/*
 * HKY.java
 *
 * Copyright (C) 2002-2006 Alexei Drummond and Andrew Rambaut
 *
 * This file is part of BEAST.
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership and licensing.
 *
 * BEAST 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; either version 2
 * of the License, or (at your option) any later version.
 *
 *  BEAST 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.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with BEAST; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
 * Boston, MA  02110-1301  USA
 */

package dr.app.beagle.evomodel.substmodel;

import dr.inference.model.Parameter;
import dr.inference.model.Statistic;
import dr.evolution.datatype.Nucleotides;
import dr.math.matrixAlgebra.Vector;


/**
 * Hasegawa-Kishino-Yano model of nucleotide evolution
 *
 * @author Alexei Drummond
 * @author Andrew Rambaut
 * @author Marc A. Suchard
 */
public class HKY extends BaseSubstitutionModel {

    private Parameter kappaParameter = null;

    /**
     * A constructor which allows a more programmatic approach with
     * fixed kappa.
     * @param kappa
     * @param freqModel
     */
    public HKY(double kappa, FrequencyModel freqModel) {
        this(new Parameter.Default(kappa), freqModel);
    }
    /**
     * Constructor
     * @param kappaParameter
     * @param freqModel
     */
    public HKY(Parameter kappaParameter, FrequencyModel freqModel) {

        super("HKY", Nucleotides.INSTANCE, freqModel);

        this.kappaParameter = kappaParameter;
        addVariable(kappaParameter);
        kappaParameter.addBounds(new Parameter.DefaultBounds(Double.POSITIVE_INFINITY, 0.0, 1));

        addStatistic(tsTvStatistic);
    }

    /**
     * set kappa
     * @param kappa
     */
    public void setKappa(double kappa) {
        kappaParameter.setParameterValue(0, kappa);
        updateMatrix = true;
    }

    /**
     * @return kappa
     */
    public final double getKappa() {
        return kappaParameter.getParameterValue(0);
    }

    /**
     * set ts/tv
     * @param tsTv
     */
    public void setTsTv(double tsTv) {
        double freqA = freqModel.getFrequency(0);
        double freqC = freqModel.getFrequency(1);
        double freqG = freqModel.getFrequency(2);
        double freqT = freqModel.getFrequency(3);
        double freqR = freqA + freqG;
        double freqY = freqC + freqT;
        setKappa((tsTv * freqR * freqY) / (freqA * freqG + freqC * freqT));
    }

    /**
     * @return tsTv
     */
    public double getTsTv() {
        double freqA = freqModel.getFrequency(0);
        double freqC = freqModel.getFrequency(1);
        double freqG = freqModel.getFrequency(2);
        double freqT = freqModel.getFrequency(3);
        double freqR = freqA + freqG;
        double freqY = freqC + freqT;
        double tsTv = (getKappa() * (freqA * freqG + freqC * freqT)) / (freqR * freqY);

        return tsTv;
    }

    protected void frequenciesChanged() {
    }

    protected void ratesChanged() {
    }

    protected void setupRelativeRates(double[] rates) {
        double kappa =  kappaParameter.getParameterValue(0);
        rates[0] = 1.0;
        rates[1] = kappa;
        rates[2] = 1.0;
        rates[3] = 1.0;
        rates[4] = kappa;
        rates[5] = 1.0;
    }

    public EigenDecomposition getEigenDecomposition() {

        if (eigenDecomposition == null) {
            double[] evec = new double[stateCount * stateCount];
            double[] ivec = new double[stateCount * stateCount];
            double[] eval = new double[stateCount];
            eigenDecomposition = new EigenDecomposition(evec, ivec, eval);

            ivec[2 * stateCount + 1] =  1; // left eigenvectors 3 = (0,1,0,-1); 4 = (1,0,-1,0)
            ivec[2 * stateCount + 3] = -1;

            ivec[3 * stateCount + 0] =  1;
            ivec[3 * stateCount + 2] = -1;

            evec[0 * stateCount + 0] =  1; // right eigenvector 1 = (1,1,1,1)'
            evec[1 * stateCount + 0] =  1;
            evec[2 * stateCount + 0] =  1;
            evec[3 * stateCount + 0] =  1;

