/* 
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.statistics;

import org.apache.commons.math3.stat.inference.TTest;
import org.geogebra.common.kernel.Construction;
import org.geogebra.common.kernel.algos.AlgoElement;
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.GeoText;
import org.geogebra.common.util.StringUtil;

/**
 * Performs a paired t-test.
 * 
 * 
 * @author G. Sturr
 */
public class AlgoTTestPaired extends AlgoElement {

	private GeoList geoList0, geoList1; // input
	private GeoText tail; // input
	private GeoList result; // output
	private TTest tTestImpl;
	private double[] val0, val1;

	public AlgoTTestPaired(Construction cons, String label, GeoList geoList0,
			GeoList geoList1, GeoText tail) {
		super(cons);
		this.geoList0 = geoList0;
		this.geoList1 = geoList1;
		this.tail = tail;
		result = new GeoList(cons);
		setInputOutput(); // for AlgoElement

		compute();
		result.setLabel(label);
	}

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

	@Override
	protected void setInputOutput() {

		input = new GeoElement[3];
		input[0] = geoList0;
		input[1] = geoList1;
		input[2] = tail;

		setOnlyOutput(result);
		setDependencies(); // done by AlgoElement
	}

	public GeoList getResult() {
		return result;
	}

	private double adjustedPValue(double p, double testStatistic) {

		// two sided test
		if (StringUtil.isNotEqual(tail.getTextString())) {
			return p;
		} else if ((tail.getTextString().equals(">") && testStatistic > 0)
				|| (tail.getTextString().equals("<") && testStatistic < 0)) {
			return p / 2;
		} else {
			return 1 - p / 2;
		}
	}

	@Override
	public final void compute() {

		if (!(StringUtil.isInequality(tail.getTextString()))) {
			result.setUndefined();
			return;
		}

		double p, testStat;

		// sample data input

		int size = geoList0.size();
		if (!geoList1.isDefined() || geoList1.size() != size) {
			result.setUndefined();
			return;
		}

		// create number value arrays
		val0 = new double[size];
		val1 = new double[size];
		GeoElement geo0, geo1;
		NumberValue num0, num1;

		for (int i = 0; i < size; i++) {
			geo0 = geoList0.get(i);
			geo1 = geoList1.get(i);
			if (geo0 instanceof NumberValue && geo1 instanceof NumberValue) {
				num0 = (NumberValue) geo0;
				num1 = (NumberValue) geo1;
				val0[i] = num0.getDouble();
				val1[i] = num1.getDouble();

			} else {
				result.setUndefined();
				return;
			}
		}

		try {

			// get the test statistic and p
			if (tTestImpl == null) {
				tTestImpl = new TTest();
			}
			testStat = tTestImpl.pairedT(val0, val1);
			p = tTestImpl.pairedTTest(val0, val1);
			testStat = tTestImpl.pairedT(val0, val1);
			p = adjustedPValue(p, testStat);

			// put these results into the output list
			result.clear();
			result.addNumber(p, null);
			result.addNumber(testStat, null);

		} catch (RuntimeException e) {
			// catches ArithmeticException, IllegalStateException and
			// ArithmeticException
			e.printStackTrace();
		}

	}

}