pricing tiers

backend/utils/rentalDurationCalculator.js

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+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 <= 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;