/*
 *  RapidMiner
 *
 *  Copyright (C) 2001-2008 by Rapid-I and the contributors
 *
 *  Complete list of developers available at our web site:
 *
 *       http://rapid-i.com
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Affero General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Affero General Public License for more details.
 *
 *  You should have received a copy of the GNU Affero General Public License
 *  along with this program.  If not, see http://www.gnu.org/licenses/.
 */
package com.rapidminer.operator.condition;

import com.rapidminer.operator.IllegalInputException;
import com.rapidminer.operator.Operator;
import com.rapidminer.operator.OperatorChain;
import com.rapidminer.operator.WrongNumberOfInnerOperatorsException;
import com.rapidminer.tools.Tools;

/**
 * This condition can be used to define a output condition for the an inner operator
 * in a chain where the first inner operator must be able to handle the specified input
 * and all inner operators must be able to handle their predecessors output. 
 * It is therefore not necessary to add a {@link SimpleChainInnerOperatorCondition} 
 * additionally to this condition to the list of conditions.
 * 
 * @author Ingo Mierswa
 * @version $Id: FirstInnerOperatorCondition.java,v 1.2 2008/07/13 16:39:42 ingomierswa Exp $
 */
public class FirstInnerOperatorCondition implements InnerOperatorCondition {

	private Class[] willGet;
	
	private boolean allowEmptyChains = false;

	/**
	 * Creates an inner operator condition. The first operator in the chain gets
	 * the input of the operator chain and additionally the given classes
	 * <code>willGet</code>. Each operator must be able to handle the output
	 * of the predecessor. The last operator must provide all classes in the
	 * given <code>mustDeliver</code> class array. Empty chains are not allowed.
	 */
	public FirstInnerOperatorCondition(Class[] willGet) {
		this(willGet, false);
	}
	
	/**
	 * Creates an inner operator condition. The first operator in the chain gets
	 * the input of the operator chain and additionally the given classes
	 * <code>willGet</code>. Each operator must be able to handle the output
	 * of the predecessor. The last operator must provide all classes in the
	 * given <code>mustDeliver</code> class array.
	 */
	public FirstInnerOperatorCondition(Class[] willGet, boolean allowEmptyChains) {
		this.willGet = willGet;
		this.allowEmptyChains = allowEmptyChains;
	}

	public Class[] checkIO(OperatorChain chain, Class[] input) throws IllegalInputException, WrongNumberOfInnerOperatorsException {
		if ((!allowEmptyChains) && (chain.getNumberOfOperators() == 0)) {
			throw new WrongNumberOfInnerOperatorsException(chain, chain.getMinNumberOfInnerOperators(), chain.getMaxNumberOfInnerOperators(), 0);
		}

		Class[] output = input;
		if (willGet != null) {
			output = new Class[input.length + willGet.length];
			System.arraycopy(input, 0, output, 0, input.length);
			System.arraycopy(willGet, 0, output, input.length, willGet.length);
		}

		for (int i = 0; i < chain.getNumberOfOperators(); i++) {
			Operator operator = chain.getOperator(i);
			if (operator.isEnabled())
				output = operator.checkIO(output);
		}

		return output;
	}

	public String toHTML() {
		StringBuffer result = new StringBuffer("The inner operators ");
		if (willGet != null) {
			result.append("must be able to handle [");
			for (int i = 0; i < willGet.length; i++) {
				if (i != 0)
					result.append(", ");
				result.append(Tools.classNameWOPackage(willGet[i]));
			}
			result.append("].");
		}
		return result.toString();
	}
}