// ============================================================
// MY RESOURCES
// A person's own generated teaching material.
//
// Private to whoever made it, and needing no role beyond being signed in. The
// server enforces that independently — every query there filters on the owner —
// so this only has to be an honest interface to it.
// ============================================================

(function () {
  var inited = false;

  // A model an administrator adds has to show up here too, without a reload.
  // loadOptions also decides whether the model row is shown at all, so this is
  // the same call rather than a partial refresh of the select.
  document.addEventListener('models-changed', function () {
    if (inited) loadOptions();
  });

  document.addEventListener('tabChanged', function (e) {
    if (!e.detail || e.detail.tab !== 'myresources') return;
    if (!inited) { init(); inited = true; }
    // Reopening the tab is a fresh start, not a resumed one. The DOM survives
    // the visit, so without this the previous run's illustration and status sit
    // under an empty form as though they belonged to it.
    else clearResults();
    acceptPendingShare();
    loadLibrary();
  });

  // What an administrator has switched on. Read once, used by both option
  // groups and by the instruction check.
  var available = { images: false, web: false, pubmed: false };

  // Someone who writes "add a diagram of the airway" in the instructions has
  // said what they want as plainly as ticking the box would. Left alone, the
  // request is simply dropped and the resource comes back without a picture
  // and without a word about why. These are the ways people actually ask.
  var IMAGE_REQUEST = /\b(image|images|diagram|diagrams|illustration|illustrations|illustrate|illustrated|figure|figures|picture|pictures|drawing|drawings|chart|charts|graphic|graphics|infographic|visual|visuals|schematic)\b/i;

  function looksLikeImageRequest(text) {
    return IMAGE_REQUEST.test(String(text || ''));
  }

  // Turning the option on is the honest response: it does what was asked, it is
  // visible, and it can be turned straight back off. Silently ignoring the
  // sentence is not. Once it has been switched off by hand, it stays off —
  // re-ticking it on every keystroke would be a fight.
  function wireImageIntent(textareaId, checkboxId, hintId) {
    var box = document.getElementById(textareaId);
    var check = document.getElementById(checkboxId);
    var hint = document.getElementById(hintId);
    if (!box || !check || !hint) return;
    var overruled = false;
    check.addEventListener('change', function () {
      if (!check.checked) overruled = true;
      if (check.checked) hint.hidden = true;
    });
    box.addEventListener('input', function () {
      var asked = looksLikeImageRequest(box.value);
      if (!asked) { hint.hidden = true; return; }
      if (!available.images) {
        hint.textContent = 'Your instructions mention a figure, but no image model is configured, so none can be made.';
        hint.hidden = false;
        return;
      }
      if (check.checked || overruled) {
        hint.hidden = overruled ? false : true;
        if (overruled) hint.textContent = 'Your instructions ask for a figure. Tick the illustration option above to get one.';
        return;
      }
      check.checked = true;
      hint.textContent = 'Illustration switched on, because your instructions ask for a figure. Untick it if you would rather not.';
      hint.hidden = false;
    });
  }

  function init() {
    var kind = document.getElementById('mr-kind');
    if (kind) kind.addEventListener('change', syncFormatFields);
    syncFormatFields();

    var generate = document.getElementById('btn-mr-generate');
    if (generate) generate.addEventListener('click', runGenerate);

    var refresh = document.getElementById('btn-mr-refresh');
    // Refreshes whichever view is showing, rather than always the documents.
    if (refresh) refresh.addEventListener('click', function () {
      var panel = document.getElementById('mr-images-panel');
      if (panel && !panel.hidden) loadImages(true); else loadLibrary();
    });

    var docsTab = document.getElementById('tab-mr-docs');
    var imagesTab = document.getElementById('tab-mr-images');
    if (docsTab) docsTab.addEventListener('click', function () { showLibraryTab('docs'); });
    if (imagesTab) imagesTab.addEventListener('click', function () { showLibraryTab('images'); });
    var moreImages = document.getElementById('btn-mr-images-more');
    if (moreImages) moreImages.addEventListener('click', function () { loadImages(false); });

    // One delegated handler: rows are rebuilt on every refresh, so binding per
    // row would leak listeners and miss anything added later.
    var list = document.getElementById('mr-list');
    if (list) list.addEventListener('click', onRowClick);

    // Filtering is local: the whole library is already in hand, so searching it
    // is instant and costs no request.
    var search = document.getElementById('mr-search');
    if (search) search.addEventListener('input', renderLibrary);

    var modify = document.getElementById('btn-mr-modify');
    if (modify) modify.addEventListener('click', runModify);

    wireImageIntent('mr-refinement', 'mr-with-images', 'mr-image-hint');
    wireImageIntent('mr-modify-instructions', 'mr-modify-images', 'mr-modify-image-hint');

    loadOptions();
  }

  // What an administrator has approved. The model row stays hidden unless there
  // is a genuine choice to make — one approved model is not a decision anyone
  // should be asked to take.
  function loadOptions() {
    fetch('/api/my-resources/options', { headers: getAuthHeaders() })
      .then(function (r) { return r.json(); })
      .then(function (data) {
        if (!data || !data.success) return;
        var select = document.getElementById('mr-model');
        var modelRow = document.getElementById('mr-model-row');
        var models = data.models || [];
        if (select) {
          // Rebuilt, but a choice already made is kept: this also runs when an
          // administrator adds a model, and moving someone off the model they
          // picked mid-form would be worse than not refreshing at all.
          var chosen = select.value;
          select.textContent = '';
          models.forEach(function (id) {
            var option = document.createElement('option');
            option.value = id;
            option.textContent = id;
            if (id === data.defaultModel) option.selected = true;
            select.appendChild(option);
          });
          if (chosen && models.indexOf(chosen) !== -1) select.value = chosen;
        }
        if (modelRow) modelRow.hidden = models.length < 2;

        // The theme catalogue. Structural slides carry no colour of their own,
        // so this is the whole of a deck's styling — one choice rather than a
        // colour field the model would have to guess a value for.
        var themeSelect = document.getElementById('mr-theme');
        var themeRow = document.getElementById('mr-theme-row');
        var themes = Array.isArray(data.themes) ? data.themes : [];
        themeCatalogue = themes;
        nextcloudConnected = Boolean(data.nextcloudConnected);
        if (themeSelect && themes.length) {
          var chosenTheme = themeSelect.value;
          themeSelect.textContent = '';
          themes.forEach(function (t) {
            var option = document.createElement('option');
            option.value = t.id;
            option.textContent = t.name;
            option.title = t.description || '';
            themeSelect.appendChild(option);
          });
          if (chosenTheme && themes.some(function (t) { return t.id === chosenTheme; })) {
            themeSelect.value = chosenTheme;
          }
          describeTheme(themes);
          themeSelect.onchange = function () { describeTheme(themes); };
        }
        if (themeRow) themeRow.hidden = themes.length < 2;

