/*
 * Copyright (c) 2003, KNOPFLERFISH project
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following
 * conditions are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above
 *   copyright notice, this list of conditions and the following
 *   disclaimer in the documentation and/or other materials
 *   provided with the distribution.
 *
 * - Neither the name of the KNOPFLERFISH project nor the names of its
 *   contributors may be used to endorse or promote products derived
 *   from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package org.knopflerfish.bundle.consoletelnet;

import java.io.IOException;
import java.io.OutputStream;
import java.io.DataOutputStream;
import java.io.FilterOutputStream;
import java.io.ByteArrayOutputStream;

/**
 ** This extension of FilterOutputStream makes the following
 ** translations on data in the output stream
 **
 ** CR LF to no change
 ** CR n, when n != LF to CR NULL n
 ** n LF to n CR LF
 **
 ** All characters in the output buffer are 
 ** anded with a mask from the session.
 ** This mask is either 0x7F (7 bit) or 0xFF (8 bit)
 **
 ** It also has a clear method to empty the output buffer
 ** and a writeCommand method to send telnet commands.
 **
 */

public class TelnetOutputStream extends FilterOutputStream {
  private TelnetSession ts;
  private ByteArrayOutputStream baos;	// Intermediate byte array stream
  private DataOutputStream dos2;	// Internal DataOutputStream
  private boolean prevWasCR = false;	// True if previous char was CR

  public TelnetOutputStream (OutputStream os, TelnetSession ts) {
    super (os);
    this.ts = ts;
    OutputStream os1 = super.out;	// get the underlaying stream
    baos = new ByteArrayOutputStream(); // intermediate array stream
    super.out = baos;			// replace underlying Stream with a ByteArrayOutputStream
    dos2 = new DataOutputStream (os1);	// a new OutputStream that uses the original output stream
  }
  
  /**
   ** Override flush and close methods,
   */

  public void flush() throws IOException {
    scanBuf();
    dos2.flush();
  }
 
  public void close() throws IOException {
    flush();
    baos.close();
    dos2.close();
  }

  /**
   ** Override all write methods, add CRLF when appropriate
   */

  public void write (byte[] b) throws IOException {
    baos.write(b);
  }

  public void write (byte[] b, int off, int len) throws IOException { 
    baos.write(b, off, len);
  }

  public void write (int b) throws IOException { 
    baos.write(b);
  }

  /**
   ** Scan the output buffer for:
   **
   ** CR LF to no change
   ** CR n, when n != LF to CR NULL n
   ** n LF to n CR LF
   **
   */
  
  private synchronized void scanBuf() throws IOException {
    byte [] buf =  baos.toByteArray();
    baos.reset();
    byte mask = (byte) ts.getMask();

    for (int i = 0; i < buf.length; i++) {
      if (prevWasCR == true) {
        if (buf[i] != (byte) TCC.LF) { // add a LF
          dos2.write ((byte) TCC.LF);
          dos2.write (buf[i] & mask);
        } else {
          dos2.write (buf[i] & mask);
        }
      } else {
        if (buf[i] == (byte) TCC.LF) { // a single LF -> CRLF
          dos2.write ((byte) TCC.CR);
          dos2.write ((byte) TCC.LF);
        } else {
          dos2.write (buf[i] & mask);
        }
      }
      prevWasCR = (buf[i] == (byte) TCC.CR) ? true : false;
    }
  }

  public synchronized void reset() {
    baos.reset();
  }

  /**
   ** Write a telnet command in the output stream.
   **
   ** @parameter tc, command string to write
   */

  public synchronized void writeCommand(String tc) throws IOException {
    if (tc != null) {
      dos2.writeBytes(tc);
      dos2.flush();
    }
  }
}