//Purchase.java

import java.util.Scanner;

/**
 * Class for the purchase of one kind of item, such as 3 oranges.
 * Prices are set supermarket style, such as 5 for $1.25.
*/
public class Purchase
{
    private String name;
    private int groupCount;   //Part of price, like the 2 in 2 for $1.99.
    private double groupPrice;//Part of price, like the $1.99 in 2 for $1.99
    private int numberBought; //Number of items bought.

    public void setName
    (
        String newName
    )
    {
        name = newName;
    }

    /**
     * Sets price to count pieces for $costForCount.
     * For example, 2 for $1.99.
    */
    public void setPrice
    (
        int count,
        double costForCount
    )
    {
        if ((count <= 0) || (costForCount <= 0))
        {
            System.out.println("Error: Bad parameter in setPrice.");
            System.exit(0);
        }
        else
        {
            groupCount = count;
            groupPrice = costForCount;
        }
    }

    public void setNumberBought
    (
        int number
    )
    {
        if (number <= 0)
        {
            System.out.println("Error: Bad parameter in setNumberBought.");
            System.exit(0);
        }
        else
            numberBought = number;
    }

    /**
     * Reads from keyboard the price and number of a purchase.
     */
    public void readInput()
    {
        Scanner keyboard = new Scanner(System.in);
        System.out.println("Enter name of item you are purchasing:");
        name = keyboard.nextLine();

        System.out.println("Enter price of item as two numbers.");
        System.out.println("For example, 3 for $2.99 is entered as");
        System.out.println("3 2.99");
        System.out.println("Enter price of item as two numbers, now:");
        groupCount = keyboard.nextInt();
        groupPrice = keyboard.nextDouble();

        while ((groupCount <= 0) || (groupPrice <= 0))
        { //Try again:
            System.out.println("Both numbers must be positive. Try again.");
            System.out.println("Enter price of item as two numbers.");
            System.out.println("For example, 3 for $2.99 is entered as");
            System.out.println("3 2.99");
            System.out.println("Enter price of item as two numbers, now:");
            groupCount = keyboard.nextInt();
            groupPrice = keyboard.nextDouble();
        }

        System.out.println("Enter number of items purchased:");
        numberBought = keyboard.nextInt();

        while (numberBought <= 0)
        { //Try again:
            System.out.println("Number must be positive. Try again.");
            System.out.println("Enter number of items purchased:");
            numberBought = keyboard.nextInt();
        }
    }

    /**
     * Displays price and number being purchased.
     */
    public void writeOutput()
    {
        System.out.println(numberBought + " " + name);
        System.out.println("at " + groupCount +
                           " for $" + groupPrice);
    }

    public String getName()
    {
        return name;
    }

    public double getTotalCost()
    {
        return (groupPrice / groupCount) * numberBought;
    }

    public double getUnitCost()
    {
        return groupPrice / groupCount;
    }

    public int getNumberBought()
    {
        return numberBought;
    }
}