/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.

 *

 * The contents of this file are subject to the terms of either the GNU

 * General Public License Version 2 only ("GPL") or the Common

 * Development and Distribution License("CDDL") (collectively, the

 * "License"). You may not use this file except in compliance with the

 * License. You can obtain a copy of the License at

 * http://www.netbeans.org/cddl-gplv2.html

 * or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the

 * specific language governing permissions and limitations under the

 * License.  When distributing the software, include this License Header

 * Notice in each file and include the License file at

 * nbbuild/licenses/CDDL-GPL-2-CP.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun in the GPL Version 2 section of the License file that

 * accompanied this code. If applicable, add the following below the

 * License Header, with the fields enclosed by brackets [] replaced by

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 * Contributor(s):

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 * Portions Copyrighted 2010 Martin Rexa

 */

package cz.xelfi.quoridor.statistics;

import java.util.Map;

import java.util.HashMap;

import java.util.List;

import java.util.Collections;

import java.util.ArrayList;

import javax.xml.bind.annotation.XmlElement;

import javax.xml.bind.annotation.XmlElementWrapper;

import javax.xml.bind.annotation.XmlRootElement;

import javax.xml.bind.annotation.XmlAccessType;

import javax.xml.bind.annotation.XmlAccessorType;

/**

 *

 * @author Martin Rexa

 */

@XmlRootElement

@XmlAccessorType(XmlAccessType.FIELD)

public class EloList {

    static int INITIAL_ELO = 1250;

    static int MAX_ELO_DIFF = 400;

    static int KVAL_START = 25;

    static int KVAL_FOLLOW = 10;

    static int KVAL_LIMIT = 30;

    private Map<String, Double> players;

    private Map<String, Integer> playerGames;

    public EloList () {

        players = new HashMap<String, Double>();

        playerGames = new HashMap<String, Integer>();

    }

    @XmlElementWrapper(name="elolist")

    @XmlElement(name="item")

    public List<EloEntry> getFinalList(){

        List<EloEntry> finalList = new ArrayList<EloEntry>();

        for (Map.Entry<String, Double> player : players.entrySet()){

            finalList.add(new EloEntry(player.getKey(), player.getValue(), playerGames.get(player.getKey())));

        }

        Collections.sort(finalList, EloEntry.BEST_FIRST);

        return finalList;

    }

    public EloList putResult(String winner, String looser){

        double wElo = getElo(winner);

        double lElo = getElo(looser);

        double eloDiff = wElo - lElo;

        if(eloDiff < - MAX_ELO_DIFF)

            eloDiff = - MAX_ELO_DIFF;

        if(eloDiff > MAX_ELO_DIFF)

            eloDiff = MAX_ELO_DIFF;

        double wDiff = Math.round(100 * getKVal(winner) * (1 - (1 / (1 + Math.pow(10, -eloDiff / MAX_ELO_DIFF)))));

        wDiff /= 100.0;

        double lDiff = Math.round(100 * getKVal(looser) * (0 - (1 / (1 + Math.pow(10, eloDiff / MAX_ELO_DIFF)))));

        lDiff /= 100.0;

        players.put(winner, wElo + wDiff);

        players.put(looser, lElo + lDiff);

        return this;

    }

    public double getElo(String player){

        Double elo = players.get(player);

        return (elo == null) ? INITIAL_ELO : elo;

    }

    private int getKVal(String player){

        Integer games = playerGames.get(player);

        int g = (games == null) ? 0 : games;

        // Side effect, method should not be called more times for the same game/player

        playerGames.put(player, g + 1);

        return g < KVAL_LIMIT ? KVAL_START : KVAL_FOLLOW;

    }

}