/**
    * Logback: the reliable, generic, fast and flexible logging framework.
    * Copyright (C) 1999-2011, QOS.ch. All rights reserved.
    *
    * This program and the accompanying materials are dual-licensed under
    * either the terms of the Eclipse Public License v1.0 as published by
    * the Eclipse Foundation
    *
    *   or (per the licensee's choosing)
   *
   * under the terms of the GNU Lesser General Public License version 2.1
   * as published by the Free Software Foundation.
   */
  package ch.qos.logback.core.net;
  
  import java.io.IOException;
  import java.io.OutputStream;
  import java.net.SocketException;
  import java.net.UnknownHostException;
  
  import ch.qos.logback.core.AppenderBase;
  import ch.qos.logback.core.CoreConstants;
  import ch.qos.logback.core.Layout;
  
  /**
   * Base class for SyslogAppender.
   * 
   * @author Ceki Gülcü
   * 
   * @param <E>
   */
  public abstract class SyslogAppenderBase<E> extends AppenderBase<E> {
  
    final static String SYSLOG_LAYOUT_URL = CoreConstants.CODES_URL
        + "#syslog_layout";
    final static int MSG_SIZE_LIMIT = 256 * 1024;
  
    Layout<E> layout;
    String facilityStr;
    String syslogHost;
    protected String suffixPattern;
    SyslogOutputStream sos;
    int port = SyslogConstants.SYSLOG_PORT;
  
    public void start() {
      int errorCount = 0;
      if (facilityStr == null) {
        addError("The Facility option is mandatory");
        errorCount++;
      }
  
      try {
        sos = new SyslogOutputStream(syslogHost, port);
      } catch (UnknownHostException e) {
        addError("Could not create SyslogWriter", e);
        errorCount++;
      } catch (SocketException e) {
        addWarn(
            "Failed to bind to a random datagram socket. Will try to reconnect later.",
            e);
      }
  
      if (layout == null) {
        layout = buildLayout(facilityStr);
      }
  
      if (errorCount == 0) {
        super.start();
      }
    }
  
    abstract public Layout<E> buildLayout(String facilityStr);
  
    abstract public int getSeverityForEvent(Object eventObject);
  
    @Override
    protected void append(E eventObject) {
      if (!isStarted()) {
        return;
      }
  
      try {
        String msg = layout.doLayout(eventObject);
        if(msg == null) {
          return;
        }
        if (msg.length() > MSG_SIZE_LIMIT) {
          msg = msg.substring(0, MSG_SIZE_LIMIT);
        }
        sos.write(msg.getBytes());
        sos.flush();
        postProcess(eventObject, sos);
      } catch (IOException ioe) {
        addError("Failed to send diagram to " + syslogHost, ioe);
      }
    }
  
