Implement scrolling through previous notes

lib/main.dart

@@ -6,6 +6,7 @@ import 'package:journaler/notes.dart';
 import 'package:system_tray/system_tray.dart';
 import 'package:window_manager/window_manager.dart';
 import 'package:audioplayers/audioplayers.dart';
+import 'package:flutter/gestures.dart';
 
 // TODO: Add an icon to the executable, simply use the existing tray icon
 // TODO: Implement some sort of scroll through notes
@@ -137,9 +138,13 @@ class MainPageState extends State<MainPage> with WindowListener {
   final TextEditingController _soundController = TextEditingController();
 
   Note? previousNote;
+  Note? _currentlyDisplayedNote;
   Duration _currentPopupInterval = _defaultPopupInterval;
   String _currentNotificationSound = _defaultNotificationSound;
 
+  bool _canGoPrevious = false;
+  bool _canGoNext = false;
+
   Timer? _popupTimer;
   Timer? _debounceTimer;
 
@@ -237,6 +242,50 @@ class MainPageState extends State<MainPage> with WindowListener {
     }
   }
 
+  Future<void> _checkNavigation() async {
+    if (_currentlyDisplayedNote == null) {
+      setState(() {
+        _canGoPrevious = false;
+        _canGoNext = false;
+      });
+      return;
+    }
+
+    final prev = await getPreviousNote(_currentlyDisplayedNote!.date);
+    final bool isLatest = _currentlyDisplayedNote!.date == previousNote?.date;
+
+    setState(() {
+      _canGoPrevious = prev != null;
+      _canGoNext = !isLatest;
+    });
+  }
+
+  Future<void> _goToPreviousNote() async {
+    if (!_canGoPrevious || _currentlyDisplayedNote == null) return;
+
+    final prevNote = await getPreviousNote(_currentlyDisplayedNote!.date);
+    if (prevNote != null) {
+      setState(() {
+        _currentlyDisplayedNote = prevNote;
+        _previousEntryController.text = prevNote.content;
+      });
+      await _checkNavigation();
+    }
+  }
+
+  Future<void> _goToNextNote() async {
+    if (!_canGoNext || _currentlyDisplayedNote == null) return;
+
+    final nextNote = await getNextNote(_currentlyDisplayedNote!.date);
+    if (nextNote != null) {
+      setState(() {
+        _currentlyDisplayedNote = nextNote;
+        _previousEntryController.text = nextNote.content;
+      });
+      await _checkNavigation();
+    }
+  }
+
   void _loadData() async {
     String? intervalMinutesStr = await DB.getSetting('popupIntervalMinutes');
     String? soundFileStr = await DB.getSetting('notificationSound');
@@ -252,12 +301,15 @@ class MainPageState extends State<MainPage> with WindowListener {
 
     final note = await getLatestNote();
     previousNote = note;
-    _previousEntryController.text = note?.content ?? "";
+    _currentlyDisplayedNote = note;
+    _previousEntryController.text = _currentlyDisplayedNote?.content ?? "";
 
     final scratch = await getLatestScratch();
     _scratchController.text = scratch?.content ?? "";
     _currentEntryController.text = "";
 
+    await _checkNavigation();
+
     debugPrint("Data loaded.");
   }
 
@@ -391,17 +443,63 @@ class MainPageState extends State<MainPage> with WindowListener {
             children: [
               Expanded(
                 flex: 9,
+                child: Listener(
+                  behavior: HitTestBehavior.opaque,
+                  onPointerSignal: (pointerSignal) {
+                    if (pointerSignal is PointerScrollEvent) {
+                      if (pointerSignal.scrollDelta.dy < 0) {
+                        if (_canGoPrevious) {
+                          _goToPreviousNote();
+                        }
+                      } else if (pointerSignal.scrollDelta.dy > 0) {
+                        if (_canGoNext) {
+                          _goToNextNote();
+                        }
+                      }
+                    }
+                  },
                   child: Column(
                     crossAxisAlignment: CrossAxisAlignment.stretch,
                     children: [
+                      // Combine Label, Buttons, and TextField for Previous Entry
+                      Row(
+                        children: [
+                          Expanded(
+                            child: Text(
+                              _currentlyDisplayedNote?.date == previousNote?.date
+                                  ? 'Previous Entry (Latest)'
+                                  : 'Entry: ${_currentlyDisplayedNote?.date ?? 'N/A'}',
+                              style: TextStyle(fontSize: 18, color: Colors.grey),
+                            ),
+                          ),
+                          IconButton(
+                            icon: const Icon(Icons.arrow_back),
+                            tooltip: 'Previous Note',
+                            onPressed: _canGoPrevious ? _goToPreviousNote : null,
+                          ),
+                          IconButton(
+                            icon: const Icon(Icons.arrow_forward),
+                            tooltip: 'Next Note',
+                            onPressed: _canGoNext ? _goToNextNote : null,
+                          ),
+                        ],
+                      ),
                       Expanded(
                         child: TextField(
                           controller: _previousEntryController,
+                          readOnly: _currentlyDisplayedNote?.date != previousNote?.date,
                           maxLines: null,
                           expands: true,
                           style: Theme.of(context).textTheme.bodyMedium,
-                        decoration: const InputDecoration(
-                          labelText: 'Previous Entry',
+                          decoration: InputDecoration(
+                            hintText: _currentlyDisplayedNote?.date != previousNote?.date
+                                ? 'Viewing note from ${_currentlyDisplayedNote?.date} (Read-Only)'
+                                : 'Latest Note',
+                            border: const OutlineInputBorder(),
+                            filled: _currentlyDisplayedNote?.date != previousNote?.date,
+                            fillColor: _currentlyDisplayedNote?.date != previousNote?.date
+                                ? Colors.grey.withOpacity(0.1)
+                                : null,
                           ),
                         ),
                       ),
@@ -422,6 +520,7 @@ class MainPageState extends State<MainPage> with WindowListener {
                     ],
                   ),
                 ),
+              ),
               const SizedBox(width: 8),
               Expanded(
                 flex: 4, // Adjust flex factor as needed

lib/notes.dart

@@ -61,3 +61,42 @@ Future<Scratch?> getLatestScratch() async {
 Future<void> createScratch(String content) async {
   await DB.db.insert('scratches', {'content': content});
 }
+
+// Get the note immediately older than the given date
+Future<Note?> getPreviousNote(String currentDate) async {
+  final List<Map<String, dynamic>> notes = await DB.db.query(
+    'notes',
+    where: 'date < ?',
+    whereArgs: [currentDate],
+    orderBy: 'date DESC',
+    limit: 1,
+  );
+  if (notes.isNotEmpty) {
+    return Note(
+      date: notes.first['date'] as String,
+      content: notes.first['content'] as String,
+    );
+  }
+  return null;
+}
+
+// Get the note immediately newer than the given date
+Future<Note?> getNextNote(String currentDate) async {
+  final List<Map<String, dynamic>> notes = await DB.db.query(
+    'notes',
+    where: 'date > ?',
+    whereArgs: [currentDate],
+    orderBy: 'date ASC',
+    limit: 1,
+  );
+  if (notes.isNotEmpty) {
+    return Note(
+      date: notes.first['date'] as String,
+      content: notes.first['content'] as String,
+    );
+  }
+  // If there's no newer note, it means we might be at the latest
+  // but let's double-check by explicitly getting the latest again.
+  // This handles the case where the `currentDate` might not be the absolute latest.
+  return getLatestNote();
+}