/**
 * {@link <a href=
 * "https://[Log in to view URL]"
 * target= "_blank"></a>}
 * 
 * @author itammb ( Italia Massimiliano Buscati )
 * @version JDK 1.15
 *
 */
class Main {
	public static class Currency {

		private int amount;

		public Currency(int amt) {
			this.amount = amt;
		}

		public int getAmount() {
			return this.amount;
		}
	}

	public interface DispenseChain {

		void setNextChain(DispenseChain nextChain);

		void dispense(Currency cur);
	}

	public static class Dollar50Dispenser implements DispenseChain {

		private DispenseChain chain;

		@Override
		public void setNextChain(DispenseChain nextChain) {
			this.chain = nextChain;
		}

		@Override
		public void dispense(Currency cur) {
			if (cur.getAmount() >= 50) {
				// elabora la richiesta
				int num = cur.getAmount() / 50;
				int remainder = cur.getAmount() % 50;
				System.out.println("Dispensing " + num + " 50$ note");
				if (remainder != 0)
					this.chain.dispense(new Currency(remainder));
			} else {
				// passa l'informazione al successivo handler
				this.chain.dispense(cur);
			}
		}
	}

	public static class Dollar20Dispenser implements DispenseChain {

		private DispenseChain chain;

		@Override
		public void setNextChain(DispenseChain nextChain) {
			this.chain = nextChain;
		}

		@Override
		public void dispense(Currency cur) {
			if (cur.getAmount() >= 20) {
				int num = cur.getAmount() / 20;
				int remainder = cur.getAmount() % 20;
				System.out.println("Dispensing " + num + " 20$ note");
				if (remainder != 0)
					this.chain.dispense(new Currency(remainder));
			} else {
				this.chain.dispense(cur);
			}
		}

	}

	public static class Dollar10Dispenser implements DispenseChain {

		private DispenseChain chain;

		@Override
		public void setNextChain(DispenseChain nextChain) {
			this.chain = nextChain;
		}

		@Override
		public void dispense(Currency cur) {
			if (cur.getAmount() >= 10) {
				int num = cur.getAmount() / 10;
				int remainder = cur.getAmount() % 10;
				System.out.println("Dispensing " + num + " 10$ note");
				if (remainder != 0)
					this.chain.dispense(new Currency(remainder));
			} else {
				this.chain.dispense(cur);
			}
		}
	}

	public static class ATMDispenseChain {

		private DispenseChain c1;

		public ATMDispenseChain() {
			// inizializza la catena
			this.c1 = new Dollar50Dispenser();
			DispenseChain c2 = new Dollar20Dispenser();
			DispenseChain c3 = new Dollar10Dispenser();

			// configura la catena delle responsabilità
			c1.setNextChain(c2);
			c2.setNextChain(c3);
		}
	}

	public static void main(String args[]) {
		// Unit test - uso del design pattern: chain of responsibility
		
		ATMDispenseChain atmDispenser = new ATMDispenseChain();
		
		int amount = 60;
		while (true) {
			System.out.println("amount to dispense: " + amount);

			if (amount % 10 != 0) {
				System.out.println("Amount should be in multiple of 10s.");
				return;
			}

			// processa la richiesta a partire da uno dei gestore a seguire lungo la catena
			atmDispenser.c1.dispense(new Currency(amount));
			
			amount--;
		}

	}
}