From 4961c5df21260cb34e9a60a2244812cc1687680e Mon Sep 17 00:00:00 2001
From: Margarita Barvinok <brita@umich.edu>
Date: Thu, 19 Mar 2026 09:33:56 -0400
Subject: [PATCH] add patch for trix editor

---
 app/javascript/trixeditorpatch.js      | 294 +++++++++++++++++++++++++
 app/views/layouts/application.html.erb |   1 +
 2 files changed, 295 insertions(+)
 create mode 100644 app/javascript/trixeditorpatch.js

diff --git a/app/javascript/trixeditorpatch.js b/app/javascript/trixeditorpatch.js
new file mode 100644
index 00000000..596c8148
--- /dev/null
+++ b/app/javascript/trixeditorpatch.js
@@ -0,0 +1,294 @@
+/* Trix A11Y Patch v3 (WCAG 2.1 AA)
+   - Hit area fix (pseudo-elements can't steal clicks)
+   - Roving tabindex (Tab enters/leaves, Arrows move, Home/End jump)
+   - Robust keyboard activation (synth pointer+mouse+click)
+   - aria-pressed/aria-disabled sync; toolbar/dialog/editor semantics
+*/
+(function trixA11yV3(){
+  if (window.__trixA11yV3Applied) return;
+  window.__trixA11yV3Applied = true;
+
+  // ---------- Inject CSS ----------
+  const STYLE_ID = 'trix-a11y-v3-styles';
+  if (!document.getElementById(STYLE_ID)) {
+    const s = document.createElement('style');
+    s.id = STYLE_ID;
+    s.textContent = `
+      /* Make the actual <button> the hit target */
+      trix-toolbar .trix-button {
+        position: relative;
+        display: inline-flex;
+        align-items: center;
+        justify-content: center;
+        width: 2.25rem;
+        height: 2.25rem;
+        padding: 0;
+        cursor: pointer;
+        -webkit-user-select: none;
+        user-select: none;
+      }
+      /* Prevent pseudo/overlays from stealing clicks */
+      trix-toolbar .trix-button::before,
+      trix-toolbar .trix-button-group::before,
+      trix-toolbar .trix-button-group::after { pointer-events: none; }
+      trix-toolbar .trix-button,
+      trix-toolbar .trix-button * { pointer-events: auto; }
+
+      /* Visible focus (2.4.7) */
+      trix-toolbar .trix-button:focus,
+      trix-toolbar .trix-button--dialog:focus,
+      trix-editor:focus {
+        outline: 2px solid #005fcc;
+        outline-offset: 2px;
+      }
+
+      /* Visually hidden utility for polite status */
+      .visually-hidden-trix-a11y {
+        position: absolute !important;
+        width: 1px !important;
+        height: 1px !important;
+        padding: 0 !important;
+        margin: -1px !important;
+        overflow: hidden !important;
+        clip: rect(0 0 0 0) !important;
+        white-space: nowrap !important;
+        border: 0 !important;
+      }
+    `;
+    document.head.appendChild(s);
+  }
+
+  // ---------- Utilities ----------
+  function synthActivate(el){
+    // Dispatch the full sequence some toolbars expect
+    const bubbles = {bubbles:true, cancelable:true, composed:true};
+    const r = el.getBoundingClientRect();
+    const clientX = Math.max(0, r.left + r.width/2);
+    const clientY = Math.max(0, r.top + r.height/2);
+
+    el.dispatchEvent(new PointerEvent('pointerdown', {pointerId:1, pointerType:'mouse', clientX, clientY, ...bubbles}));
+    el.dispatchEvent(new MouseEvent('mousedown', {clientX, clientY, ...bubbles}));
+    el.dispatchEvent(new PointerEvent('pointerup',   {pointerId:1, pointerType:'mouse', clientX, clientY, ...bubbles}));
+    el.dispatchEvent(new MouseEvent('mouseup', {clientX, clientY, ...bubbles}));
+    el.dispatchEvent(new MouseEvent('click',   {clientX, clientY, ...bubbles}));
+  }
+
+  function isDisabled(btn){
+    return btn.hasAttribute('disabled') || btn.getAttribute('aria-disabled') === 'true';
+  }
+
+  function isVisibleAndEnabled(button) {
+    const style = window.getComputedStyle(button);
+    const notDisplayed = style.display === 'none' || style.visibility === 'hidden';
+    const isDisabled = button.disabled || button.getAttribute('aria-disabled') === 'true';
+    return !notDisplayed && !isDisabled;
+  }
+
+  function getButtons(toolbar){
+    // Only return visible and enabled buttons
+    return Array.from(toolbar.querySelectorAll('.trix-button, .trix-button--dialog, input.trix-button')).filter(isVisibleAndEnabled);
