/*
 * [PersistReceiverState.java]
 *
 * Summary: Persist receiver state of what has already been downloaded in the registry.
 *
 * 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:
 *  1.0 2007-07-18 Created with IntelliJ IDEA.
 */
package com.mindprod.replicator;

import com.mindprod.common18.EIO;
import com.mindprod.replicatorcommon.Config;
import com.mindprod.replicatorcommon.MiniFD;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;

import static java.lang.System.*;

/**
 * Persist receiver state of what has already been downloaded in the registry.
 *
 * @author Roedy Green, Canadian Mind Products
 * @version 1.0 2007-07-18 Created with IntelliJ IDEA.
 * @since 2007
 */
final class PersistReceiverState
    {
    /**
     * Layout version number.
     */
    private static final long serialVersionUID = 501L;

    /**
     * The most recent file we have processed so far. Since we process zips in order, we must have handled everything
     * prior to this. We need not download zips prior to this.
     */
    static long clumpingProcessedSoFar;

    /**
     * restore state of Receiver from receiver.ser
     */
    static void restoreStateFromReceiverSer()
        {
        String persistFilename =
                ConfigForReceiver.RECEIVER_ZIP_STAGING_DIR + File.separatorChar
                + ConfigForReceiver.PERSIST_RECEIVER_SER;
        try
            {
            ObjectInputStream ois = EIO.getObjectInputStream( new File( persistFilename ), 4 * 1024, false );
            long fileSerialVersionUID = ( Long ) ois.readObject();
            if ( fileSerialVersionUID != PersistReceiverState.serialVersionUID )
                {
                throw new IOException( "wrong version of "
                                       + ConfigForReceiver
                                               .PERSIST_RECEIVER_SER
                                       + " got: "
                                       + fileSerialVersionUID
                                       + " expected: "
                                       + MiniFD
                                               .serialVersionUID );
                }
            clumpingProcessedSoFar = ( Long ) ois.readObject();
            Log.println( "So far files have been downloaded up to "
                         + Config.TIMESTAMP_MILLISECOND_FORMAT
                                 .format( clumpingProcessedSoFar ) );
            ois.close();
            }
        catch ( Exception e )
            {
            final String trouble =
                    new StringBuilder( 100 ).append(
                            "Unable to retrieve previous program state from " )
                            .append( persistFilename )
                            .append( "\n" )
                            .append( e.getMessage() )
                            .append( "\n" )
                            .append( "Incompatible version. Starting over." )
                            .toString();
            err.println( trouble );
            Log.println( trouble );
            clumpingProcessedSoFar = 0;
            }
        }

    /**
     * Save state of client in receiver.ser
     */
    static void saveStateToReceiverSer()
        {
        String persistFilename = ConfigForReceiver
                                         .RECEIVER_ZIP_STAGING_DIR + File
                                         .separatorChar + ConfigForReceiver
                                         .PERSIST_RECEIVER_SER;
        try
            {
            FileOutputStream fos = new FileOutputStream( persistFilename );
            ObjectOutputStream oos = new ObjectOutputStream( fos );
            oos.writeObject( PersistReceiverState.serialVersionUID );
            oos.writeObject( clumpingProcessedSoFar );
            oos.close();
            }
        catch ( IOException e )
            {
            Replicator.fatal( "Unable to save system state in receiver.ser."
                              + "\n"
                              + e.getMessage() );
            }
        }
    }