Rename server->core (#638)

packages/core/src/utils/getFolderStructure.ts

@@ -0,0 +1,325 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import * as fs from 'fs/promises';
+import { Dirent } from 'fs';
+import * as path from 'path';
+import { getErrorMessage, isNodeError } from './errors.js';
+
+const MAX_ITEMS = 200;
+const TRUNCATION_INDICATOR = '...';
+const DEFAULT_IGNORED_FOLDERS = new Set(['node_modules', '.git', 'dist']);
+
+// --- Interfaces ---
+
+/** Options for customizing folder structure retrieval. */
+interface FolderStructureOptions {
+  /** Maximum number of files and folders combined to display. Defaults to 200. */
+  maxItems?: number;
+  /** Set of folder names to ignore completely. Case-sensitive. */
+  ignoredFolders?: Set<string>;
+  /** Optional regex to filter included files by name. */
+  fileIncludePattern?: RegExp;
+}
+
+// Define a type for the merged options where fileIncludePattern remains optional
+type MergedFolderStructureOptions = Required<
+  Omit<FolderStructureOptions, 'fileIncludePattern'>
+> & {
+  fileIncludePattern?: RegExp;
+};
+
+/** Represents the full, unfiltered information about a folder and its contents. */
+interface FullFolderInfo {
+  name: string;
+  path: string;
+  files: string[];
+  subFolders: FullFolderInfo[];
+  totalChildren: number; // Number of files and subfolders included from this folder during BFS scan
+  totalFiles: number; // Number of files included from this folder during BFS scan
+  isIgnored?: boolean; // Flag to easily identify ignored folders later
+  hasMoreFiles?: boolean; // Indicates if files were truncated for this specific folder
+  hasMoreSubfolders?: boolean; // Indicates if subfolders were truncated for this specific folder
+}
+
+// --- Interfaces ---
+
+// --- Helper Functions ---
+
+async function readFullStructure(
+  rootPath: string,
+  options: MergedFolderStructureOptions,
+): Promise<FullFolderInfo | null> {
+  const rootName = path.basename(rootPath);
+  const rootNode: FullFolderInfo = {
+    name: rootName,
+    path: rootPath,
+    files: [],
+    subFolders: [],
+    totalChildren: 0,
+    totalFiles: 0,
+  };
+
+  const queue: Array<{ folderInfo: FullFolderInfo; currentPath: string }> = [
+    { folderInfo: rootNode, currentPath: rootPath },
+  ];
+  let currentItemCount = 0;
+  // Count the root node itself as one item if we are not just listing its content
+
+  const processedPaths = new Set<string>(); // To avoid processing same path if symlinks create loops
+
+  while (queue.length > 0) {
+    const { folderInfo, currentPath } = queue.shift()!;
+
+    if (processedPaths.has(currentPath)) {
+      continue;
+    }
+    processedPaths.add(currentPath);
+
+    if (currentItemCount >= options.maxItems) {
+      // If the root itself caused us to exceed, we can't really show anything.
+      // Otherwise, this folder won't be processed further.
+      // The parent that queued this would have set its own hasMoreSubfolders flag.
+      continue;
+    }
+
+    let entries: Dirent[];
+    try {
+      const rawEntries = await fs.readdir(currentPath, { withFileTypes: true });
+      // Sort entries alphabetically by name for consistent processing order
+      entries = rawEntries.sort((a, b) => a.name.localeCompare(b.name));
+    } catch (error: unknown) {
+      if (
+        isNodeError(error) &&
+        (error.code === 'EACCES' || error.code === 'ENOENT')
+      ) {
+        console.warn(
+          `Warning: Could not read directory ${currentPath}: ${error.message}`,
+        );
+        if (currentPath === rootPath && error.code === 'ENOENT') {
+          return null; // Root directory itself not found
+        }
+        // For other EACCES/ENOENT on subdirectories, just skip them.
