/*
 * 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.
 * <p>
 * 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 G&uuml;lc&uuml;
 */
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() {
        StringBuilder sbuf = new StringBuilder();
        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() {
        StringBuilder sbuf = new StringBuilder();
        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;
    }
}