        // Hidden entirely unless an administrator enabled it, so an option
        // never appears that someone could tick and then be refused. Both
        // groups are driven from the same answer: Generate and Modify offer
        // the same choices, so they must offer the same ones.
        available = {
          images: Boolean(data.imagesAvailable),
          web: Boolean(data.webSearchAvailable),
          pubmed: Boolean(data.pubmedAvailable)
        };
        [['mr-images-row', 'images'], ['mr-web-row', 'web'], ['mr-pubmed-row', 'pubmed'],
         ['mr-modify-images-row', 'images'], ['mr-modify-web-row', 'web'],
         ['mr-modify-pubmed-row', 'pubmed']].forEach(function (pair) {
          var row = document.getElementById(pair[0]);
          if (row) row.hidden = !available[pair[1]];
        });
      })
      .catch(function () { /* the defaults still work without this */ });
  }

  function syncFormatFields() {
    var isArticle = (document.getElementById('mr-kind') || {}).value === 'article';
    var slides = document.getElementById('mr-slide-count');
    var words = document.getElementById('mr-word-wrap');
    if (slides && slides.parentElement) slides.parentElement.hidden = isArticle;
    if (words) words.hidden = !isArticle;
  }

  function status(text, tone) {
    var el = document.getElementById('mr-status');
    if (!el) return;
    el.textContent = text || '';
    el.style.color = tone === 'bad' ? 'var(--red)' : tone === 'good' ? 'var(--green)' : 'var(--g600)';
  }

  // Everything the last run left on screen. The tab keeps its DOM between
  // visits — app.js loads a component once and marks it data-loaded — so an
  // illustration from a previous generation stayed visible under an empty form
  // when the tab was reopened, looking like output for a topic nobody had
  // typed. It cleared on a full page refresh and only then, which is why it
  // read as a leak.
  // A sample deck to download: every layout, filler text, this theme.
  //
  // Not a picture of one slide, and not a picture of their deck. The question a
  // theme picker answers is what the thing will look like, and the file itself
  // answers it better than any screenshot — opened in PowerPoint, at the size it
  // will be shown, with the fonts actually substituted the way they will be.
  //
  // An ordinary link, so it is there whether or not anything renders.
  function showThemeSample() {
    var select = document.getElementById('mr-theme');
    var box = document.getElementById('mr-theme-preview');
    if (!select || !select.value || !box) return;
    var name = (select.options[select.selectedIndex] || {}).text || 'this theme';
    var link = box.querySelector('a') || document.createElement('a');
    link.href = '/api/my-resources/theme-sample/' + encodeURIComponent(select.value);
    link.textContent = 'Download a sample deck in ' + name;
    link.title = 'Every slide layout, with placeholder text, as a PowerPoint file';
    link.style.cssText = 'font-size:12px;color:var(--blue);text-decoration:none;';
    if (!link.parentNode) box.appendChild(link);
    // And the same sample as pages, here, for a phone with no PowerPoint.
    var look = box.querySelector('button') || document.createElement('button');
    look.type = 'button';
    look.className = 'btn-sm btn-ghost';
    look.style.cssText = 'margin-left:10px;font-size:12px;';
    look.innerHTML = '<i class="fas fa-eye"></i> Preview';
    look.onclick = function () { openPreview('/api/my-resources/theme-sample/' + encodeURIComponent(select.value) + '/preview', 'Sample deck: ' + name); };
    if (!look.parentNode) box.appendChild(look);
    box.hidden = false;
  }

  // Says what the chosen theme is for, which is the part a name cannot carry.
  function describeTheme(themes) {
    var select = document.getElementById('mr-theme');
    var hint = document.getElementById('mr-theme-hint');
    if (!select || !hint) return;
    var chosen = themes.filter(function (t) { return t.id === select.value; })[0];
    hint.textContent = chosen ? (chosen.description || '') : '';
    showThemeSample();
  }

  function clearResults() {
    ['mr-images', 'mr-searches', 'mr-image-failures'].forEach(function (id) {
      var el = document.getElementById(id);
      if (el) el.textContent = '';
    });
    status('');
  }

  function runGenerate() {
    var topic = (document.getElementById('mr-topic') || {}).value || '';
    if (!topic.trim()) { status('Enter a topic first.', 'bad'); return; }

    clearResults();
    var btn = document.getElementById('btn-mr-generate');
    if (btn) { btn.disabled = true; btn.innerHTML = '<i class="fas fa-spinner fa-spin"></i> Generating...'; }
    status('Searching the library and writing. This takes a moment.');

    var corpusBox = document.getElementById('mr-use-corpus');
    fetch('/api/my-resources/generate', {
      method: 'POST',
      headers: getAuthHeaders(),
      body: JSON.stringify({
        topic: topic.trim(),
        kind: (document.getElementById('mr-kind') || {}).value || 'presentation',
        slideCount: (document.getElementById('mr-slide-count') || {}).value,
        wordCount: (document.getElementById('mr-word-count') || {}).value,
        refinement: (document.getElementById('mr-refinement') || {}).value || '',
        details: (document.getElementById('mr-details') || {}).value || '',
        useCorpus: corpusBox && corpusBox.checked === false ? 'false' : 'true',
        model: (document.getElementById('mr-model') || {}).value || '',
        theme: (document.getElementById('mr-theme') || {}).value || '',
        withImages: (document.getElementById('mr-with-images') || {}).checked ? 'true' : 'false',
        withWebSearch: (document.getElementById('mr-web-search') || {}).checked ? 'true' : 'false',
        withPubmed: (document.getElementById('mr-pubmed') || {}).checked ? 'true' : 'false'
      })
    })
      .then(function (r) { return r.json(); })
      .then(function (data) {
        if (!data.success) throw new Error(data.error || 'Generation failed');
        // Say what it was written from. Ungrounded material presented as
        // grounded is the failure worth preventing.
        var g = data.grounding || {};
        status(g.used
          ? 'Saved. Written from ' + g.count + ' library excerpt' + (g.count === 1 ? '' : 's') + '.'
          : 'Saved. Not grounded' + (g.reason ? ' — ' + g.reason : '') + '; written from the model alone.',
          g.used ? 'good' : null);
        reportSearches(data.searches);
        // A deck that fell back came out as plain slides. Silently handing
        // someone the plainer artifact left them comparing two decks with no
        // idea why one had layouts and the other did not — and asking again
        // usually gets the designed one, which is only worth knowing if the
        // fallback is visible.
        if (data.deckFallback) {
          status('Saved, but as plain slides: the model could not produce a slide ' +
                 'design twice (' + data.deckFallback + '). Generating again usually gets one.', 'bad');
        }
        showIllustrations(data.imageJobs || []);
        reportImageFailures(data.imageFailures);
        loadLibrary();
      })
      .catch(function (err) { status(err.message, 'bad'); })
      .finally(function () {
        if (btn) { btn.disabled = false; btn.innerHTML = '<i class="fas fa-wand-magic-sparkles"></i> Generate'; }
      });
  }

