/* 
GeoGebra - Dynamic Mathematics for Everyone
http://www.geogebra.org

This file is part of GeoGebra.

This program is free software; you can redistribute it and/or modify it 
under the terms of the GNU General Public License as published by 
the Free Software Foundation.

 */

package org.geogebra.common.kernel.algos;

import org.geogebra.common.kernel.Construction;
import org.geogebra.common.kernel.arithmetic.NumberValue;
import org.geogebra.common.kernel.commands.Commands;
import org.geogebra.common.kernel.geos.GeoElement;
import org.geogebra.common.kernel.geos.GeoList;
import org.geogebra.common.kernel.geos.GeoNumeric;

/**
 * Maximum value of a list.
 * 
 * @author Markus Hohenwarter
 * @version 15-07-2007
 */

public class AlgoListMax extends AlgoElement {

	private GeoList geoList; // input
	private GeoList freqList; // input
	private GeoNumeric max; // output

	public AlgoListMax(Construction cons, String label, GeoList geoList,
			GeoList freqList) {
		this(cons, geoList, freqList);
		max.setLabel(label);
	}

	public AlgoListMax(Construction cons, String label, GeoList geoList) {
		this(cons, geoList, null);
		max.setLabel(label);
	}

	public AlgoListMax(Construction cons, GeoList geoList) {
		this(cons, geoList, null);
	}

	public AlgoListMax(Construction cons, GeoList geoList, GeoList freqList) {
		super(cons);
		this.geoList = geoList;
		this.freqList = freqList;
		max = new GeoNumeric(cons);

		setInputOutput();
		compute();
	}

	@Override
	public Commands getClassName() {
		return Commands.Max;
	}

	@Override
	protected void setInputOutput() {
		if (freqList == null) {
			input = new GeoElement[1];
			input[0] = geoList;
		} else {
			input = new GeoElement[2];
			input[0] = geoList;
			input[1] = freqList;
		}

		setOutputLength(1);
		setOutput(0, max);
		setDependencies(); // done by AlgoElement
	}

	public GeoNumeric getMax() {
		return max;
	}

	@Override
	public final void compute() {
		int size = geoList.size();
		if (!geoList.isDefined() || size == 0) {
			max.setUndefined();
			return;
		}

		double maxVal = Double.NEGATIVE_INFINITY;

		if (freqList == null) {
			for (int i = 0; i < size; i++) {
				GeoElement geo = geoList.get(i);
				if (geo instanceof NumberValue) {
					NumberValue num = (NumberValue) geo;
					maxVal = Math.max(maxVal, num.getDouble());
				} else {
					max.setUndefined();
					return;
				}
			}
		} else {
			if (!freqList.isDefined() || freqList.size() != geoList.size()) {
				max.setUndefined();
				return;
			}

			boolean hasPositiveFrequency = false;

			for (int i = 0; i < size; i++) {
				GeoElement geo = geoList.get(i);
				GeoElement freqGeo = freqList.get(i);

				if (!(geo instanceof NumberValue)
						|| !(freqGeo instanceof NumberValue)) {
					max.setUndefined();
					return;
				}

				// handle bad frequency
				double frequency = ((NumberValue) freqGeo).getDouble();
				if (frequency < 0) {
					max.setUndefined();
					return;
				} else if (frequency == 0) {
					continue;
				}
				hasPositiveFrequency = true;
				NumberValue num = (NumberValue) geo;
				maxVal = Math.max(maxVal, num.getDouble());
			}

			// make sure not all frequencies are zero
			if (!hasPositiveFrequency) {
				max.setUndefined();
				return;
			}
		}

		max.setValue(maxVal);
	}

}