Add saving to and reading from a file

To make sure when our timer runs it runs

lib/main.dart

@@ -1,6 +1,8 @@
 import 'package:flutter/material.dart';
 import 'dart:async';
 import 'package:flutter/services.dart';
+import 'dart:io';
+import 'dart:convert';
 
 void main() {
   runApp(const MyApp());
@@ -28,6 +30,25 @@ class MyHomePage extends StatefulWidget {
   State<MyHomePage> createState() => _MyHomePageState();
 }
 
+class TimerEvent {
+  final String type; // "start", "pause", "lap", "stop"
+  final DateTime timestamp;
+
+  TimerEvent(this.type, this.timestamp);
+
+  Map<String, dynamic> toJson() => {
+    'type': type,
+    'timestamp': timestamp.toIso8601String(),
+  };
+
+  factory TimerEvent.fromJson(Map<String, dynamic> json) {
+    return TimerEvent(
+      json['type'] as String,
+      DateTime.parse(json['timestamp'] as String),
+    );
+  }
+}
+
 class _MyHomePageState extends State<MyHomePage> {
   Timer? _timer;
   DateTime? _startTime;
@@ -36,6 +57,154 @@ class _MyHomePageState extends State<MyHomePage> {
   bool _isRunning = false;
   List<String> _laps = [];
   final FocusNode _focusNode = FocusNode();
+  List<TimerEvent> _events = [];
+
+  @override
+  void initState() {
+    super.initState();
+    _focusNode.requestFocus();
+    _loadTimerData();
+  }
+
+  // Simple file operations using app's temporary directory
+  Future<File> get _timerFile async {
+    final directory = Directory.systemTemp.path;
+    return File('$directory/timer_data.json');
+  }
+
+  Future<void> _saveTimerData() async {
+    try {
+      final file = await _timerFile;
+      final data = {
+        'events': _events.map((e) => e.toJson()).toList(),
+        'laps': _laps,
+      };
+      await file.writeAsString(jsonEncode(data));
+    } catch (e) {
+      // Handle error silently for simplicity
+      print('Failed to save timer data: $e');
+    }
+  }
+
+  Future<void> _loadTimerData() async {
+    try {
+      final file = await _timerFile;
+      if (await file.exists()) {
+        final jsonData = await file.readAsString();
+        final data = jsonDecode(jsonData) as Map<String, dynamic>;
+        
+        // Load events
+        _events = (data['events'] as List)
+            .map((e) => TimerEvent.fromJson(e as Map<String, dynamic>))
+            .toList();
+        
+        // Load laps
+        _laps = (data['laps'] as List).cast<String>();
+        
+        // Reconstruct timer state from events
+        _reconstructTimerState();
+      }
+    } catch (e) {
+      // Handle error silently for simplicity
+      print('Failed to load timer data: $e');
+    }
+    }
+
+  void _reconstructTimerState() {
+    if (_events.isEmpty) return;
+    
+    // Find the most recent event sequence
+    DateTime? lastStartTime;
+    DateTime? lastPauseTime;
+    Duration totalPausedTime = Duration.zero;
+    Duration accumulatedRunningTime = Duration.zero;
+    bool wasRunning = false;
+    
+    // Process events chronologically to determine the current state
+    for (int i = 0; i < _events.length; i++) {
+      final event = _events[i];
+      
+      switch (event.type) {
+        case 'start':
+          if (lastStartTime == null) {
+            // New start
+            lastStartTime = event.timestamp;
+            wasRunning = true;
+          } else if (lastPauseTime != null) {
+            // Resume after pause - add the pause duration to totalPausedTime
+            totalPausedTime += event.timestamp.difference(lastPauseTime);
+            lastPauseTime = null;
+            wasRunning = true;
+          }
+          break;
+          
+        case 'pause':
+          if (lastStartTime != null && lastPauseTime == null) {
+            // Pause an active timer
+            lastPauseTime = event.timestamp;
+            accumulatedRunningTime += lastPauseTime.difference(lastStartTime);
+            wasRunning = false;
+          }
+          break;
+          
+        case 'stop':
+          // Reset everything
+          lastStartTime = null;
+          lastPauseTime = null;
+          totalPausedTime = Duration.zero;
+          accumulatedRunningTime = Duration.zero;
+          wasRunning = false;
+          break;
+      }
+    }
+    
+    // Determine timer state based on most recent events
+    if (lastStartTime != null) {
+      if (wasRunning) {
+        // Timer was running when app was closed
+        // Calculate elapsed time: current time - start time - total paused time
+        final now = DateTime.now();
+        _elapsedTime = now.difference(lastStartTime) - totalPausedTime;
+        _startTime = lastStartTime;
+        _pauseTime = null;
+        _isRunning = true;
+        
+        // Start the timer without resetting anything
+        _resumeTimerFromSavedState();
+      } else {
+        // Timer was paused
+        _startTime = lastStartTime;
+        _pauseTime = lastPauseTime;
+        _elapsedTime = accumulatedRunningTime;
+        _isRunning = false;
+      }
+    }
+  }
+
+  // Resume the timer from a saved state without resetting anything
+  void _resumeTimerFromSavedState() {
+    // Safety check
+    if (_startTime == null) return;
+    
+    _timer = Timer.periodic(const Duration(milliseconds: 16), (timer) {
+      setState(() {
+        // When restoring, we need the total elapsed time since the original start
+        // This accounts for any pauses that happened before
+        final now = DateTime.now();
+        _elapsedTime = now.difference(_startTime!);
+      });
+    });
+    
+    setState(() {
+      _isRunning = true;
+    });
+  }
+
+  void _addEvent(String type) {
+    final event = TimerEvent(type, DateTime.now());
+    _events.add(event);
+    _saveTimerData();
+  }
 
