/*
 * 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.ml.genetic;

import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.ignite.Ignite;
import org.apache.ignite.IgniteException;
import org.apache.ignite.cache.affinity.Affinity;
import org.apache.ignite.cluster.ClusterNode;
import org.apache.ignite.compute.ComputeJob;
import org.apache.ignite.compute.ComputeJobResult;
import org.apache.ignite.compute.ComputeJobResultPolicy;
import org.apache.ignite.compute.ComputeTaskAdapter;
import org.apache.ignite.ml.genetic.parameter.GAConfiguration;
import org.apache.ignite.ml.genetic.parameter.GAGridConstants;
import org.apache.ignite.resources.IgniteInstanceResource;
import org.jetbrains.annotations.NotNull;

/**
 * Responsible for fitness operation
 */
public class FitnessTask extends ComputeTaskAdapter<List<Long>, Boolean> {
    /** Ignite instance */
    @IgniteInstanceResource
    private Ignite ignite;

    /** GAConfiguration */
    private GAConfiguration cfg;

    /**
     * @param cfg GAConfiguration
     */
    public FitnessTask(GAConfiguration cfg) {
        this.cfg = cfg;
    }

    /** {@inheritDoc} */
    @NotNull @Override public Map map(List<ClusterNode> nodes, List<Long> chromosomeKeys) throws IgniteException {

        Map<ComputeJob, ClusterNode> map = new HashMap<>();

        Affinity affinity = ignite.affinity(GAGridConstants.POPULATION_CACHE);

        for (Long key : chromosomeKeys) {

            FitnessJob ajob = new FitnessJob(key, this.cfg.getFitnessFunction());

            ClusterNode primary = affinity.mapKeyToNode(key);

            map.put(ajob, primary);
        }
        return map;
    }

    /** {@inheritDoc} */
    @Override public Boolean reduce(List<ComputeJobResult> list) throws IgniteException {

        return Boolean.TRUE;
    }

    /** {@inheritDoc} */
    @Override public ComputeJobResultPolicy result(ComputeJobResult res, List<ComputeJobResult> rcvd) {
        IgniteException err = res.getException();

        if (err != null)
            return ComputeJobResultPolicy.FAILOVER;

        // If there is no exception, wait for all job results.
        return ComputeJobResultPolicy.WAIT;

    }
}