/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You under the Apache License, Version 2.0
    * (the "License"); you may not use this file except in compliance with
    * the License.  You may obtain a copy of the License at
    * 
    *      http://www.apache.org/licenses/LICENSE-2.0
   * 
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package org.apache.log4j;
  
  import org.apache.log4j.spi.LoggingEvent;
  import org.apache.log4j.spi.LocationInfo;
  import org.apache.log4j.helpers.Transform;
  
  /**
   * This layout outputs events in a HTML table.
   *
   * Appenders using this layout should have their encoding
   * set to UTF-8 or UTF-16, otherwise events containing
   * non ASCII characters could result in corrupted
   * log files.
   *
   *  @author Ceki Gülcü
   */
  public class HTMLLayout extends Layout {
  
    protected final int BUF_SIZE = 256;
    protected final int MAX_CAPACITY = 1024;
  
    static String TRACE_PREFIX = "<br>&nbsp;&nbsp;&nbsp;&nbsp;";
  
    // output buffer appended to when format() is invoked
    private StringBuffer sbuf = new StringBuffer(BUF_SIZE);
  
    /**
       A string constant used in naming the option for setting the the
       location information flag.  Current value of this string
       constant is <b>LocationInfo</b>.
  
       <p>Note that all option keys are case sensitive.
  
       @deprecated Options are now handled using the JavaBeans paradigm.
       This constant is not longer needed and will be removed in the
       <em>near</em> term.
  
    */
    public static final String LOCATION_INFO_OPTION = "LocationInfo";
  
    /**
       A string constant used in naming the option for setting the the
       HTML document title.  Current value of this string
       constant is <b>Title</b>.
    */
    public static final String TITLE_OPTION = "Title";
  
    // Print no location info by default
    boolean locationInfo = false;
  
    String title = "Log4J Log Messages";
  
    /**
       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;
    }
  
    /**
      The <b>Title</b> option takes a String value. This option sets the
      document title of the generated HTML document.
  
      <p>Defaults to 'Log4J Log Messages'.
    */
   public
   void setTitle(String title) {
     this.title = title;
   }
 
   /**
      Returns the current value of the <b>Title</b> option.
   */
   public
   String getTitle() {
     return title;
   }
 
  /**
      Returns the content type output by this layout, i.e "text/html".
   */
   public
   String getContentType() {
     return "text/html";
   }
 
   /**
      No options to activate.
   */
   public
   void activateOptions() {
   }
 
   public
   String format(LoggingEvent event) {
 
     if(sbuf.capacity() > MAX_CAPACITY) {
       sbuf = new StringBuffer(BUF_SIZE);
     } else {
       sbuf.setLength(0);
     }
 
     sbuf.append(Layout.LINE_SEP + "<tr>" + Layout.LINE_SEP);
 
     sbuf.append("<td>");
     sbuf.append(event.timeStamp - LoggingEvent.getStartTime());
     sbuf.append("</td>" + Layout.LINE_SEP);
 
     String escapedThread = Transform.escapeTags(event.getThreadName());
     sbuf.append("<td title=\"" + escapedThread + " thread\">");
     sbuf.append(escapedThread);
     sbuf.append("</td>" + Layout.LINE_SEP);
 
     sbuf.append("<td title=\"Level\">");
     if (event.getLevel().equals(Level.DEBUG)) {
       sbuf.append("<font color=\"#339933\">");
       sbuf.append(Transform.escapeTags(String.valueOf(event.getLevel())));
       sbuf.append("</font>");
     }
     else if(event.getLevel().isGreaterOrEqual(Level.WARN)) {
       sbuf.append("<font color=\"#993300\"><strong>");
       sbuf.append(Transform.escapeTags(String.valueOf(event.getLevel())));
       sbuf.append("</strong></font>");
     } else {
       sbuf.append(Transform.escapeTags(String.valueOf(event.getLevel())));
     }
     sbuf.append("</td>" + Layout.LINE_SEP);
 
