/*
 * [Changes.java]
 *
 * Summary: Notice the changes between files we distributed before and what we are about to distribute.
 *
 * Copyright: (c) 2009-2017 Roedy Green, Canadian Mind Products, http://mindprod.com
 *
 * Licence: This software may be copied and used freely for any purpose but military.
 *          http://mindprod.com/contact/nonmil.html
 *
 * Requires: JDK 1.8+
 *
 * Created with: JetBrains IntelliJ IDEA IDE http://www.jetbrains.com/idea/
 *
 * Version History:
 * 10.2 2009-04-03 tidy up code to check presence of necessary files to make it more WORA.
 *                 When done have filesToDistribute sorted by MaxiFD.BY_DATE_AND_FILENAME
 */
package com.mindprod.replicatorsender;

import com.mindprod.sorted.Merge;
import com.mindprod.sorted.SortedArrayList;

/**
 * Notice the changes between files we distributed before and what we are about to distribute.
 *
 * @author Roedy Green, Canadian Mind Products
 * @version 10.2 2009-04-03 tidy up code to check presence of necessary files to make it more WORA.
 * When done have filesToDistribute sorted by MaxiFD.BY_DATE_AND_FILENAME
 * @since 2002-09-10
 */
final class Changes
    {
    /**
     * Avoid repacking unchanged, still extant files in new zips.
     */
    @SuppressWarnings( { "UnusedAssignment" } )
    private static void avoidAlreadyDistributed()
        {
        // compare by filename and elapsedTime, old in zip replaces new if totally
        // unchanged.
        // If timestamps don't match, we use the new file, otherwise the old.
        ReplicatorSender.oldFilesDistributed
                .sort( MaxiFD.BY_DATE_AND_FILENAME );
        // collect unchanged, just to get count
        SortedArrayList unchanged =
                Merge.intersection( ReplicatorSender.oldFilesDistributed,
                        ReplicatorSender.filesToDistribute,
                        MaxiFD.BY_DATE_AND_FILENAME );
        StatsForSender.recentUnchangedFilesCount = unchanged.size();
        unchanged = null; // free RAM
        // mixture of old, updated and new, no deletions.
        ReplicatorSender.filesToDistribute =
                Merge.replace( ReplicatorSender.filesToDistribute,
                        ReplicatorSender.oldFilesDistributed,
                        MaxiFD.BY_DATE_AND_FILENAME );
        StatsForSender.recentNewFilesCount = ReplicatorSender.filesToDistribute.size()
                                             - StatsForSender.recentUnchangedFilesCount
                                             - StatsForSender.recentUpdatedFilesCount;
        }

    /**
     * Newly appearing files with old dates, must be given recent clumping dates to be handled properly. It is too late
     * to assign them to the natural zip. They must be lumped just before the new files.
     */
    private static void handleLateArrivals()
        {
        // newly appearing files prior to this cutoff date will have to be
        // redated so they will fit in a new jar.
        ReplicatorSender.filesToDistribute
                .sort( MaxiFD.BY_DATE_AND_FILENAME );
        for ( MaxiFD fd : ReplicatorSender.filesToDistribute )
            {
            if ( fd.getTimestamp() >= ReplicatorSender.cutOffTimestamp )
                {
                break;
                }
            if ( fd.getZipNumber() == 0 )
                {
                // does not disturb BY_DATE_AND_FILENAME order.
                fd.setClumping( ReplicatorSender.cutOffTimestamp );
                }
            } // end for
        }

    /**
     * detect and handle changes since last distribution.
     */
    public static void process()
        {
        avoidAlreadyDistributed();
        handleLateArrivals();
        StatsForSender.activeFilesCount = ReplicatorSender.filesToDistribute.size();
        }
    }