+        continue;
+      }
+      throw error;
+    }
+
+    const filesInCurrentDir: string[] = [];
+    const subFoldersInCurrentDir: FullFolderInfo[] = [];
+
+    // Process files first in the current directory
+    for (const entry of entries) {
+      if (entry.isFile()) {
+        if (currentItemCount >= options.maxItems) {
+          folderInfo.hasMoreFiles = true;
+          break;
+        }
+        const fileName = entry.name;
+        if (
+          !options.fileIncludePattern ||
+          options.fileIncludePattern.test(fileName)
+        ) {
+          filesInCurrentDir.push(fileName);
+          currentItemCount++;
+          folderInfo.totalFiles++;
+          folderInfo.totalChildren++;
+        }
+      }
+    }
+    folderInfo.files = filesInCurrentDir;
+
+    // Then process directories and queue them
+    for (const entry of entries) {
+      if (entry.isDirectory()) {
+        // Check if adding this directory ITSELF would meet or exceed maxItems
+        // (currentItemCount refers to items *already* added before this one)
+        if (currentItemCount >= options.maxItems) {
+          folderInfo.hasMoreSubfolders = true;
+          break; // Already at limit, cannot add this folder or any more
+        }
+        // If adding THIS folder makes us hit the limit exactly, and it might have children,
+        // it's better to show '...' for the parent, unless this is the very last item slot.
+        // This logic is tricky. Let's try a simpler: if we can't add this item, mark and break.
+
+        const subFolderName = entry.name;
+        const subFolderPath = path.join(currentPath, subFolderName);
+
+        if (options.ignoredFolders.has(subFolderName)) {
+          const ignoredSubFolder: FullFolderInfo = {
+            name: subFolderName,
+            path: subFolderPath,
+            files: [],
+            subFolders: [],
+            totalChildren: 0,
+            totalFiles: 0,
+            isIgnored: true,
+          };
+          subFoldersInCurrentDir.push(ignoredSubFolder);
+          currentItemCount++; // Count the ignored folder itself
+          folderInfo.totalChildren++; // Also counts towards parent's children
+          continue;
+        }
+
+        const subFolderNode: FullFolderInfo = {
+          name: subFolderName,
+          path: subFolderPath,
+          files: [],
+          subFolders: [],
+          totalChildren: 0,
+          totalFiles: 0,
+        };
+        subFoldersInCurrentDir.push(subFolderNode);
+        currentItemCount++;
+        folderInfo.totalChildren++; // Counts towards parent's children
+
+        // Add to queue for processing its children later
+        queue.push({ folderInfo: subFolderNode, currentPath: subFolderPath });
+      }
+    }
+    folderInfo.subFolders = subFoldersInCurrentDir;
+  }
+
+  return rootNode;
+}
+
+/**
+ * Reads the directory structure using BFS, respecting maxItems.
+ * @param node The current node in the reduced structure.
+ * @param indent The current indentation string.
+ * @param isLast Sibling indicator.
+ * @param builder Array to build the string lines.
+ */
+function formatStructure(
+  node: FullFolderInfo,
+  currentIndent: string,
+  isLastChildOfParent: boolean,
+  isProcessingRootNode: boolean,
+  builder: string[],
+): void {
+  const connector = isLastChildOfParent ? '└───' : '├───';
+
+  // The root node of the structure (the one passed initially to getFolderStructure)
+  // is not printed with a connector line itself, only its name as a header.
+  // Its children are printed relative to that conceptual root.
+  // Ignored root nodes ARE printed with a connector.
+  if (!isProcessingRootNode || node.isIgnored) {
+    builder.push(
+      `${currentIndent}${connector}${node.name}/${node.isIgnored ? TRUNCATION_INDICATOR : ''}`,
+    );
+  }
+
+  // Determine the indent for the children of *this* node.
+  // If *this* node was the root of the whole structure, its children start with no indent before their connectors.
+  // Otherwise, children's indent extends from the current node's indent.
