/**
    * Logback: the reliable, generic, fast and flexible logging framework.
    * Copyright (C) 1999-2015, 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 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(Transform.escapeTags(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(Transform.escapeTags(event.getThreadName()));
         buf.append("\">\r\n");
 
         buf.append("  <log4j:message>");
         buf.append(Transform.escapeTags(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(Transform.escapeTags(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";
     }
 
 }