   void _startTimer() {
     final now = DateTime.now();
@@ -44,11 +213,14 @@ class _MyHomePageState extends State<MyHomePage> {
       final pausedDuration = now.difference(_pauseTime!);
       _startTime = _startTime?.add(pausedDuration);
       _pauseTime = null;
+      _addEvent('start');
     } else {
       // Starting fresh
       _startTime = now;
       _elapsedTime = Duration.zero;
       _laps = [];
+      _events = []; // Clear previous events
+      _addEvent('start');
     }
     
     _timer = Timer.periodic(const Duration(milliseconds: 16), (timer) {
@@ -65,6 +237,7 @@ class _MyHomePageState extends State<MyHomePage> {
   void _pauseTimer() {
     _timer?.cancel();
     _pauseTime = DateTime.now();
+    _addEvent('pause');
     setState(() {
       _isRunning = false;
     });
@@ -72,51 +245,64 @@ class _MyHomePageState extends State<MyHomePage> {
 
   void _stopTimer() {
     _timer?.cancel();
+    _addEvent('stop');
     setState(() {
       _isRunning = false;
       _startTime = null;
       _pauseTime = null;
       _elapsedTime = Duration.zero;
     });
+    _saveTimerData();
   }
 
   void _recordLap() {
     if (_isRunning) {
       final now = DateTime.now();
+      _addEvent('lap');
       setState(() {
         // Store both timestamp and formatted duration for this lap
-        _laps.add('${now.toIso8601String()} - ${_formatDuration(_elapsedTime)}');
+        _laps.add('${now.toIso8601String()} - ${_formatDurationForLap(_elapsedTime)}');
       });
+      _saveTimerData();
     }
   }
 
   String _formatDuration(Duration duration) {
-    // Format the duration as ISO 8601 duration format without 0 values
+    // Format as ISO 8601 duration without unnecessary zeros
     final hours = duration.inHours;
     final minutes = duration.inMinutes.remainder(60);
     final seconds = duration.inSeconds.remainder(60);
+    final milliseconds = duration.inMilliseconds.remainder(1000);
     
-    // Round milliseconds to nearest 100ms for more consistent display
+    // Round milliseconds to tenths of a second
-    // This helps avoid floating point inconsistencies (0.201, 0.301, etc.)
+    final tenthsOfSecond = (milliseconds / 100).round();
-    final milliseconds = ((duration.inMilliseconds % 1000) / 100).round() * 100;
-    final formattedMs = (milliseconds ~/ 100).toString();
     
-    // Start with PT prefix
+    // Build ISO 8601 format without unnecessary zeros
-    String result = 'PT';
+    StringBuffer buffer = StringBuffer();
     
-    // Only add parts that are non-zero (except if everything is zero, then show 0S)
+    // Add hours only if non-zero
     if (hours > 0) {
-      result += '${hours}H';
+      buffer.write('${hours}H');
     }
     
