hotelOptimized.swift

hotelOptimized.swift

class Hotel {

  // MARK: - Public
   
  // Another major improvement in our design,
  // is to clearly define the desired access level of a function.
  // We mark this function as public, as we want 
  // consumers to be able to access this function.
  public func checkIn(_ dog: Dog) -> String? {
	
    // Declare a nil roomID
    var roomID: String?
		
    // In the new design we're going to 
    // try to get a roomID from a private method
    // This function is not async! 
    // This function is just written with a closure,
    // because we're returns a reference.
    // That's the inout equivalent of returns.
    getRooms(for: dog) { rooms in
      // If we have rooms, then we want to create an ID
      roomID = UUID().uuidString
      // Assign the dog to that room
      rooms[roomID!] = dog
    }

    // And lastly return the ID.
    return roomID
  }

  // MARK: - Private 

  // To define a clear API for consumers of our object, 
  // we're going to set the access level of this function to private.
  // No one outside of this class needs access to it.
  // The function executes syncronous and utilizes a closure 
  // to return the reference of the available sizes dictionary.
  //
  // It's possible to optimize or further refactor this function.
  // But you need to think small when it comes to those kind of details.
  // You typically got less than 20 mins for implementation.
  private func getRooms(for dog: Dog, result: (inout [String: Dog]) -> Void) {
	
    // For large dogs we can only return large rooms.
    // They won't fit into the smaller rooms.
    // #PETA.
    if dog.size == .large, largeRooms.keys.count < largeRoomsCount {
      // If we have availability, 
      // complete with the reference to the rooms dictionary.
      result(&largeRooms)
    }
		
    // For medium sized dogs...
    if dog.size == .medium {
      // We can use medium sized rooms... 
      if mediumRooms.keys.count < mediumRoomsCount {
        result(&mediumRooms)
      }
      // As well as large rooms.
      if largeRooms.keys.count < largeRoomsCount {
         result(&largeRooms)
      }
    }
		
    // For small dogs...
    if dog.size == .small {
      // Small..
      if smallRooms.keys.count < smallRoomsCount {
        result(&smallRooms)
      }
      // Medium..
      if mediumRooms.keys.count < mediumRoomsCount {
        result(&mediumRooms)
      }
      // And large...
      if largeRooms.keys.count < largeRoomsCount {
        result(&largeRooms)
      }
    }
  }
}