  // Say what was searched for. A query that left the network is worth showing
  // plainly rather than leaving someone to wonder whether it happened.
  function reportSearches(searches) {
    (searches || []).forEach(function (s) {
      if (typeof showToast !== 'function') return;
      var where = s.tool === 'pubmed_search' ? 'PubMed' : 'the web';
      showToast(s.count
        ? 'Searched ' + where + ' for "' + s.query + '" \u2014 ' + s.count + ' used.'
        : 'Nothing found on ' + where + ' for "' + s.query + '".', 'info');
    });
  }

  function ticked(id) {
    var el = document.getElementById(id);
    return Boolean(el && el.checked);
  }

  // The shared poller, so an image made here behaves exactly like one made in
  // the assistant: same status line, same durable job, same asset endpoint. It
  // lives in an ES module and this file is a classic script, hence the dynamic
  // import — which also means a failure to load it cannot break generation.
  function reportImageFailures(failures) {
    if (!(failures || []).length || typeof showToast !== 'function') return;
    // Fewer pictures than asked for, without a word, would look like the model
    // ignoring the request rather than the queue refusing it.
    showToast(failures.length === 1
      ? 'One illustration could not be started: ' + failures[0]
      : failures.length + ' illustrations could not be started.', 'error');
  }

  function showIllustrations(jobs) {
    var box = document.getElementById('mr-images');
    if (!box) return;
    box.innerHTML = '';
    if (!jobs.length) return;
    import('/js/generatedImages.js').then(function (m) {
      m.renderImageJobs(box, jobs, 'my_resources', function (card, data) {
        var img = document.createElement('img');
        img.alt = 'Generated teaching illustration';
        img.style.maxWidth = '100%';
        card.append(img);
        m.hydrateImage(img, data.imageUrl).catch(function () { img.alt = 'Private image unavailable'; });
      });
    }).catch(function () {
      if (typeof showToast === 'function') showToast('An illustration was generated but could not be displayed.', 'info');
    });
  }

  // ── The image library ──────────────────────────────────────────────────────
  // Every picture this account has generated, across all three features. Kept
  // because a figure outlives the deck it was drawn for: the deck gets replaced,
  // the diagram is still good.
  //
  // Thumbnails, not originals. The server stores a 256px preview beside each
  // asset, so a grid of thirty costs a few kB each instead of thirty full-size
  // renders — data-image-thumb is what asks hydrateImage for the small copy.
  // The catalogue, once, shared by the generate form and every library row.
  var themeCatalogue = [];
  var nextcloudConnected = false;
  var imagesLoaded = false;
  var nextImagesBefore = null;

  function showLibraryTab(which) {
    var docs = which !== 'images';
    [['tab-mr-docs', docs], ['tab-mr-images', !docs]].forEach(function (pair) {
      var tab = document.getElementById(pair[0]);
      if (!tab) return;
      // aria-selected is the whole state: the stylesheet keys off it, so the
      // visible highlight and what a screen reader announces cannot disagree.
      tab.setAttribute('aria-selected', pair[1] ? 'true' : 'false');
    });
    var list = document.getElementById('mr-list');
    var panel = document.getElementById('mr-images-panel');
    var search = document.getElementById('mr-docs-search');
    if (list) list.hidden = !docs;
    if (search) search.hidden = !docs;
    if (panel) panel.hidden = docs;
    // Fetched the first time the tab is opened, not on page load: most visits
    // never open it, and it is a database read plus a thumbnail per tile.
    if (!docs && !imagesLoaded) loadImages(true);
  }

  function loadImages(reset) {
    var grid = document.getElementById('mr-images-grid');
    var empty = document.getElementById('mr-images-empty');
    var more = document.getElementById('btn-mr-images-more');
    if (!grid) return;
    if (reset) { grid.textContent = ''; nextImagesBefore = null; }
    if (empty) { empty.hidden = false; empty.textContent = 'Loading…'; }

    var url = '/api/generated-images?limit=60' +
      (nextImagesBefore && !reset ? '&before=' + encodeURIComponent(nextImagesBefore) : '');
    fetch(url, { headers: getAuthHeaders() })
      .then(function (r) { return r.json(); })
      .then(function (data) {
        if (!data.success) throw new Error(data.error || 'Could not load your images');
        imagesLoaded = true;
        nextImagesBefore = data.nextBefore || null;
        if (more) more.hidden = !nextImagesBefore;
        if (empty) {
          empty.hidden = Boolean(data.images.length) || Boolean(grid.children.length);
          empty.textContent = 'No images yet. Tick "Add illustrations" when you generate, ' +
            'or ask the Clinical Assistant for a diagram.';
        }
        import('/js/generatedImages.js').then(function (m) {
          data.images.forEach(function (image) { grid.appendChild(imageTile(image, m)); });
        }).catch(function () {
          if (empty) { empty.hidden = false; empty.textContent = 'Images could not be displayed.'; }
        });
      })
      .catch(function (err) {
        if (empty) { empty.hidden = false; empty.textContent = err.message; }
      });
  }

  // Built as elements, never innerHTML: the caption is a model-written prompt.
  function imageTile(image, m) {
    var tile = document.createElement('figure');
    tile.className = 'img-tile';

