From edacf7ad1a3ecff481c5e174fabbf1f21ba157d8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lukas=20M=C3=BCllner?= <derkauzigekoala@gmail.com>
Date: Thu, 5 Mar 2026 14:45:00 +0100
Subject: [PATCH] perf(scanner): add adaptive cooldown backoff for repeated OCR
 misses

---
 lib/scanner_screen.dart | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/lib/scanner_screen.dart b/lib/scanner_screen.dart
index 00e9ad9..fe18aa3 100644
--- a/lib/scanner_screen.dart
+++ b/lib/scanner_screen.dart
@@ -37,6 +37,7 @@ class _ScannerScreenState extends State<ScannerScreen>
   static const _scanCooldownSuccess = Duration(milliseconds: 1500);
   static const _scanCooldownNoMatch = Duration(milliseconds: 2200);
   static const _scanCooldownError = Duration(milliseconds: 2600);
+  static const _scanCooldownNoMatchMax = Duration(milliseconds: 5000);
 
   CameraController? _cameraController;
   late final TextRecognizer _textRecognizer;
@@ -52,6 +53,7 @@ class _ScannerScreenState extends State<ScannerScreen>
   DateTime _nextScanAllowedAt = DateTime.fromMillisecondsSinceEpoch(0);
   bool _isInitializingCamera = false;
   String? _cameraError;
+  int _consecutiveMisses = 0;
 
   @override
   void initState() {
@@ -202,13 +204,23 @@ class _ScannerScreenState extends State<ScannerScreen>
       if (!mounted) return;
 
       if (found != null) {
+        _consecutiveMisses = 0;
         _nextScanAllowedAt = DateTime.now().add(_scanCooldownSuccess);
         setState(() => _lastDetected = found);
         if (widget.onDetected != null) {
           await _submitDetected(found);
         }
       } else {
-        _nextScanAllowedAt = DateTime.now().add(_scanCooldownNoMatch);
+        _consecutiveMisses += 1;
+        final missBackoffMs = (_scanCooldownNoMatch.inMilliseconds +
+                (_consecutiveMisses * 300))
+            .clamp(
+              _scanCooldownNoMatch.inMilliseconds,
+              _scanCooldownNoMatchMax.inMilliseconds,
+            );
+        _nextScanAllowedAt = DateTime.now().add(
+          Duration(milliseconds: missBackoffMs),
+        );
         setState(() {
           _scanAccepted = false;
           _scanNotFound = true;
@@ -216,6 +228,7 @@ class _ScannerScreenState extends State<ScannerScreen>
         });
       }
     } catch (e) {
+      _consecutiveMisses += 1;
       _nextScanAllowedAt = DateTime.now().add(_scanCooldownError);
       if (!mounted) return;
       logError('scanner.capture', e);