/*
    * This file is part of Waarp Project (named also Waarp or GG).
    *
    *  Copyright (c) 2019, Waarp SAS, and individual contributors by the @author
    *  tags. See the COPYRIGHT.txt in the distribution for a full listing of
    * individual contributors.
    *
    *  All Waarp Project is free software: you can redistribute it and/or
    * modify it under the terms of the GNU General Public License as published by
   * the Free Software Foundation, either version 3 of the License, or (at your
   * option) any later version.
   *
   * Waarp 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 General Public License for more details.
   *
   *  You should have received a copy of the GNU General Public License along with
   * Waarp . If not, see <http://www.gnu.org/licenses/>.
   */
  package org.waarp.ftp.core.control;
  
  import io.netty.channel.Channel;
  import org.waarp.common.command.exception.CommandAbstractException;
  import org.waarp.common.file.Restart;
  import org.waarp.common.file.filesystembased.FilesystemBasedOptsMLSxImpl;
  import org.waarp.ftp.core.command.AbstractCommand;
  import org.waarp.ftp.core.command.FtpCommandCode;
  import org.waarp.ftp.core.data.FtpTransfer;
  import org.waarp.ftp.core.file.FtpAuth;
  import org.waarp.ftp.core.file.FtpDir;
  import org.waarp.ftp.core.session.FtpSession;
  
  /**
   * This class is to be implemented in order to allow Business actions according
   * to FTP service
   */
  public abstract class BusinessHandler {
    private static final String FILENAME = " \"filename\"";
    private static final String[] PROPERTIES_0_LENGTH = new String[0];
    /**
     * NettyHandler that holds this BusinessHandler
     */
    private NetworkHandler networkHandler;
  
    /**
     * FtpSession
     */
    private FtpSession session;
  
    /**
     * Constructor with no argument (mandatory)
     */
    protected BusinessHandler() {
      // nothing to do
    }
  
    /**
     * Called when the NetworkHandler is created
     *
     * @param networkHandler the networkHandler to set
     */
    public final void setNetworkHandler(final NetworkHandler networkHandler) {
      this.networkHandler = networkHandler;
      session = this.networkHandler.getFtpSession();
    }
  
    /**
     * @return the networkHandler
     */
    public final NetworkHandler getNetworkHandler() {
      return networkHandler;
    }
  
    // Some helpful functions
  
    /**
     * @return the ftpSession
     */
    public final FtpSession getFtpSession() {
      return session;
    }
  
    /**
     * Create a new AuthInterface according to business choice
     *
     * @return the new FtpAuth
     */
    public abstract FtpAuth getBusinessNewAuth();
  
    /**
     * Create a new FtpDir according to business choice
     *
     * @return the new FtpDir
     */
    public abstract FtpDir getBusinessNewDir();
  
    /**
     * Create a new Restart according to business choice
     *
    * @return the new Restart
    */
   public abstract Restart getBusinessNewRestart();
 
   /**
    * @param arg the argument from HELP command
    *
    * @return the string to return to the client for the HELP command
    */
   public abstract String getHelpMessage(String arg);
 
   /**
    * @return the string to return to the client for the FEAT command
    */
   public abstract String getFeatMessage();
 
   protected final String getSslFeatMessage() {
     return "AUTH TLS\nAUTH SSL\nCCC\nPROT P\nPROT C";
   }
 
   /**
    * @return the string to return to the client for the FEAT command without
    *     surrounding by "Extensions
    *     supported:\n" and "\nEnd"
    */
   protected final String getDefaultFeatMessage() {
     final StringBuilder builder = new StringBuilder();
     builder.append(FtpCommandCode.MODE.name()).append(" Z\n")
            .append(FtpCommandCode.MDTM.name()).append('\n')
            .append(FtpCommandCode.MLSD.name())
            .append(getFtpSession().getDir().getOptsMLSx().getFeat())
            .append('\n').append(FtpCommandCode.MLST.name())
            .append(getFtpSession().getDir().getOptsMLSx().getFeat())
            .append('\n').append(FtpCommandCode.SIZE.name()).append('\n')
            .append(FtpCommandCode.XCUP.name()).append('\n')
            .append(FtpCommandCode.XCWD.name()).append('\n')
            .append(FtpCommandCode.XMKD.name()).append('\n')
            .append(FtpCommandCode.XPWD.name()).append('\n')
            .append(FtpCommandCode.XRMD.name()).append('\n')
            .append(FtpCommandCode.PASV.name()).append('\n')
            .append(FtpCommandCode.ALLO.name()).append('\n')
            .append(FtpCommandCode.EPRT.name()).append('\n')
            .append(FtpCommandCode.EPSV.name()).append('\n')
            .append(FtpCommandCode.XCRC.name()).append(' ').append(FILENAME)
            .append('\n').append(FtpCommandCode.XMD5.name()).append(' ')
            .append(FILENAME).append('\n').append(FtpCommandCode.XSHA1.name())
            .append(' ').append(FILENAME).append('\n')
            .append(FtpCommandCode.XDIGEST.name()).append(' ').append(
                "Digest_algo_among(CRC32,ADLER32,MD5,MD2,SHA-1,SHA-256,SHA-384,SHA-512)")
            .append(' ').append(FILENAME).append('\n')
            .append(FtpCommandCode.SITE.name()).append(' ')
            .append(FtpCommandCode.XCRC.name())
            // .append(" \"filename\"")
            .append('\n').append(FtpCommandCode.SITE.name()).append(' ')
            .append(FtpCommandCode.XMD5.name())
            // .append(" \"filename\"")
            .append('\n').append(FtpCommandCode.SITE.name()).append(' ')
            .append(FtpCommandCode.XSHA1.name())
            // .append(" \"filename\"")
            .append('\n').append(FtpCommandCode.SITE.name()).append(' ')
            .append(FtpCommandCode.XDIGEST.name()).append(' ').append(
                "Digest_algo_among(CRC32,ADLER32,MD5,MD2,SHA-1,SHA-256,SHA-384,SHA-512)")
            // .append(" \"filename\"")
            .append('\n').append("LAN EN*").append('\n')
            .append(FtpCommandCode.REST.name()).append(" STREAM\n");
     return builder.toString();
   }
 
