Refactored Booking.cs

Refactored Booking Class for Better Encapsulation & Method Design

Exposed private fields as read-only properties.
Marked IsBetween() as static since it does not depend on instance state.
Added null-checks in the constructor to ensure valid input.
Closes CodelyTV#62

Author: Mykyta-Panchenko

examples/csharp/csharp-booking-03_preserve_whole_object/src/Booking/Booking.cs

@@ -1,15 +1,15 @@
-using System;
+using System;
 
 namespace CodelyTv.Booking
 {
     public sealed class Booking
     {
-        private readonly BookingId id;
-        private readonly DateRange dateRange;
-        private readonly Customer customer;
-        private readonly BookingType bookingType;
-        private readonly Discount discount;
-        private readonly Tax tax;
+        public BookingId Id { get; }
+        public DateRange DateRange { get; }
+        public Customer Customer { get; }
+        public BookingType BookingType { get; }
+        public Discount Discount { get; }
+        public Tax Tax { get; }
 
         public Booking(
             BookingId id,
@@ -20,30 +20,25 @@ public Booking(
             Tax tax
         )
         {
-            this.id = id;
-            this.dateRange = dateRange;
-            this.customer = customer;
-            this.bookingType = bookingType;
-            this.discount = discount;
-            this.tax = tax;
+            Id = id ?? throw new ArgumentNullException(nameof(id), "Booking ID cannot be null.");
+            DateRange = dateRange ?? throw new ArgumentNullException(nameof(dateRange), "Date range cannot be null.");
+            Customer = customer ?? throw new ArgumentNullException(nameof(customer), "Customer cannot be null.");
+            BookingType = bookingType; 
+            Discount = discount ?? throw new ArgumentNullException(nameof(discount), "Discount cannot be null.");
+            Tax = tax ?? throw new ArgumentNullException(nameof(tax), "Tax cannot be null.");
         }
 
         public BookingStatus StatusFor(DateTime date)
         {
-            if (date < dateRange.StartDate)
+            if (date < DateRange.StartDate)
             {
                 return BookingStatus.NOT_STARTED;
             }
 
-            if (IsBetween(date, dateRange))
-            {
-                return BookingStatus.ACTIVE;
-            }
-
-            return BookingStatus.FINISHED;
+            return IsBetween(date, DateRange) ? BookingStatus.ACTIVE : BookingStatus.FINISHED;
         }
 
-        private bool IsBetween(DateTime date, DateRange dateRange)
+        private static bool IsBetween(DateTime date, DateRange dateRange)
         {
             return date > dateRange.StartDate && date < dateRange.EndDate;
         }