-    if (minutes > 0 || hours > 0) {
+    // Add minutes only if hours exist or minutes non-zero
-      result += '${minutes}M';
+    if (minutes > 0) {
+      buffer.write('${minutes}M');
     }
     
-    // Always include seconds with a single decimal place (tenth of a second)
+    // Always include seconds
-    result += '${seconds}.${formattedMs}S';
+    buffer.write('${seconds}');
+    if (tenthsOfSecond > 0) {
+      buffer.write('.${tenthsOfSecond}');
+    }
+    buffer.write('S');
     
-    return result;
+    return buffer.toString();
+  }
+
+  // For lap recording
+  String _formatDurationForLap(Duration duration) {
+    return _formatDuration(duration);
   }
 
   void _handleKeyEvent(RawKeyEvent event) {
@@ -139,12 +325,6 @@ class _MyHomePageState extends State<MyHomePage> {
     }
   }
 
-  @override
-  void initState() {
-    super.initState();
-    _focusNode.requestFocus();
-  }
-
   @override
   void dispose() {
     _timer?.cancel();

macos/Flutter/GeneratedPluginRegistrant.swift

@@ -5,6 +5,8 @@
 import FlutterMacOS
 import Foundation
 
+import path_provider_foundation
 
 func RegisterGeneratedPlugins(registry: FlutterPluginRegistry) {
+  PathProviderPlugin.register(with: registry.registrar(forPlugin: "PathProviderPlugin"))
 }

pubspec.lock

@@ -57,6 +57,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.3.2"
+  ffi:
+    dependency: transitive
+    description:
+      name: ffi
+      sha256: "289279317b4b16eb2bb7e271abccd4bf84ec9bdcbe999e278a94b804f5630418"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.1.4"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -139,6 +147,70 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.9.1"
+  path_provider:
+    dependency: "direct main"
+    description:
+      name: path_provider
+      sha256: "50c5dd5b6e1aaf6fb3a78b33f6aa3afca52bf903a8a5298f53101fdaee55bbcd"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.1.5"
+  path_provider_android:
+    dependency: transitive
+    description:
+      name: path_provider_android
+      sha256: "0ca7359dad67fd7063cb2892ab0c0737b2daafd807cf1acecd62374c8fae6c12"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.2.16"
+  path_provider_foundation:
+    dependency: transitive
+    description:
+      name: path_provider_foundation
+      sha256: "4843174df4d288f5e29185bd6e72a6fbdf5a4a4602717eed565497429f179942"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.4.1"
+  path_provider_linux:
+    dependency: transitive
+    description:
+      name: path_provider_linux
+      sha256: f7a1fe3a634fe7734c8d3f2766ad746ae2a2884abe22e241a8b301bf5cac3279
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.2.1"
+  path_provider_platform_interface:
+    dependency: transitive
+    description:
+      name: path_provider_platform_interface
+      sha256: "88f5779f72ba699763fa3a3b06aa4bf6de76c8e5de842cf6f29e2e06476c2334"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.1.2"
+  path_provider_windows:
+    dependency: transitive
+    description:
+      name: path_provider_windows
+      sha256: bd6f00dbd873bfb70d0761682da2b3a2c2fccc2b9e84c495821639601d81afe7
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.3.0"
+  platform:
+    dependency: transitive
+    description:
+      name: platform
+      sha256: "5d6b1b0036a5f331ebc77c850ebc8506cbc1e9416c27e59b439f917a902a4984"
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.1.6"
+  plugin_platform_interface:
+    dependency: transitive
+    description:
+      name: plugin_platform_interface
+      sha256: "4820fbfdb9478b1ebae27888254d445073732dae3d6ea81f0b7e06d5dedc3f02"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.1.8"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -208,6 +280,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "14.3.1"
+  xdg_directories:
+    dependency: transitive
+    description:
+      name: xdg_directories
+      sha256: "7a3f37b05d989967cdddcbb571f1ea834867ae2faa29725fd085180e0883aa15"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.1.0"
 sdks:
   dart: ">=3.7.0 <4.0.0"
-  flutter: ">=3.18.0-18.0.pre.54"
+  flutter: ">=3.27.0"

pubspec.yaml

@@ -34,6 +34,7 @@ dependencies:
   # The following adds the Cupertino Icons font to your application.
   # Use with the CupertinoIcons class for iOS style icons.
   cupertino_icons: ^1.0.8
+  path_provider: ^2.1.2  # For accessing local file system
 
 dev_dependencies:
   flutter_test: