Improve same-window folder drops

server/public/app.js

@@ -727,6 +727,7 @@ function startItemPointerDrag(event, win, entry) {
     sourceWindowId: win.id,
     path: entry.path,
     name: entry.name,
+    type: entry.type,
     startX: event.clientX,
     startY: event.clientY,
     active: false,
@@ -756,6 +757,7 @@ function updateItemPointerDrag(event) {
   event.preventDefault();
   document.body.classList.add('u-nav-dragging');
   markDraggingRow(drag.path, true);
+  markDropCandidates(drag.path, true);
   updatePointerDropTarget(event);
 }
 
@@ -769,6 +771,7 @@ async function finishItemPointerDrag(event, move, up) {
   if (!drag) return;
 
   markDraggingRow(drag.path, false);
+  markDropCandidates(drag.path, false);
   state.pointerDrag = null;
 
   if (!drag.active) {
@@ -794,6 +797,9 @@ async function finishItemPointerDrag(event, move, up) {
     if (destination === drag.path) {
       throw new Error('Quelle und Ziel sind identisch.');
     }
+    if (drag.type === 'directory' && target.path.startsWith(`${drag.path.replace(/\/$/, '')}/`)) {
+      throw new Error('Ein Ordner kann nicht in sich selbst verschoben werden.');
+    }
     await createJob(event.altKey ? 'copy' : 'move', drag.path, destination, [drag.sourceWindowId, target.windowId]);
   } catch (error) {
     showError(error);
@@ -825,8 +831,10 @@ function clearPointerDropTarget() {
 
 function findPointerDropTarget(event) {
   let element;
+  let elements = [];
   try {
     element = document.elementFromPoint(event.clientX, event.clientY);
+    elements = document.elementsFromPoint ? document.elementsFromPoint(event.clientX, event.clientY) : [element];
   } catch (error) {
     recordDebug('elementFromPoint.error', {
       x: event.clientX,
@@ -847,13 +855,30 @@ function findPointerDropTarget(event) {
   const win = state.windows.find((item) => item.id === windowEl.dataset.windowId);
   if (!win || win.kind !== 'explorer') return null;
 
-  let row;
-  try {
-    row = element.closest?.('.file-row');
-  } catch (error) {
-    recordDebug('closest.row.error', { error: serializeError(error), element: element?.tagName });
+  const drag = state.pointerDrag;
+  let row = null;
+  for (const candidate of elements) {
+    try {
+      const candidateRow = candidate.closest?.('.file-row');
+      if (!candidateRow || candidateRow.dataset.type !== 'directory') {
+        continue;
+      }
+      if (candidateRow.dataset.path === drag?.path) {
+        continue;
+      }
+      if (drag?.type === 'directory' && candidateRow.dataset.path.startsWith(`${drag.path.replace(/\/$/, '')}/`)) {
+        continue;
+      }
+      if (candidateRow.closest?.('.window') !== windowEl) {
+        continue;
+      }
+      row = candidateRow;
+      break;
+    } catch (error) {
+      recordDebug('closest.row.error', { error: serializeError(error), element: candidate?.tagName });
+    }
   }
-  if (row?.dataset.type === 'directory') {
+  if (row) {
     return { windowId: win.id, path: row.dataset.path, row };
   }
 
@@ -868,6 +893,15 @@ function markDraggingRow(path, dragging) {
   }
 }
 
+function markDropCandidates(sourcePath, active) {
+  const source = state.pointerDrag;
+  for (const row of workspace.querySelectorAll('.file-row[data-type="directory"]')) {
+    const path = row.dataset.path || '';
+    const valid = path !== sourcePath && !(source?.type === 'directory' && path.startsWith(`${sourcePath.replace(/\/$/, '')}/`));
+    row.classList.toggle('drop-candidate', active && valid);
+  }
+}
+
 function lockExplorerScroll(win, body) {
   win.data.lockScroll = true;
   win.data.lockScrollTop = body.scrollTop;