/*
    * 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.commandexec.client;
  
  import io.netty.channel.Channel;
  import io.netty.channel.ChannelHandlerContext;
  import io.netty.channel.SimpleChannelInboundHandler;
  import org.waarp.commandexec.utils.LocalExecDefaultResult;
  import org.waarp.commandexec.utils.LocalExecResult;
  import org.waarp.common.crypto.ssl.WaarpSslUtility;
  import org.waarp.common.future.WaarpFuture;
  import org.waarp.common.logging.WaarpLogger;
  import org.waarp.common.logging.WaarpLoggerFactory;
  import org.waarp.common.utility.WaarpNettyUtil;
  
  /**
   * Handles a client-side channel for LocalExec
   */
  public class LocalExecClientHandler
      extends SimpleChannelInboundHandler<String> {
  
    /**
     * Internal Logger
     */
    private static final WaarpLogger logger =
        WaarpLoggerFactory.getLogger(LocalExecClientHandler.class);
  
    protected LocalExecResult result;
    protected StringBuilder back;
    protected boolean firstMessage = true;
    protected WaarpFuture future;
    protected final LocalExecClientInitializer factory;
    protected long delay;
    protected String command;
    protected Channel channel;
    protected final WaarpFuture ready = new WaarpFuture(true);
  
    /**
     * Constructor
     */
    public LocalExecClientHandler(final LocalExecClientInitializer factory) {
      this.factory = factory;
    }
  
    /**
     * Initialize the client status for a new execution
     *
     * @param delay
     * @param command
     */
    public final void initExecClient(final long delay, final String command) {
      result = new LocalExecResult(LocalExecDefaultResult.NoStatus);
      back = new StringBuilder();
      firstMessage = true;
      future = new WaarpFuture(true);
      this.delay = delay;
      this.command = command;
      // Sends the received line to the server.
      if (!ready.awaitOrInterruptible() && channel == null) {
        throw new RuntimeException("Cannot get client connected");
      }
      logger.debug("write command: {}", this.command);
      if (this.delay != 0) {
        WaarpNettyUtil.awaitOrInterrupted(
            channel.writeAndFlush(this.delay + " " + this.command + '\n'));
      } else {
        WaarpNettyUtil.awaitOrInterrupted(
            channel.writeAndFlush(this.command + '\n'));
      }
    }
  
    @Override
    public void channelActive(final ChannelHandlerContext ctx) throws Exception {
      channel = ctx.channel();
      factory.addChannel(channel);
      ready.setSuccess();
      super.channelActive(ctx);
    }
  
    /**
     * When closed, <br>
     * If no messaged were received => NoMessage error is set to future<br>
    * Else if an error was detected => Set the future to error (with or without
    * exception)<br>
    * Else if no error occurs => Set success to the future<br>
    */
   @Override
   public void channelInactive(final ChannelHandlerContext ctx)
       throws Exception {
     if (future == null || !future.isDone()) {
       // Should not be
       finalizeMessage();
     }
     super.channelInactive(ctx);
   }
 
   /**
    * Finalize a message
    */
   private void finalizeMessage() {
     if (result == null) {
       if (future != null) {
         future.cancel();
       }
       return;
     }
     if (firstMessage) {
       result.set(LocalExecDefaultResult.NoMessage);
     } else {
       result.setResult(back.toString());
     }
     if (result.getStatus() < 0) {
       if (result.getException() != null) {
         future.setFailure(result.getException());
       } else {
         future.cancel();
       }
     } else {
       future.setSuccess();
     }
   }
 
   /**
    * Waiting for the close of the exec
    *
    * @return The LocalExecResult
    */
   public final LocalExecResult waitFor(final long delay) {
     if (delay <= 0) {
       future.awaitOrInterruptible();
     } else {
       future.awaitOrInterruptible(delay);
     }
     result.setSuccess(future.isSuccess());
     return result;
   }
 
   /**
    * Action to do before close
    */
   public final void actionBeforeClose(final Channel channel) {
     // here nothing to do
   }
 
   @Override
   protected void channelRead0(final ChannelHandlerContext ctx, String mesg) {
     // Add the line received from the server.
     // If first message, then take the status and then the message
     if (firstMessage) {
       firstMessage = false;
       final int pos = mesg.indexOf(' ');
       try {
         result.setStatus(Integer.parseInt(mesg.substring(0, pos)));
       } catch (final NumberFormatException e1) {
         // Error
         logger.debug(
             command + ':' + "Bad Transmission: " + mesg + "\n\t" + back);
         result.set(LocalExecDefaultResult.BadTransmition);
         back.append(mesg);
         actionBeforeClose(ctx.channel());
         WaarpSslUtility.closingSslChannel(ctx.channel());
         return;
       }
       mesg = mesg.substring(pos + 1);
       if (mesg.startsWith(LocalExecDefaultResult.ENDOFCOMMAND)) {
         logger.debug("{}:Receive End of Command", command);
         result.setResult(LocalExecDefaultResult.NoMessage.getResult());
         back.append(result.getResult());
         finalizeMessage();
       } else {
         result.setResult(mesg);
         back.append(mesg);
       }
     } else if (mesg.startsWith(LocalExecDefaultResult.ENDOFCOMMAND)) {
       logger.debug("{}:Receive End of Command", command);
       finalizeMessage();
     } else {
       back.append('\n').append(mesg);
     }
   }
 
   @Override
   public void exceptionCaught(final ChannelHandlerContext ctx,
                               final Throwable cause) {
     logger.warn(command + ':' +
                 "Unexpected exception from Outband while get information: " +
                 firstMessage, cause);
     if (firstMessage) {
       firstMessage = false;
       result.set(LocalExecDefaultResult.BadTransmition);
       result.setException((Exception) cause);
       back = new StringBuilder("Error in LocalExec: ").append(
           result.getException().getMessage()).append('\n');
     } else {
       back.append("\nERROR while receiving answer: ");
       result.setException((Exception) cause);
       back.append(result.getException().getMessage()).append('\n');
     }
     actionBeforeClose(ctx.channel());
     WaarpSslUtility.closingSslChannel(ctx.channel());
   }
 }