import javax.swing.*;

public class CashierSeven {	

	public boolean isRegularCustomer(String customerName) {
		if (customerName.equals("John Sanders") ||
			customerName.equals("Rose Perez")   || 
			customerName.equals("Elizabeth Smith")) {
			return true;
		}
		else { 
			return false;	
		}
	}
	
	public void ringUpCustomer(String customerName) {
		String item;
		double total, change;
		
		total = costOfItems();
		change = processPayment(total, customerName);
		printThankYouNote(customerName, change);
	}
	
	private double costOfItems() {
		String item;
		double total = 0.0, milkPrice = 3.50; 
		double bottleWaterPrice = 1.0, sugarPrice = 4.0;
		
		do 
		{
			item = JOptionPane.showInputDialog("Enter Item Description");
			if (item.equals("milk")) 
			{
				total = total + milkPrice;
			} 
			else if (item.equals("bottleWater")) 
			{
				total = total + bottleWaterPrice;
			} 
			else if (item.equals("sugar")) 
			{
				total = total + sugarPrice;
			}
			
		} while (!item.equals("end"));
		
		return total;
	}
	
	private double processPayment(double total, String customerName) {
		double discount = .50;
		if (isRegularCustomer(customerName)) {
			total = total * discount;
		}
		
		String reply = "Your total is: $" + total + "\nPlease enter payment amount.";
		String paymentString = JOptionPane.showInputDialog(reply);
		double payment = Double.parseDouble(paymentString);
		while (payment < total) {
			String wrongAmountReply = "Insufficient payment provided. \n" + reply;
			paymentString = JOptionPane.showInputDialog(wrongAmountReply);
			payment = Double.parseDouble(paymentString);	
		}
		
		return payment - total;
	}
	
	private void printThankYouNote(String customerName, double change) {
		String reply = customerName + ", thank you for shopping with us.\n";
		
		// Notice the use of += operator
		reply += ("Your change is: $" + change);
		JOptionPane.showMessageDialog(null, reply);
	}
}