Add accent colour picker, fix empty user card when accepting friend request, add button to transfer allocations

lib/components/pages/settings.dart

@@ -3,8 +3,10 @@ import 'dart:convert';
 import 'package:flutter/material.dart';
 import 'package:go_router/go_router.dart';
 import 'package:http/http.dart' as http;
+import 'package:mileograph_flutter/services/accent_color_service.dart';
 import 'package:mileograph_flutter/services/distance_unit_service.dart';
 import 'package:mileograph_flutter/services/endpoint_service.dart';
+import 'package:mileograph_flutter/services/theme_mode_service.dart';
 import 'package:mileograph_flutter/services/data_service.dart';
 import 'package:provider/provider.dart';
 
@@ -18,6 +20,18 @@ class SettingsPage extends StatefulWidget {
 class _SettingsPageState extends State<SettingsPage> {
   late final TextEditingController _endpointController;
   bool _saving = false;
+  static const List<Color> _accentPalette = [
+    Colors.red,
+    Colors.pink,
+    Colors.orange,
+    Colors.amber,
+    Colors.green,
+    Colors.teal,
+    Colors.blue,
+    Colors.indigo,
+    Colors.purple,
+    Colors.cyan,
+  ];
 
   @override
   void initState() {
@@ -130,7 +144,12 @@ class _SettingsPageState extends State<SettingsPage> {
   Widget build(BuildContext context) {
     final endpointService = context.watch<EndpointService>();
     final distanceUnitService = context.watch<DistanceUnitService>();
-    if (!endpointService.isLoaded || !distanceUnitService.isLoaded) {
+    final accentService = context.watch<AccentColorService>();
+    final themeModeService = context.watch<ThemeModeService>();
+    if (!endpointService.isLoaded ||
+        !distanceUnitService.isLoaded ||
+        !accentService.isLoaded ||
+        !themeModeService.isLoaded) {
       return const Scaffold(
         body: Center(child: CircularProgressIndicator()),
       );
@@ -184,6 +203,73 @@ class _SettingsPageState extends State<SettingsPage> {
               },
             ),
             const SizedBox(height: 24),
+            Text(
+              'Accent colour',
+              style: Theme.of(context).textTheme.titleMedium?.copyWith(
+                    fontWeight: FontWeight.w700,
+                  ),
+            ),
+            const SizedBox(height: 8),
+            Text(
+              'Choose your preferred accent colour or use system colours.',
+              style: Theme.of(context).textTheme.bodySmall,
+            ),
+            const SizedBox(height: 12),
+            Wrap(
+              spacing: 12,
+              runSpacing: 8,
+              crossAxisAlignment: WrapCrossAlignment.center,
+              children: [
+                OutlinedButton.icon(
+                  onPressed:
+                      accentService.useSystem ? null : () => accentService.setUseSystem(true),
+                  icon: const Icon(Icons.phone_android),
+                  label: const Text('Use system colours'),
+                ),
+                ..._accentPalette.map(
+                  (color) => _AccentSwatchButton(
+                    color: color,
+                    selected:
+                        !accentService.useSystem &&
+                            accentService.seedColor.toARGB32() == color.toARGB32(),
+                    onTap: () => accentService.setSeedColor(color),
+                  ),
+                ),
+              ],
+            ),
+            const SizedBox(height: 24),
+            Text(
+              'Theme mode',
+              style: Theme.of(context).textTheme.titleMedium?.copyWith(
+                    fontWeight: FontWeight.w700,
+                  ),
+            ),
+            const SizedBox(height: 8),
+            SegmentedButton<ThemeMode>(
+              segments: const [
+                ButtonSegment(
+                  value: ThemeMode.system,
+                  icon: Icon(Icons.settings_suggest),
+                  label: Text('System'),
+                ),
+                ButtonSegment(
+                  value: ThemeMode.light,
+                  icon: Icon(Icons.light_mode),
+                  label: Text('Light'),
+                ),
+                ButtonSegment(
+                  value: ThemeMode.dark,
+                  icon: Icon(Icons.dark_mode),
+                  label: Text('Dark'),
+                ),
+              ],
+              selected: {themeModeService.mode},
+              onSelectionChanged: (selection) {
+                final mode = selection.first;
+                themeModeService.setMode(mode);
+              },
+            ),
+            const SizedBox(height: 24),
             Text(
               'API endpoint',
               style: Theme.of(context).textTheme.titleMedium?.copyWith(
@@ -241,3 +327,54 @@ class _SettingsPageState extends State<SettingsPage> {
     );
   }
 }
+
+class _AccentSwatchButton extends StatelessWidget {
+  const _AccentSwatchButton({
+    required this.color,
+    required this.selected,
+    required this.onTap,
+  });
+
+  final Color color;
+  final bool selected;
+  final VoidCallback onTap;
+
+  @override
+  Widget build(BuildContext context) {
+    final borderColor = selected
+        ? Theme.of(context).colorScheme.onSurface
+        : Colors.black26;
+    return InkWell(
+      onTap: onTap,
+      customBorder: const CircleBorder(),
+      child: Container(
+        width: 40,
+        height: 40,
+        decoration: BoxDecoration(
+          color: color,
+          shape: BoxShape.circle,
+          border: Border.all(
+            color: borderColor,
+            width: selected ? 3 : 1,
+          ),
+          boxShadow: [
+            BoxShadow(
+              color: Colors.black.withValues(alpha: 0.15),
+              blurRadius: 4,
+              offset: const Offset(0, 2),
+            ),
+          ],
+        ),
+        child: selected
+            ? const Center(
+                child: Icon(
+                  Icons.check,
+                  size: 18,
+                  color: Colors.white,
+                ),
+              )
+            : null,
+      ),
+    );
+  }
+}