        }

        if (updateMatrix) {

            double[] evec = eigenDecomposition.getEigenVectors();
            double[] ivec = eigenDecomposition.getInverseEigenVectors();
            double[] pi = freqModel.getFrequencies();
            double piR = pi[0] + pi[2];
            double piY = pi[1] + pi[3];

            // left eigenvector #1
            ivec[0 * stateCount + 0] = pi[0]; // or, evec[0] = pi;
            ivec[0 * stateCount + 1] = pi[1];
            ivec[0 * stateCount + 2] = pi[2];
            ivec[0 * stateCount + 3] = pi[3];

            // left eigenvector #2
            ivec[1 * stateCount + 0] =  pi[0]*piY;
            ivec[1 * stateCount + 1] = -pi[1]*piR;
            ivec[1 * stateCount + 2] =  pi[2]*piY;
            ivec[1 * stateCount + 3] = -pi[3]*piR;

            // right eigenvector #2
            evec[0 * stateCount + 1] =  1.0/piR;
            evec[1 * stateCount + 1] = -1.0/piY;
            evec[2 * stateCount + 1] =  1.0/piR;
            evec[3 * stateCount + 1] = -1.0/piY;

            // right eigenvector #3
            evec[1 * stateCount + 2] =  pi[3]/piY;
            evec[3 * stateCount + 2] = -pi[1]/piY;

            // right eigenvector #4
            evec[0 * stateCount + 3] =  pi[2]/piR;
            evec[2 * stateCount + 3] = -pi[0]/piR;

            // eigenvectors
            double[] eval = eigenDecomposition.getEigenValues();
            final double kappa = getKappa();

            final double beta = -1.0 / (2.0 * (piR * piY + kappa * (pi[0] * pi[2] + pi[1] * pi[3])));
            final double A_R  =  1.0 + piR * (kappa - 1);
            final double A_Y  =  1.0 + piY * (kappa - 1);

            eval[1] = beta;
            eval[2] = beta*A_Y;
            eval[3] = beta*A_R;

            updateMatrix = false;

        }

        return eigenDecomposition;
    }

    //
    // Private stuff
    //

    private Statistic tsTvStatistic = new Statistic.Abstract() {

        public String getStatisticName() {
            return "tsTv";
        }

        public int getDimension() {
            return 1;
        }

        public double getStatisticValue(int dim) {
            return getTsTv();
        }

    };

    public static void main(String[] args) {
//        double kappa = 2.0;
//        double[] pi = new double[]{0.15,0.30,0.20,0.35};
//        double time = 0.1;

        double kappa = 1.0;
        double[] pi = new double[]{0.25,0.25,0.25,0.25};
        double time = 0.1;

        FrequencyModel freqModel= new FrequencyModel(Nucleotides.INSTANCE, pi);
        HKY hky = new HKY(kappa,freqModel);

        EigenDecomposition decomp = hky.getEigenDecomposition();
//        Matrix evec = new Matrix(decomp.getEigenVectors());
//        Matrix ivec = new Matrix(decomp.getInverseEigenVectors());
//        System.out.println("Evec =\n"+evec);
//        System.out.println("Ivec =\n"+ivec);

        Vector eval = new Vector(decomp.getEigenValues());
        System.out.println("Eval = "+eval);

        double[] probs = new double[16];
        hky.getTransitionProbabilities(time,probs);
        System.out.println("new probs = "+new Vector(probs));

        // check against old implementation
        dr.evomodel.substmodel.FrequencyModel oldFreq = new dr.evomodel.substmodel.FrequencyModel(Nucleotides.INSTANCE,pi);
        dr.evomodel.substmodel.HKY oldHKY = new dr.evomodel.substmodel.HKY(kappa,oldFreq);
        oldHKY.setKappa(kappa);

        oldHKY.getTransitionProbabilities(time,probs);
        System.out.println("old probs = "+new Vector(probs));

    }
}