package org.cpsolver.ifs.example.jobshop;

import java.util.ArrayList;
import java.util.List;

import org.cpsolver.ifs.model.Variable;


/**
 * Operation. <br>
 * <br>
 * Each operation has its number, job, machine and processing time
 * 
 * @author  Tomas Muller
 * @version IFS 1.3 (Iterative Forward Search)<br>
 *          Copyright (C) 2006 - 2014 Tomas Muller<br>
 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
 * <br>
 *          This library 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 3 of the
 *          License, or (at your option) any later version. <br>
 * <br>
 *          This library 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. <br>
 * <br>
 *          You should have received a copy of the GNU Lesser General Public
 *          License along with this library; if not see
 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
 */
public class Operation extends Variable<Operation, Location> {
    private Job iJob = null;
    private Machine iMachine = null;
    private int iProcessingTime = 0;
    private int iOperationNumber = 0;

    /**
     * Constructor
     * 
     * @param job
     *            job
     * @param machine
     *            machine
     * @param operationNumber
     *            operation number
     * @param processingTime
     *            processing time
     */
    public Operation(Job job, Machine machine, int operationNumber, int processingTime) {
        super(null);
        iJob = job;
        iMachine = machine;
        iProcessingTime = processingTime;
        iOperationNumber = operationNumber;
    }

    /** Get job 
     * @return job
     **/
    public Job getJob() {
        return iJob;
    }

    /** Get job number
     * @return job number
     **/
    public int getJobNumber() {
        return iJob.getJobNumner();
    }

    /** Get operation number 
     * @return operation number
     **/
    public int getOperationNumber() {
        return iOperationNumber;
    }

    /** Get machine 
     * @return machine
     **/
    public Machine getMachine() {
        return iMachine;
    }

    /** Get machine number 
     * @return machine number
     **/
    public int getMachineNumber() {
        return iMachine.getMachineNumber();
    }

    /** Get processing time
     * @return processing time
     **/
    public int getProcessingTime() {
        return iProcessingTime;
    }

    /** Get the preceding operation (if any)
     * @return preceding operation
     **/
    public Operation getPrecedingOperation() {
        return (iOperationNumber == 0 ? null : iJob.getOperation(iOperationNumber - 1));
    }

    /** Get the subsequent operation (if any)
     * @return subsequent operation
     **/
    public Operation getSubsequentOperation() {
        return (iOperationNumber + 1 == iJob.countOperations() ? null : iJob.getOperation(iOperationNumber + 1));
    }

    /** Get minimal starting time
     * @return minimal starting time
     **/
    public int getMinStartTime() {
        if (iOperationNumber == 0)
            return 0;
        else
            return getPrecedingOperation().getMinStartTime() + iProcessingTime;
    }

    /** Get maximal starting time
     * @return maximal starting time
     **/
    public int getMaxStartTime() {
        if (iOperationNumber + 1 == iJob.countOperations())
            return ((JobShopModel) getModel()).getTotalNumberOfSlots() - iProcessingTime;
        else
            return getSubsequentOperation().getMaxStartTime() - iProcessingTime;
    }

    /** Compares two operations -- job number and operation number must match */
    @Override
    public boolean equals(Object o) {
        if (o == null || !(o instanceof Operation))
            return false;
        Operation op = (Operation) o;
        return getJobNumber() == op.getJobNumber() && getOperationNumber() == op.getOperationNumber();
    }

    /** Initialozation -- fills the variable's domain */
    public void init() {
        setValues(computeValues());
    }

    private List<Location> computeValues() {
        List<Location> ret = new ArrayList<Location>();
        for (int i = getMinStartTime(); i <= getMaxStartTime(); i++)
            ret.add(new Location(this, i));
        return ret;
    }

    /** string representation -- for debuging and printing purposes */
    @Override
    public String toString() {
        return getName();
    }

    /**
     * Operation's name (e.g., O[2,4] where 2 is the job number and 4 is the
     * operation number
     */
    @Override
    public String getName() {
        return "O[" + getJobNumber() + "," + getOperationNumber() + "]";
    }
}
