const forms = document.querySelectorAll('.booking-form');

const formatCurrency = (cents) =>
  new Intl.NumberFormat('de-DE', {
    style: 'currency',
    currency: 'EUR',
  }).format(cents / 100);

const calculateDays = (start, end) => {
  if (!start || !end) return null;
  const startDate = new Date(start);
  const endDate = new Date(end);
  if (Number.isNaN(startDate.valueOf()) || Number.isNaN(endDate.valueOf())) return null;
  const milliseconds = endDate.getTime() - startDate.getTime();
  const days = Math.floor(milliseconds / 86400000) + 1;
  return days > 0 ? days : null;
};

forms.forEach((form) => {
  const startInput = form.querySelector('[data-booking-start]');
  const endInput = form.querySelector('[data-booking-end]');
  const daysOutput = form.querySelector('[data-summary-days]');
  const totalOutput = form.querySelector('[data-summary-total]');
  const rateInput = form.querySelector('input[name="price_per_day_cents"]');
  const defaultRate = Number(form.dataset.dayRate || 9999);

  const render = () => {
    const days = calculateDays(startInput?.value, endInput?.value);
    const rate = Number(rateInput?.value || defaultRate);

    if (!days || rate < 0) {
      if (daysOutput) daysOutput.textContent = 'Noch nicht gewaehlt';
      if (totalOutput) totalOutput.textContent = formatCurrency(defaultRate);
      return;
    }

    if (daysOutput) {
      daysOutput.textContent = `${days} ${days === 1 ? 'Tag' : 'Tage'}`;
    }

    if (totalOutput) {
      totalOutput.textContent = formatCurrency(days * rate);
    }
  };

  startInput?.addEventListener('input', render);
  endInput?.addEventListener('input', render);
  rateInput?.addEventListener('input', render);
  render();
});