/*
 * Author: CHEN Yongyuan (Walter) 1930006025 from OOP(1007)
 * Date: 2022-04-25
 * Description: This is the borrower class.
 */

public class Borrower extends User {
	/**
	 * Constructor.
	 *
	 * @param name Borrower's name
	 * @param int  book number of books borrowed by user
	 */
	public Borrower(String name, int book) throws NotALenderException {
		super(name, book);

		// check
		if (book < 0) {
			throw new NotALenderException("A new borrower cannot lend books.");
		}
	}

	/**
	 * increase the number of books borrowed by the user.
	 *
	 * @param number Incrased number of books
	 * @throws NotALenderException
	 */
	public void moreBook(int number) throws NotALenderException {
		int newBook = getBook() + number;
		if (number < 0 && newBook < 0) {
			throw new NotALenderException("A borrower cannot lend " + (-newBook) + " book(s).");
		}
		setBook(newBook);
	}

	/**
	 * Test.
	 */
	public static void testBorrower() {
		try {
			Borrower b = new Borrower("Bob", -1);
		} catch (NotALenderException e) {
			System.out.println(e.getMessage().equals("A new borrower cannot lend books."));
		}
		try {
			Borrower b = new Borrower("Bob", 10);
			System.out.println(b.getName() == "Bob");
			System.out.println(b.getBook() == 10);
			b.setBook(5);
			System.out.println(b.getBook() == 5);
			b.moreBook(2);
			System.out.println(b.getBook() == 7);
			b.moreBook(-2);
			System.out.println(b.getBook() == 5);
			b.moreBook(-5);
			System.out.println(b.getBook() == 0);
			b.moreBook(-1);
		} catch (NotALenderException e) {
			System.out.println(e.getMessage().equals("A borrower cannot lend 1 book(s)."));
		}
	}
}