move notes to separate page

.vscode/launch.json

@@ -6,20 +6,23 @@
     "configurations": [
         {
             "name": "infusion_timer (debug mode)",
+            "program": "lib/main.dart",
             "request": "launch",
             "type": "dart",
             "flutterMode": "debug",
             "args": ["--flavor", "ci"]
         },
         {
             "name": "infusion_timer (profile mode)",
+            "program": "lib/main.dart",
             "request": "launch",
             "type": "dart",
             "flutterMode": "profile",
             "args": ["--flavor", "ci"]
         },
         {
             "name": "infusion_timer (release mode)",
+            "program": "lib/main.dart",
             "request": "launch",
             "type": "dart",
             "flutterMode": "release",

lib/widgets/notes_page.dart

@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+import 'dart:async';
+
+import 'package:infusion_timer/persistence_service.dart';
+import 'package:flutter/material.dart';
+import 'package:infusion_timer/tea.dart';
+
+class NotesPage extends StatefulWidget {
+  final Tea tea;
+
+  const NotesPage({Key? key, required this.tea}) : super(key: key);
+
+  @override
+  NotesPageState createState() => NotesPageState();
+}
+
+class NotesPageState extends State<NotesPage> {
+  final _formKey = GlobalKey<FormState>();
+  bool _hasUnsavedChanges = false;
+  Future<void> _onPopInvoked(bool didPop) async {
+    // confirm cancelling infusion if going back to collection page
+    if (didPop) {
+      return;
+    }
+    final int? action = await showDialog<int>(
+      context: context,
+      builder: (context) {
+        return AlertDialog(
+          title: const Text('Save unsaved changes?'),
+          content: const Text('You have unsaved changes.'),
+          actions: [
+            TextButton(
+              onPressed: () {
+                Navigator.pop(context, 0);
+              },
+              child: const Text('Save and Close'),
+            ),
+            TextButton(
+              onPressed: () => Navigator.pop(context, 1),
+              child: const Text('Discard and Close'),
+            ),
+            TextButton(
+              onPressed: () => Navigator.pop(context, 2),
+              child: const Text('Cancel'),
+            ),
+          ],
+        );
+      },
+    );
+    switch (action) {
+      case 0:
+        _formKey.currentState!.save();
+        PersistenceService.updateTea(widget.tea);
+        if (context.mounted) {
+          Navigator.pop(context);
+        }
+        break;
+      case 1:
+        if (context.mounted) {
+          Navigator.pop(context);
+        }
+        break;
+      case 2:
+        // nothing to do
+        break;
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return PopScope(
+      canPop: !_hasUnsavedChanges,
+      onPopInvoked: _onPopInvoked,
+      child: Scaffold(
+        appBar: AppBar(
+          title: const Text("Notes"),
+        ),
+        body: Form(
+          key: _formKey,
+          child: Column(
+            children: [
+              Expanded(
+                child: Card(
+                  child: Column(
+                    children: [
+                      ListTile(
+                        title: Center(child: Text(widget.tea.name!)),
+                      ),
+                      Expanded(
+                        child: TextFormField(
+                          minLines: 15,
+                          initialValue: widget.tea.detailedNotes,
+                          maxLines: null,
+                          // using collapsed to hide black line on the bottom
+                          decoration: const InputDecoration.collapsed(
+                            hintText: 'Enter your notes here',
+                          ),
+                          onChanged: (value) {
+                            setState(() => _hasUnsavedChanges = true);
+                          },
+                          onSaved: (value) {
+                            widget.tea.detailedNotes = value;
+                          },
+                        ),
+                      ),
+                      const SizedBox(height: 10),
+                      FilledButton(
+                        onPressed: () {
+                          _formKey.currentState!.save();
+                          PersistenceService.updateTea(widget.tea);
+                          Navigator.pop(context);
+                        },
+                        child: const Text(
+                          'Save and Close',
+                          style: TextStyle(fontWeight: FontWeight.bold),
+                        ),
+                      ),
+                    ],
+                  ),
+                ),
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+}