    // The picture is the control: clicking it opens the full size. A button
    // rather than a div, so it is reachable and announced without inventing
    // keyboard handling.
    var frame = document.createElement('button');
    frame.type = 'button';
    frame.className = 'img-tile-frame loading';
    frame.title = 'Open full size';

    var img = document.createElement('img');
    img.alt = image.prompt ? 'Generated illustration: ' + image.prompt.slice(0, 80) : 'Generated illustration';
    img.setAttribute('data-image-thumb', '256');
    img.loading = 'lazy';
    frame.appendChild(img);
    frame.addEventListener('click', function () { openImage(image, m); });

    var badge = document.createElement('span');
    badge.className = 'img-tile-badge';
    badge.textContent = image.source;
    frame.appendChild(badge);

    m.hydrateImage(img, image.imageUrl)
      .then(function () { frame.classList.remove('loading'); })
      .catch(function () {
        frame.classList.remove('loading');
        img.remove();
        var gone = document.createElement('span');
        gone.style.cssText = 'font-size:11px;color:var(--g500);';
        gone.textContent = 'Unavailable';
        frame.appendChild(gone);
      });

    var body = document.createElement('div');
    body.className = 'img-tile-body';

    var prompt = document.createElement('figcaption');
    prompt.className = 'img-tile-prompt';
    prompt.textContent = image.prompt || 'No description recorded';
    prompt.title = image.prompt || '';

    var meta = document.createElement('div');
    meta.className = 'img-tile-meta';
    meta.textContent = new Date(image.createdAt).toLocaleDateString(undefined,
      { year: 'numeric', month: 'short', day: 'numeric' }) +
      (image.bytes ? ' · ' + Math.max(1, Math.round(image.bytes / 1024)) + ' kB' : '');

    var actions = document.createElement('div');
    actions.className = 'img-tile-actions';

    var download = document.createElement('button');
    download.type = 'button';
    download.className = 'img-tile-action';
    download.textContent = 'Download';
    download.addEventListener('click', function () { saveImage(image, m, download); });

    var remove = document.createElement('button');
    remove.type = 'button';
    remove.className = 'img-tile-action danger';
    remove.textContent = 'Delete';
    remove.addEventListener('click', function () { deleteImage(image, tile, remove); });

    actions.append(download, remove);
    body.append(prompt, meta, actions);
    tile.append(frame, body);
    return tile;
  }

  // The full-size copy, fetched the same authenticated way as the tile. A plain
  // link would not carry the session on a mobile client, and the asset is served
  // no-store on purpose.
  function openImage(image, m) {
    var overlay = document.createElement('div');
    overlay.className = 'img-lightbox';
    overlay.setAttribute('role', 'dialog');
    overlay.setAttribute('aria-modal', 'true');
    overlay.setAttribute('aria-label', 'Generated illustration');

    var full = document.createElement('img');
    full.alt = image.prompt || 'Generated illustration';

    var bar = document.createElement('div');
    bar.className = 'img-lightbox-bar';
    var caption = document.createElement('p');
    caption.className = 'img-lightbox-caption';
    caption.textContent = image.prompt || 'No description recorded';

    var close = document.createElement('button');
    close.type = 'button';
    close.className = 'img-tile-action';
    close.textContent = 'Close';

    var save = document.createElement('button');
    save.type = 'button';
    save.className = 'img-tile-action';
    save.textContent = 'Download';
    save.addEventListener('click', function () { saveImage(image, m, save); });

    bar.append(save, close);
    overlay.append(full, caption, bar);

    // Escape and a click on the backdrop both close it; a click on the picture
    // or the buttons does not.
    function dismiss() {
      overlay.remove();
      document.removeEventListener('keydown', onKey);
      if (lastFocus && lastFocus.focus) lastFocus.focus();
    }
    function onKey(e) { if (e.key === 'Escape') dismiss(); }
    var lastFocus = document.activeElement;
    overlay.addEventListener('click', function (e) { if (e.target === overlay) dismiss(); });
    close.addEventListener('click', dismiss);
    document.addEventListener('keydown', onKey);

    document.body.appendChild(overlay);
    close.focus();
    m.hydrateImage(full, image.imageUrl).catch(function () {
      full.remove();
      caption.textContent = 'That image could not be loaded.';
    });
  }

  // Fetched, then saved from memory. A plain <a download href> would work in a
  // browser carrying the session cookie and fail on a mobile client, whose
  // session is a bearer token an <a> cannot send — and these assets are served
  // no-store precisely so they are not sitting in a cache to be linked to.
  function saveImage(image, m, button) {
    var label = button.textContent;
    button.disabled = true;
    button.textContent = 'Saving…';
    m.privateImageBlob(image.imageUrl)
      .then(function (blob) {
        var url = URL.createObjectURL(blob);
        var link = document.createElement('a');
        link.href = url;
        link.download = 'illustration-' + image.id.slice(0, 8) + '.' +
          ({ 'image/png': 'png', 'image/jpeg': 'jpg', 'image/webp': 'webp' })[image.mime] || 'png';
        document.body.appendChild(link);
        link.click();
        link.remove();
        // Revoked on the next frame: revoking immediately races the download in
        // some browsers.
        setTimeout(function () { URL.revokeObjectURL(url); }, 1000);
      })
      .catch(function () {
        if (typeof showToast === 'function') showToast('That image could not be downloaded.', 'error');
      })
      .finally(function () { button.disabled = false; button.textContent = label; });
  }

  function deleteImage(image, tile, button) {
    // Asked, because it removes the picture from every deck that used it. The
    // deck keeps working; the figure is simply no longer there.
    if (!window.confirm('Delete this image? Any resource that used it will render without it.')) return;
    button.disabled = true;
    fetch('/api/generated-images/' + encodeURIComponent(image.id), {
      method: 'DELETE', headers: getAuthHeaders()
    })
      .then(function (r) { return r.json(); })
      .then(function (data) {
        if (!data.success) throw new Error(data.error || 'Could not delete that image');
        tile.remove();
        var grid = document.getElementById('mr-images-grid');
        var empty = document.getElementById('mr-images-empty');
        if (grid && !grid.children.length && empty) {
          empty.hidden = false;
          empty.textContent = 'No images yet.';
        }
      })
      .catch(function (err) {
        button.disabled = false;
        if (typeof showToast === 'function') showToast(err.message, 'error');
      });
  }

  // The library as last fetched. Held so searching and the Modify picker both
  // work from one copy rather than each asking the server again.
  var library = [];

  // Someone followed a share link. The token was set aside at page load (it
  // survives the trip through the SSO); now that they are signed in and on
  // this tab, say what it is and who from, and add it when they say yes.
  function acceptPendingShare() {
    var token = '';
    try { token = localStorage.getItem('ped_pending_share') || ''; localStorage.removeItem('ped_pending_share'); } catch (e) {}
    if (!token) return;
    var base = '/api/my-resources/share-link/' + encodeURIComponent(token);
    fetch(base, { headers: getAuthHeaders() })
      .then(function (r) { return r.json(); })
      .then(function (d) {
        if (!d.success) throw new Error(d.error || 'That link is not valid any more');
        if (d.own) { showToast('That is your own resource', 'info'); return; }
        var what = (d.kind === 'article' ? 'the article' : 'the deck') + ' "' + d.title + '"';
        showConfirm((d.sharedBy || 'Someone') + ' shared ' + what + ' with you. Add it to your resources?', function () {
          fetch(base + '/accept', { method: 'POST', headers: getAuthHeaders() })
            .then(function (r) { return r.json(); })
            .then(function (a) { if (!a.success) throw new Error(a.error || 'Could not add it'); showToast('"' + a.title + '" is in your resources', 'success'); loadLibrary(); })
            .catch(function (err) { showToast(err.message, 'error'); });
        }, { confirmText: 'Add to my resources' });
      })
      .catch(function (err) { showToast(err.message, 'error'); });
  }

