/**
    * Logback: the reliable, generic, fast and flexible logging framework.
    * Copyright (C) 1999-2009, 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.classic.log4j;
  
  import java.util.Map;
  import java.util.Set;
  import java.util.Map.Entry;
  
  import ch.qos.logback.classic.spi.ILoggingEvent;
  import ch.qos.logback.classic.spi.IThrowableProxy;
  import ch.qos.logback.classic.spi.StackTraceElementProxy;
  import ch.qos.logback.core.CoreConstants;
  import ch.qos.logback.core.LayoutBase;
  import ch.qos.logback.core.helpers.Transform;
  
  // Code is based on revision 309623 of org.apache.log4j.xml.XMLLayout dated "Wed
  // Jul 31 09:25:14 2002 UTC" as authored by Ceki Gulcu.
  // See also http://tinyurl.com/dch9mr
  
  /**
   * 
   * Generates log4j.dtd compliant XML documents.
   * 
   * 
   * @author Ceki Gülcü
   */
  public class XMLLayout extends LayoutBase<ILoggingEvent> {
  
    private final int DEFAULT_SIZE = 256;
    private final int UPPER_LIMIT = 2048;
  
    private StringBuilder buf = new StringBuilder(DEFAULT_SIZE);
    private boolean locationInfo = false;
    private boolean properties = false;
  
    @Override
    public void start() {
      super.start();
    }
  
    /**
     * The <b>LocationInfo</b> option takes a boolean value. By default, it is
     * set to false which means there will be no location information output by
     * this layout. If the the option is set to true, then the file name and line
     * number of the statement at the origin of the log statement will be output.
     * 
     * <p>If you are embedding this layout within an {@link
     * org.apache.log4j.net.SMTPAppender} then make sure to set the
     * <b>LocationInfo</b> option of that appender as well.
     */
    public void setLocationInfo(boolean flag) {
      locationInfo = flag;
    }
  
    /**
     * Returns the current value of the <b>LocationInfo</b> option.
     */
    public boolean getLocationInfo() {
      return locationInfo;
    }
  
    /**
     * Sets whether MDC key-value pairs should be output, default false.
     * 
     * @param flag
     *                new value.
     * @since 1.2.15
     */
    public void setProperties(final boolean flag) {
      properties = flag;
    }
  
    /**
     * Gets whether MDC key-value pairs should be output.
     * 
     * @return true if MDC key-value pairs are output.
     * @since 1.2.15
     */
    public boolean getProperties() {
      return properties;
    }
  
    /**
     * Formats a {@link ILoggingEvent} in conformity with the log4j.dtd.
     */
    public String doLayout(ILoggingEvent event) {
  
      // Reset working buffer. If the buffer is too large, then we need a new
     // one in order to avoid the penalty of creating a large array.
     if (buf.capacity() > UPPER_LIMIT) {
       buf = new StringBuilder(DEFAULT_SIZE);
     } else {
       buf.setLength(0);
     }
 
     // We yield to the \r\n heresy.
 
     buf.append("<log4j:event logger=\"");
     buf.append(event.getLoggerName());
     buf.append("\"\r\n");
     buf.append("             timestamp=\"");
     buf.append(event.getTimeStamp());
     buf.append("\" level=\"");
     buf.append(event.getLevel());
     buf.append("\" thread=\"");
     buf.append(event.getThreadName());
     buf.append("\">\r\n");
 
     buf.append("  <log4j:message><![CDATA[");
     // Append the rendered message. Also make sure to escape any
     // existing CDATA sections.
     Transform.appendEscapingCDATA(buf, event.getFormattedMessage());
     buf.append("]]></log4j:message>\r\n");
 
     // logback does not support NDC
     // String ndc = event.getNDC();
 
 
     IThrowableProxy tp = event.getThrowableProxy();
     if (tp != null) {
       StackTraceElementProxy[] stepArray = tp.getStackTraceElementProxyArray();
       buf.append("  <log4j:throwable><![CDATA[");
       for (StackTraceElementProxy step : stepArray) {
         buf.append(CoreConstants.TAB);
         buf.append(step.toString());
         buf.append("\r\n");
       }
       buf.append("]]></log4j:throwable>\r\n");
     }
 
     if (locationInfo) {
       StackTraceElement[] callerDataArray = event.getCallerData();
       if (callerDataArray != null && callerDataArray.length > 0) {
         StackTraceElement immediateCallerData = callerDataArray[0];
         buf.append("  <log4j:locationInfo class=\"");
         buf.append(immediateCallerData.getClassName());
         buf.append("\"\r\n");
         buf.append("                      method=\"");
         buf.append(Transform.escapeTags(immediateCallerData.getMethodName()));
         buf.append("\" file=\"");
         buf.append(immediateCallerData.getFileName());
         buf.append("\" line=\"");
         buf.append(immediateCallerData.getLineNumber());
         buf.append("\"/>\r\n");
       }
     }
 
     /*
      * <log4j:properties> <log4j:data name="name" value="value"/>
      * </log4j:properties>
      */
     if (this.getProperties()) {
       Map<String, String> propertyMap = event.getMDCPropertyMap();
 
       if ((propertyMap != null) && (propertyMap.size() != 0)) {
         Set<Entry<String, String>> entrySet = propertyMap.entrySet();
         buf.append("  <log4j:properties>");
         for (Entry<String, String> entry : entrySet) {
           buf.append("\r\n    <log4j:data");
           buf.append(" name='" + Transform.escapeTags(entry.getKey()) + "'");
           buf.append(" value='" + Transform.escapeTags(entry.getValue()) + "'");
           buf.append(" />");
         }
         buf.append("\r\n  </log4j:properties>");
       }
     }
 
     buf.append("\r\n</log4j:event>\r\n\r\n");
 
     return buf.toString();
   }
 
   @Override
   public String getContentType() {
     return "text/xml";
   }
 
 }