Make tracker anchoring self-healing against comment lazy-load

extension/content.js

@@ -309,6 +309,13 @@ function getTrackerInsertionAnchorInPost(postElement, buttonBar) {
   return anchor && anchor.parentElement === postElement ? anchor : null;
 }
 
+function isNodeAfter(node, referenceNode) {
+  if (!node || !referenceNode || node === referenceNode) {
+    return false;
+  }
+  return Boolean(node.compareDocumentPosition(referenceNode) & Node.DOCUMENT_POSITION_PRECEDING);
+}
+
 function hasCommentComposerSignal(node) {
   if (!node || !node.querySelector) {
     return false;
@@ -321,6 +328,34 @@ function hasCommentComposerSignal(node) {
   );
 }
 
+function findCommentComposerAnchorInPost(postElement) {
+  if (!postElement) {
+    return null;
+  }
+
+  const composerCandidates = Array.from(
+    postElement.querySelectorAll(
+      'div[role="textbox"][contenteditable="true"], [role="textbox"][aria-label*="komment" i], [role="textbox"][aria-label*="comment" i], [role="textbox"][aria-placeholder*="komment" i], [role="textbox"][aria-placeholder*="comment" i]'
+    )
+  );
+
+  for (const composer of composerCandidates) {
+    if (!composer || composer.closest('.fb-tracker-ui')) {
+      continue;
+    }
+
+    const composerRoot = composer.closest('form[role="presentation"]')
+      || composer.closest('form')
+      || composer;
+    const topLevelAnchor = getTopLevelAnchorWithinPost(postElement, composerRoot) || composerRoot;
+    if (topLevelAnchor && topLevelAnchor.parentElement && postElement.contains(topLevelAnchor)) {
+      return topLevelAnchor;
+    }
+  }
+
+  return null;
+}
+
 function countActionRoleSignals(node) {
   if (!node || !node.querySelector) {
     return 0;
@@ -364,13 +399,28 @@ function findActionBarByDataRoles(postElement) {
     return null;
   }
 
+  const commentBoundary = findCommentComposerAnchorInPost(postElement)
+    || findCommentSortAnchorInPost(postElement);
   const markers = Array.from(postElement.querySelectorAll(
     '[data-ad-rendering-role="like_button"], [data-ad-rendering-role*="gefällt" i], [data-ad-rendering-role="comment_button"], [data-ad-rendering-role="share_button"]'
   ));
 
   for (const marker of markers) {
+    if (
+      marker.closest('[aria-roledescription*="comment" i], [aria-roledescription*="kommentar" i], [data-testid*="comment" i], [data-scope="comment"]')
+    ) {
+      continue;
+    }
+    if (commentBoundary && isNodeAfter(marker, commentBoundary)) {
+      continue;
+    }
+
     let current = marker;
     for (let depth = 0; depth < 8 && current && current !== postElement; depth++) {
+      if (commentBoundary && isNodeAfter(current, commentBoundary)) {
+        current = current.parentElement;
+        continue;
+      }
       if (isReliableActionBarCandidate(postElement, current)) {
         return current;
       }
@@ -528,6 +578,21 @@ function findCommentSortAnchorInPost(postElement) {
   return null;
 }
 
+function findCommentBoundaryAnchorInPost(postElement, actionAnchor = null) {
+  if (!postElement) {
+    return null;
+  }
+
+  const adjacentSortAnchor = actionAnchor
+    ? findAdjacentCommentSortAnchor(postElement, actionAnchor)
+    : null;
+  if (adjacentSortAnchor) {
+    return adjacentSortAnchor;
+  }
+
+  return findCommentSortAnchorInPost(postElement) || findCommentComposerAnchorInPost(postElement);
+}
+
 function createTrackerInsertionMarker() {
   const marker = document.createElement('div');
   marker.className = 'fb-tracker-insertion-anchor';
@@ -552,10 +617,16 @@ function positionTrackerInsertionMarker(postElement, marker, buttonBar, postNum
 
   const resolvedButtonBar = resolveActionButtonBar(postElement, buttonBar);
   const actionAnchor = getDirectActionAnchorInPost(postElement, resolvedButtonBar);
-  const preferredAnchor = actionAnchor;
+  const commentBoundary = findCommentBoundaryAnchorInPost(postElement, actionAnchor);
 
-  if (preferredAnchor && preferredAnchor.parentElement) {
+  if (actionAnchor && commentBoundary && commentBoundary.parentElement && isNodeAfter(commentBoundary, actionAnchor)) {
-    preferredAnchor.parentElement.insertBefore(marker, preferredAnchor.nextSibling);
+    commentBoundary.parentElement.insertBefore(marker, commentBoundary);
+    setTrackerInsertionMarkerLocked(marker, true);
+    return true;
+  }
+
+  if (actionAnchor && actionAnchor.parentElement) {
+    actionAnchor.parentElement.insertBefore(marker, actionAnchor.nextSibling);
     setTrackerInsertionMarkerLocked(marker, true);
     return true;
   }
@@ -572,11 +643,10 @@ function positionTrackerInsertionMarker(postElement, marker, buttonBar, postNum
     return true;
   }
 