  function loadLibrary() {
    var list = document.getElementById('mr-list');
    if (!list) return;
    fetch('/api/my-resources', { headers: getAuthHeaders() })
      .then(function (r) { return r.json(); })
      .then(function (data) {
        library = (data && data.resources) || [];
        renderLibrary();
        syncModifyTargets();
      })
      .catch(function () {
        library = [];
        list.textContent = '';
        var failed = document.createElement('p');
        failed.style.cssText = 'margin:0;font-size:13px;color:var(--red);';
        failed.textContent = 'Could not load your resources.';
        list.appendChild(failed);
        syncModifyTargets();
      });
  }

  function matches(row, needle) {
    if (!needle) return true;
    return (String(row.title || '') + ' ' + String(row.topic || '')).toLowerCase().indexOf(needle) !== -1;
  }

  function renderLibrary() {
    var list = document.getElementById('mr-list');
    if (!list) return;
    var search = document.getElementById('mr-search');
    var needle = String((search && search.value) || '').trim().toLowerCase();
    var rows = library.filter(function (row) { return matches(row, needle); });

    list.textContent = '';
    if (!rows.length) {
      var empty = document.createElement('p');
      empty.style.cssText = 'margin:0;font-size:13px;color:var(--g400);';
      // Two different situations, and saying "nothing yet" to someone whose
      // search simply missed would be wrong.
      empty.textContent = library.length
        ? 'Nothing matches "' + needle + '".'
        : 'Nothing yet. Generate something above and it will appear here.';
      list.appendChild(empty);
      return;
    }
    rows.forEach(function (row) { list.appendChild(renderRow(row)); });
  }

  // The Modify picker is the same library, so it is rebuilt from it — and the
  // selection survives a refresh, because losing it mid-sentence is maddening.
  function syncModifyTargets() {
    var select = document.getElementById('mr-modify-target');
    if (!select) return;
    var previous = select.value;
    select.textContent = '';
    if (!library.length) {
      var none = document.createElement('option');
      none.value = '';
      none.textContent = 'Nothing to modify yet';
      select.appendChild(none);
      select.disabled = true;
      return;
    }
    select.disabled = false;
    // Only what is mine can be modified; a share is read-only.
    library.filter(function (row) { return row.owned !== false; }).forEach(function (row) {
      var option = document.createElement('option');
      option.value = String(row.id);
      option.textContent = (row.title || 'Untitled') +
        ' \u2014 ' + (row.kind === 'article' ? 'article'
          : row.has_deck === false ? 'presentation, plain text' : 'presentation');
      select.appendChild(option);
    });
    if (previous && library.some(function (row) { return String(row.id) === previous; })) {
      select.value = previous;
    }
  }

  function runModify() {
    var select = document.getElementById('mr-modify-target');
    var box = document.getElementById('mr-modify-instructions');
    var status = document.getElementById('mr-modify-status');
    var btn = document.getElementById('btn-mr-modify');
    function say(message, tone) {
      if (!status) return;
      status.textContent = message || '';
      status.style.color = tone === 'bad' ? 'var(--red)' : tone === 'good' ? 'var(--green)' : 'var(--g600)';
    }

    var id = select && select.value;
    var instructions = String((box && box.value) || '').trim();
    if (!id) return say('Nothing to modify yet.', 'bad');
    if (!instructions) return say('Say what to change.', 'bad');

    if (btn) { btn.disabled = true; btn.innerHTML = '<i class="fas fa-spinner fa-spin"></i> Applying'; }
    clearResults();
    say('Rewriting…');
    fetch('/api/my-resources/' + encodeURIComponent(id) + '/refine', {
      method: 'POST',
      headers: getAuthHeaders(),
      body: JSON.stringify({
        instructions: instructions,
        useCorpus: ticked('mr-modify-corpus') ? 'true' : 'false',
        withPubmed: ticked('mr-modify-pubmed') ? 'true' : 'false',
        withWebSearch: ticked('mr-modify-web-search') ? 'true' : 'false',
        withImages: ticked('mr-modify-images') ? 'true' : 'false',
        model: (document.getElementById('mr-model') || {}).value || ''
      })
    })
      .then(function (r) { return r.json(); })
      .then(function (data) {
        if (!data.success) throw new Error(data.error || 'Could not apply the changes');
        // Same reporting as generating: what it was written from, what was
        // searched, and any figure that came back.
        var g = data.grounding || {};
        // The model can return the document back unchanged. That is a failed
        // modification, and saying "Applied" for it sent people off to download
        // an identical file and conclude the feature was broken.
        if (data.unchanged) {
          say('The model returned it unchanged — nothing was modified. ' +
              'Try naming the slide or section to change, and what to change about it.', 'bad');
        } else {
          // Whether it could see the slides is worth saying: it is the
          // difference between "slide 4 looks crowded" being actionable and
          // being guesswork, and it explains why this took longer.
          say('Applied' +
              (data.saw ? ', after looking at all ' + data.saw + ' slides' : '') +
              (g.used ? ', using ' + g.count + ' library excerpt' + (g.count === 1 ? '' : 's') : '') +
              '. Download it to see the result.', 'good');
        }
        reportSearches(data.searches);
        showIllustrations(data.imageJobs || []);
        reportImageFailures(data.imageFailures);
        if (box && !data.unchanged) box.value = '';
        loadLibrary();
      })
      .catch(function (err) { say(err.message, 'bad'); })
      .finally(function () {
        if (btn) { btn.disabled = false; btn.innerHTML = '<i class="fas fa-pen-to-square"></i> Apply changes'; }
      });
  }

  // Built as elements rather than innerHTML: a title comes from a model, and
  // this is the one place it reaches the page.
  function renderRow(row) {
    var wrap = document.createElement('div');
    wrap.className = 'saved-enc-item';
    wrap.style.cssText = 'padding:8px 12px;display:flex;align-items:center;gap:10px;flex-wrap:wrap;';

    var body = document.createElement('div');
    body.className = 'mr-row-body';
    body.style.flex = '1';
    body.style.minWidth = '180px';

    var title = document.createElement('div');
    title.style.cssText = 'font-weight:600;font-size:13px;';
    title.textContent = row.title || 'Untitled';