     String escapedLogger = Transform.escapeTags(event.getLoggerName());
     sbuf.append("<td title=\"" + escapedLogger + " category\">");
     sbuf.append(escapedLogger);
     sbuf.append("</td>" + Layout.LINE_SEP);
 
     if(locationInfo) {
       LocationInfo locInfo = event.getLocationInformation();
       sbuf.append("<td>");
       sbuf.append(Transform.escapeTags(locInfo.getFileName()));
       sbuf.append(':');
       sbuf.append(locInfo.getLineNumber());
       sbuf.append("</td>" + Layout.LINE_SEP);
     }
 
     sbuf.append("<td title=\"Message\">");
     sbuf.append(Transform.escapeTags(event.getRenderedMessage()));
     sbuf.append("</td>" + Layout.LINE_SEP);
     sbuf.append("</tr>" + Layout.LINE_SEP);
 
     if (event.getNDC() != null) {
       sbuf.append("<tr><td bgcolor=\"#EEEEEE\" style=\"font-size : xx-small;\" colspan=\"6\" title=\"Nested Diagnostic Context\">");
       sbuf.append("NDC: " + Transform.escapeTags(event.getNDC()));
       sbuf.append("</td></tr>" + Layout.LINE_SEP);
     }
 
     String[] s = event.getThrowableStrRep();
     if(s != null) {
       sbuf.append("<tr><td bgcolor=\"#993300\" style=\"color:White; font-size : xx-small;\" colspan=\"6\">");
       appendThrowableAsHTML(s, sbuf);
       sbuf.append("</td></tr>" + Layout.LINE_SEP);
     }
 
     return sbuf.toString();
   }
 
   void appendThrowableAsHTML(String[] s, StringBuffer sbuf) {
     if(s != null) {
       int len = s.length;
       if(len == 0)
 	return;
       sbuf.append(Transform.escapeTags(s[0]));
       sbuf.append(Layout.LINE_SEP);
       for(int i = 1; i < len; i++) {
 	sbuf.append(TRACE_PREFIX);
 	sbuf.append(Transform.escapeTags(s[i]));
 	sbuf.append(Layout.LINE_SEP);
       }
     }
   }
 
   /**
      Returns appropriate HTML headers.
   */
   public
   String getHeader() {
     StringBuffer sbuf = new StringBuffer();
     sbuf.append("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\" \"http://www.w3.org/TR/html4/loose.dtd\">"  + Layout.LINE_SEP);
     sbuf.append("<html>" + Layout.LINE_SEP);
     sbuf.append("<head>" + Layout.LINE_SEP);
     sbuf.append("<title>" + title + "</title>" + Layout.LINE_SEP);
     sbuf.append("<style type=\"text/css\">"  + Layout.LINE_SEP);
     sbuf.append("<!--"  + Layout.LINE_SEP);
     sbuf.append("body, table {font-family: arial,sans-serif; font-size: x-small;}" + Layout.LINE_SEP);
     sbuf.append("th {background: #336699; color: #FFFFFF; text-align: left;}" + Layout.LINE_SEP);
     sbuf.append("-->" + Layout.LINE_SEP);
     sbuf.append("</style>" + Layout.LINE_SEP);
     sbuf.append("</head>" + Layout.LINE_SEP);
     sbuf.append("<body bgcolor=\"#FFFFFF\" topmargin=\"6\" leftmargin=\"6\">" + Layout.LINE_SEP);
     sbuf.append("<hr size=\"1\" noshade>" + Layout.LINE_SEP);
     sbuf.append("Log session start time " + new java.util.Date() + "<br>" + Layout.LINE_SEP);
     sbuf.append("<br>" + Layout.LINE_SEP);
     sbuf.append("<table cellspacing=\"0\" cellpadding=\"4\" border=\"1\" bordercolor=\"#224466\" width=\"100%\">" + Layout.LINE_SEP);
     sbuf.append("<tr>" + Layout.LINE_SEP);
     sbuf.append("<th>Time</th>" + Layout.LINE_SEP);
     sbuf.append("<th>Thread</th>" + Layout.LINE_SEP);
     sbuf.append("<th>Level</th>" + Layout.LINE_SEP);
     sbuf.append("<th>Category</th>" + Layout.LINE_SEP);
     if(locationInfo) {
       sbuf.append("<th>File:Line</th>" + Layout.LINE_SEP);
     }
     sbuf.append("<th>Message</th>" + Layout.LINE_SEP);
     sbuf.append("</tr>" + Layout.LINE_SEP);
     return sbuf.toString();
   }
 
   /**
      Returns the appropriate HTML footers.
   */
   public
   String getFooter() {
     StringBuffer sbuf = new StringBuffer();
     sbuf.append("</table>" + Layout.LINE_SEP);
     sbuf.append("<br>" + Layout.LINE_SEP);
     sbuf.append("</body></html>");
     return sbuf.toString();
   }
 
   /**
      The HTML layout handles the throwable contained in logging
      events. Hence, this method return <code>false</code>.  */
   public
   boolean ignoresThrowable() {
     return false;
   }
 }