/**
 * Copyright (C) 2001-2017 by RapidMiner and the contributors
 * 
 * Complete list of developers available at our web site:
 * 
 * http://rapidminer.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;

import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;


/**
 * This class is a description of the (expected) input and (guaranteed) output classes of operators.
 * It provides easy default implementations. <br>
 * 
 * @author Simon Fischer, Ingo Mierswa
 */
public class DefaultIODescription implements IODescription {

	public static final int PASS_UNUSED_INPUT_TO_OUTPUT = 1;

	public static final int DELETE_UNUSED_INPUT = 2;

	// must be ? since it is not allowed to create generic arrays with a specific type
	private Class<?>[] inputClasses;

	private Class<?>[] outputClasses;

	private int outputBehaviour;

	/**
	 * Constructs a new IODescription where all input and output classes are expected exactly once.
	 * Output is the minimum set of output classes, the real output classes are determined by the
	 * outputBehaviour. Both <tt>input</tt> and <tt>output</tt> may be null and may contain a class
	 * more than once.
	 */
	public DefaultIODescription(Class<?>[] input, Class<?>[] output, int outputBehaviour) {
		this.inputClasses = input;
		this.outputClasses = output;
		if (inputClasses == null) {
			inputClasses = new Class[0];
		}
		if (outputClasses == null) {
			outputClasses = new Class[0];
		}
		this.outputBehaviour = outputBehaviour;
	}

	/** Assumes PASS_UNUSED_INPUT_TO_OUTPUT. */
	public DefaultIODescription(Class<?>[] input, Class<?>[] output) {
		this(input, output, PASS_UNUSED_INPUT_TO_OUTPUT);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see com.rapidminer.operator.IODescription#getInputClasses()
	 */
	@Override
	public Class<?>[] getInputClasses() {
		return inputClasses;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see com.rapidminer.operator.IODescription#getOutputClasses(java.lang.Class,
	 * com.rapidminer.operator.Operator)
	 */
	@Override
	public Class<?>[] getOutputClasses(Class<?>[] input, Operator operator) throws IllegalInputException {
		switch (outputBehaviour) {
			case PASS_UNUSED_INPUT_TO_OUTPUT:
				List<Class<?>> outputList = new LinkedList<Class<?>>();
				for (int i = 0; i < input.length; i++) {
					outputList.add(input[i]);
				}
				for (int i = 0; i < inputClasses.length; i++) {
					boolean found = false;
					Iterator<Class<?>> j = outputList.iterator();
					while (j.hasNext()) {
						if (inputClasses[i].isAssignableFrom(j.next())) {
							j.remove();
							found = true;
							break;
						}
					}
					if (!found) {
						throw new IllegalInputException(operator, inputClasses[i]);
					}
				}

				for (int i = 0; i < outputClasses.length; i++) {
					outputList.add(outputClasses[i]);
				}

				Class<?>[] outputArray = new Class[outputList.size()];
				outputList.toArray(outputArray);
				return outputArray;
			case DELETE_UNUSED_INPUT:
				return outputClasses;
		}
		return null;
	}

	/** Returns true if oc contains a class which is a superclass of c. */
	public static boolean containsClass(Class<?> c, Class<?>[] oc) {
		for (int i = 0; i < oc.length; i++) {
			if (c.isAssignableFrom(oc[i])) {
				return true;
			}
		}
		return false;
	}

}