feat: Improve @-command file path completion with fzf integration (#5650)

Co-authored-by: Jacob Richman <jacob314@gmail.com>

packages/core/package.json

@@ -35,6 +35,7 @@
     "diff": "^7.0.0",
     "dotenv": "^17.1.0",
     "fdir": "^6.4.6",
+    "fzf": "^0.5.2",
     "glob": "^10.4.5",
     "google-auth-library": "^9.11.0",
     "html-to-text": "^9.0.5",

packages/core/src/utils/filesearch/fileSearch.test.ts

@@ -290,6 +290,30 @@ describe('FileSearch', () => {
     expect(results).toEqual(['src/file1.js', 'src/file2.js']); // Assuming alphabetical sort
   });
 
+  it('should use fzf for fuzzy matching when pattern does not contain wildcards', async () => {
+    tmpDir = await createTmpDir({
+      src: {
+        'main.js': '',
+        'util.ts': '',
+        'style.css': '',
+      },
+    });
+
+    const fileSearch = new FileSearch({
+      projectRoot: tmpDir,
+      useGitignore: false,
+      useGeminiignore: false,
+      ignoreDirs: [],
+      cache: false,
+      cacheTtl: 0,
+    });
+
+    await fileSearch.initialize();
+    const results = await fileSearch.search('sst');
+
+    expect(results).toEqual(['src/style.css']);
+  });
+
   it('should return empty array when no matches are found', async () => {
     tmpDir = await createTmpDir({
       src: ['file1.js'],

packages/core/src/utils/filesearch/fileSearch.ts

@@ -11,6 +11,7 @@ import picomatch from 'picomatch';
 import { Ignore } from './ignore.js';
 import { ResultCache } from './result-cache.js';
 import * as cache from './crawlCache.js';
+import { Fzf, FzfResultItem } from 'fzf';
 
 export type FileSearchOptions = {
   projectRoot: string;
@@ -77,6 +78,18 @@ export async function filter(
   return results;
 }
 
+/**
+ * Filters a list of paths based on a given pattern using fzf.
+ * @param allPaths The list of all paths to filter.
+ * @param pattern The fzf pattern to filter by.
+ * @returns The filtered and sorted list of paths.
+ */
+function filterByFzf(allPaths: string[], pattern: string) {
+  return new Fzf(allPaths)
+    .find(pattern)
+    .map((entry: FzfResultItem) => entry.item);
+}
+
 export type SearchOptions = {
   signal?: AbortSignal;
   maxResults?: number;
@@ -137,7 +150,9 @@ export class FileSearch {
       filteredCandidates = candidates;
     } else {
       // Apply the user's picomatch pattern filter
-      filteredCandidates = await filter(candidates, pattern, options.signal);
+      filteredCandidates = pattern.includes('*')
+        ? await filter(candidates, pattern, options.signal)
+        : filterByFzf(this.allFiles, pattern);
       this.resultCache!.set(pattern, filteredCandidates);
     }