(() => {
  const $ = (sel) => document.querySelector(sel);
  const $$ = (sel) => document.querySelectorAll(sel);

  let currentFile = null;
  let galleryOffset = 0;
  let tableOffset = 0;
  const PER_PAGE = 60;
  let compareSet = new Map();
  let searchText = '';
  let dataCache = null;
  let drawerRowIdx = null;
  let drawerNavList = [];

  function showLoading() { $('#loading').classList.remove('hidden'); }
  function hideLoading() { $('#loading').classList.add('hidden'); }

  function fmtSize(b) {
    if (!b) return '—';
    if (b < 1024) return b + ' B';
    if (b < 1048576) return (b / 1024).toFixed(1) + ' KB';
    if (b < 1073741824) return (b / 1048576).toFixed(1) + ' MB';
    return (b / 1073741824).toFixed(2) + ' GB';
  }

  function fmtNum(n) {
    if (n == null) return '—';
    return Number.isInteger(n) ? n.toLocaleString() : n.toLocaleString(undefined, { maximumFractionDigits: 2 });
  }

  function esc(s) {
    const d = document.createElement('div');
    d.textContent = s;
    return d.innerHTML;
  }

  function trunc(s, len) {
    if (!s) return '';
    return s.length > len ? s.slice(0, len) + '…' : s;
  }

  function imgSrc(fid, rowIdx, col) {
    return `/api/image/${fid}/${rowIdx}/${col}`;
  }

  // ── Folder browser ───────────────────────────────────────────────
  function openSidebar(path) {
    $('#sidebar').classList.add('open');
    $('#sidebar-backdrop').classList.add('open');
    loadFolder(path || '');
  }

  function closeSidebar() {
    $('#sidebar').classList.remove('open');
    $('#sidebar-backdrop').classList.remove('open');
  }

  async function loadFolder(path) {
    try {
      const res = await fetch(`/api/browse?path=${encodeURIComponent(path)}`);
      if (!res.ok) throw new Error();
      const data = await res.json();
      renderBreadcrumb(data.path);
      renderFolderList(data);
    } catch (e) { console.error(e); }
  }

  function renderBreadcrumb(path) {
    const parts = path.split('/').filter(Boolean);
    let h = '<span class="breadcrumb-item" data-path="/">/</span>';
    let acc = '';
    parts.forEach((p) => {
      acc += '/' + p;
      h += '<span class="breadcrumb-sep">/</span>';
      h += '<span class="breadcrumb-item" data-path="' + esc(acc) + '">' + esc(p) + '</span>';
    });
    $('#breadcrumb').innerHTML = h;
    $$('.breadcrumb-item').forEach((el) => el.addEventListener('click', () => loadFolder(el.dataset.path)));
  }

  function renderFolderList(data) {
    let h = '';
    if (data.parent) {
      h += '<div class="folder-entry is-parent" data-path="' + esc(data.parent) + '"><span class="fe-icon">..</span><span class="fe-name">Up</span></div>';
    }
    data.entries.forEach((e) => {
      let icon = '📄', cls = 'is-file';
      if (e.is_dir) { icon = '📁'; cls = 'is-dir'; }
      else if (e.is_dataset) { icon = '◉'; cls = 'is-dataset'; }
      h += '<div class="folder-entry ' + cls + '" data-path="' + esc(e.path) + '" data-dir="' + e.is_dir + '" data-ds="' + e.is_dataset + '">';
      h += '<span class="fe-icon">' + icon + '</span>';
      h += '<span class="fe-name">' + esc(e.name) + '</span>';
      if (!e.is_dir) h += '<span class="fe-meta">' + fmtSize(e.size) + '</span>';
      h += '</div>';
    });
    if (!data.entries.length) h = '<div style="padding:24px;text-align:center;color:var(--text-tertiary);font-size:12px">Empty directory</div>';
    $('#folder-list').innerHTML = h;
    $$('.folder-entry').forEach((el) => el.addEventListener('click', () => {
      if (el.dataset.dir === 'true') loadFolder(el.dataset.path);
      else if (el.dataset.ds === 'true') {
        $('#file-path').value = el.dataset.path;
        closeSidebar();
        openFile(el.dataset.path);
      }
    }));
  }

  $('#btn-browse').addEventListener('click', () => openSidebar(''));
  $('#btn-close-sidebar').addEventListener('click', closeSidebar);
  $('#sidebar-backdrop').addEventListener('click', closeSidebar);

