import 'package:flutter_test/flutter_test.dart';
import 'package:buzz/features/channels/date_formatters.dart';

/// Helper: build a unix-second timestamp from a local DateTime.
int _ts(DateTime local) => local.millisecondsSinceEpoch ~/ 1000;

void main() {
  group('formatDayHeading', () {
    // Fix "now" so tests are deterministic.
    final now = DateTime(2026, 4, 23, 14, 30); // Apr 23 2026, 2:30 PM local

    test('same day returns "Today"', () {
      final morning = _ts(DateTime(2026, 4, 23, 8, 0));
      expect(formatDayHeading(morning, now: now), 'Today');
    });

    test('yesterday returns "Yesterday"', () {
      final yesterday = _ts(DateTime(2026, 4, 22, 18, 0));
      expect(formatDayHeading(yesterday, now: now), 'Yesterday');
    });

    test('older date returns full formatted date', () {
      final older = _ts(DateTime(2026, 3, 31, 12, 0));
      expect(formatDayHeading(older, now: now), 'Tuesday, March 31, 2026');
    });

    test('midnight boundary: 11:59 PM today vs 12:01 AM tomorrow', () {
      final lateTonight = _ts(DateTime(2026, 4, 23, 23, 59));
      final earlyTomorrow = _ts(DateTime(2026, 4, 24, 0, 1));

      expect(formatDayHeading(lateTonight, now: now), 'Today');
      // Tomorrow relative to our fixed "now" is not today or yesterday.
      expect(
        formatDayHeading(earlyTomorrow, now: now),
        'Friday, April 24, 2026',
      );
    });

    test('cross-month boundary: April 1 → March 31 is yesterday', () {
      final april1 = DateTime(2026, 4, 1, 10, 0);
      final march31 = _ts(DateTime(2026, 3, 31, 20, 0));
      expect(formatDayHeading(march31, now: april1), 'Yesterday');
    });
  });

  group('isSameDay', () {
    test('same calendar day returns true', () {
      final a = _ts(DateTime(2026, 4, 23, 1, 0));
      final b = _ts(DateTime(2026, 4, 23, 23, 59));
      expect(isSameDay(a, b), isTrue);
    });

    test('different days returns false', () {
      final a = _ts(DateTime(2026, 4, 23, 23, 59));
      final b = _ts(DateTime(2026, 4, 24, 0, 1));
      expect(isSameDay(a, b), isFalse);
    });
  });

  group('formatThreadSummaryLastReplyTime', () {
    const now = 2_000_000;

    test('uses expanded relative units', () {
      expect(
        formatThreadSummaryLastReplyTime(now - 30, nowSeconds: now),
        'just now',
      );
      expect(
        formatThreadSummaryLastReplyTime(now - 60, nowSeconds: now),
        '1 minute ago',
      );
      expect(
        formatThreadSummaryLastReplyTime(now - 3 * 3600, nowSeconds: now),
        '3 hours ago',
      );
      expect(
        formatThreadSummaryLastReplyTime(now - 2 * 86400, nowSeconds: now),
        '2 days ago',
      );
    });

    test('uses a short month and ordinal for older replies', () {
      final may19 = _ts(DateTime(2026, 5, 19, 12));
      final may27 = _ts(DateTime(2026, 5, 27, 12));

      expect(
        formatThreadSummaryLastReplyTime(
          may19,
          nowSeconds: _ts(DateTime(2026, 5, 27, 12)),
        ),
        'on May 19th',
      );
      expect(
        formatThreadSummaryLastReplyTime(
          may27,
          nowSeconds: _ts(DateTime(2026, 6, 4, 12)),
        ),
        'on May 27th',
      );
    });
  });
}