    // The modified time, when there is one. Showing only the creation time meant
    // a modification that did apply still looked like nothing had happened, so
    // the timestamp was the thing people used to conclude modify was broken.
    var created = new Date(row.created_at);
    var updated = row.updated_at ? new Date(row.updated_at) : created;
    var edited = updated - created > 2000;

    var meta = document.createElement('div');
    meta.style.cssText = 'font-size:11px;color:var(--g500);';
    meta.textContent = (row.kind === 'article' ? 'Article' : 'Presentation') +
      ' · ' + (edited ? 'modified ' + updated.toLocaleString()
                           : created.toLocaleString()) +
      (row.grounded_count ? ' · ' + row.grounded_count + ' library excerpts' : ' · not grounded') +
      // Only worth saying when it is the weaker kind. A deck is the normal case.
      (row.kind !== 'article' && row.has_deck === false ? ' · plain text, no slide layout' : '');

    if (row.owned === false && row.shared_by_name) {
      var from = document.createElement('div');
      from.style.cssText = 'font-size:11px;color:var(--blue);';
      from.textContent = 'Shared by ' + row.shared_by_name;
      body.appendChild(from);
    }
    body.appendChild(title);
    body.appendChild(meta);
    wrap.appendChild(body);

    // An article has no slides, so offering PowerPoint would produce a deck of
    // paragraphs. A presentation as Word is fine — prose absorbs slide content
    // without overflowing anything.
    // Look first, download after. The preview is the file's own pages as
    // pictures, so it shows exactly what the download would.
    var formats = row.kind === 'article' ? ['docx', 'pdf'] : ['pptx', 'docx', 'pdf'];
    var look = document.createElement('button');
    look.className = 'btn-sm btn-ghost';
    look.type = 'button';
    look.dataset.preview = String(row.id);
    look.innerHTML = '<i class="fas fa-eye"></i> Preview';
    look.dataset.previewTitle = row.title || row.topic || 'Preview';
    look.dataset.previewFormats = formats.join(',');
    look.title = 'See every page here, without downloading';
    wrap.appendChild(look);

    formats.forEach(function (format) {
      var btn = document.createElement('button');
      btn.className = 'btn-sm btn-ghost';
      btn.type = 'button';
      btn.dataset.download = String(row.id);
      btn.dataset.format = format;
      btn.textContent = format.toUpperCase();
      btn.title = 'Download as ' + format.toUpperCase();
      wrap.appendChild(btn);
    });

    // Re-skinning is a column write, not a regeneration: the next download
    // renders from the same deck in different colours. Only for a row that has
    // a deck — flat markdown has no palette to change.
    // Reading is what a share gives; changing is the author's.
    if (row.owned === false) { return wrap; }

    var share = document.createElement('button');
    share.className = 'btn-sm btn-ghost';
    share.type = 'button';
    share.dataset.share = String(row.id);
    share.innerHTML = '<i class="fas fa-user-plus"></i> Share';
    share.title = 'Share with people on this site';
    wrap.appendChild(share);

    // The theme is chosen in the editor when the deck is made or modified;
    // the list row only looks and downloads.

    // Send the rendered file to the owner's own Nextcloud. Offered only when
    // there is a Nextcloud to send it to.
    if (nextcloudConnected) {
      var cloud = document.createElement('button');
      cloud.className = 'btn-sm btn-ghost';
      cloud.type = 'button';
      cloud.dataset.nextcloud = String(row.id);
      cloud.dataset.format = row.kind === 'article' ? 'docx' : 'pptx';
      cloud.title = 'Upload to your Nextcloud as ' + cloud.dataset.format.toUpperCase();
      var cloudIcon = document.createElement('i');
      cloudIcon.className = 'fas fa-cloud-arrow-up';
      cloud.appendChild(cloudIcon);
      cloud.appendChild(document.createTextNode(' Nextcloud'));
      wrap.appendChild(cloud);
    }

    var del = document.createElement('button');
    del.className = 'btn-sm btn-ghost';
    del.type = 'button';
    del.dataset.remove = String(row.id);
    del.style.color = 'var(--red)';
    del.title = 'Delete';
    var icon = document.createElement('i');
    icon.className = 'fas fa-trash';
    del.appendChild(icon);
    wrap.appendChild(del);

    return wrap;
  }


  // Rendered server-side and pushed straight to their storage — the file never
  // travels through this browser, which is the point: it is a copy in their own
  // Nextcloud, not a download they then have to file away.
  function sendToNextcloud(id, format, btn) {
    var icon = btn.querySelector('i');
    var was = icon ? icon.className : '';
    btn.disabled = true;
    if (icon) icon.className = 'fas fa-spinner fa-spin';
    fetch('/api/my-resources/' + encodeURIComponent(id) + '/to-nextcloud', {
      method: 'POST', headers: getAuthHeaders(), body: JSON.stringify({ format: format })
    })
      .then(function (r) { return r.json(); })
      .then(function (data) {
        if (!data.success) throw new Error(data.error || 'Could not send it');
        if (icon) icon.className = 'fas fa-cloud-arrow-up';
        if (typeof showToast === 'function') showToast('Saved to your Nextcloud: ' + data.path, 'success');
      })
      .catch(function (err) {
        if (icon) icon.className = was;
        if (typeof showToast === 'function') showToast(err.message, 'error');
      })
      .finally(function () { btn.disabled = false; });
  }

  function onRowClick(event) {
    var cloud = event.target.closest && event.target.closest('[data-nextcloud]');
    if (cloud) return sendToNextcloud(cloud.dataset.nextcloud, cloud.dataset.format, cloud);

    var shareBtn = event.target.closest && event.target.closest('[data-share]');
    if (shareBtn) { openSharePanel(shareBtn.dataset.share, shareBtn.closest('.saved-enc-item')); return; }
    var preview = event.target.closest && event.target.closest('[data-preview]');
    if (preview) {
      var pid = encodeURIComponent(preview.dataset.preview);
      openPreview('/api/my-resources/' + pid + '/preview', preview.dataset.previewTitle || 'Preview', {
        pdf: '/api/my-resources/' + pid + '/export?format=pdf',
        downloads: (preview.dataset.previewFormats || '').split(',').filter(Boolean).map(function (f) {
          return { label: f.toUpperCase(), url: '/api/my-resources/' + pid + '/export?format=' + f };
        })
      });
      return;
    }
    var download = event.target.closest && event.target.closest('[data-download]');
    if (download) return downloadResource(download.dataset.download, download.dataset.format, download);

    var remove = event.target.closest && event.target.closest('[data-remove]');
    if (remove) {
      showConfirm('Delete this resource? This cannot be undone.', function () {
        fetch('/api/my-resources/' + encodeURIComponent(remove.dataset.remove), {
          method: 'DELETE', headers: getAuthHeaders()
        })
          .then(function (r) { return r.json(); })
          .then(function (d) {
            if (!d.success) throw new Error(d.error || 'Could not delete');
            loadLibrary();
          })
          .catch(function (err) { showToast(err.message, 'error'); });
      }, { danger: true, confirmText: 'Delete' });
    }
  }