+  const indentForChildren = isProcessingRootNode
+    ? ''
+    : currentIndent + (isLastChildOfParent ? '    ' : '│   ');
+
+  // Render files of the current node
+  const fileCount = node.files.length;
+  for (let i = 0; i < fileCount; i++) {
+    const isLastFileAmongSiblings =
+      i === fileCount - 1 &&
+      node.subFolders.length === 0 &&
+      !node.hasMoreSubfolders;
+    const fileConnector = isLastFileAmongSiblings ? '└───' : '├───';
+    builder.push(`${indentForChildren}${fileConnector}${node.files[i]}`);
+  }
+  if (node.hasMoreFiles) {
+    const isLastIndicatorAmongSiblings =
+      node.subFolders.length === 0 && !node.hasMoreSubfolders;
+    const fileConnector = isLastIndicatorAmongSiblings ? '└───' : '├───';
+    builder.push(`${indentForChildren}${fileConnector}${TRUNCATION_INDICATOR}`);
+  }
+
+  // Render subfolders of the current node
+  const subFolderCount = node.subFolders.length;
+  for (let i = 0; i < subFolderCount; i++) {
+    const isLastSubfolderAmongSiblings =
+      i === subFolderCount - 1 && !node.hasMoreSubfolders;
+    // Children are never the root node being processed initially.
+    formatStructure(
+      node.subFolders[i],
+      indentForChildren,
+      isLastSubfolderAmongSiblings,
+      false,
+      builder,
+    );
+  }
+  if (node.hasMoreSubfolders) {
+    builder.push(`${indentForChildren}└───${TRUNCATION_INDICATOR}`);
+  }
+}
+
+// --- Main Exported Function ---
+
+/**
+ * Generates a string representation of a directory's structure,
+ * limiting the number of items displayed. Ignored folders are shown
+ * followed by '...' instead of their contents.
+ *
+ * @param directory The absolute or relative path to the directory.
+ * @param options Optional configuration settings.
+ * @returns A promise resolving to the formatted folder structure string.
+ */
+export async function getFolderStructure(
+  directory: string,
+  options?: FolderStructureOptions,
+): Promise<string> {
+  const resolvedPath = path.resolve(directory);
+  const mergedOptions: MergedFolderStructureOptions = {
+    maxItems: options?.maxItems ?? MAX_ITEMS,
+    ignoredFolders: options?.ignoredFolders ?? DEFAULT_IGNORED_FOLDERS,
+    fileIncludePattern: options?.fileIncludePattern,
+  };
+
+  try {
+    // 1. Read the structure using BFS, respecting maxItems
+    const structureRoot = await readFullStructure(resolvedPath, mergedOptions);
+
+    if (!structureRoot) {
+      return `Error: Could not read directory "${resolvedPath}". Check path and permissions.`;
+    }
+
+    // 2. Format the structure into a string
+    const structureLines: string[] = [];
+    // Pass true for isRoot for the initial call
+    formatStructure(structureRoot, '', true, true, structureLines);
+
+    // 3. Build the final output string
+    const displayPath = resolvedPath.replace(/\\/g, '/');
+
+    let disclaimer = '';
+    // Check if truncation occurred anywhere or if ignored folders are present.
+    // A simple check: if any node indicates more files/subfolders, or is ignored.
+    let truncationOccurred = false;
+    function checkForTruncation(node: FullFolderInfo) {
+      if (node.hasMoreFiles || node.hasMoreSubfolders || node.isIgnored) {
+        truncationOccurred = true;
+      }
+      if (!truncationOccurred) {
+        for (const sub of node.subFolders) {
+          checkForTruncation(sub);
+          if (truncationOccurred) break;
+        }
+      }
+    }
+    checkForTruncation(structureRoot);
+
+    if (truncationOccurred) {
+      disclaimer = `Folders or files indicated with ${TRUNCATION_INDICATOR} contain more items not shown, were ignored, or the display limit (${mergedOptions.maxItems} items) was reached.`;
+    }
+
+    const summary =
+      `Showing up to ${mergedOptions.maxItems} items (files + folders). ${disclaimer}`.trim();
+
+    return `${summary}\n\n${displayPath}/\n${structureLines.join('\n')}`;
+  } catch (error: unknown) {
+    console.error(`Error getting folder structure for ${resolvedPath}:`, error);
+    return `Error processing directory "${resolvedPath}": ${getErrorMessage(error)}`;
+  }
+}