import { describe, it, expect } from 'vitest';
import { calculateRaceDates, getNextWeekday, ScheduleConfig } from './ScheduleCalculator';

describe('ScheduleCalculator', () => {
  describe('calculateRaceDates', () => {
    it('should return empty array if no weekdays or rounds', () => {
      const config: ScheduleConfig = {
        weekdays: [],
        frequency: 'weekly',
        rounds: 10,
        startDate: new Date('2024-01-01'),
      };
      expect(calculateRaceDates(config).raceDates).toHaveLength(0);
    });

    it('should schedule weekly races', () => {
      const config: ScheduleConfig = {
        weekdays: ['Mon'],
        frequency: 'weekly',
        rounds: 3,
        startDate: new Date('2024-01-01'), // Monday
      };
      const result = calculateRaceDates(config);
      expect(result.raceDates).toHaveLength(3);
      expect(result.raceDates[0].getDay()).toBe(1);
      expect(result.raceDates[1].getDay()).toBe(1);
      expect(result.raceDates[2].getDay()).toBe(1);
      // Check dates are 7 days apart
      const diff = result.raceDates[1].getTime() - result.raceDates[0].getTime();
      expect(diff).toBe(7 * 24 * 60 * 60 * 1000);
    });

    it('should schedule bi-weekly races', () => {
      const config: ScheduleConfig = {
        weekdays: ['Mon'],
        frequency: 'everyNWeeks',
        intervalWeeks: 2,
        rounds: 2,
        startDate: new Date('2024-01-01'),
      };
      const result = calculateRaceDates(config);
      expect(result.raceDates).toHaveLength(2);
      const diff = result.raceDates[1].getTime() - result.raceDates[0].getTime();
      expect(diff).toBe(14 * 24 * 60 * 60 * 1000);
    });

    it('should distribute races between start and end date', () => {
      const config: ScheduleConfig = {
        weekdays: ['Mon', 'Wed', 'Fri'],
        frequency: 'weekly',
        rounds: 2,
        startDate: new Date('2024-01-01'), // Mon
        endDate: new Date('2024-01-15'), // Mon
      };
      const result = calculateRaceDates(config);
      expect(result.raceDates).toHaveLength(2);
      // Use getTime() to avoid timezone issues in comparison
      const expectedDate = new Date('2024-01-01');
      expectedDate.setHours(12, 0, 0, 0);
      expect(result.raceDates[0].getTime()).toBe(expectedDate.getTime());
    });
  });

  describe('getNextWeekday', () => {
    it('should return the next Monday', () => {
      const from = new Date('2024-01-01'); // Monday
      const next = getNextWeekday(from, 'Mon');
      expect(next.getDay()).toBe(1);
      expect(next.getDate()).toBe(8);
    });
  });
});