Merge pull request 'fixes timestamping across timezones' (#3) from fix_time into main

Reviewed-on: http://192.168.1.74:30008/kfj001/kryz-go-flutter/pulls/3

lib/live_info_panel.dart

@@ -112,19 +112,21 @@ class LiveInfoPanel extends StatelessWidget {
             ShowCard(
               label: 'On Air Show',
               show: currentShow,
+              sourceTimezone: snapshot?.timezone,
               titleColor: themeColors.statusText,
             ),
             const SizedBox(height: 6),
             ShowCard(
               label: 'Up Next Show',
               show: nextShow,
+              sourceTimezone: snapshot?.timezone,
               titleColor: themeColors.statusText,
             ),
             const SizedBox(height: 6),
             Text(
               liveInfo.lastUpdatedAt == null
                   ? 'Waiting for API response...'
-                  : 'Last update: ${DateFormat.yMd().format(liveInfo.lastUpdatedAt!.toLocal())} ${DateFormat.jm().format(liveInfo.lastUpdatedAt!.toLocal())} • ${snapshot?.timezone ?? '--'}',
+                  : 'Last update (Local): ${DateFormat.yMd().format(liveInfo.lastUpdatedAt!.toLocal())} ${DateFormat.jm().format(liveInfo.lastUpdatedAt!.toLocal())}',
               style: Theme.of(context).textTheme.labelSmall,
             ),
           ],

lib/main.dart

@@ -2,6 +2,7 @@ import 'package:flutter/material.dart';
 import 'package:flutter/foundation.dart';
 import 'package:just_audio_background/just_audio_background.dart';
 import 'package:flutter/services.dart';
+import 'package:timezone/data/latest.dart' as tz;
 import 'app_theme_business_object.dart';
 import 'casting_business_object.dart';
 import 'live_info_business_object.dart';
@@ -10,6 +11,7 @@ import 'streaming_audio_business_object.dart';
 
 Future<void> main() async {
   WidgetsFlutterBinding.ensureInitialized();
+  tz.initializeTimeZones();
   await JustAudioBackground.init(
     androidNotificationChannelId: 'com.kryzgoflutter.audio.channel',
     androidNotificationChannelName: 'KRYZ Audio Playback',

lib/show_card.dart

@@ -8,11 +8,13 @@ class ShowCard extends StatelessWidget {
     super.key,
     required this.label,
     required this.show,
+    required this.sourceTimezone,
     required this.titleColor,
   });
 
   final String label;
   final LiveInfoShowInfo? show;
+  final String? sourceTimezone;
   final Color titleColor;
 
   @override
@@ -40,7 +42,10 @@ class ShowCard extends StatelessWidget {
           ),
           const SizedBox(width: 8),
           Text(
-            formatStartingTime(show?.starts),
+            formatStartingTime(
+              show?.starts,
+              sourceTimezone: sourceTimezone,
+            ),
             style: Theme.of(context).textTheme.labelSmall,
           ),
         ],

lib/time_formatter.dart

@@ -1,4 +1,5 @@
 import 'package:intl/intl.dart';
+import 'package:timezone/timezone.dart' as tz;
 
 // Source - https://stackoverflow.com/a/54775297
 // Posted by diegoveloper, modified by community. See post 'Timeline' for change history
@@ -14,8 +15,11 @@ String _printDuration(Duration duration) {
 
 String formatTimeWindow(String? starts, String? ends) {
   if (starts != null && ends != null) {
-    DateTime startDt = DateTime.parse(starts);
+    DateTime? startDt = _tryParseServerDateTime(starts);
-    DateTime endDt = DateTime.parse(ends);
+    DateTime? endDt = _tryParseServerDateTime(ends);
+    if (startDt == null || endDt == null) {
+      return '--:--';
+    }
 
     Duration songLength = endDt.difference(startDt);
 
@@ -25,10 +29,108 @@ String formatTimeWindow(String? starts, String? ends) {
   return "--:--";
 }
 
