///////////////////////////////////////////////////////////////////////////////
// For information as to what this class does, see the Javadoc, below.       //
// Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,       //
// 2007, 2008, 2009, 2010, 2014, 2015 by Peter Spirtes, Richard Scheines, Joseph   //
// Ramsey, and Clark Glymour.                                                //
//                                                                           //
// 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; either version 2 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 General Public License for more details.                              //
//                                                                           //
// You should have received a copy of the GNU General Public License         //
// along with this program; if not, write to the Free Software               //
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA //
///////////////////////////////////////////////////////////////////////////////

package edu.cmu.tetrad.search;

import edu.cmu.tetrad.data.DataSet;
import edu.cmu.tetrad.data.ICovarianceMatrix;
import edu.cmu.tetrad.graph.Node;
import edu.cmu.tetrad.util.ProbUtils;
import edu.cmu.tetrad.util.TetradLogger;
import edu.cmu.tetrad.util.TetradMatrix;

import java.util.*;

/**
 * Pools together a set of independence tests using a specified methods
 *
 * @author Robert Tillman
 */
public final class IndTestMulti implements IndependenceTest {


    /**
     * The variables of the covariance matrix, in order. (Unmodifiable list.)
     */
    private final List<Node> variables;

    /**
     * The independence test associated with each data set.
     */
    private List<IndependenceTest> independenceTests;

    /**
     * Pooling method
     */
    private ResolveSepsets.Method method;
    private double p = Double.NaN;

//    private DataSet concatenatedData;

    //==========================CONSTRUCTORS=============================//

    public IndTestMulti(List<IndependenceTest> independenceTests, ResolveSepsets.Method method) {
        Set<String> nodeNames = new HashSet<>();
        for (IndependenceTest independenceTest : independenceTests) {
            nodeNames.addAll(independenceTest.getVariableNames());
        }
        if (independenceTests.get(0).getVariables().size() != nodeNames.size()) {
            throw new IllegalArgumentException("Data sets must have same variables.");
        }
        this.variables = independenceTests.get(0).getVariables();
        this.independenceTests = independenceTests;
        this.method = method;

        List<DataSet> dataSets = new ArrayList<>();

        for (IndependenceTest test : independenceTests) {
            dataSets.add((DataSet) test.getData());
        }

//        this.concatenatedData = DataUtils.concatenate(dataSets);
    }

    //==========================PUBLIC METHODS=============================//

    public IndependenceTest indTestSubset(List<Node> vars) {
        throw new UnsupportedOperationException();
    }

    /**
     * Determines whether variable x is independent of variable y given a list of conditioning variables z.
     *
     * @param x the one variable being compared.
     * @param y the second variable being compared.
     * @param z the list of conditioning variables.
     * @return true iff x _||_ y | z.
     * @throws RuntimeException if a matrix singularity is encountered.
     */
    public boolean isIndependent(Node x, Node y, List<Node> z) {
        boolean independent = ResolveSepsets.isIndependentPooled(method, independenceTests, x, y, z);


        if (independent) {
            TetradLogger.getInstance().log("independencies", "In aggregate independent: " + SearchLogUtils.independenceFact(x, y, z));
        } else {
            TetradLogger.getInstance().log("dependencies", "In aggregate dependent: " + SearchLogUtils.independenceFact(x, y, z));
        }

        return independent;
    }

    public boolean isIndependentPooledFisher2(List<IndependenceTest> independenceTests, Node x, Node y, List<Node> condSet) {
        double alpha = independenceTests.get(0).getAlpha();
        List<Double> pValues = getAvailablePValues(independenceTests, x, y, condSet);

        double tf = 0.0;
        int numPValues = 0;

        for (double p : pValues) {
//            if (p > 0) {
            tf += -2.0 * Math.log(p);
            numPValues++;
//            }
        }

        double p = 1.0 - ProbUtils.chisqCdf(tf, 2 * numPValues);
        this.p = p;

        return (p > alpha);
    }

    private static List<Double> getAvailablePValues(List<IndependenceTest> independenceTests, Node x, Node y, List<Node> condSet) {
        List<Double> allPValues = new ArrayList<>();

        for (IndependenceTest test : independenceTests) {
            List<Node> localCondSet = new ArrayList<>();
            for (Node node : condSet) {
                localCondSet.add(test.getVariable(node.getName()));
            }

            try {
                test.isIndependent(test.getVariable(x.getName()), test.getVariable(y.getName()), localCondSet);
                allPValues.add(test.getPValue());
            } catch (Exception e) {
                // Skip that test.
            }
        }

        return allPValues;
    }

    public boolean isIndependent(Node x, Node y, Node... z) {
        List<Node> zList = Arrays.asList(z);
        return isIndependent(x, y, zList);
    }

    public boolean isDependent(Node x, Node y, List<Node> z) {
        return !isIndependent(x, y, z);
    }

    public boolean isDependent(Node x, Node y, Node... z) {
        List<Node> zList = Arrays.asList(z);
        return isDependent(x, y, zList);
    }

    /**
     * @throws UnsupportedOperationException
     */
    public double getPValue() {
        return p;
    }

    /**
     * @throws UnsupportedOperationException
     */
    public void setAlpha(double alpha) {
        throw new UnsupportedOperationException();
    }

    /**
     * Gets the getModel significance level.
     */
    public double getAlpha() {
        throw new UnsupportedOperationException();
    }

    /**
     * @return the list of variables over which this independence checker is capable of determinine independence
     * relations-- that is, all the variables in the given graph or the given data set.
     */
    public List<Node> getVariables() {
        return this.variables;
    }

    /**
     * @return the variable with the given name.
     */
    public Node getVariable(String name) {
        for (int i = 0; i < getVariables().size(); i++) {
            Node variable = getVariables().get(i);
            if (variable.getName().equals(name)) {
                return variable;
            }
        }

        return null;
    }

    /**
     * @return the list of variable varNames.
     */
    public List<String> getVariableNames() {
        List<Node> variables = getVariables();
        List<String> variableNames = new ArrayList<>();
        for (Node variable1 : variables) {
            variableNames.add(variable1.getName());
        }
        return variableNames;
    }

    /**
     * @throws UnsupportedOperationException
     */
    public boolean determines(List z, Node x) throws UnsupportedOperationException {
        throw new UnsupportedOperationException();
    }

    /**
     * @throws UnsupportedOperationException
     */
    public DataSet getData() {
        throw new UnsupportedOperationException();
//        return concatenatedData;
    }

    @Override
    public ICovarianceMatrix getCov() {
        return null;
    }

    @Override
    public List<DataSet> getDataSets() {
        return null;
    }

    @Override
    public int getSampleSize() {
        return 0;
    }

    @Override
    public List<TetradMatrix> getCovMatrices() {
        return null;
    }

    @Override
    public double getScore() {
        return getPValue();
    }

    /**
     * @return a string representation of this test.
     */
    public String toString() {
        return "Pooled Independence Test:  alpha = " + independenceTests.get(0).getAlpha();
    }
}