frontend: folders

frontend/src/index.jsx

@@ -594,6 +594,7 @@ const AppLayout = () => {
   const selectionInitializedRef = useRef(false);
   const dragCounterRef = useRef(0);
   const prefetchedFoldersRef = useRef(new Set(['root']));
+  const detailFolderFetchRef = useRef(new Set());
   const selectionAnchorRef = useRef(initialRowSelection[initialRowSelection.length - 1] || null);
   const selectionOrderRef = useRef(initialRowSelection);
 
@@ -643,6 +644,7 @@ const AppLayout = () => {
     dragCounterRef.current = 0;
     prefetchedFoldersRef.current = new Set(['root']);
     breadcrumbFetchRef.current = new Set();
+    detailFolderFetchRef.current = new Set();
     bootstrapInitializedRef.current = false;
     selectionInitializedRef.current = false;
   }, [assetManager]);
@@ -1868,19 +1870,134 @@ const AppLayout = () => {
     greedyPrefetchFolders(pendingIds).catch(() => {});
   }, [folderContents, greedyPrefetchFolders]);
 
+  const expandFolderAncestors = useCallback(
+    (targetId) => {
+      if (!targetId || targetId === 'root') {
+        setFolderNodes((prev) => {
+          if (prev.get('root')?.expanded) {
+            return prev;
+          }
+          const next = new Map(prev);
+          const rootNode = next.get('root');
+          if (rootNode) {
+            next.set('root', { ...rootNode, expanded: true });
+          }
+          return next;
+        });
+        return;
+      }
+
+      setFolderNodes((prev) => {
+        const next = new Map(prev);
+        let currentId = targetId;
+        let guard = 0;
+        while (currentId && !next.has(currentId) && guard < 32) {
+          guard += 1;
+          const node = prev.get(currentId);
+          if (!node) {
+            break;
+          }
+          currentId = node.parentId ?? 'root';
+        }
+
+        currentId = targetId;
+        guard = 0;
+        while (currentId && guard < 32) {
+          guard += 1;
+          const node = next.get(currentId);
+          if (!node) {
+            break;
+          }
+          if (!node.expanded && currentId !== targetId) {
+            next.set(currentId, { ...node, expanded: true });
+          }
+          currentId = node.parentId ?? 'root';
+          if (!currentId || currentId === 'root') {
+            const rootNode = next.get('root');
+            if (rootNode && !rootNode.expanded) {
+              next.set('root', { ...rootNode, expanded: true });
+            }
+            break;
+          }
+        }
+        return next;
+      });
+    },
+    []);
+
+  const ensureFolderAncestorsLoaded = useCallback(
+    async (targetId) => {
+      if (!targetId || targetId === 'root') {
+        return;
+      }
+
+      const visited = new Set();
+      const stack = [];
+
+      let currentId = targetId;
+      let guard = 0;
+      while (currentId && currentId !== 'root' && guard < 32) {
+        guard += 1;
+        if (visited.has(currentId)) {
+          break;
+        }
+        visited.add(currentId);
+
+        const node = folderNodes.get(currentId);
+        if (!node) {
+          stack.push(currentId);
+          break;
+        }
+
+        const parentId = node.parentId ?? 'root';
+        if (!parentId || parentId === 'root') {
+          break;
+        }
+        stack.push(parentId);
+        currentId = parentId;
+      }
+
+      while (stack.length) {
+        const ancestorId = stack.pop();
+        if (!ancestorId || ancestorId === 'root') {
+          continue;
+        }
+        if (!folderNodes.has(ancestorId)) {
+          try {
+            await ensureFolderData(ancestorId, { includeDocuments: false, force: false });
+          } catch (error) {
+            console.warn('Failed to ensure ancestor folder for navigation', ancestorId, error);
+          }
+        }
+      }
+    },
+    [folderNodes, ensureFolderData],
+  );
+
   const selectFolder = useCallback(
     async (folderId, { replace = false, immediate = false } = {}) => {
       const targetId = folderId && folderId !== 'root' ? folderId : 'root';
 
+      await ensureFolderAncestorsLoaded(targetId);
+      expandFolderAncestors(targetId);
+
       if (!navigate || immediate) {
         await loadFolder(targetId, { preserveSearch: isFilterActive });
+        setSelectedFolder(targetId);
         return;
       }
 
       const path = targetId === 'root' ? '/documents' : `/documents/folder/${targetId}`;
       navigate(path, { replace });
     },
-    [loadFolder, navigate, isFilterActive],
+    [
+      ensureFolderAncestorsLoaded,
+      expandFolderAncestors,
+      navigate,
+      loadFolder,
+      isFilterActive,
+      setSelectedFolder,
+    ],
   );
 
   const initializeAfterLogin = useCallback(async () => {
@@ -4450,6 +4567,95 @@ const AppLayout = () => {
     });
   }, [missingBreadcrumbAncestors, ensureFolderData]);
 
+  useEffect(() => {
+    if (!orderedSelectedDocuments.length) {
+      return;
+    }
+
+    const visited = new Set();
+
+    orderedSelectedDocuments.forEach((doc) => {
+      const folderId = doc?.folder_id;
+      if (!folderId) {
+        return;
+      }
+      let currentId = folderId;
+      let guard = 0;
+      while (currentId && currentId !== 'root' && guard < 32) {
+        guard += 1;
+        if (visited.has(currentId)) {
+          break;
+        }
+        visited.add(currentId);
+        const node = folderNodes.get(currentId);
+        if (!node) {
+          if (!detailFolderFetchRef.current.has(currentId)) {
+            detailFolderFetchRef.current.add(currentId);
+            ensureFolderData(currentId, { force: false, includeDocuments: false })
+              .catch((error) => {
+                console.warn('Failed to preload folder metadata for detail path', currentId, error);
+              })
+              .finally(() => {
+                detailFolderFetchRef.current.delete(currentId);
+              });
+          }
+          break;
+        }
+
+        const parentId = node.parentId ?? 'root';
+        if (!parentId || parentId === 'root') {
+          break;
+        }
+        currentId = parentId;
+      }
+    });
+  }, [orderedSelectedDocuments, folderNodes, ensureFolderData]);
+
+  const resolveFolderPath = useCallback(
+    (folderId) => {
+      if (!folderId || folderId === 'root') {
+        return [];
+      }
+
+      const segments = [];
+      const visited = new Set();
+      let currentId = folderId;
+      let guard = 0;
+
+      while (currentId && guard < 32 && !visited.has(currentId)) {
+        guard += 1;
+        visited.add(currentId);
+
+        if (currentId === 'root') {
+          break;
+        }
+
+        const node = folderNodes.get(currentId);
+        if (!node) {
+          segments.push({ id: currentId, name: '…' });
+          break;
+        }
+
+        segments.push({ id: node.id, name: node.name || 'Folder' });
+
+        const parentId = node.parentId ?? 'root';
+        if (!parentId || parentId === 'root') {
+          segments.push({ id: 'root', name: DEFAULT_FOLDER_NAME });
+          break;
+        }
+
+        currentId = parentId;
+      }
+
+      if (!segments.some((segment) => segment.id === 'root')) {
+        segments.push({ id: 'root', name: DEFAULT_FOLDER_NAME });
+      }
+
+      return segments.reverse();
+    },
+    [folderNodes],
+  );
+
   const selectedPreviewEntry = useMemo(() => {
     if (!selectedDocument) {
       return null;
@@ -4598,7 +4804,9 @@ const AppLayout = () => {
     onCorrespondentAdd: handleCorrespondentAdd,
     onCorrespondentRemove: handleCorrespondentRemove,
     resolveApiPath,
+    onFolderNavigate: selectFolder,
     onClose: clearDocumentSelection,
+    resolveFolderPath,
   };
 
   const skeuoWorkspaceProps = useMemo(