-String formatStartingTime(String? startingTime) {
+String formatStartingTime(String? startingTime, {String? sourceTimezone}) {
   if (startingTime != null) {
-    DateTime dtStartTime = DateTime.parse(startingTime);
+    final DateTime? localStart = _serverTimeToLocal(
-    return DateFormat('jm').format(dtStartTime);
+      startingTime,
+      sourceTimezone: sourceTimezone,
+    );
+    if (localStart == null) {
+      return '--:--';
+    }
+    return DateFormat('jm').format(localStart);
   }
   return "--:--";
 }
+
+DateTime? _serverTimeToLocal(String rawTime, {String? sourceTimezone}) {
+  final DateTime? parsed = _tryParseServerDateTime(rawTime);
+  if (parsed == null) {
+    return null;
+  }
+
+  if (_hasExplicitTimezone(rawTime)) {
+    return parsed.toLocal();
+  }
+
+  // API timestamps are wall-clock values in the API timezone field.
+  if (sourceTimezone == null || sourceTimezone.trim().isEmpty) {
+    return parsed;
+  }
+
+  try {
+    final tz.Location sourceLocation = tz.getLocation(sourceTimezone.trim());
+    final tz.TZDateTime sourceTime = tz.TZDateTime(
+      sourceLocation,
+      parsed.year,
+      parsed.month,
+      parsed.day,
+      parsed.hour,
+      parsed.minute,
+      parsed.second,
+      parsed.millisecond,
+      parsed.microsecond,
+    );
+    return DateTime.fromMillisecondsSinceEpoch(
+      sourceTime.millisecondsSinceEpoch,
+      isUtc: true,
+    ).toLocal();
+  } catch (_) {
+    return parsed;
+  }
+}
+
+bool _hasExplicitTimezone(String value) {
+  final String trimmed = value.trim();
+
+  if (trimmed.endsWith('Z') || trimmed.endsWith('z')) {
+    return true;
+  }
+
+  final RegExp offsetPattern = RegExp(r'[+-]\d{2}:?\d{2}$');
+  return offsetPattern.hasMatch(trimmed);
+}
+
+DateTime? _tryParseServerDateTime(String value) {
+  final String trimmed = value.trim();
+  if (trimmed.isEmpty) {
+    return null;
+  }
+
+  final DateTime? isoAttempt = DateTime.tryParse(trimmed);
+  if (isoAttempt != null) {
+    return isoAttempt;
+  }
+
+  final RegExp serverDateTimePattern = RegExp(
+    r'^(\d{4})-(\d{2})-(\d{2})\s+(\d{2}):(\d{2}):(\d{2})(?:\.(\d{1,6}))?$',
+  );
+  final RegExpMatch? match = serverDateTimePattern.firstMatch(trimmed);
+  if (match == null) {
+    return null;
+  }
+
+  int parsePart(int group) => int.parse(match.group(group)!);
+
+  final int year = parsePart(1);
+  final int month = parsePart(2);
+  final int day = parsePart(3);
+  final int hour = parsePart(4);
+  final int minute = parsePart(5);
+  final int second = parsePart(6);
+
+  final String fraction = (match.group(7) ?? '').padRight(6, '0');
+  final int microseconds =
+      fraction.isEmpty ? 0 : int.parse(fraction.substring(0, 6));
+
+  return DateTime(
+    year,
+    month,
+    day,
+    hour,
+    minute,
+    second,
+    microseconds ~/ 1000,
+    microseconds % 1000,
+  );
+}

pubspec.yaml

@@ -40,6 +40,7 @@ dependencies:
   webview_flutter: ^4.13.0
   http: ^1.5.0
   intl: ^0.20.2
+  timezone: ^0.10.1
 
 dev_dependencies:
   flutter_name_manager: ^1.0.0

test/time_formatter_test.dart

@@ -0,0 +1,106 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:intl/intl.dart';
+import 'package:kryz_go_flutter/time_formatter.dart';
+import 'package:timezone/data/latest.dart' as tz;
+import 'package:timezone/timezone.dart' as tz;
+
+void main() {
+  setUpAll(() {
+    tz.initializeTimeZones();
+  });
+
+  group('formatStartingTime', () {
+    test('returns local display from source timezone naive server time', () {
+      const String sourceTime = '2026-05-14 20:00:00';
+      const String sourceZone = 'America/Los_Angeles';
+
+      final tz.TZDateTime source = tz.TZDateTime(
+        tz.getLocation(sourceZone),
+        2026,
+        5,
+        14,
+        20,
+      );
+      final String expected = DateFormat('jm').format(
+        DateTime.fromMillisecondsSinceEpoch(
+          source.millisecondsSinceEpoch,
+          isUtc: true,
+        ).toLocal(),
+      );
+
+      expect(
+        formatStartingTime(sourceTime, sourceTimezone: sourceZone),
+        expected,
+      );
+    });
+
+    test('falls back to parsed local time when timezone is invalid', () {
+      final DateTime parsed = DateTime.parse('2026-05-14 20:00:00');
+      final String expected = DateFormat('jm').format(parsed);
+
+      expect(
+        formatStartingTime(
+          '2026-05-14 20:00:00',
+          sourceTimezone: 'Invalid/Timezone',
+        ),
+        expected,
+      );
+    });
+
+    test('returns placeholder for invalid input', () {
+      expect(formatStartingTime('not-a-time'), '--:--');
+      expect(formatStartingTime(null), '--:--');
+    });
+
+    test('does not double-convert timestamps with explicit UTC designator', () {
+      const String utcStamp = '2026-05-15T03:00:00Z';
+      final String expected = DateFormat('jm').format(DateTime.parse(utcStamp).toLocal());
+
+      expect(
+        formatStartingTime(
+          utcStamp,
+          sourceTimezone: 'America/Los_Angeles',
+        ),
+        expected,
+      );
+    });
+
+    test('keeps wall-clock time when local matches source zone for naive input', () {
+      const String sourceTime = '2026-05-14 20:00:00';
+      const String sourceZone = 'America/Los_Angeles';
+
+      final tz.TZDateTime source = tz.TZDateTime(
+        tz.getLocation(sourceZone),
+        2026,
+        5,
+        14,
+        20,
+      );
+      final String expected = DateFormat('jm').format(
+        DateTime.fromMillisecondsSinceEpoch(
+          source.millisecondsSinceEpoch,
+          isUtc: true,
+        ).toLocal(),
+      );
+
+      expect(
+        formatStartingTime(sourceTime, sourceTimezone: sourceZone),
+        expected,
+      );
+    });
+  });
+
+  group('formatTimeWindow', () {
+    test('returns mm:ss style duration from server times', () {
+      expect(
+        formatTimeWindow('2026-05-15 05:18:46.000000', '2026-05-15 05:23:21.000000'),
+        '04:35',
+      );
+    });
+
+    test('returns placeholder for invalid windows', () {
+      expect(formatTimeWindow('nope', '2026-05-15 05:23:21.000000'), '--:--');
+      expect(formatTimeWindow(null, '2026-05-15 05:23:21.000000'), '--:--');
+    });
+  });
+}