+  }
+
+  function firstEnabledIndex(buttons){
+    return buttons.findIndex(b => !isDisabled(b));
+  }
+  function lastEnabledIndex(buttons){
+    for (let i=buttons.length-1;i>=0;i--) if (!isDisabled(buttons[i])) return i;
+    return -1;
+  }
+  function nextEnabled(buttons, start, dir){
+    let i = start;
+    for (let n=0;n<buttons.length;n++){
+      i = (i + dir + buttons.length) % buttons.length;
+      if (!isDisabled(buttons[i])) return i;
+    }
+    return start;
+  }
+
+  // ---------- Toolbar Enhancement ----------
+  function enableRovingTabindex(toolbar){
+    const buttons = getButtons(toolbar);
+    if (!buttons.length) return;
+
+    // Make only the first enabled button tabbable
+    buttons.forEach(b => b.tabIndex = -1);
+    const firstIdx = Math.max(0, firstEnabledIndex(buttons));
+    if (firstIdx >= 0) buttons[firstIdx].tabIndex = 0;
+
+    // Keep roving model stable if DOM changes (buttons enable/disable)
+    const refresh = () => {
+      const bs = getButtons(toolbar);
+      // If currently focused button is in set, keep it tabbable; else set first enabled
+      const active = document.activeElement;
+      bs.forEach(b => b.tabIndex = -1);
+      let idx = bs.indexOf(active);
+      if (idx === -1) idx = firstEnabledIndex(bs);
+      if (idx >= 0) bs[idx].tabIndex = 0;
+    };
+
+    const rovingKeydown = (e) => {
+      const bs = getButtons(toolbar);
+      if (!bs.length) return;
+      const current = bs.indexOf(document.activeElement);
+      if (current === -1) return;
+
+      let targetIndex = null;
+      switch (e.key) {
+        case 'ArrowRight':
+          e.preventDefault();
+          targetIndex = nextEnabled(bs, current, +1);
+          break;
+        case 'ArrowLeft':
+          e.preventDefault();
+          targetIndex = nextEnabled(bs, current, -1);
+          break;
+        case 'Home':
+          e.preventDefault();
+          targetIndex = firstEnabledIndex(bs);
+          break;
+        case 'End':
+          e.preventDefault();
+          targetIndex = lastEnabledIndex(bs);
+          break;
+      }
+      if (targetIndex !== null && targetIndex >= 0) {
+        bs.forEach(b => b.tabIndex = -1);
+        bs[targetIndex].tabIndex = 0;
+        bs[targetIndex].focus();
+      }
+    };
+
+    toolbar.addEventListener('keydown', rovingKeydown);
+    new MutationObserver(refresh).observe(toolbar, {subtree:true, childList:true, attributes:true, attributeFilter:['disabled','class']});
+  }
+
+  function enhanceToolbar(toolbar){
+    if (!toolbar || toolbar.__trixA11yDone) return;
+    toolbar.__trixA11yDone = true;
+
+    toolbar.setAttribute('role','toolbar');
+    if (!toolbar.hasAttribute('aria-label')) {
+      toolbar.setAttribute('aria-label','Rich text formatting');
+    }
+
+    const buttons = getButtons(toolbar);
+
+    // Ensure buttons are focusable and keyboard-activatable
+    buttons.forEach(btn => {
+      btn.setAttribute('role','button');
+
+      // Sync disabled → aria-disabled
+      const syncDisabled = () => {
+        if (btn.hasAttribute('disabled')) btn.setAttribute('aria-disabled','true');
+        else btn.removeAttribute('aria-disabled');
+      };
+      syncDisabled();
+      new MutationObserver(syncDisabled).observe(btn, {attributes:true, attributeFilter:['disabled']});
+
+      // aria-pressed for toggles
+      const setPressedFor = () => {
+        if (btn.hasAttribute('data-trix-attribute')) {
+          btn.setAttribute('aria-pressed', btn.classList.contains('trix-active') ? 'true' : 'false');
+        }
+      };
+      setPressedFor();
+      new MutationObserver((muts) => {
+        muts.forEach(m => { if (m.attributeName === 'class') setPressedFor(); });
+      }).observe(btn, {attributes:true, attributeFilter:['class']});
+
+      // Robust keyboard activation (Enter on keydown; Space on keyup)
+      btn.addEventListener('keydown', e => {
+        if (isDisabled(btn)) return;
+        if (e.key === 'Enter') {
+          e.preventDefault(); e.stopPropagation();
+          synthActivate(btn);
+        } else if (e.key === ' ') {