  // Fetched rather than linked, because the download needs the auth header and
  // an <a href> cannot carry one.
  function downloadResource(id, format, btn) {
    var original = btn.textContent;
    btn.disabled = true;
    btn.textContent = '...';
    fetch('/api/my-resources/' + encodeURIComponent(id) + '/export?format=' + encodeURIComponent(format), {
      headers: getAuthHeaders()
    })
      .then(function (r) {
        if (!r.ok) return r.json().then(function (d) { throw new Error(d.error || 'Download failed'); });
        var name = 'resource.' + format;
        var disposition = r.headers.get('Content-Disposition') || '';
        var match = disposition.match(/filename="([^"]+)"/);
        if (match) name = match[1];
        return r.blob().then(function (blob) { saveBlob(blob, name); });
      })
      .catch(function (err) { showToast(err.message, 'error'); })
      .finally(function () { btn.disabled = false; btn.textContent = original; });
  }

  // ── Sharing ──────────────────────────────────────────────
  // Under the row: a switch for everyone, an email to add one person, and the
  // list of people it is shared with, each with a way to withdraw.
  function openSharePanel(id, rowEl) {
    if (!rowEl) return;
    var existing = rowEl.querySelector('.mr-share');
    if (existing) { existing.remove(); return; }
    var panel = document.createElement('div');
    panel.className = 'mr-share';
    panel.style.cssText = 'flex-basis:100%;margin-top:8px;padding:10px 12px;border:1px solid var(--g200);border-radius:8px;background:var(--g50);display:grid;gap:8px;font-size:13px;';
    panel.innerHTML = '<div style="display:flex;gap:8px;flex-wrap:wrap;align-items:center;">' +
      '<button type="button" class="btn-sm btn-primary mr-share-link"><i class="fas fa-link"></i> Copy a share link</button>' +
      '<span class="mr-share-link-note" style="font-size:12px;color:var(--g500);">Send it however you like. Whoever follows it and accepts gets it in their resources; the link works for 30 days.</span>' +
      '<input type="text" class="mr-share-link-url admin-control" readonly hidden style="flex-basis:100%;font-size:12px;"></div>' +
      '<div class="mr-share-people" style="display:grid;gap:4px;"></div>';
    rowEl.appendChild(panel);
    var base = '/api/my-resources/' + encodeURIComponent(id) + '/shares';
    function paint(state) {
      var list = panel.querySelector('.mr-share-people');
      list.innerHTML = '';
      if (!state.people.length) {
        var none = document.createElement('div'); none.style.cssText = 'font-size:12px;color:var(--g500);';
        none.textContent = 'Nobody has accepted a link yet.';
        list.appendChild(none); return;
      }
      state.people.forEach(function (p) {
        var line = document.createElement('div');
        line.style.cssText = 'display:flex;align-items:center;gap:8px;';
        var who = document.createElement('span'); who.style.flex = '1';
        who.textContent = (p.name ? p.name + ' · ' : '') + p.email;
        var out = document.createElement('button'); out.type = 'button'; out.className = 'btn-sm btn-ghost';
        out.textContent = 'Remove'; out.title = 'Withdraw the share';
        out.addEventListener('click', function () {
          fetch(base + '/' + encodeURIComponent(p.id), { method: 'DELETE', headers: getAuthHeaders() })
            .then(function (r) { return r.json(); }).then(load).catch(function (e) { showToast(e.message, 'error'); });
        });
        line.appendChild(who); line.appendChild(out); list.appendChild(line);
      });
    }
    function load() {
      return fetch(base, { headers: getAuthHeaders() }).then(function (r) { return r.json(); })
        // Painting the panel must not redraw the library: a redraw rebuilds the
        // rows and the panel vanished the moment it opened. The row's own
        // "shared with everyone" line is updated in place instead.
        .then(function (d) {
          if (!d.success) throw new Error(d.error || 'Could not load');
          paint(d);
        })
        .catch(function (e) { showToast(e.message, 'error'); });
    }
    panel.querySelector('.mr-share-link').addEventListener('click', function () {
      var out = panel.querySelector('.mr-share-link-url');
      fetch('/api/my-resources/' + encodeURIComponent(id) + '/share-link', { method: 'POST', headers: getAuthHeaders(), body: JSON.stringify({ days: 30 }) })
        .then(function (r) { return r.json(); })
        .then(function (d) {
          if (!d.success) throw new Error(d.error || 'Could not make a link');
          out.value = d.url; out.hidden = false; out.select();
          var copy = navigator.clipboard ? navigator.clipboard.writeText(d.url) : Promise.reject();
          return copy.then(function () { showToast('Link copied — send it to whoever should have this', 'success'); })
            .catch(function () { showToast('Link ready below — copy it by hand', 'info'); });
        })
        .catch(function (err) { showToast(err.message, 'error'); });
    });
    load();
  }

  // ── The preview gallery ──────────────────────────────────
  // One overlay: the pages of a document, top to bottom, at the width of the
  // screen. Each page is fetched with the auth header (an <img src> cannot
  // carry one) and shown as it arrives, so the first page is up before the
  // last is rendered. Pinch-zoom is the browser's own.
  // One page at a time, the way a deck is shown: arrows, keys, a swipe on a
  // phone, a counter, and the PDF itself on a second tab for anyone who wants
  // to read it as a document or print it. Pages are fetched as they are
  // reached, two ahead, and kept as object URLs until the viewer closes.
  function openPreview(base, title, opts) {
    opts = opts || {};
    var old = document.getElementById('mr-preview');
    if (old) old.remove();
    var overlay = document.createElement('div');
    overlay.id = 'mr-preview';
    overlay.className = 'mr-preview';
    overlay.setAttribute('role', 'dialog');
    overlay.setAttribute('aria-modal', 'true');
    overlay.innerHTML =
      '<div class="mr-preview-bar">' +
        '<span class="mr-preview-title"></span>' +
        '<div class="mr-preview-tabs" role="tablist">' +
          '<button type="button" class="mr-preview-tab is-on" data-view="pages" role="tab">Pages</button>' +
          (opts.pdf ? '<button type="button" class="mr-preview-tab" data-view="pdf" role="tab">PDF</button>' : '') +
        '</div>' +
        '<span class="mr-preview-downloads"></span>' +
        '<button type="button" class="mr-preview-close" aria-label="Close preview">&#10005; Close</button>' +
      '</div>' +
      '<div class="mr-preview-stage" data-view="pages">' +
        '<button type="button" class="mr-preview-nav" data-step="-1" aria-label="Previous page">&#8249;</button>' +
        '<div class="mr-preview-frame"><p class="mr-preview-status">Rendering pages…</p></div>' +
        '<button type="button" class="mr-preview-nav" data-step="1" aria-label="Next page">&#8250;</button>' +
      '</div>' +
      '<div class="mr-preview-foot"><span class="mr-preview-count" role="status"></span></div>';
    overlay.querySelector('.mr-preview-title').textContent = title || 'Preview';
    var downloadsEl = overlay.querySelector('.mr-preview-downloads');
    (opts.downloads || []).forEach(function (d) {
      var b = document.createElement('button');
      b.type = 'button'; b.className = 'mr-preview-dl'; b.textContent = d.label; b.title = 'Download as ' + d.label;
      b.addEventListener('click', function () { fetchToFile(d.url, (title || 'resource') + '.' + d.label.toLowerCase()); });
      downloadsEl.appendChild(b);
    });
    document.body.appendChild(overlay);
    document.body.classList.add('mr-preview-open');

