/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.ignite.examples.ml.genetic.change;

import java.util.ArrayList;
import java.util.List;
import org.apache.ignite.Ignite;
import org.apache.ignite.Ignition;
import org.apache.ignite.ml.genetic.Chromosome;
import org.apache.ignite.ml.genetic.GAGrid;
import org.apache.ignite.ml.genetic.Gene;
import org.apache.ignite.ml.genetic.parameter.ChromosomeCriteria;
import org.apache.ignite.ml.genetic.parameter.GAConfiguration;
import org.apache.ignite.ml.genetic.parameter.GAGridConstants;

/**
 * This example demonstrates how to use the {@link GAGrid} framework. It is inspired by
 * <a href="https://github.com/martin-steghoefer/jgap/blob/master/examples/src/examples/MinimizingMakeChange.java">
 * JGAP's "Minimize Make Change"</a> example.
 * <p>
 * In this example, the objective is to calculate the minimum number of coins that equal user specified amount of change
 * ie: {@code -DAMOUNTCHANGE}.</p>
 * <p>
 * {@code mvn exec:java -Dexec.mainClass="org.apache.ignite.examples.ml.genetic.change.OptimizeMakeChangeGAExample"
 * -DAMOUNTCHANGE=75}</p>
 * <p>
 * Code in this example launches Ignite grid, prepares simple test data (gene pool) and configures GA grid.</p>
 * <p>
 * After that it launches the process of evolution on GA grid and outputs the progress and results.</p>
 * <p>
 * You can change the test data and parameters of GA grid used in this example and re-run it to explore this
 * functionality further.</p>
 * <p>
 * Remote nodes should always be started with special configuration file which enables P2P class loading: {@code
 * 'ignite.{sh|bat} examples/config/example-ignite.xml'}.</p>
 * <p>
 * Alternatively you can run ExampleNodeStartup in another JVM which will start node with {@code
 * examples/config/example-ignite.xml} configuration.</p>
 */
public class OptimizeMakeChangeGAExample {
    /**
     * Executes example.
     * <p>
     * Specify value for {@code -DAMOUNTCHANGE} JVM system variable.
     *
     * @param args Command line arguments, none required.
     */
    public static void main(String args[]) {
        System.out.println(">>> OptimizeMakeChange GA grid example started.");

        String sAmountChange = "75";

        StringBuilder sbErrorMsg = new StringBuilder();
        sbErrorMsg.append("AMOUNTCHANGE System property not set. Please provide a valid value between 1 and 99. ");
        sbErrorMsg.append(" ");
        sbErrorMsg.append("IE: -DAMOUNTCHANGE=75");
        sbErrorMsg.append("\n");
        sbErrorMsg.append("Using default value: 75");

        //Check if -DAMOUNTCHANGE JVM system variable is provided.
        if (System.getProperty("AMOUNTCHANGE") == null)
            System.out.println(sbErrorMsg);
        else
            sAmountChange = System.getProperty("AMOUNTCHANGE");

        try {
            // Create an Ignite instance as you would in any other use case.
            Ignite ignite = Ignition.start("examples/config/example-ignite.xml");

            // Create GAConfiguration.
            GAConfiguration gaCfg = new GAConfiguration();

            // Set Gene Pool.
            List<Gene> genes = getGenePool();

            // Set selection method.
            gaCfg.setSelectionMtd(GAGridConstants.SELECTION_METHOD.SELECTION_METHOD_ELITISM);
            gaCfg.setElitismCnt(10);

            // Set the Chromosome Length to '4' since we have 4 coins.
            gaCfg.setChromosomeLen(4);

            // Set population size.
            gaCfg.setPopulationSize(500);

            // Initialize gene pool.
            gaCfg.setGenePool(genes);

            // Set Truncate Rate.
            gaCfg.setTruncateRate(.10);

            // Set Cross Over Rate.
            gaCfg.setCrossOverRate(.50);

            // Set Mutation Rate.
            gaCfg.setMutationRate(.50);

            // Create and set Fitness function.
            OptimizeMakeChangeFitnessFunction function = new OptimizeMakeChangeFitnessFunction(new Integer(sAmountChange));
            gaCfg.setFitnessFunction(function);

            // Create and set TerminateCriteria.
            OptimizeMakeChangeTerminateCriteria termCriteria = new OptimizeMakeChangeTerminateCriteria(ignite,
                System.out::println);

            ChromosomeCriteria chromosomeCriteria = new ChromosomeCriteria();

            List<String> values = new ArrayList<>();

            values.add("coinType=QUARTER");
            values.add("coinType=DIME");
            values.add("coinType=NICKEL");
            values.add("coinType=PENNY");

            chromosomeCriteria.setCriteria(values);

            gaCfg.setChromosomeCriteria(chromosomeCriteria);
            gaCfg.setTerminateCriteria(termCriteria);

            // Initialize GAGrid.
            GAGrid gaGrid = new GAGrid(gaCfg, ignite);

            System.out.println("##########################################################################################");

            System.out.println("Calculating optimal set of coins where amount of change is " + sAmountChange);

            System.out.println("##########################################################################################");

            Chromosome chromosome = gaGrid.evolve();

            System.out.println(">>> Evolution result: " + chromosome);

            Ignition.stop(true);

            System.out.println(">>> OptimizeMakeChange GA grid example completed.");
        }
        catch (Exception e) {
            System.out.println(e.getMessage());
            e.printStackTrace();
        }
    }

    /**
     * Helper routine to initialize Gene pool.
     * <p>
     * In typical use case genes may be stored in database.
     *
     * @return List of Genes.
     */
    private static List<Gene> getGenePool() {
        List<Gene> list = new ArrayList<>();

        Gene quarterGene1 = new Gene(new Coin(Coin.CoinType.QUARTER, 3));
        Gene quarterGene2 = new Gene(new Coin(Coin.CoinType.QUARTER, 2));
        Gene quarterGene3 = new Gene(new Coin(Coin.CoinType.QUARTER, 1));
        Gene quarterGene4 = new Gene(new Coin(Coin.CoinType.QUARTER, 0));

        Gene dimeGene1 = new Gene(new Coin(Coin.CoinType.DIME, 2));
        Gene dimeGene2 = new Gene(new Coin(Coin.CoinType.DIME, 1));
        Gene dimeGene3 = new Gene(new Coin(Coin.CoinType.DIME, 0));

        Gene nickelGene1 = new Gene(new Coin(Coin.CoinType.NICKEL, 1));
        Gene nickelGene2 = new Gene(new Coin(Coin.CoinType.NICKEL, 0));

        Gene pennyGene1 = new Gene(new Coin(Coin.CoinType.PENNY, 4));
        Gene pennyGene2 = new Gene(new Coin(Coin.CoinType.PENNY, 3));
        Gene pennyGene3 = new Gene(new Coin(Coin.CoinType.PENNY, 2));
        Gene pennyGene4 = new Gene(new Coin(Coin.CoinType.PENNY, 1));
        Gene pennyGene5 = new Gene(new Coin(Coin.CoinType.PENNY, 0));

        list.add(quarterGene1);
        list.add(quarterGene2);
        list.add(quarterGene3);
        list.add(quarterGene4);
        list.add(dimeGene1);
        list.add(dimeGene2);
        list.add(dimeGene3);
        list.add(nickelGene1);
        list.add(nickelGene2);
        list.add(pennyGene1);
        list.add(pennyGene2);
        list.add(pennyGene3);
        list.add(pennyGene4);
        list.add(pennyGene5);

        return list;
    }
}