  // ── Open file ────────────────────────────────────────────────────
  async function openFile(path) {
    showLoading();
    try {
      const res = await fetch('/api/open', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ path }),
      });
      if (!res.ok) { const e = await res.json(); alert(e.detail || 'Failed to open file'); return; }
      currentFile = await res.json();
      renderInfoBar();
      renderColumnSelects();
      galleryOffset = 0;
      tableOffset = 0;
      compareSet.clear();
      updateCompareBadge();
      closeDrawer();
      $('#main').classList.remove('hidden');
      $('#welcome').classList.add('hidden');
      switchView('gallery');
    } finally { hideLoading(); }
  }

  function renderInfoBar() {
    $('#pill-file').textContent = currentFile.path.split('/').pop();
    $('#pill-rows').textContent = fmtNum(currentFile.num_rows) + ' rows';
    $('#pill-cols').textContent = currentFile.columns.length + ' cols';
  }

  function renderColumnSelects() {
    const imgCols = currentFile.columns.filter((c) => c.is_image);
    const textCols = currentFile.columns.filter((c) => !c.is_image);
    $('#sel-img-col').innerHTML = imgCols.map((c) => '<option value="' + c.name + '">' + c.name + '</option>').join('');
    $('#sel-txt-col').innerHTML = '<option value="">None</option>' + textCols.map((c) => '<option value="' + c.name + '">' + c.name + '</option>').join('');
    const prefer = textCols.find((c) => c.name === 'text') || textCols[0];
    if (prefer) {
      const sel = $('#sel-txt-col');
      for (let i = 0; i < sel.options.length; i++) {
        if (sel.options[i].value === prefer.name) { sel.selectedIndex = i; break; }
      }
    }
  }

  // ── View switching ───────────────────────────────────────────────
  function switchView(name) {
    $$('.vs-btn').forEach((b) => b.classList.toggle('active', b.dataset.view === name));
    $$('.view').forEach((v) => v.classList.add('hidden'));
    $('#view-' + name).classList.remove('hidden');
    if (name === 'gallery') loadGallery();
    else if (name === 'table') loadTable();
    else if (name === 'compare') renderCompare();
  }

  $$('.vs-btn').forEach((b) => b.addEventListener('click', () => switchView(b.dataset.view)));

  // ── Search ───────────────────────────────────────────────────────
  let searchTimer;
  $('#search-input').addEventListener('input', (e) => {
    clearTimeout(searchTimer);
    searchTimer = setTimeout(() => {
      searchText = e.target.value.trim().toLowerCase();
      galleryOffset = 0;
      tableOffset = 0;
      const active = $('.vs-btn.active');
      if (active) {
        const v = active.dataset.view;
        if (v === 'gallery') loadGallery();
        else if (v === 'table') loadTable();
      }
    }, 200);
  });

  // ── Gallery ──────────────────────────────────────────────────────
  async function loadGallery() {
    if (!currentFile) return;
    showLoading();
    try {
      const imgCol = $('#sel-img-col').value;
      const txtCol = $('#sel-txt-col').value;
      if (!imgCol) { hideLoading(); return; }
      const cols = [imgCol];
      if (txtCol) cols.push(txtCol);
      const res = await fetch('/api/data/' + currentFile.id + '?offset=' + galleryOffset + '&limit=' + PER_PAGE + '&columns=' + cols.join(','));
      if (!res.ok) throw new Error();
      const data = await res.json();
      dataCache = data;
      drawerNavList = data.data.map((_, ri) => data.offset + ri);
      renderGallery(data, imgCol, txtCol);
    } finally { hideLoading(); }
  }

  function renderGallery(data, imgCol, txtCol) {
    const totalPages = Math.ceil(data.total / PER_PAGE);
    const page = Math.floor(data.offset / PER_PAGE) + 1;
    $('#gallery-page').textContent = page + '/' + totalPages + '  (' + fmtNum(data.total) + ')';
    $('#gallery-prev').disabled = data.offset === 0;
    $('#gallery-next').disabled = data.offset + PER_PAGE >= data.total;

    const fid = currentFile.id;
    let h = '';
    data.data.forEach((row, ri) => {
      const rowIdx = data.offset + ri;
      const caption = txtCol ? (row[txtCol] || '') : '';
      const w = row.width || '';
      const hm = row.height || '';
      const sel = compareSet.has(rowIdx);
      const isOpen = drawerRowIdx === rowIdx;