   /**
    * @param args
    *
    * @return the string to return to the client for the FEAT command
    *
    * @throws CommandAbstractException
    */
   public abstract String getOptsMessage(String[] args)
       throws CommandAbstractException;
 
   /**
    * Check if a command pass to SITE command is legal
    *
    * @param session
    * @param line
    *
    * @return the AbstractCommand to execute if it is a Specialized Command,
    *     else
    *     Null
    */
   public abstract AbstractCommand getSpecializedSiteCommand(FtpSession session,
                                                             String line);
 
   /**
    * @param args
    *
    * @return the string to return to the client for the FEAT command for the
    *     MLSx argument
    */
   protected final String getMLSxOptsMessage(final String[] args) {
     String[] properties = PROPERTIES_0_LENGTH;
     if (args.length >= 2) {
       properties = args[1].split(";");
     }
 
     final FilesystemBasedOptsMLSxImpl optsMLSx =
         (FilesystemBasedOptsMLSxImpl) getFtpSession().getDir().getOptsMLSx();
     optsMLSx.setOptsModify((byte) 0);
     optsMLSx.setOptsPerm((byte) 0);
     optsMLSx.setOptsSize((byte) 0);
     optsMLSx.setOptsType((byte) 0);
     for (final String propertie : properties) {
       if ("modify".equalsIgnoreCase(propertie)) {
         optsMLSx.setOptsModify((byte) 1);
       } else if ("perm".equalsIgnoreCase(propertie)) {
         optsMLSx.setOptsPerm((byte) 1);
       } else if ("size".equalsIgnoreCase(propertie)) {
         optsMLSx.setOptsSize((byte) 1);
       } else if ("type".equalsIgnoreCase(propertie)) {
         optsMLSx.setOptsType((byte) 1);
       }
     }
     return args[0] + ' ' + FtpCommandCode.OPTS.name() + optsMLSx.getFeat();
   }
 
   /**
    * Is executed when the channel is closed, just before cleaning and just
    * after.<br>
    * <I>Note: In some circumstances, it could be a good idea to call the clean
    * operation on FtpAuth in order to
    * relax constraints on user authentication. It will be called however at
    * least when the session will be clean
    * just after this call.</I>
    */
   public abstract void executeChannelClosed();
 
   /**
    * To Clean the session attached objects
    */
   protected abstract void cleanSession();
 
   /**
    * Clean the BusinessHandler.
    */
   public final void clear() {
     cleanSession();
   }
 
   /**
    * Is executed when the channel is connected after the handler is on, before
    * answering OK or not on
    * connection, except if the global service is going to shutdown.
    *
    * @param channel
    */
   public abstract void executeChannelConnected(Channel channel);
 
   /**
    * Run when an exception is get before the channel is closed. This must set
    * a
    * correct answer.
    *
    * @param e
    */
   public abstract void exceptionLocalCaught(Throwable e);
 
   /**
    * This method is called for every received message before the execution of
    * the command. If an exception is
    * raised, the reply is immediate and no action taken.
    *
    * @throws CommandAbstractException
    */
   public abstract void beforeRunCommand() throws CommandAbstractException;
 
   /**
    * This method is called for every received message after the execution of
    * the
    * command but before the final
    * reply to the client. If an exception is raised, the reply is immediate.
    * This is the last call before
    * finishing the command.
    *
    * @throws CommandAbstractException
    */
   public abstract void afterRunCommandOk() throws CommandAbstractException;
 
   /**
    * Run when a FTP exception is catch (the channel is not necessary closed
    * after). This must set a correct
    * answer and a correct code of reply. If the code of reply is 421, then the
    * channel will be closed after this
    * call. This is the last call before finishing the command.
    *
    * @param e
    */
   public abstract void afterRunCommandKo(CommandAbstractException e);
 
   /**
    * Run when a transfer is finished (eventually in error) but before
    * answering.
    * Note that this is called only
    * for a Transfer Request (or LIST) but called before afterRunCommandXX is
    * called (Ok or Ko).
    *
    * @param transfer
    *
    * @throws CommandAbstractException
    */
   public abstract void afterTransferDoneBeforeAnswer(FtpTransfer transfer)
       throws CommandAbstractException;
 }