// Root todo.txt rail widget. Surfaces wiki-root/todo.txt at the top of the // left navigation rail (above the folder tree) and keeps it editable in place: // a plain read view paints first (fast, no dependency), then a minimal // CodeMirror instance (todo.txt highlighting from the bundle) always mounts — // lazily, off the critical path, so the bundle fetch never delays first paint. // Autosave is debounced + saves on blur via POST /_todo. If the file is absent // (GET /_todo → 404) the widget renders nothing and no FAB is created; the // file is only ever created out-of-band. Mobile: a dedicated todo FAB opens // the widget in the full-viewport Overlay (overlay.js), saving on dismiss. (function () { var container = document.querySelector('[data-todo-rail]'); if (!container) return; var TODO_URL = '/_todo'; var DEBOUNCE_MS = 800; var RETRY_MS = 5000; var view = null; // CM EditorView once mounted var fallback = null; //

fallback if the bundle fails to load
    var readView = null;      // pre-focus read view
    var bodyEl = null;        // hosts readView, then the editor
    var marker = null;        // "unsaved" indicator (shown on save failure)
    var lastSaved = '';       // last text confirmed written to disk
    var saveTimer = null;
    var retryTimer = null;
    var saving = false;
    var loadingBundle = false;
    var wantFocus = false;    // user reached for the editor before it mounted

fetch(TODO_URL, { credentials: 'same-origin' }).then(function (r) {
        if (r.status === 404) return null; // no todo.txt — no widget
        if (!r.ok) throw new Error('HTTP ' + r.status);
        return r.text();
    }).then(function (text) {
        if (typeof text === 'string') init(text);
    }).catch(function () { /* fetch failed — leave the widget hidden */ });

function init(text) {
        lastSaved = text;

var head = document.createElement('div');
        head.className = 'row space-between todo-rail-head';
        var label = document.createElement('span');
        label.className = 'muted';
        label.textContent = 'todo.txt';
        marker = document.createElement('span');
        marker.className = 'todo-unsaved';
        marker.textContent = 'unsaved';
        marker.hidden = true;
        head.appendChild(label);
        head.appendChild(marker);

bodyEl = document.createElement('div');
        readView = document.createElement('div');
        readView.className = 'todo-rail-view';
        readView.tabIndex = 0;
        readView.textContent = text;
        // If the user reaches for the read view before the idle upgrade fires,
        // remember it so the mounting editor takes focus.
        readView.addEventListener('focus', focusUpgrade);
        readView.addEventListener('click', focusUpgrade);
        bodyEl.appendChild(readView);

container.appendChild(head);
        container.appendChild(bodyEl);
        container.hidden = false;

setupFab();

// Always upgrade to the live editor, but only once the browser is idle
        // so the CM bundle fetch never competes with first paint. The read view
        // is the placeholder shown until then.
        scheduleUpgrade();
    }

function focusUpgrade() {
        wantFocus = true;
        upgrade();
    }

function scheduleUpgrade() {
        if (window.requestIdleCallback) {
            requestIdleCallback(function () { upgrade(); }, { timeout: 2000 });
        } else {
            setTimeout(upgrade, 200);
        }
    }

// Inject the vendored CM bundle (cache-busted with the same content hash the
    // edit template uses, exposed on <body>), then mount the editor. If the
    // bundle cannot load (offline/VPN blip), fall back to a plain textarea so
    // editing and saving still work unstyled.
    function upgrade() {
        if (view || fallback || loadingBundle) return;
        if (window.CM) { mountEditor(); return; }
        loadingBundle = true;
        var v = document.body.getAttribute('data-editor-version') || '';
        var s = document.createElement('script');
        s.src = '/_/editor/vendor/codemirror.bundle.js' + (v ? '?v=' + v : '');
        s.onload = function () { loadingBundle = false; mountEditor(); };
        s.onerror = function () { loadingBundle = false; mountFallback(); };
        document.head.appendChild(s);
    }