      h += '<div class="card' + (sel ? ' selected' : '') + (isOpen ? ' card-open' : '') + '" data-row="' + rowIdx + '">';
      h += '<span class="card-row">#' + (rowIdx + 1) + '</span>';
      h += '<span class="card-check">&#10003;</span>';
      h += '<img class="card-img" src="' + imgSrc(fid, rowIdx, imgCol) + '" loading="lazy" data-row="' + rowIdx + '" data-col="' + imgCol + '">';
      if (w && hm) h += '<span class="card-dims">' + w + '&times;' + hm + '</span>';
      if (caption) h += '<div class="card-caption">' + esc(trunc(caption, 140)) + '</div>';
      h += '</div>';
    });
    if (!data.data.length) {
      h = '<p style="color:var(--text-tertiary);padding:48px;text-align:center;grid-column:1/-1">No matching rows</p>';
    }
    $('#gallery-grid').innerHTML = h;
  }

  // Gallery event delegation
  $('#gallery-grid').addEventListener('click', (e) => {
    const img = e.target.closest('.card-img');
    const card = e.target.closest('.card');
    if (!card) return;
    const rowIdx = parseInt(card.dataset.row);

    if (e.shiftKey || e.metaKey || e.ctrlKey) {
      toggleCompare(rowIdx);
      return;
    }
    if (img) openDrawer(rowIdx);
  });

  $('#sel-img-col').addEventListener('change', () => { galleryOffset = 0; loadGallery(); });
  $('#sel-txt-col').addEventListener('change', () => { galleryOffset = 0; loadGallery(); });
  $('#sel-thumb-size').addEventListener('change', (e) => {
    $('#gallery-grid').style.gridTemplateColumns = 'repeat(auto-fill, minmax(' + e.target.value + 'px, 1fr))';
  });
  $('#gallery-prev').addEventListener('click', () => { galleryOffset = Math.max(0, galleryOffset - PER_PAGE); loadGallery(); });
  $('#gallery-next').addEventListener('click', () => { galleryOffset += PER_PAGE; loadGallery(); });

  // ── Compare ──────────────────────────────────────────────────────
  function toggleCompare(rowIdx) {
    const imgCol = $('#sel-img-col').value;
    if (compareSet.has(rowIdx)) {
      compareSet.delete(rowIdx);
    } else {
      if (compareSet.size >= 4) {
        const oldest = compareSet.keys().next().value;
        compareSet.delete(oldest);
        const oldCard = document.querySelector('.card[data-row="' + oldest + '"]');
        if (oldCard) oldCard.classList.remove('selected');
      }
      compareSet.set(rowIdx, { src: imgSrc(currentFile.id, rowIdx, imgCol), rowIdx });
    }
    updateCompareBadge();
    const card = document.querySelector('.card[data-row="' + rowIdx + '"]');
    if (card) card.classList.toggle('selected', compareSet.has(rowIdx));
  }

  function updateCompareBadge() {
    const badge = $('#compare-badge');
    const n = compareSet.size;
    badge.textContent = n;
    badge.classList.toggle('hidden', n === 0);
  }

  function renderCompare() {
    const content = $('#compare-content');
    const empty = $('#compare-empty');
    if (compareSet.size < 2) {
      content.classList.add('hidden');
      empty.classList.remove('hidden');
      return;
    }
    content.classList.remove('hidden');
    empty.classList.add('hidden');
    const txtCol = $('#sel-txt-col').value;
    let h = '';
    let idx = 0;
    for (const [rowIdx, item] of compareSet) {
      const label = String.fromCharCode(65 + idx);
      h += '<div class="compare-card">';
      h += '<div class="cc-head"><span class="cc-label">' + label + ' &middot; Row ' + (rowIdx + 1) + '</span>';
      h += '<button class="cc-remove" data-row="' + rowIdx + '">&times;</button></div>';
      h += '<img src="' + item.src + '" alt="Row ' + (rowIdx + 1) + '">';
      if (txtCol && dataCache) {
        const row = dataCache.data.find((_, ri) => dataCache.offset + ri === rowIdx);
        if (row && row[txtCol]) {
          h += '<div class="cc-prompt">' + esc(row[txtCol]) + '</div>';
        }
      }
      h += '<div class="cc-meta">';
      currentFile.columns.forEach((col) => {
        if (col.is_image) return;
        const row = dataCache?.data?.find((_, ri) => dataCache.offset + ri === rowIdx);
        const val = row ? row[col.name] : null;
        if (val === null || val === undefined) return;
        const s = String(val);
        if (s.length > 200) return;
        h += '<div class="cc-meta-row"><span class="cc-meta-key">' + esc(col.name) + '</span><span class="cc-meta-val">' + esc(s) + '</span></div>';
      });
      h += '</div></div>';
      idx++;
    }
    content.innerHTML = h;
    content.querySelectorAll('.cc-remove').forEach((btn) => {
      btn.addEventListener('click', () => {
        const r = parseInt(btn.dataset.row);
        compareSet.delete(r);
        updateCompareBadge();
        renderCompare();
        const card = document.querySelector('.card[data-row="' + r + '"]');
        if (card) card.classList.remove('selected');
      });
    });
  }