    var urls = [], pages = 0, current = 1, blobs = {}, pending = {}, view = 'pages';
    var frame = overlay.querySelector('.mr-preview-frame');
    var countEl = overlay.querySelector('.mr-preview-count');
    var stage = overlay.querySelector('.mr-preview-stage');
    var pdfFrame = null;

    function close() {
      overlay.remove();
      document.body.classList.remove('mr-preview-open');
      urls.forEach(function (u) { URL.revokeObjectURL(u); });
      document.removeEventListener('keydown', onKey);
    }
    function onKey(e) {
      if (e.key === 'Escape') close();
      else if (view === 'pages' && (e.key === 'ArrowRight' || e.key === 'PageDown' || e.key === ' ')) { e.preventDefault(); go(current + 1); }
      else if (view === 'pages' && (e.key === 'ArrowLeft' || e.key === 'PageUp')) { e.preventDefault(); go(current - 1); }
      else if (view === 'pages' && e.key === 'Home') go(1);
      else if (view === 'pages' && e.key === 'End') go(pages);
    }
    document.addEventListener('keydown', onKey);
    overlay.querySelector('.mr-preview-close').addEventListener('click', close);
    overlay.querySelectorAll('.mr-preview-nav').forEach(function (b) {
      b.addEventListener('click', function () { go(current + Number(b.dataset.step)); });
    });
    // A swipe on a phone turns the page.
    var touchX = null;
    stage.addEventListener('touchstart', function (e) { touchX = e.touches[0].clientX; }, { passive: true });
    stage.addEventListener('touchend', function (e) {
      if (touchX === null || view !== 'pages') return;
      var dx = e.changedTouches[0].clientX - touchX; touchX = null;
      if (Math.abs(dx) > 50) go(current + (dx < 0 ? 1 : -1));
    }, { passive: true });

    function fetchPage(n) {
      if (blobs[n] || pending[n] || n < 1 || n > pages) return Promise.resolve(blobs[n]);
      pending[n] = fetch(base + '/' + n, { headers: getAuthHeaders() })
        .then(function (r) { if (!r.ok) throw new Error('page ' + n); return r.blob(); })
        .then(function (blob) { var u = URL.createObjectURL(blob); urls.push(u); blobs[n] = u; return u; })
        .finally(function () { delete pending[n]; });
      return pending[n];
    }
    function show(n) {
      frame.innerHTML = '';
      var img = document.createElement('img');
      img.className = 'mr-preview-page';
      img.alt = 'Page ' + n + ' of ' + pages;
      img.draggable = false;
      frame.appendChild(img);
      fetchPage(n).then(function (u) { if (current === n && u) img.src = u; })
        .catch(function () { if (current === n) frame.innerHTML = '<p class="mr-preview-status">Page ' + n + ' could not be shown</p>'; });
      fetchPage(n + 1); fetchPage(n + 2);
      countEl.textContent = 'Page ' + n + ' of ' + pages;
      overlay.querySelectorAll('.mr-preview-nav').forEach(function (b) {
        b.disabled = Number(b.dataset.step) < 0 ? n <= 1 : n >= pages;
      });
    }
    function go(n) {
      if (!pages) return;
      n = Math.max(1, Math.min(pages, n));
      if (n === current && frame.querySelector('img')) return;
      current = n;
      show(n);
    }
    function switchView(name) {
      view = name;
      overlay.querySelectorAll('.mr-preview-tab').forEach(function (t) { t.classList.toggle('is-on', t.dataset.view === name); t.setAttribute('aria-selected', String(t.dataset.view === name)); });
      stage.dataset.view = name;
      overlay.querySelector('.mr-preview-foot').hidden = name !== 'pages';
      if (name === 'pdf') {
        if (!pdfFrame) {
          pdfFrame = document.createElement('iframe');
          pdfFrame.className = 'mr-preview-pdf';
          pdfFrame.title = (title || 'Preview') + ' as PDF';
          stage.appendChild(pdfFrame);
          fetch(opts.pdf, { headers: getAuthHeaders() })
            .then(function (r) { if (!r.ok) throw new Error('The PDF could not be produced'); return r.blob(); })
            .then(function (blob) { var u = URL.createObjectURL(new Blob([blob], { type: 'application/pdf' })); urls.push(u); pdfFrame.src = u; })
            .catch(function (err) { pdfFrame.remove(); pdfFrame = null; frame.innerHTML = '<p class="mr-preview-status">' + err.message + '</p>'; });
        }
      }
    }
    overlay.querySelectorAll('.mr-preview-tab').forEach(function (t) { t.addEventListener('click', function () { switchView(t.dataset.view); }); });

    fetch(base, { headers: getAuthHeaders() })
      .then(function (r) { return r.json(); })
      .then(function (d) {
        if (!d.success) throw new Error(d.error || 'Could not render a preview');
        pages = d.pages;
        show(1);
      })
      .catch(function (err) {
        frame.innerHTML = '';
        var p = document.createElement('p');
        p.className = 'mr-preview-status';
        p.textContent = err.message;
        frame.appendChild(p);
      });
  }

  function fetchToFile(url, name) {
    fetch(url, { headers: getAuthHeaders() })
      .then(function (r) { if (!r.ok) throw new Error('Download failed'); return r.blob(); })
      .then(function (blob) { saveBlob(blob, name); })
      .catch(function (err) { status(err.message); });
  }

  function saveBlob(blob, name) {
    var url = URL.createObjectURL(blob);
    var link = document.createElement('a');
    link.href = url;
    link.download = name;
    document.body.appendChild(link);
    link.click();
    link.remove();
    setTimeout(function () { URL.revokeObjectURL(url); }, 1000);
  }
}());