From 5901446094988aa5cd8e11efdaa131c3949106f1 Mon Sep 17 00:00:00 2001
From: David Brailovsky <davidbrai@gmail.com>
Date: Fri, 18 Sep 2026 12:47:20 +0200
Subject: [PATCH] fix(tui): reduce fuzzy search latency

Use native substring search to find successive fuzzy-match characters while preserving scoring and result ordering.

Closes #9267
---
 packages/tui/CHANGELOG.md |  4 ++++
 packages/tui/src/fuzzy.ts | 49 ++++++++++++++++++++-------------------
 2 files changed, 29 insertions(+), 24 deletions(-)

diff --git a/packages/tui/CHANGELOG.md b/packages/tui/CHANGELOG.md
index 7926e8d2f..5b129fb52 100644
--- a/packages/tui/CHANGELOG.md
+++ b/packages/tui/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Changed
+
+- Reduced fuzzy search latency for long texts by using native substring search instead of scanning each character in JavaScript ([#9267](https://github.com/earendil-works/pi/issues/9267)).
+
 ### Fixed
 
 - Fixed fullscreen clipboard failures hiding actionable backend error messages behind a generic notice, and extended failure notices to five seconds ([#9618](https://github.com/earendil-works/pi/issues/9618)).
diff --git a/packages/tui/src/fuzzy.ts b/packages/tui/src/fuzzy.ts
index 73c10dcf4..1b5352c1c 100644
--- a/packages/tui/src/fuzzy.ts
+++ b/packages/tui/src/fuzzy.ts
@@ -27,33 +27,34 @@ export function fuzzyMatch(query: string, text: string): FuzzyMatch {
 		let lastMatchIndex = -1;
 		let consecutiveMatches = 0;
 
-		for (let i = 0; i < textLower.length && queryIndex < normalizedQuery.length; i++) {
-			if (textLower[i] === normalizedQuery[queryIndex]) {
-				const isWordBoundary = i === 0 || /[\s\-_./:]/.test(textLower[i - 1]!);
+		while (queryIndex < normalizedQuery.length) {
+			const i = textLower.indexOf(normalizedQuery[queryIndex]!, lastMatchIndex + 1);
+			if (i === -1) break;
 
-				// Reward consecutive matches
-				if (lastMatchIndex === i - 1) {
-					consecutiveMatches++;
-					score -= consecutiveMatches * 5;
-				} else {
-					consecutiveMatches = 0;
-					// Penalize gaps
-					if (lastMatchIndex >= 0) {
-						score += (i - lastMatchIndex - 1) * 2;
-					}
+			const isWordBoundary = i === 0 || /[\s\-_./:]/.test(textLower[i - 1]!);
+
+			// Reward consecutive matches
+			if (lastMatchIndex === i - 1) {
+				consecutiveMatches++;
+				score -= consecutiveMatches * 5;
+			} else {
+				consecutiveMatches = 0;
+				// Penalize gaps
+				if (lastMatchIndex >= 0) {
+					score += (i - lastMatchIndex - 1) * 2;
 				}
-
-				// Reward word boundary matches
-				if (isWordBoundary) {
-					score -= 10;
-				}
-
-				// Slight penalty for later matches
-				score += i * 0.1;
-
-				lastMatchIndex = i;
-				queryIndex++;
 			}
+
+			// Reward word boundary matches
+			if (isWordBoundary) {
+				score -= 10;
+			}
+
+			// Slight penalty for later matches
+			score += i * 0.1;
+
+			lastMatchIndex = i;
+			queryIndex++;
 		}
 
 		if (queryIndex < normalizedQuery.length) {