  // ── Table ────────────────────────────────────────────────────────
  async function loadTable() {
    if (!currentFile) return;
    showLoading();
    try {
      const limit = parseInt($('#sel-page-size').value);
      const res = await fetch('/api/data/' + currentFile.id + '?offset=' + tableOffset + '&limit=' + limit);
      if (!res.ok) throw new Error();
      const data = await res.json();
      renderTable(data);
    } finally { hideLoading(); }
  }

  function renderTable(data) {
    const limit = parseInt($('#sel-page-size').value);
    const totalPages = Math.ceil(data.total / limit);
    const page = Math.floor(data.offset / limit) + 1;
    $('#table-page').textContent = page + '/' + totalPages + '  (' + fmtNum(data.total) + ')';
    $('#table-prev').disabled = data.offset === 0;
    $('#table-next').disabled = data.offset + limit >= data.total;

    const imgCols = currentFile.columns.filter((c) => c.is_image).map((c) => c.name);
    const cols = currentFile.columns.map((c) => c.name);
    const fid = currentFile.id;

    let h = '<table><thead><tr><th style="width:36px">#</th>';
    cols.forEach((c) => { h += '<th>' + esc(c) + '</th>'; });
    h += '</tr></thead><tbody>';

    data.data.forEach((row, ri) => {
      const rowIdx = data.offset + ri;
      h += '<tr><td class="row-num">' + (rowIdx + 1) + '</td>';
      cols.forEach((col) => {
        const val = row[col];
        if (val === null || val === undefined) {
          h += '<td class="cell-null">—</td>';
        } else if (typeof val === 'object' && val._type === 'image') {
          if (imgCols.includes(col)) {
            h += '<td><img class="cell-thumb" src="' + imgSrc(fid, rowIdx, col) + '" loading="lazy" data-row="' + rowIdx + '" data-col="' + col + '"></td>';
          } else {
            h += '<td class="cell-null">' + fmtSize(val.size) + '</td>';
          }
        } else if (typeof val === 'string' && val.length > 120) {
          h += '<td title="' + esc(val) + '">' + esc(trunc(val, 120)) + '</td>';
        } else {
          h += '<td>' + esc(String(val)) + '</td>';
        }
      });
      h += '</tr>';
    });
    h += '</tbody></table>';
    $('#table-container').innerHTML = h;

    $('#table-container').querySelectorAll('.cell-thumb').forEach((img) => {
      img.addEventListener('click', () => {
        const rowIdx = parseInt(img.dataset.row);
        openDrawer(rowIdx);
      });
    });
  }

  $('#sel-page-size').addEventListener('change', () => { tableOffset = 0; loadTable(); });
  $('#table-prev').addEventListener('click', () => { tableOffset = Math.max(0, tableOffset - parseInt($('#sel-page-size').value)); loadTable(); });
  $('#table-next').addEventListener('click', () => { tableOffset += parseInt($('#sel-page-size').value); loadTable(); });

  // ── Drawer ───────────────────────────────────────────────────────
  function openDrawer(rowIdx) {
    if (!currentFile || !dataCache) return;
    const row = dataCache.data.find((_, ri) => dataCache.offset + ri === rowIdx);
    if (!row) return;

    drawerRowIdx = rowIdx;
    const imgCol = $('#sel-img-col').value;
    const txtCol = $('#sel-txt-col').value;
    const fid = currentFile.id;

