Stabilize tracker bar placement above Facebook action row

extension/content.js

@@ -368,6 +368,82 @@ function countActionRoleSignals(node) {
   return [hasLike, hasComment, hasShare].filter(Boolean).length;
 }
 
+function hasCommentSortSignal(node) {
+  if (!node || !node.querySelector) {
+    return false;
+  }
+
+  return Boolean(
+    node.querySelector(
+      '[aria-label*="relevantes zuerst" i], [aria-label*="most relevant" i], [aria-label*="neueste" i], [aria-label*="newest" i]'
+    )
+  );
+}
+
+function isActionRowShapeCandidate(postElement, candidate) {
+  if (!postElement || !candidate || !candidate.isConnected || !postElement.contains(candidate)) {
+    return false;
+  }
+
+  if (candidate.closest('.fb-tracker-ui')) {
+    return false;
+  }
+
+  if (
+    hasCommentComposerSignal(candidate)
+    || hasCommentContentSignal(candidate)
+    || hasCommentSortSignal(candidate)
+  ) {
+    return false;
+  }
+
+  const buttonCount = candidate.querySelectorAll('[role="button"], button').length;
+  if (buttonCount < 3 || buttonCount > 24) {
+    return false;
+  }
+
+  return true;
+}
+
+function isCompactActionBarCandidate(postElement, candidate) {
+  if (!isActionRowShapeCandidate(postElement, candidate)) {
+    return false;
+  }
+
+  const actionRoleSignals = countActionRoleSignals(candidate);
+  if (actionRoleSignals >= 2) {
+    return true;
+  }
+
+  return hasInteractionButtons(candidate);
+}
+
+function normalizeActionBarCandidate(postElement, candidate) {
+  if (!postElement || !candidate || !candidate.isConnected || !postElement.contains(candidate)) {
+    return null;
+  }
+
+  let fallback = null;
+  let current = candidate;
+  for (let depth = 0; depth < 12 && current && current !== postElement; depth++) {
+    if (isCompactActionBarCandidate(postElement, current)) {
+      return current;
+    }
+
+    if (!fallback && isActionRowShapeCandidate(postElement, current)) {
+      fallback = current;
+    }
+
+    current = current.parentElement;
+  }
+
+  if (fallback) {
+    return fallback;
+  }
+
+  return isReliableActionBarCandidate(postElement, candidate) ? candidate : null;
+}
+
 function isReliableActionBarCandidate(postElement, candidate) {
   if (!postElement || !candidate || !candidate.isConnected || !postElement.contains(candidate)) {
     return false;
@@ -377,7 +453,11 @@ function isReliableActionBarCandidate(postElement, candidate) {
     return false;
   }
 
-  if (hasCommentComposerSignal(candidate)) {
+  if (
+    hasCommentComposerSignal(candidate)
+    || hasCommentContentSignal(candidate)
+    || hasCommentSortSignal(candidate)
+  ) {
     return false;
   }
 
@@ -436,18 +516,20 @@ function resolveActionButtonBar(postElement, buttonBar) {
     return null;
   }
 
-  const dataRoleResolved = findActionBarByDataRoles(postElement);
-  if (dataRoleResolved) {
-    return dataRoleResolved;
-  }
+  const candidates = [
+    findActionBarByDataRoles(postElement),
+    buttonBar,
+    findButtonBar(postElement)
+  ];
 
-  if (buttonBar && isReliableActionBarCandidate(postElement, buttonBar)) {
-    return buttonBar;
-  }
-
-  const resolved = findButtonBar(postElement);
-  if (resolved && isReliableActionBarCandidate(postElement, resolved)) {
-    return resolved;
+  for (const candidate of candidates) {
+    if (!candidate) {
+      continue;
+    }
+    const normalized = normalizeActionBarCandidate(postElement, candidate);
+    if (normalized) {
+      return normalized;
+    }
   }
 
   return null;
@@ -661,6 +743,28 @@ function insertMarkerAfterAnchor(postElement, marker, anchor) {
   return true;
 }
 