function mountEditor() {
        var state = CM.EditorState.create({
            doc: readView.textContent,
            extensions: [
                CM.history(),
                CM.drawSelection(),
                CM.EditorView.lineWrapping,
                CM.todoLanguage,
                CM.syntaxHighlighting(CM.todoHighlightStyle),
                CM.todoTheme,
                CM.keymap.of([].concat(CM.defaultKeymap, CM.historyKeymap)),
                CM.EditorView.updateListener.of(function (u) {
                    if (u.docChanged) scheduleSave();
                }),
                CM.EditorView.domEventHandlers({ blur: function () { saveNow(); } }),
            ],
        });
        bodyEl.textContent = '';
        view = new CM.EditorView({ state: state, parent: bodyEl });
        // Only steal focus if the user actually reached for the editor — the
        // passive idle mount must not grab focus or scroll the page.
        if (wantFocus) view.focus();
    }

function mountFallback() {
        fallback = document.createElement('textarea');
        fallback.className = 'input todo-fallback';
        fallback.value = readView.textContent;
        fallback.addEventListener('input', scheduleSave);
        fallback.addEventListener('blur', saveNow);
        bodyEl.textContent = '';
        bodyEl.appendChild(fallback);
        if (wantFocus) fallback.focus();
    }

function currentText() {
        if (view) return view.state.doc.toString();
        if (fallback) return fallback.value;
        return readView.textContent;
    }

function scheduleSave() {
        if (saveTimer) clearTimeout(saveTimer);
        saveTimer = setTimeout(save, DEBOUNCE_MS);
    }

function saveNow() {
        if (saveTimer) { clearTimeout(saveTimer); saveTimer = null; }
        save();
    }

// Last write wins, no conflict detection (accepted). On failure: show the
    // "unsaved" marker, keep the buffer untouched, retry silently.
    function save() {
        saveTimer = null;
        var text = currentText();
        if (text === lastSaved) return;
        if (saving) { scheduleSave(); return; } // serialize; re-check afterwards
        saving = true;
        fetch(TODO_URL, {
            method: 'POST',
            credentials: 'same-origin',
            headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
            body: 'content=' + encodeURIComponent(text),
        }).then(function (r) {
            saving = false;
            if (!r.ok) throw new Error('HTTP ' + r.status);
            lastSaved = text;
            marker.hidden = true;
            if (currentText() !== text) scheduleSave(); // typed while saving
        }).catch(function () {
            saving = false;
            marker.hidden = false;
            if (retryTimer) clearTimeout(retryTimer);
            retryTimer = setTimeout(save, RETRY_MS);
        });
    }

// Closing the tab mid-debounce would drop the last jot; sendBeacon
    // survives page teardown where fetch does not.
    window.addEventListener('pagehide', function () {
        var text = currentText();
        if (text === lastSaved || !navigator.sendBeacon) return;
        var body = new Blob(['content=' + encodeURIComponent(text)],
            { type: 'application/x-www-form-urlencoded' });
        navigator.sendBeacon(TODO_URL, body);
    });

// Mobile: dedicated todo FAB (above the tree FAB in the stacked group,
    // created only when todo.txt exists) opens the widget in the full-viewport
    // Overlay; dismissing the overlay flushes any pending save.
    function setupFab() {
        var fab = document.createElement('button');
        fab.type = 'button';
        fab.className = 'btn btn-fab fab fab-todo';
        fab.title = 'Todo';
        fab.setAttribute('aria-label', 'Todo');
        fab.innerHTML = '<svg viewBox="0 0 16 16" width="1em" height="1em" fill="none" stroke="currentColor" stroke-width="1.5" stroke-linejoin="miter"><path d="M2 2h12v12H2z"/><path d="M5 8.5l2 2L11 5.5"/></svg>';
        fab.addEventListener('click', function () {
            if (typeof openOverlay !== 'function') return;
            openOverlay(container, { onClose: saveNow });
            wantFocus = true;
            if (view) {
                // The editor may have mounted while the rail was display:none
                // (measured at zero size); re-measure now that it is visible.
                view.requestMeasure();
                view.focus();
            } else {
                upgrade(); // idle mount hasn't run yet — force it, focused
            }
        });
        document.body.appendChild(fab);
    }
})();