    $('#drawer-title').textContent = 'Row ' + (rowIdx + 1);
    $('#drawer-img').src = imgSrc(fid, rowIdx, imgCol);

    const prompt = txtCol ? (row[txtCol] || '') : '';
    $('#drawer-prompt').textContent = prompt || 'No prompt text';

    let meta = '';
    currentFile.columns.forEach((col) => {
      if (col.is_image) return;
      const val = row[col.name];
      if (val === null || val === undefined) return;
      meta += '<div class="drawer-meta-row"><span class="drawer-meta-key">' + esc(col.name) + '</span><span class="drawer-meta-val">' + esc(String(val)) + '</span></div>';
    });
    $('#drawer-meta').innerHTML = meta;
    $('#drawer-meta-section').classList.toggle('hidden', !meta);

    updateDrawerNav();
    $('#drawer').classList.add('open');
    $('#drawer-backdrop').classList.add('open');
    highlightOpenCard();
  }

  function closeDrawer() {
    drawerRowIdx = null;
    $('#drawer').classList.remove('open');
    $('#drawer-backdrop').classList.remove('open');
    $$('.card.card-open').forEach((c) => c.classList.remove('card-open'));
  }

  function highlightOpenCard() {
    $$('.card.card-open').forEach((c) => c.classList.remove('card-open'));
    if (drawerRowIdx != null) {
      const card = document.querySelector('.card[data-row="' + drawerRowIdx + '"]');
      if (card) card.classList.add('card-open');
    }
  }

  function updateDrawerNav() {
    if (drawerRowIdx == null) return;
    const idx = drawerNavList.indexOf(drawerRowIdx);
    $('#drawer-prev').disabled = idx <= 0;
    $('#drawer-next').disabled = idx < 0 || idx >= drawerNavList.length - 1;
  }

  function drawerNavigate(dir) {
    if (drawerRowIdx == null) return;
    const idx = drawerNavList.indexOf(drawerRowIdx);
    const newIdx = idx + dir;
    if (newIdx < 0 || newIdx >= drawerNavList.length) return;
    openDrawer(drawerNavList[newIdx]);
  }

  $('#btn-close-drawer').addEventListener('click', closeDrawer);
  $('#drawer-backdrop').addEventListener('click', closeDrawer);
  $('#drawer-prev').addEventListener('click', () => drawerNavigate(-1));
  $('#drawer-next').addEventListener('click', () => drawerNavigate(1));

  $('#drawer-zoom').addEventListener('click', () => {
    if (drawerRowIdx == null) return;
    const imgCol = $('#sel-img-col').value;
    openLightbox(imgSrc(currentFile.id, drawerRowIdx, imgCol));
  });

  $('#drawer-img').addEventListener('click', () => {
    if (drawerRowIdx == null) return;
    const imgCol = $('#sel-img-col').value;
    openLightbox(imgSrc(currentFile.id, drawerRowIdx, imgCol));
  });

  // ── Lightbox ─────────────────────────────────────────────────────
  const lightbox = $('#lightbox');
  const lbImg = $('#lb-img');

  function openLightbox(src) {
    lbImg.src = src;
    lightbox.classList.add('active');
  }

  function closeLightbox() {
    lightbox.classList.remove('active');
  }

  lightbox.addEventListener('click', (e) => {
    if (e.target === lightbox || e.target.classList.contains('lb-close')) closeLightbox();
  });

  // ── Keyboard shortcuts ───────────────────────────────────────────
  document.addEventListener('keydown', (e) => {
    if (lightbox.classList.contains('active')) {
      if (e.key === 'Escape') closeLightbox();
      return;
    }
    if ($('#drawer').classList.contains('open')) {
      if (e.key === 'Escape') closeDrawer();
      if (e.key === 'ArrowLeft') drawerNavigate(-1);
      if (e.key === 'ArrowRight') drawerNavigate(1);
      return;
    }
  });

  // ── Init ─────────────────────────────────────────────────────────
  $('#btn-open').addEventListener('click', () => {
    const path = $('#file-path').value.trim();
    if (path) openFile(path);
  });
  $('#file-path').addEventListener('keydown', (e) => {
    if (e.key === 'Enter') {
      const path = $('#file-path').value.trim();
      if (path) openFile(path);
    }
  });

  if (window.location.hash) {
    const path = decodeURIComponent(window.location.hash.slice(1));
    $('#file-path').value = path;
    openFile(path);
  }
})();