/*
 * RandomWalkOnMapOperator.java
 *
 * Copyright (c) 2002-2015 Alexei Drummond, Andrew Rambaut and Marc Suchard
 *
 * 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.evomodel.operators;

import dr.evomodel.continuous.MapDiffusionModel;
import dr.evomodel.continuous.TopographicalMap;
import dr.inference.model.Parameter;
import dr.inference.operators.*;
import dr.math.MathUtils;
import dr.xml.*;
//import org.apiacoa.games.terrain.CostNodeTileTerrain;


/**
 * @author Marc Suchard
 */
public class RandomWalkOnMapOperator extends AbstractCoercableOperator {

    public static final String OPERATOR_NAME = "randomWalkOnMapOperator";
    public static final String WINDOW_SIZE = "windowSize";
    public static final String UPDATE_INDEX = "updateIndex";
    public static final String GRID_X_DIMENSION = "xGridDimension";
    public static final String GRID_Y_DIMENSION = "yGridDimension";

    public RandomWalkOnMapOperator(Parameter parameter,
                                   MapDiffusionModel mapModel,
                                   double windowSize,
                                   double weight, CoercionMode mode) {
        super(mode);
        this.parameter = parameter;
        this.model = mapModel;
        this.map = mapModel.getMap();
//		this.terrain = mapModel.getTerrain();
//
//		if (this.terrain != null) {
//			maxX = terrain.getColumns();
//			maxY = terrain.getRows();
//		}
        this.windowSize = windowSize;
        setWeight(weight);
        this.numberPoints = parameter.getDimension() / 2;

    }


    /**
     * @return the parameter this operator acts on.
     */
    public Parameter getParameter() {
        return parameter;
    }

    public final double getWindowSize() {
        return windowSize;
    }

    /**
     * change the parameter and return the hastings ratio.
     */
    public final double doOperation() throws OperatorFailedException {

        // a random dimension to perturb

        int index;
        index = MathUtils.nextInt(numberPoints) * 2;

        int deltaX = 0;
        int deltaY = 0;

        while (deltaX == 0 && deltaY == 0) {  // eight uniform choices
            deltaX = MathUtils.nextInt(3) - 1;
            deltaY = MathUtils.nextInt(3) - 1;
        }

        // a random point around old value within window [-1,1]  todo expand windowsize

        int newX = (int) parameter.getParameterValue(index) + deltaX;
        int newY = (int) parameter.getParameterValue(index + 1) + deltaY;

        if (map != null) {
            if (!map.isValidPoint(newX, newY)) {
                throw new OperatorFailedException("proposed value outside boundaries");
            }
        }

//		if (terrain != null) {
//			if (newX < 0 || newY < 0 || newX >= maxX || newY >= maxY || model.isBlocked(newX, newY)) {
//				throw new OperatorFailedException("proposed value outside boundaries");
//			}
//		}

        parameter.setParameterValue(index, newX);
        parameter.setParameterValue(index + 1, newY);

        return 0.0;
    }

    //MCMCOperator INTERFACE
    public final String getOperatorName() {
        return parameter.getParameterName();
    }


    public double getCoercableParameter() {
        return Math.log(windowSize);
    }

    public void setCoercableParameter(double value) {
        windowSize = Math.exp(value);
    }

    public double getRawParameter() {
        return windowSize;
    }

    public double getTargetAcceptanceProbability() {
        return 0.234;
    }

    public double getMinimumAcceptanceLevel() {
        return 0.1;
    }

    public double getMaximumAcceptanceLevel() {
        return 0.4;
    }

    public double getMinimumGoodAcceptanceLevel() {
        return 0.20;
    }

    public double getMaximumGoodAcceptanceLevel() {
        return 0.30;
    }

    public final String getPerformanceSuggestion() {

        double prob = MCMCOperator.Utils.getAcceptanceProbability(this);
        double targetProb = getTargetAcceptanceProbability();

        double ws = OperatorUtils.optimizeWindowSize(windowSize, parameter.getParameterValue(0) * 2.0, prob, targetProb);

        if (prob < getMinimumGoodAcceptanceLevel()) {
            return "Try decreasing windowSize to about " + ws;
        } else if (prob > getMaximumGoodAcceptanceLevel()) {
            return "Try increasing windowSize to about " + ws;
        } else return "";
    }

    public static dr.xml.XMLObjectParser PARSER = new AbstractXMLObjectParser() {


        public String getParserName() {
            return OPERATOR_NAME;
        }

        public Object parseXMLObject(XMLObject xo) throws XMLParseException {

            CoercionMode mode = CoercionMode.parseMode(xo);

            double weight = xo.getDoubleAttribute(WEIGHT);
            double windowSize = xo.getDoubleAttribute(WINDOW_SIZE);
            Parameter parameter = (Parameter) xo.getChild(Parameter.class);

            MapDiffusionModel mapModel = (MapDiffusionModel) xo.getChild(MapDiffusionModel.class);


            return new RandomWalkOnMapOperator(parameter, mapModel, windowSize, weight, mode);
        }

        //************************************************************************
        // AbstractXMLObjectParser implementation
        //************************************************************************

        public String getParserDescription() {
            return "This element returns a random walk operator on a given map.";
        }

        public Class getReturnType() {
            return MCMCOperator.class;
        }

        public XMLSyntaxRule[] getSyntaxRules() {
            return rules;
        }

        private XMLSyntaxRule[] rules = new XMLSyntaxRule[]{
                AttributeRule.newDoubleRule(WINDOW_SIZE),
                AttributeRule.newDoubleRule(WEIGHT),
                AttributeRule.newBooleanRule(AUTO_OPTIMIZE, true),
                new ElementRule(MapDiffusionModel.class),
                new ElementRule(Parameter.class)
        };

    };

    public String toString() {
        return OPERATOR_NAME + "(" + parameter.getParameterName() + ")";
    }

    //PRIVATE STUFF

    private Parameter parameter = null;
    private double windowSize = 0.01;
    private TopographicalMap map;
    private MapDiffusionModel model;
    private int numberPoints;

    private int maxX;
    private int maxY;

}

