/*
 *    Geotoolkit - An Open Source Java GIS Toolkit
 *    http://www.geotoolkit.org
 *
 *    (C) 2011, Geomatys
 *
 *    This library is free software; you can redistribute it and/or
 *    modify it under the terms of the GNU Lesser General Public
 *    License as published by the Free Software Foundation;
 *    version 2.1 of the License.
 *
 *    This library 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
 *    Lesser General Public License for more details.
 */
package org.geotoolkit.processing.math.median;

import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import org.geotoolkit.processing.AbstractProcess;
import org.opengis.parameter.ParameterValueGroup;

import static org.geotoolkit.parameter.Parameters.*;
/**
 * @author Quentin Boileau (Geomatys)
 * @module
 */
public class MedianProcess extends AbstractProcess {

    public MedianProcess(final ParameterValueGroup input) {
        super(MedianDescriptor.INSTANCE,input);
    }

    @Override
    protected void execute() {

        final Double[] set = value(MedianDescriptor.SET, inputParameters);
        List<Double> list = Arrays.asList(set);

        //Sort the set of double
        Collections.sort(list);

        //index of the median
        int indexMedian = ((list.size()+1)/2)-1;
        double median = 0.0;

        if(list.size()%2 == 0) {
            median = (list.get(indexMedian) + list.get(indexMedian+1))/2;//avg of index and index +1
        }else{
            median = list.get(indexMedian);
        }

        getOrCreate(MedianDescriptor.RESULT_NUMBER, outputParameters).setValue(median);
    }

}