/*
   Copyright 2011 frank asseg

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

 */
package de.congrace.exp4j;

import java.util.Stack;

/**
 * Token for parenthesis
 * 
 * @author fas@congrace.de
 */
class ParenthesisToken extends Token {

	ParenthesisToken(String value) {
		super(value);
	}

	@Override
	public boolean equals(Object obj) {
		if (obj instanceof ParenthesisToken) {
			final ParenthesisToken t = (ParenthesisToken) obj;
			return t.getValue().equals(this.getValue());
		}
		return false;
	}

	@Override
	public int hashCode() {
		return getValue().hashCode();
	}

	/**
	 * check the direction of the parenthesis
	 * 
	 * @return true if it's a left parenthesis (open) false if it is a right
	 *         parenthesis (closed)
	 */
	boolean isOpen() {
		return getValue().equals("(") || getValue().equals("[") || getValue().equals("{");
	}

	@Override
	void mutateStackForInfixTranslation(Stack<Token> operatorStack, StringBuilder output) {
		if (this.isOpen()) {
			operatorStack.push(this);
		} else {
			Token next;
			while ((next = operatorStack.peek()) instanceof OperatorToken || next instanceof FunctionToken || next instanceof CustomFunction
					|| (next instanceof ParenthesisToken && !((ParenthesisToken) next).isOpen())) {
				output.append(operatorStack.pop().getValue()).append(" ");
			}
			operatorStack.pop();
		}
	}
}