+function getNextNonTrackerSibling(node) {
+  if (!node) {
+    return null;
+  }
+
+  let current = node.nextElementSibling;
+  while (current) {
+    if (
+      !current.classList
+      || (
+        !current.classList.contains('fb-tracker-ui')
+        && !current.classList.contains('fb-tracker-insertion-anchor')
+      )
+    ) {
+      return current;
+    }
+    current = current.nextElementSibling;
+  }
+
+  return null;
+}
+
 function positionTrackerInsertionMarker(postElement, marker, buttonBar, postNum = '?') {
   if (!postElement || !marker) {
     return false;
@@ -668,7 +772,6 @@ function positionTrackerInsertionMarker(postElement, marker, buttonBar, postNum
 
   const resolvedButtonBar = resolveActionButtonBar(postElement, buttonBar);
   const actionAnchor = getDirectActionAnchorInPost(postElement, resolvedButtonBar);
-  const commentBoundary = findCommentBoundaryAnchorInPost(postElement, actionAnchor);
 
   if (actionAnchor && insertMarkerBeforeAnchor(postElement, marker, actionAnchor)) {
     setTrackerInsertionMarkerLocked(marker, true);
@@ -682,28 +785,13 @@ function positionTrackerInsertionMarker(postElement, marker, buttonBar, postNum
     return true;
   }
 
-  const commentComposerAnchor = findCommentComposerAnchorInPost(postElement);
-  if (commentComposerAnchor && insertMarkerBeforeAnchor(postElement, marker, commentComposerAnchor)) {
-    setTrackerInsertionMarkerLocked(marker, true);
-    console.log('[FB Tracker] Post #' + postNum + ' - Marker inserted before comment composer');
-    return true;
+  if (postElement.firstChild) {
+    postElement.insertBefore(marker, postElement.firstChild);
+  } else {
+    postElement.appendChild(marker);
   }
-
-  if (commentBoundary && insertMarkerBeforeAnchor(postElement, marker, commentBoundary)) {
-    setTrackerInsertionMarkerLocked(marker, true);
-    console.log('[FB Tracker] Post #' + postNum + ' - Marker inserted before comment boundary');
-    return true;
-  }
-
-  if (buttonBar && buttonBar.parentElement && buttonBar.parentElement.parentElement && !postElement.contains(buttonBar.parentElement.parentElement)) {
-    buttonBar.parentElement.parentElement.insertBefore(marker, buttonBar.parentElement.nextSibling);
-    setTrackerInsertionMarkerLocked(marker, false);
-    return true;
-  }
-
-  postElement.appendChild(marker);
   setTrackerInsertionMarkerLocked(marker, false);
-  console.log('[FB Tracker] Post #' + postNum + ' - Marker fallback appended to post');
+  console.log('[FB Tracker] Post #' + postNum + ' - Marker fallback prepended to post');
   return true;
 }
 
@@ -717,8 +805,21 @@ function isTrackerInsertionMarkerPlacementValid(postElement, marker, buttonBar)
   }
 
   const actionAnchor = getDirectActionAnchorInPost(postElement, buttonBar);
-  if (actionAnchor && isNodeAfter(marker, actionAnchor)) {
-    return false;
+  if (actionAnchor) {
+    if (isNodeAfter(marker, actionAnchor)) {
+      return false;
+    }
+
+    if (actionAnchor.contains(marker) || marker.contains(actionAnchor)) {
+      return false;
+    }
+
+    if (marker.parentElement === actionAnchor.parentElement) {
+      const nextSibling = getNextNonTrackerSibling(marker);
+      if (nextSibling && nextSibling !== actionAnchor) {
+        return false;
+      }
+    }
   }
 
   const commentBoundary = findCommentBoundaryAnchorInPost(postElement);