-  const fallbackSortAnchor = findCommentSortAnchorInPost(postElement);
+  if (commentBoundary && commentBoundary.parentElement) {
-  if (fallbackSortAnchor && fallbackSortAnchor.parentElement) {
+    commentBoundary.parentElement.insertBefore(marker, commentBoundary);
-    fallbackSortAnchor.parentElement.insertBefore(marker, fallbackSortAnchor);
     setTrackerInsertionMarkerLocked(marker, true);
-    console.log('[FB Tracker] Post #' + postNum + ' - Marker fallback inserted before comment sort');
+    console.log('[FB Tracker] Post #' + postNum + ' - Marker fallback inserted before comment boundary');
     return true;
   }
 
@@ -586,6 +656,25 @@ function positionTrackerInsertionMarker(postElement, marker, buttonBar, postNum
   return true;
 }
 
+function isTrackerInsertionMarkerPlacementValid(postElement, marker, buttonBar) {
+  if (!postElement || !marker || !marker.isConnected || !postElement.contains(marker)) {
+    return false;
+  }
+
+  const actionAnchor = getDirectActionAnchorInPost(postElement, buttonBar);
+  const commentBoundary = findCommentBoundaryAnchorInPost(postElement, actionAnchor);
+
+  if (actionAnchor && isNodeAfter(actionAnchor, marker)) {
+    return false;
+  }
+
+  if (commentBoundary && isNodeAfter(marker, commentBoundary)) {
+    return false;
+  }
+
+  return true;
+}
+
 function ensureTrackerInsertionMarker(postElement, buttonBar, postNum = '?') {
   if (!postElement) {
     return null;
@@ -607,9 +696,20 @@ function ensureTrackerInsertionMarker(postElement, buttonBar, postNum = '?') {
   }
 
   if (marker.isConnected && postElement.contains(marker) && isTrackerInsertionMarkerLocked(marker)) {
+    if (!isTrackerInsertionMarkerPlacementValid(postElement, marker, buttonBar)) {
+      setTrackerInsertionMarkerLocked(marker, false);
+    } else {
       setTrackerAnchorForPost(postElement, marker);
       return marker;
     }
+  }
+
+  if (marker.isConnected && postElement.contains(marker) && !isTrackerInsertionMarkerLocked(marker)) {
+    if (isTrackerInsertionMarkerPlacementValid(postElement, marker, buttonBar)) {
+      setTrackerAnchorForPost(postElement, marker);
+      return marker;
+    }
+  }
 
   const positioned = positionTrackerInsertionMarker(postElement, marker, buttonBar, postNum);
   if (!positioned || !marker.isConnected) {
@@ -630,6 +730,19 @@ function insertTrackerAtMarker(marker, trackerElement) {
   return true;
 }
 
+function realignExistingTrackerUI(postElement, buttonBar, trackerElement, postNum = '?') {
+  if (!postElement || !trackerElement || !trackerElement.isConnected) {
+    return false;
+  }
+
+  const marker = ensureTrackerInsertionMarker(postElement, buttonBar, postNum);
+  if (!marker) {
+    return false;
+  }
+
+  return insertTrackerAtMarker(marker, trackerElement);
+}
+
 const AI_CREDENTIAL_CACHE_TTL = 60 * 1000; // 1 minute cache
 const aiCredentialCache = {
   data: null,
@@ -3492,10 +3605,7 @@ async function createTrackerUI(postElement, buttonBar, postNum = '?', options =
   }
 
   if (existingUI) {
-    const marker = ensureTrackerInsertionMarker(postElement, buttonBar, postNum);
+    realignExistingTrackerUI(postElement, buttonBar, existingUI, postNum);
-    if (marker) {
-      insertTrackerAtMarker(marker, existingUI);
-    }
     console.log('[FB Tracker] Post #' + postNum + ' - UI already exists on normalized element');
     postElement.setAttribute(PROCESSED_ATTR, '1');
     return;
@@ -3531,10 +3641,7 @@ async function createTrackerUI(postElement, buttonBar, postNum = '?', options =
         postElement.setAttribute(PROCESSED_ATTR, '1');
         return;
       }
-      const marker = ensureTrackerInsertionMarker(postElement, buttonBar, postNum);
+      realignExistingTrackerUI(postElement, buttonBar, scopedTracker, postNum);
-      if (marker) {
-        insertTrackerAtMarker(marker, scopedTracker);
-      }
       console.log('[FB Tracker] Post #' + postNum + ' - Reusing existing tracker UI in same scope');
       setTrackerElementForPost(postElement, scopedTracker);
       postElement.setAttribute(PROCESSED_ATTR, '1');
@@ -4386,6 +4493,7 @@ function findPosts() {
 
     if (isInDialog) {
       if (trackerInSameDialog) {
+        realignExistingTrackerUI(container, precomputedButtonBar || null, existingTracker, 'existing');
         seenSet.add(container);
         continue;
       }
@@ -4400,6 +4508,12 @@ function findPosts() {
       }
     } else {
       if (alreadyProcessed || (existingTracker && existingTracker.isConnected)) {
+        if (existingTracker && existingTracker.isConnected) {
+          realignExistingTrackerUI(container, precomputedButtonBar || null, existingTracker, 'existing');
+          setTrackerElementForPost(container, existingTracker);
+        } else if (alreadyProcessed) {
+          container.removeAttribute(PROCESSED_ATTR);
+        }
         seenSet.add(container);
         continue;
       }