A whole bunch of changes

lib/screens/edit_fuel_entry_screen.dart

@@ -0,0 +1,186 @@
+import 'package:flutter/material.dart';
+import 'package:intl/intl.dart';
+import 'package:provider/provider.dart';
+
+import '../models/fuel_entry.dart';
+import '../services/app_state.dart';
+import '../widgets/receipt_thumbnail.dart';
+
+/// Lets the user correct the *data* logged about a receipt (date, gallons,
+/// price/gal, total cost) — not the receipt photo itself, which is shown
+/// read-only up top (tap it to view full-screen, same as everywhere else
+/// it's shown) and can't be replaced from here.
+class EditFuelEntryScreen extends StatefulWidget {
+  final FuelEntry entry;
+
+  const EditFuelEntryScreen({super.key, required this.entry});
+
+  @override
+  State<EditFuelEntryScreen> createState() => _EditFuelEntryScreenState();
+}
+
+class _EditFuelEntryScreenState extends State<EditFuelEntryScreen> {
+  final _formKey = GlobalKey<FormState>();
+  late final TextEditingController _gallonsController;
+  late final TextEditingController _priceController;
+  late final TextEditingController _totalController;
+  late DateTime _date;
+  bool _saving = false;
+
+  @override
+  void initState() {
+    super.initState();
+    _date = widget.entry.date;
+    _gallonsController = TextEditingController(text: widget.entry.gallons.toStringAsFixed(3));
+    _priceController = TextEditingController(text: widget.entry.pricePerGallon.toStringAsFixed(3));
+    _totalController = TextEditingController(text: widget.entry.totalCost.toStringAsFixed(2));
+  }
+
+  @override
+  void dispose() {
+    _gallonsController.dispose();
+    _priceController.dispose();
+    _totalController.dispose();
+    super.dispose();
+  }
+
+  void _calculateTotal() {
+    final gallons = double.tryParse(_gallonsController.text);
+    final price = double.tryParse(_priceController.text);
+    if (gallons != null && price != null) {
+      setState(() {
+        _totalController.text = (gallons * price).toStringAsFixed(2);
+      });
+    }
+  }
+
+  Future<void> _pickDate() async {
+    // initialDate must fall within [firstDate, lastDate] or the picker
+    // throws — widen the bounds to cover _date in case it's already
+    // outside the normal 5-years-back-to-today window.
+    final today = DateTime.now();
+    final firstDate = _date.isBefore(today.subtract(const Duration(days: 365 * 5)))
+        ? _date
+        : today.subtract(const Duration(days: 365 * 5));
+    final lastDate = _date.isAfter(today) ? _date : today;
+
+    final pickedDate = await showDatePicker(
+      context: context,
+      initialDate: _date,
+      firstDate: firstDate,
+      lastDate: lastDate,
+    );
+    if (pickedDate == null || !mounted) return;
+
+    final pickedTime = await showTimePicker(
+      context: context,
+      initialTime: TimeOfDay.fromDateTime(_date),
+    );
+    if (pickedTime == null) return;
+
+    setState(() {
+      _date = DateTime(
+        pickedDate.year,
+        pickedDate.month,
+        pickedDate.day,
+        pickedTime.hour,
+        pickedTime.minute,
+      );
+    });
+  }
+
+  Future<void> _save() async {
+    if (!_formKey.currentState!.validate()) return;
+
+    setState(() => _saving = true);
+    try {
+      await context.read<AppState>().updateFuelEntry(
+            entryId: widget.entry.id,
+            date: _date,
+            gallons: double.parse(_gallonsController.text),
+            pricePerGallon: double.parse(_priceController.text),
+            totalCost: double.parse(_totalController.text),
+          );
+      if (mounted) Navigator.of(context).pop();
+    } finally {
+      if (mounted) setState(() => _saving = false);
+    }
+  }
+
+  String? _requiredDecimal(String? value) {
+    if (value == null || value.trim().isEmpty) return 'Required';
+    if (double.tryParse(value) == null) return 'Enter a valid number';
+    return null;
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final dateFormat = DateFormat.yMMMd().add_jm();
+
+    return Scaffold(
+      appBar: AppBar(title: const Text('Edit Fuel Entry')),
+      body: Form(
+        key: _formKey,
+        child: ListView(
+          padding: const EdgeInsets.all(16),
+          children: [
+            Center(
+              child: ReceiptThumbnail(entry: widget.entry, size: 180),
+            ),
+            const SizedBox(height: 8),
+            Text(
+              'Tap the photo to view it full-screen. The photo itself can\'t '
+              "be changed here — only the data below can.",
+              style: Theme.of(context).textTheme.bodySmall,
+              textAlign: TextAlign.center,
+            ),
+            const SizedBox(height: 16),
+            ListTile(
+              contentPadding: EdgeInsets.zero,
+              title: const Text('Date & time'),
+              subtitle: Text(dateFormat.format(_date)),
+              trailing: const Icon(Icons.edit_calendar_outlined),
+              onTap: _pickDate,
+            ),
+            const SizedBox(height: 8),
+            TextFormField(
+              controller: _gallonsController,
+              decoration: const InputDecoration(labelText: 'Gallons', suffixText: 'gal'),
+              keyboardType: const TextInputType.numberWithOptions(decimal: true),
+              validator: _requiredDecimal,
+            ),
+            const SizedBox(height: 12),
+            TextFormField(
+              controller: _priceController,
+              decoration: const InputDecoration(labelText: 'Price per gallon', prefixText: '\$'),
+              keyboardType: const TextInputType.numberWithOptions(decimal: true),
+              validator: _requiredDecimal,
+            ),
+            const SizedBox(height: 12),
+            TextFormField(
+              controller: _totalController,
+              decoration: InputDecoration(
+                labelText: 'Total cost',
+                prefixText: '\$',
+                suffixIcon: IconButton(
+                  icon: const Icon(Icons.calculate_outlined),
+                  tooltip: 'Calculate from gallons × price',
+                  onPressed: _calculateTotal,
+                ),
+              ),
+              keyboardType: const TextInputType.numberWithOptions(decimal: true),
+              validator: _requiredDecimal,
+            ),
+            const SizedBox(height: 24),
+            FilledButton(
+              onPressed: _saving ? null : _save,
+              child: _saving
+                  ? const SizedBox(height: 20, width: 20, child: CircularProgressIndicator(strokeWidth: 2))
+                  : const Text('Save Changes'),
+            ),
+          ],
+        ),
+      ),
+    );
+  }
+}