From 16d1145efdaecc411ab03fc09a015d285de232c2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lukas=20M=C3=BCllner?= <derkauzigekoala@gmail.com>
Date: Mon, 23 Feb 2026 08:53:04 +0100
Subject: [PATCH] fix: convert HomeScreen to StatefulWidget with mounted checks

Prevents Duplicate GlobalKeys / wrong build scope crashes when opening
dialogs from async scanner and DB operations. The scan button is also
disabled while a query is in flight to prevent double-taps.
---
 lib/main.dart | 40 +++++++++++++++++++++++-----------------
 1 file changed, 23 insertions(+), 17 deletions(-)

diff --git a/lib/main.dart b/lib/main.dart
index 76d3bea..2a28b2e 100644
--- a/lib/main.dart
+++ b/lib/main.dart
@@ -339,9 +339,16 @@ class _LoginScreenState extends State<LoginScreen> {
 }
 
 // ── Home Screen ───────────────────────────────────────────────────────
-class HomeScreen extends StatelessWidget {
+class HomeScreen extends StatefulWidget {
   const HomeScreen({super.key});
 
+  @override
+  State<HomeScreen> createState() => _HomeScreenState();
+}
+
+class _HomeScreenState extends State<HomeScreen> {
+  bool _isBusy = false;
+
   @override
   Widget build(BuildContext context) {
     final user = supabase.auth.currentUser;
@@ -379,18 +386,20 @@ class HomeScreen extends StatelessWidget {
       floatingActionButton: FloatingActionButton.extended(
         icon: const Icon(Icons.camera_alt),
         label: const Text('Scan'),
-        onPressed: () => _openScanner(context),
+        onPressed: _isBusy ? null : _openScanner,
       ),
     );
   }
 
   /// Opens the scanner, gets the hw_id, then queries the DB.
-  Future<void> _openScanner(BuildContext context) async {
+  Future<void> _openScanner() async {
     final hwId = await Navigator.of(context).push<String>(
       MaterialPageRoute(builder: (_) => const ScannerScreen()),
     );
 
-    if (hwId == null || !context.mounted) return;
+    if (hwId == null || !mounted) return;
+
+    setState(() => _isBusy = true);
 
     try {
       final data = await supabase
@@ -399,21 +408,18 @@ class HomeScreen extends StatelessWidget {
           .eq('hw_id', hwId)
           .maybeSingle();
 
-      if (!context.mounted) return;
+      if (!mounted) return;
+      setState(() => _isBusy = false);
 
-      if (data != null) {
-        showDialog<void>(
-          context: context,
-          builder: (_) => _AlreadyExistsDialog(hwId: hwId),
-        );
-      } else {
-        showDialog<void>(
-          context: context,
-          builder: (_) => _AddCarDialog(hwId: hwId),
-        );
-      }
+      await showDialog<void>(
+        context: context,
+        builder: (_) => data != null
+            ? _AlreadyExistsDialog(hwId: hwId)
+            : _AddCarDialog(hwId: hwId),
+      );
     } catch (e) {
-      if (!context.mounted) return;
+      if (!mounted) return;
+      setState(() => _isBusy = false);
       ScaffoldMessenger.of(context).showSnackBar(
         SnackBar(content: Text('DB error: $e'), backgroundColor: Colors.red),
       );