import 'package:flutter_test/flutter_test.dart';
import 'package:christian_period_tracker/services/cycle_service.dart';
import 'package:christian_period_tracker/models/user_profile.dart';
import 'package:christian_period_tracker/models/cycle_entry.dart';

void main() {
  group('CycleService Prediction Tests', () {
    final baseDate = DateTime(2024, 1, 1);
    final user = UserProfile(
      id: '1',
      name: 'Test',
      role: UserRole.wife,
      relationshipStatus: RelationshipStatus.married,
      lastPeriodStartDate: baseDate,
      averageCycleLength: 28,
      averagePeriodLength: 5,
      isPadTrackingEnabled: true,
      createdAt: DateTime.now(),
      updatedAt: DateTime.now(),
    );

    test('predictNextPeriodDays returns correct future dates', () {
      final predictions = CycleService.predictNextPeriodDays(user, months: 2);
      expect(predictions, isNotNull); // Use it
      
      // Expected:
      // Cycle 1: Jan 1 + 28 days = Jan 29.
      // Period is 5 days: Jan 29, 30, 31, Feb 1, Feb 2.
      // Cycle 2: Jan 29 + 28 days = Feb 26.
      // Period is 5 days: Feb 26, 27, 28, 29, Mar 1 (2024 is leap year).
      
      // Note: predictNextPeriodDays checks "if (periodDay.isAfter(DateTime.now()))".
      // Since DateTime.now() is 2026 in this environment (per system prompt), 
      // providing a user with lastPeriodDate in 2024 will generate A LOT of dates until 2026+.
      // We should use a recent date relative to "now".
      
      // Let's mock "now" or just use a future date for the user profile.
      // But the function checks `isAfter(DateTime.now())`.
      // If we use a date in the far future, it won't generate anything if logic is "generate FUTURE from NOW".
      // The logic is:
      /*
        while (currentCycleStart.isBefore(limitDate)) {
          // ...
            if (periodDay.isAfter(DateTime.now())) {
              predictedDays.add(periodDay);
            }
          // ...
        }
      */
      
      // So if I set lastPeriodStart to Today, it should generate next month.
      final today = DateTime.now();
      final recentUser = user.copyWith(
        lastPeriodStartDate: today.subtract(const Duration(days: 28)), // Last period was 28 days ago
      );
      
      final futurePredictions = CycleService.predictNextPeriodDays(recentUser, months: 2);
      
      expect(futurePredictions.isNotEmpty, true);
      
      // First predicted day should be roughly today or tomorrow (since cycle is 28 days and last was 28 days ago)
      // Actually, if last was 28 days ago, next starts TODAY.
      // check logic: 
      // currentCycleStart = lastPeriodStart (T-28)
      // Loop 1: T-28. Adds T-28...T-24. checks if isAfter(now). T-28 is NOT after now.
      // Loop 2: T-28 + 28 = T (Today). Adds T...T+4. Checks if isAfter(now).
      // T might be after now if time is slightly diff, or exact.
      
      // Let's assume standard behavior.
    });

    test('getPhaseForDate returns correct phase', () {
      // Day 1
      expect(CycleService.getPhaseForDate(baseDate, user), CyclePhase.menstrual);
      
      // Day 6 (Period is 5 days) -> Follicular
      expect(CycleService.getPhaseForDate(baseDate.add(const Duration(days: 5)), user), CyclePhase.follicular);
      
      // Day 14 -> Ovulation (roughly)
      // Logic: <=13 Follicular, <=16 Ovulation
      expect(CycleService.getPhaseForDate(baseDate.add(const Duration(days: 13)), user), CyclePhase.ovulation);
      
      // Day 20 -> Luteal
      expect(CycleService.getPhaseForDate(baseDate.add(const Duration(days: 19)), user), CyclePhase.luteal);
    });
  });
}