import { describe, expect, it } from 'bun:test';
import { CLASS_WINDOW_HOURS, nextClassOccurrence } from '@/modules/home/lib/scheduler';

const TZ = 'America/Mexico_City';

describe('nextClassOccurrence', () => {
  it('devuelve la próxima clase de hoy cuando aún no arrancó', () => {
    const now = new Date('2026-09-23T18:00:00.000Z'); // miércoles 12:00 hora CDMX

    const result = nextClassOccurrence({
      days: ['WEDNESDAY'],
      time: '18:00',
      now,
      timeZone: TZ,
    });

    expect(result).toEqual({
      occurrenceAt: new Date('2026-09-24T00:00:00.000Z'),
      isNow: false,
    });
  });

  it('marca en curso si la clase arrancó hace menos de la ventana', () => {
    const now = new Date('2026-09-24T01:00:00.000Z'); // miércoles 19:00 hora CDMX (1 h tras la clase)

    const result = nextClassOccurrence({
      days: ['WEDNESDAY'],
      time: '18:00',
      now,
      timeZone: TZ,
    });

    expect(result).toEqual({
      occurrenceAt: new Date('2026-09-24T00:00:00.000Z'),
      isNow: true,
    });
  });

  it('salta a la próxima semana si la clase ya pasó la ventana', () => {
    const now = new Date('2026-09-24T03:00:00.000Z'); // miércoles 21:00 hora CDMX (3 h tras la clase)

    const result = nextClassOccurrence({
      days: ['WEDNESDAY'],
      time: '18:00',
      now,
      timeZone: TZ,
    });

    expect(result).toEqual({
      occurrenceAt: new Date('2026-10-01T00:00:00.000Z'),
      isNow: false,
    });
  });

  it('elige la ocurrencia más próxima entre varios días', () => {
    const now = new Date('2026-09-23T18:00:00.000Z'); // miércoles 12:00 hora CDMX

    const result = nextClassOccurrence({
      days: ['MONDAY', 'WEDNESDAY', 'FRIDAY'],
      time: '18:00',
      now,
      timeZone: TZ,
    });

    expect(result).toEqual({
      occurrenceAt: new Date('2026-09-24T00:00:00.000Z'),
      isNow: false,
    });
  });

  it('cruza de mes sin problema', () => {
    const now = new Date('2026-09-29T18:00:00.000Z'); // martes 12:00 hora CDMX (último día de septiembre es miércoles 30)

    const result = nextClassOccurrence({
      days: ['THURSDAY'],
      time: '09:00',
      now,
      timeZone: TZ,
    });

    expect(result).toEqual({
      occurrenceAt: new Date('2026-10-01T15:00:00.000Z'),
      isNow: false,
    });
  });

  it('devuelve null si no hay días de clase', () => {
    const result = nextClassOccurrence({
      days: [],
      time: '18:00',
      now: new Date('2026-09-23T18:00:00.000Z'),
      timeZone: TZ,
    });

    expect(result).toBeNull();
  });

  it('devuelve null si la hora es inválida', () => {
    const result = nextClassOccurrence({
      days: ['WEDNESDAY'],
      time: '99:99',
      now: new Date('2026-09-23T18:00:00.000Z'),
      timeZone: TZ,
    });

    expect(result).toBeNull();
  });

  it('expone el tamaño de la ventana de "en curso"', () => {
    expect(CLASS_WINDOW_HOURS).toBeGreaterThan(0);
  });
});