class RentalDurationCalculator {
  /**
   * Calculate rental cost based on duration and item pricing tiers
   * @param {Date|string} startDateTime - Rental start date/time
   * @param {Date|string} endDateTime - Rental end date/time
   * @param {Object} item - Item object with pricing information
   * @returns {number} Total rental cost
   */
  static calculateRentalCost(startDateTime, endDateTime, item) {
    const rentalStartDateTime = new Date(startDateTime);
    const rentalEndDateTime = new Date(endDateTime);

    // Calculate rental duration
    const diffMs = rentalEndDateTime.getTime() - rentalStartDateTime.getTime();
    const diffHours = Math.ceil(diffMs / (1000 * 60 * 60));
    const diffDays = Math.ceil(diffMs / (1000 * 60 * 60 * 24));
    const diffWeeks = Math.ceil(diffDays / 7);

    // Calculate difference in calendar months
    let diffMonths = (rentalEndDateTime.getFullYear() - rentalStartDateTime.getFullYear()) * 12;
    diffMonths += rentalEndDateTime.getMonth() - rentalStartDateTime.getMonth();

    // Add 1 if we're past the start day/time in the end month
    if (rentalEndDateTime.getDate() > rentalStartDateTime.getDate()) {
      diffMonths += 1;
    } else if (rentalEndDateTime.getDate() === rentalStartDateTime.getDate() &&
               rentalEndDateTime.getTime() > rentalStartDateTime.getTime()) {
      diffMonths += 1;
    }

    diffMonths = Math.max(1, diffMonths);

    // Calculate base amount based on duration (tiered pricing)
    let totalAmount;

    if (item.pricePerHour && diffHours < 24) {
      // Use hourly rate for rentals under 24 hours
      totalAmount = diffHours * Number(item.pricePerHour);
    } else if (diffDays <= 7 && item.pricePerDay) {
      // Use daily rate for rentals <= 7 days
      totalAmount = diffDays * Number(item.pricePerDay);
    } else if (diffMonths <= 1 && item.pricePerWeek) {
      // Use weekly rate for rentals <= 1 calendar month
      totalAmount = diffWeeks * Number(item.pricePerWeek);
    } else if (diffMonths > 1 && item.pricePerMonth) {
      // Use monthly rate for rentals > 1 calendar month
      totalAmount = diffMonths * Number(item.pricePerMonth);
    } else if (item.pricePerWeek) {
      // Fallback to weekly rate if monthly not available
      totalAmount = diffWeeks * Number(item.pricePerWeek);
    } else if (item.pricePerDay) {
      // Fallback to daily rate
      totalAmount = diffDays * Number(item.pricePerDay);
    } else {
      totalAmount = 0;
    }

    return totalAmount;
  }
}

module.exports = RentalDurationCalculator;