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'), '--:--');
    });
  });
}