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// represents the operation to be performed on two variables
// @author Chris Tsuei

public class ArithmeticOperation extends Expression{

	/*operation is the action(+, -, *, /, %) to be done
	 * fistVariable and SecondVariable are the variables the operation is to be applied to
	 * firstValue and secondValue are the values of the firstVariable and secondVariable respectively
	 */
	public Operator operation;
	public Expression firstVariable;
	public Expression secondVariable;
	public int firstValue;
	public int secondValue;

	//enum class of the ArithmeticOperation class
	private static enum Operator{
		//the user can either add, subtract, multiply, divide or moduolo
		Add, Sub, Mult, Div, Rem;}

	public ArithmeticOperation(Operator operator, Expression variable, Expression variable2) {
		this.operation = operator;
		this.firstVariable = variable;
		this.secondVariable = variable2;
	}

	/*gets the value of the operation
	 * @Override
	 * @param state the hashtable holding all of the variables
	 * @return	the result of the operation
	 */
	public int value(State state) {
		this.firstValue = firstVariable.value(state);
		this.secondValue = secondVariable.value(state);

		if(operation.equals("Add")) {
			return firstValue + secondValue;
		}
		else if(operation.equals("Sub")) {
			return firstValue - secondValue;
		}
		else if(operation.equals("Mult")) {
			return firstValue * secondValue;
		}
		else if(operation.equals("Div")) {
			return firstValue / secondValue;
		}
		else {
			return firstValue % secondValue;
		}
	}

	/*	@Override overides the toString() method
	 * 	@return returns the string value of the operation
	 */
	public String toString() {
		char op;
		if(operation.equals("Add")) {
			op = '+';
		}
		else if(operation.equals("Sub")) {
			op = '-';
		}
		else if(operation.equals("Mult")) {
			op = '*';
		}
		else if(operation.equals("Div")) {
			op = '/';
		}
		else {
			op = '%';
		}
		return firstValue + " " + op + " " + secondValue;
	}
}