolean)
  );
}

function isNumber(s) {
  return s !== "" && !Number.isNaN(Number(s));
}

function renderQuestion(data) {
  const card = document.getElementById("questionCard");
  card.innerHTML = `
    <h2>${data.Game} <span class="id-tag">(ID ${data.ID})</span></h2>
    <p class="question-label">Question:</p>
    <p class="question-text">${data.Question}</p>
  `;

  const info = document.getElementById("answerInfo");
  info.textContent = "";
  info.className = "answer-info";
}

function attachAnswerLogic(data) {
  const raw = String(data.Answer || "").trim();
  const accepted = normalizedAnswers(raw);

  const input = document.getElementById("answerInput");
  const button = document.getElementById("checkButton");
  const info = document.getElementById("answerInfo");

  const sol = document.getElementById("solutionText");
  sol.innerHTML = `<strong>Expected:</strong> ${raw || "\u2014"}`;

  button.onclick = () => {
    const user = input.value.trim().toLowerCase();
    let ok = false;

    if (accepted.has(user)) ok = true;
    else if (isNumber(user)) {
      for (const a of accepted)
        if (isNumber(a) && Math.abs(Number(a) - Number(user)) < 1e-9)
          ok = true;
    }

    info.textContent = ok ? "Correct!" : "Not quite. Try again.";
    info.className = "answer-info " + (ok ? "correct" : "wrong");
  };
}

// -----------------------
// Render images (local paths)
// -----------------------
function renderImage(data) {
  const container = document.getElementById("imageContainer");
  const multi = document.getElementById("multiImages");

  multi.innerHTML = "";
  container.classList.add("hidden");

  let urls = data.game_state_url;
  if (!urls) return;
  if (!Array.isArray(urls)) urls = [urls];

  const folder = data.Game.toLowerCase().replace(/\s+/g, "_");

  urls.forEach(url => {
    const file = url.split("/").pop();
    const localPath = `${IMAGE_BASE_URL}/${folder}/${file}`;

    const block = document.createElement("div");
    block.className = "multi-img-block";

    const spinner = document.createElement("div");
    spinner.className = "spinner";
    block.appendChild(spinner);

    const img = document.createElement("img");
    img.style.display = "none";
    img.src = localPath;

    img.onload = () => {
      spinner.style.display = "none";
      img.style.display = "block";
    };

    img.onerror = () => {
      spinner.style.display = "none";
      const err = document.createElement("div");
      err.textContent = "Failed to load " + localPath;
      err.style.color = "#d44";
      block.appendChild(err);
    };

    const link = document.createElement("a");
    link.href = localPath;
    link.target = "_blank";
    link.rel = "noopener noreferrer";
    link.appendChild(img);
    block.appendChild(link);

    const caption = document.createElement("div");
    caption.className = "multi-img-caption";
    caption.textContent = file;
    block.appendChild(caption);

    const full = document.createElement("a");
    full.href = localPath;
    full.target = "_blank";
    full.rel = "noopener noreferrer";
    full.className = "full-img-link";
    full.textContent = "View full image";
    block.appendChild(full);

    multi.appendChild(block);
  });

  container.classList.remove("hidden");
}

// -----------------------
// Navigation (prev / next)
// -----------------------
let GLOBAL_FILES = [];
let GLOBAL_CURRENT_FOLDER = "";
let loadAndRenderRef = null;

function goRelative(offset) {
  const fileSelect = document.getElementById("fileSelect");
  const options = Array.from(fileSelect.options);
  if (options.length === 0) return;

  const values = options.map(o => o.value);
  const current = fileSelect.value;
  let idx = values.indexOf(current);
  if (idx === -1) return;

  let next = idx + offset;
  if (next < 0) next = values.length - 1;
  if (next >= values.length) next = 0;

  fileSelect.value = values[next];
  if (loadAndRenderRef) loadAndRenderRef(values[next]);
}

// -----------------------
// Lazy initialization
// -----------------------
async function initViewer() {
  if (_viewerInitialized) return;
  _viewerInitialized = true;

  document.getElementById("prevBtn").onclick = () => goRelative(-1);
  document.getElementById("nextBtn").onclick = () => goRelative(1);

  const questionCard = document.getElementById("questionCard");

  try {
    const files = await loadManifest();
    GLOBAL_FILES = files;

    const folders = buildFolderIndex(files);
    populateFolderSelect(folders);

    const folderSel = document.getElementById("folderSelect");
    const fileSel = document.getElementById("fileSelect");

    async function loadAndRender(path) {
      const data = await loadJson(path);
      renderQuestion(data);
      attachAnswerLogic(data);
      renderImage(data);
    }

    loadAndRenderRef = loadAndRender;

    function refresh() {
      GLOBAL_CURRENT_FOLDER = folderSel.value;
      const filtered = filterFiles(files, GLOBAL_CURRENT_FOLDER);
      populateFileSelect(filtered);
      if (filtered.length > 0)
        loadAndRender(filtered[0].json_path);
    }

    folderSel.onchange = refresh;
    fileSel.onchange = () => loadAndRender(fileSel.value);

    folderSel.value = "kingdomino_tier1";
    refresh();

  } catch (err) {
    console.error(err);
    questionCard.innerHTML = `<p style="color:#f55;">Init error: ${err}</p>`;
  }
}