package com.runjva.logback.xml;

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Map;
import java.util.Set;
import java.util.Map.Entry;

import ch.qos.logback.classic.pattern.ClassOfCallerConverter;
import ch.qos.logback.classic.pattern.FileOfCallerConverter;
import ch.qos.logback.classic.pattern.LineOfCallerConverter;
import ch.qos.logback.classic.pattern.MethodOfCallerConverter;
import ch.qos.logback.classic.spi.LoggingEvent;
import ch.qos.logback.classic.spi.ThrowableDataPoint;
import ch.qos.logback.classic.spi.ThrowableProxy;
import ch.qos.logback.core.CoreConstants;

/**
 * <p>
 * XMLLayout creates XML fragments conforming to the log4j.dtd from the Apache
 * log4j project, and generates output compatible with the log4j XMLLayout
 * class. Files written with this layout are readable by Chainsaw (note that
 * output is in 7-bit ASCII so encoding should not be a problem).
 * </p>
 * <p>
 * The physical layout is intended to be somewhat readable by human eyes. Each
 * event generates two lines. The first starts with
 * 
 * <pre>
 * &lt;log4j:event time='2009-02-04 13:00:16,650' logger='com.runjva.logback.xml.XMLLayoutMain'
 * </pre>
 * 
 * where the time attribute (which is valid but unused in the log4j XMLLayout)
 * is used to render a humanly readable form of the timestamp in the ISO8601
 * pattern used in PatternLayout dates. The second line starts with
 * 
 * <pre>
 * &lt;log4j:message&gt;A debug message&lt;/log4j:message&gt;
 * </pre>
 * 
 * which is the message with a prefix common to all lines giving the same
 * indention hopefully making it readable to the human eye.
 * </p>
 * 
 */
public class XMLLayout extends ch.qos.logback.core.LayoutBase<LoggingEvent> {

	// The following attributes are listed on

	// http://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/xml/XMLLayout.html
	boolean locationInfo = true;
	boolean properties = true;

	DateFormat simpleFormat = new SimpleDateFormat(
			CoreConstants.ISO8601_PATTERN);

	public String doLayout(LoggingEvent event) {
		/*
		 * <log4j:event logger="foo" time="whee" timestamp="0" thread="thread"
		 * level="info"> <log4j:message>Hey you!</log4j:message> <log4j:NDC/>
		 * <log4j:throwable/> <log4j:locationInfo class="Foo" method="bar"
		 * file="Foo.java" line="10"/> <log4j:properties> <log4j:data
		 * name="name" value="value"/> </log4j:properties> </log4j:event>
		 */
		java.util.Date then = new java.util.Date(event.getTimeStamp());

		StringBuffer sb = new StringBuffer();
		sb.append("<log4j:event");
		sb.append(" time='" + q(simpleFormat.format(then)) + "'");
		sb.append(" logger='" + q(event.getLoggerRemoteView().getName()) + "'");
		sb.append(" timestamp='" + event.getTimeStamp() + "'");
		sb.append(" thread='" + q(event.getThreadName()) + "'");
		sb.append(" level='" + q(event.getLevel().toString()) + "'");
		sb.append(">");
		sb.append("\n");
		sb.append("<log4j:message>");
		sb.append(q(event.getFormattedMessage()));
		sb.append("</log4j:message>");
		// <log4j:NDC/>
		// not available in slf4j

		// <log4j:throwable/> #CONTENT is lines separated with \n
		ThrowableProxy throwableProxy = event.getThrowableProxy();
		if (throwableProxy != null) {
			sb.append("<log4j:throwable>");
			ThrowableDataPoint[] dataPoints;
			dataPoints = throwableProxy.getThrowableDataPointArray();

			for (int i = 0; i < dataPoints.length; i++) {
				ThrowableDataPoint throwableDataPoint = dataPoints[i];
				sb.append(q(throwableDataPoint.toString()));
				sb.append(q("\n"));
			}
			sb.append("</log4j:throwable>");
		}
		// <log4j:locationInfo class="Foo" method="bar" file="Foo.java"
		// line="10"/>
		if (this.getLocationInfo()) {
			sb.append("<log4j:locationInfo");
			sb.append(" class='"
					+ q(new ClassOfCallerConverter().convert(event)) + "'");
			sb.append(" method='"
					+ q(new MethodOfCallerConverter().convert(event)) + "'");
			sb.append(" file='" + q(new FileOfCallerConverter().convert(event))
					+ "'");
			sb.append(" line='" + q(new LineOfCallerConverter().convert(event))
					+ "'");
			sb.append(" />");
		}
		/*
		 * <log4j:properties> <log4j:data name="name" value="value"/>
		 * </log4j:properties>
		 */
		if (this.getProperties()) {
			Map<String, String> propertyMap = event.getMDCPropertyMap();
			if (propertyMap != null) {
				Set<Entry<String, String>> entrySet = propertyMap.entrySet();
				sb.append("<log4j:properties>");
				for (Entry<String, String> entry : entrySet) {
					sb.append("<log4j:data");
					sb.append(" name='" + q(entry.getKey()) + "'");
					sb.append(" value='" + q(entry.getValue()) + "'");
					sb.append(" />");
				}
				sb.append("</log4j:properties>");
			}
		}

		sb.append("</log4j:event>\n");

		// System.err.println(" << " + sb.toString());
		return sb.toString();
	}

	public boolean getLocationInfo() {
		return locationInfo;
	}

	/**
	 * setLocationInfo sets the locationInfo flag. If true each event layouted
	 * by XMLLayout include the file name and line number where the log event
	 * was created. If false, no location information is included-
	 * 
	 * @param locationInfo
	 *            new value to set
	 */
	public void setLocationInfo(boolean locationInfo) {
		// System.out.println("locationInfo= " + locationInfo);
		this.locationInfo = locationInfo;
	}

	public boolean getProperties() {
		return properties;
	}

	/**
	 * setProperties sets the properties flag. If true each event layouted by
	 * XMLLayout include the complete set of key-value pairs in the MDC. If
	 * false, no MDC information is layouted.
	 * 
	 * @param properties
	 */
	public void setProperties(boolean properties) {
		// System.err.println("properties=" + properties);
		this.properties = properties;
	}

	/**
	 * q quotes the string s so it can be used directly as an XML payload
	 * without worrying about reserved characters or character encodings as all
	 * non-ASCII characters plus those reserved in XML are rendered as
	 * &amp;#entity; - e.g. renders &amp; as &amp;#35;.
	 * 
	 * @param s
	 * @return StringBuffer with a XML representation of s
	 */
	private StringBuffer q(String s) {
		StringBuffer sb = new StringBuffer();
		for (int i = 0; i < s.length(); i++) {
			char ch = s.charAt(i);
			if (ch < 32 || ch == '&' || ch == '<' || ch == '>' || ch > 126) {
				sb.append("&#" + ((int) ch) + ";");
			} else {
				sb.append(ch);
			}
		}
		return sb;
	}

}