fix: handle datetime outside the valid range supported by dart (#21526)

* fix: handle datetime outside the valid range supported by dart

* add tests for tryFromSecondsSinceEpoch

---------

Co-authored-by: shenlong-tanwen <139912620+shalong-tanwen@users.noreply.github.com>

mobile/test/modules/utils/datetime_helpers_test.dart

@@ -0,0 +1,58 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:immich_mobile/utils/datetime_helpers.dart';
+
+void main() {
+  group('tryFromSecondsSinceEpoch', () {
+    test('returns null for null input', () {
+      final result = tryFromSecondsSinceEpoch(null);
+      expect(result, isNull);
+    });
+
+    test('returns null for value below minimum allowed range', () {
+      // _minMillisecondsSinceEpoch = -62135596800000
+      final seconds = -62135596800000 ~/ 1000 - 1; // One second before min allowed
+      final result = tryFromSecondsSinceEpoch(seconds);
+      expect(result, isNull);
+    });
+
+    test('returns null for value above maximum allowed range', () {
+      // _maxMillisecondsSinceEpoch = 8640000000000000
+      final seconds = 8640000000000000 ~/ 1000 + 1; // One second after max allowed
+      final result = tryFromSecondsSinceEpoch(seconds);
+      expect(result, isNull);
+    });
+
+    test('returns correct DateTime for minimum allowed value', () {
+      final seconds = -62135596800000 ~/ 1000; // Minimum allowed timestamp
+      final result = tryFromSecondsSinceEpoch(seconds);
+      expect(result, DateTime.fromMillisecondsSinceEpoch(-62135596800000));
+    });
+
+    test('returns correct DateTime for maximum allowed value', () {
+      final seconds = 8640000000000000 ~/ 1000; // Maximum allowed timestamp
+      final result = tryFromSecondsSinceEpoch(seconds);
+      expect(result, DateTime.fromMillisecondsSinceEpoch(8640000000000000));
+    });
+
+    test('returns correct DateTime for negative timestamp', () {
+      final seconds = -1577836800; // Dec 31, 1919 (pre-epoch)
+      final result = tryFromSecondsSinceEpoch(seconds);
+      expect(result, DateTime.fromMillisecondsSinceEpoch(-1577836800 * 1000));
+    });
+
+    test('returns correct DateTime for zero timestamp', () {
+      final seconds = 0; // Jan 1, 1970 (epoch)
+      final result = tryFromSecondsSinceEpoch(seconds);
+      expect(result, DateTime.fromMillisecondsSinceEpoch(0));
+    });
+
+    test('returns correct DateTime for recent timestamp', () {
+      final now = DateTime.now();
+      final seconds = now.millisecondsSinceEpoch ~/ 1000;
+      final result = tryFromSecondsSinceEpoch(seconds);
+      expect(result?.year, now.year);
+      expect(result?.month, now.month);
+      expect(result?.day, now.day);
+    });
+  });
+}