+          e.preventDefault(); e.stopPropagation(); // prevent scroll
+        }
+      });
+      btn.addEventListener('keyup', e => {
+        if (isDisabled(btn)) return;
+        if (e.key === ' ') {
+          e.preventDefault(); e.stopPropagation();
+          synthActivate(btn);
+        }
+      });
+    });
+
+    // Link dialog semantics (if present)
+    const linkDialog = toolbar.querySelector('[data-trix-dialog="href"]');
+    if (linkDialog) {
+      linkDialog.setAttribute('role','dialog');
+      linkDialog.setAttribute('aria-modal','true');
+      const urlInput = linkDialog.querySelector('input.trix-input--dialog');
+      if (urlInput) {
+        if (!urlInput.id) urlInput.id = 'trix-url-' + Math.random().toString(36).slice(2);
+        linkDialog.setAttribute('aria-labelledby', urlInput.id);
+      }
+    }
+
+    // Roving tabindex last (after individual wiring)
+    enableRovingTabindex(toolbar);
+  }
+
+  // ---------- Editor Enhancement ----------
+  function enhanceEditor(editor){
+    if (!editor || editor.__trixA11yDone) return;
+    editor.__trixA11yDone = true;
+
+    // Ensure textbox semantics
+    editor.setAttribute('role','textbox'); // Trix usually sets this
+    editor.setAttribute('aria-multiline','true');
+
+    // Prefer aria-labelledby (use nearby H1 if present), else aria-label
+    if (!editor.hasAttribute('aria-labelledby') && !editor.hasAttribute('aria-label')) {
+      const heading = document.querySelector('h1, h2, [data-editor-label]');
+      if (heading) {
+        if (!heading.id) heading.id = 'trix-editor-label-' + Math.random().toString(36).slice(2);
+        editor.setAttribute('aria-labelledby', heading.id);
+      } else {
+        editor.setAttribute('aria-label','Rich text editor');
+      }
+    }
+
+    // Live region for subtle announcements
+    let status = document.getElementById('trix-a11y-status');
+    if (!status) {
+      status = document.createElement('div');
+      status.id = 'trix-a11y-status';
+      status.className = 'visually-hidden-trix-a11y';
+      status.setAttribute('role','status');
+      status.setAttribute('aria-live','polite');
+      document.body.appendChild(status);
+    }
+    const announce = (msg) => { status.textContent = msg; };
+    editor.addEventListener('trix-undo', () => announce('Undo'));
+    editor.addEventListener('trix-redo', () => announce('Redo'));
+    // Uncomment if you want content-change announcements:
+    // editor.addEventListener('trix-change', () => announce('Content updated'));
+
+    // Enhance referenced toolbar
+    const toolbarId = editor.getAttribute('toolbar');
+    if (toolbarId) {
+      const tb = document.getElementById(toolbarId);
+      if (tb) enhanceToolbar(tb);
+    }
+  }
+
+  // ---------- Apply to existing + future instances ----------
+  document.querySelectorAll('trix-toolbar').forEach(enhanceToolbar);
+  document.querySelectorAll('trix-editor').forEach(enhanceEditor);
+
+  const rootObserver = new MutationObserver((muts) => {
+    muts.forEach(m => {
+      m.addedNodes && m.addedNodes.forEach(node => {
+        if (!(node instanceof HTMLElement)) return;
+        if (node.matches?.('trix-toolbar')) enhanceToolbar(node);
+        if (node.matches?.('trix-editor')) enhanceEditor(node);
+        node.querySelectorAll?.('trix-toolbar').forEach(enhanceToolbar);
+        node.querySelectorAll?.('trix-editor').forEach(enhanceEditor);
+      });
+    });
+  });
+  rootObserver.observe(document.documentElement, { childList:true, subtree:true });
+})();
diff --git a/app/views/layouts/application.html.erb b/app/views/layouts/application.html.erb
index 377ea23d..64dbf310 100644
--- a/app/views/layouts/application.html.erb
+++ b/app/views/layouts/application.html.erb
@@ -9,6 +9,7 @@
     <%= stylesheet_link_tag "application", "data-turbo-track": "reload" %>
     <%= stylesheet_link_tag "actiontext", "data-turbo-track": "reload" %>
     <%= javascript_include_tag "application", "data-turbo-track": "reload", type: "module" %>
+    <%= javascript_include_tag 'trixeditorpatch', async: true %>
 
     <noscript>
       <meta http-equiv="refresh" content="2;url=/nojavascript.html">