    protected void postProcess(Object event, OutputStream sw) {
  
   }
 
   /**
    * Returns the integer value corresponding to the named syslog facility.
    * 
    * @throws IllegalArgumentException
    *           if the facility string is not recognized
    */
   static public int facilityStringToint(String facilityStr) {
     if ("KERN".equalsIgnoreCase(facilityStr)) {
       return SyslogConstants.LOG_KERN;
     } else if ("USER".equalsIgnoreCase(facilityStr)) {
       return SyslogConstants.LOG_USER;
     } else if ("MAIL".equalsIgnoreCase(facilityStr)) {
       return SyslogConstants.LOG_MAIL;
     } else if ("DAEMON".equalsIgnoreCase(facilityStr)) {
       return SyslogConstants.LOG_DAEMON;
     } else if ("AUTH".equalsIgnoreCase(facilityStr)) {
       return SyslogConstants.LOG_AUTH;
     } else if ("SYSLOG".equalsIgnoreCase(facilityStr)) {
       return SyslogConstants.LOG_SYSLOG;
     } else if ("LPR".equalsIgnoreCase(facilityStr)) {
       return SyslogConstants.LOG_LPR;
     } else if ("NEWS".equalsIgnoreCase(facilityStr)) {
       return SyslogConstants.LOG_NEWS;
     } else if ("UUCP".equalsIgnoreCase(facilityStr)) {
       return SyslogConstants.LOG_UUCP;
     } else if ("CRON".equalsIgnoreCase(facilityStr)) {
       return SyslogConstants.LOG_CRON;
     } else if ("AUTHPRIV".equalsIgnoreCase(facilityStr)) {
       return SyslogConstants.LOG_AUTHPRIV;
     } else if ("FTP".equalsIgnoreCase(facilityStr)) {
       return SyslogConstants.LOG_FTP;
     } else if ("LOCAL0".equalsIgnoreCase(facilityStr)) {
       return SyslogConstants.LOG_LOCAL0;
     } else if ("LOCAL1".equalsIgnoreCase(facilityStr)) {
       return SyslogConstants.LOG_LOCAL1;
     } else if ("LOCAL2".equalsIgnoreCase(facilityStr)) {
       return SyslogConstants.LOG_LOCAL2;
     } else if ("LOCAL3".equalsIgnoreCase(facilityStr)) {
       return SyslogConstants.LOG_LOCAL3;
     } else if ("LOCAL4".equalsIgnoreCase(facilityStr)) {
       return SyslogConstants.LOG_LOCAL4;
     } else if ("LOCAL5".equalsIgnoreCase(facilityStr)) {
       return SyslogConstants.LOG_LOCAL5;
     } else if ("LOCAL6".equalsIgnoreCase(facilityStr)) {
       return SyslogConstants.LOG_LOCAL6;
     } else if ("LOCAL7".equalsIgnoreCase(facilityStr)) {
       return SyslogConstants.LOG_LOCAL7;
     } else {
       throw new IllegalArgumentException(facilityStr
           + " is not a valid syslog facility string");
     }
   }
 
   /**
    * Returns the value of the <b>SyslogHost</b> option.
    */
   public String getSyslogHost() {
     return syslogHost;
   }
 
   /**
    * The <b>SyslogHost</b> option is the name of the the syslog host where log
    * output should go.
    * 
    * <b>WARNING</b> If the SyslogHost is not set, then this appender will fail.
    */
   public void setSyslogHost(String syslogHost) {
     this.syslogHost = syslogHost;
   }
 
   /**
    * Returns the string value of the <b>Facility</b> option.
    * 
    * See {@link #setFacility} for the set of allowed values.
    */
   public String getFacility() {
     return facilityStr;
   }
 
   /**
    * The <b>Facility</b> option must be set one of the strings KERN, USER, MAIL,
    * DAEMON, AUTH, SYSLOG, LPR, NEWS, UUCP, CRON, AUTHPRIV, FTP, NTP, AUDIT,
    * ALERT, CLOCK, LOCAL0, LOCAL1, LOCAL2, LOCAL3, LOCAL4, LOCAL5, LOCAL6,
    * LOCAL7. Case is not important.
    * 
    * <p>
    * See {@link SyslogConstants} and RFC 3164 for more information about the
    * <b>Facility</b> option.
    */
   public void setFacility(String facilityStr) {
     if (facilityStr != null) {
       facilityStr = facilityStr.trim();
     }
     this.facilityStr = facilityStr;
   }
 
   /**
    * 
    * @return
    */
   public int getPort() {
     return port;
   }
 
   /**
    * The port number on the syslog server to connect to. Normally, you would not
    * want to change the default value, that is 514.
    */
   public void setPort(int port) {
     this.port = port;
   }
 
   public Layout<E> getLayout() {
     return layout;
   }
 
   public void setLayout(Layout<E> layout) {
     addWarn("The layout of a SyslogAppender cannot be set directly. See also "
         + SYSLOG_LAYOUT_URL);
   }
 
   @Override
   public void stop() {
     sos.close();
     super.stop();
   }
 
 /**
    * See {@link #setSuffixPattern(String).
    * 
    * @return
    */
   public String getSuffixPattern() {
     return suffixPattern;
   }
 
   /**
    * The <b>suffixPattern</b> option specifies the format of the
    * non-standardized part of the message sent to the syslog server.
    * 
    * @param suffixPattern
    */
   public void setSuffixPattern(String suffixPattern) {
     this.suffixPattern = suffixPattern;
   }
 }