/*

Copyright 2010, Google Inc.
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

    * Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following disclaimer
in the documentation and/or other materials provided with the
distribution.
    * Neither the name of Google Inc. nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,           
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY           
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

*/

package com.google.refine.logging;

/*
 * Copyright (c) Massachusetts Institute of Technology, 2007 
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *    Original code:  http://simile.mit.edu/repository/tracer/trunk/
 */

import java.util.Calendar;
import java.util.Date;

import org.apache.log4j.Layout;
import org.apache.log4j.spi.LoggingEvent;

/**
 * This is a special Log4j log formatter that is capable of reacting on special log messages
 * and 'indent' the logs accordingly. This is very useful to visually inspect a debug log
 * and see what calls what. An example of logs are "> method()" and "< method()" where > and <
 * are used to indicate respectively "entering" and "exiting".
 */
public class IndentingLayout extends Layout {

    protected static final int CONTEXT_SIZE = 25;
    protected static final long MAX_DELTA = 10000;

    protected Calendar calendar = Calendar.getInstance();
    protected long previousTime = 0;
    protected int indentation = 0;

    @Override
    public void activateOptions() {
        // no options at this time
    }

    @Override
    public String format(LoggingEvent event) {
        String message = event.getRenderedMessage();
        if (message == null) {
            return "";
        }
        if (message.length() < 2) {
            return message;
        }
        
        char leader = message.charAt(0);
        char secondLeader = message.charAt(1);
        if ((leader == '<') && (secondLeader == ' ') && (this.indentation > 0)) {
            this.indentation--;
        }

        // Reset buf
        StringBuffer buf = new StringBuffer(256);

        Date date = new Date();
        long now = date.getTime();
        calendar.setTime(date);

        long delta = 0;
        if (previousTime > 0) {
            delta = now - previousTime;
        }
        previousTime = now;

//        if ((previousTime == 0) || (delta > MAX_DELTA)) {
//            buf.append('\n');
//            indentation = 0; // reset indentation after a while, as we might
//            // have runaway/unmatched log entries
//        }

        int hour = calendar.get(Calendar.HOUR_OF_DAY);
        if (hour < 10) {
            buf.append('0');
        }
        buf.append(hour);
        buf.append(':');

        int mins = calendar.get(Calendar.MINUTE);
        if (mins < 10) {
            buf.append('0');
        }
        buf.append(mins);
        buf.append(':');

        int secs = calendar.get(Calendar.SECOND);
        if (secs < 10) {
            buf.append('0');
        }
        buf.append(secs);
        buf.append('.');

        int millis = (int) (now % 1000);
        if (millis < 100) {
            buf.append('0');
        }
        if (millis < 10) {
            buf.append('0');
        }
        buf.append(millis);

        buf.append(" [");
        String context = ((String) event.getMDC("LogEvent"));
        if (context == null) {
            context = event.getLoggerName();
        }
        if (context.length() < CONTEXT_SIZE) {
            pad(buf, CONTEXT_SIZE - context.length(), ' ');
            buf.append(context);
        } else {
            buf.append("..");
            buf.append(context.substring(context.length() - CONTEXT_SIZE + 2));
        }
        buf.append("] ");

        pad(buf, indentation, ' ');

        buf.append(message);

        buf.append(" (");
        buf.append(delta);
        buf.append("ms)\n");

        if ((leader == '>') && (secondLeader == ' ')) {
            indentation++;
        }

        return buf.toString();
    }

    private void pad(StringBuffer buffer, int pads, char padchar) {
        for (int i = 0; i < pads; i++) {
            buffer.append(padchar);
        }
    }

    @Override
    public boolean ignoresThrowable() {
        return true;
    }
}
