/*
 * 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.config;

import org.apache.log4j.Appender;
import org.apache.log4j.Category;
import org.apache.log4j.Level;
import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;

import java.io.PrintWriter;
import java.util.Enumeration;
import java.util.Hashtable;

/**
 * Prints the configuration of the log4j default hierarchy (which needs to be
 * auto-initialized) as a propoperties file on a {@link PrintWriter}.
 * 
 * @author Anders Kristensen
 */
public class PropertyPrinter implements PropertyGetter.PropertyCallback {
    protected int numAppenders = 0;
    protected Hashtable appenderNames = new Hashtable();
    protected Hashtable layoutNames = new Hashtable();
    protected PrintWriter out;
    protected boolean doCapitalize;

    public PropertyPrinter(PrintWriter out) {
	this(out, false);
    }

    public PropertyPrinter(PrintWriter out, boolean doCapitalize) {
	this.out = out;
	this.doCapitalize = doCapitalize;

	print(out);
	out.flush();
    }

    protected String genAppName() {
	return "A" + numAppenders++;
    }

    /**
     * Returns true if the specified appender name is considered to have been
     * generated, that is, if it is of the form A[0-9]+.
     */
    protected boolean isGenAppName(String name) {
	if (name.length() < 2 || name.charAt(0) != 'A')
	    return false;

	for (int i = 0; i < name.length(); i++) {
	    if (name.charAt(i) < '0' || name.charAt(i) > '9')
		return false;
	}
	return true;
    }

    /**
     * Prints the configuration of the default log4j hierarchy as a Java properties
     * file on the specified Writer.
     * 
     * <p>
     * N.B. print() can be invoked only once!
     */
    public void print(PrintWriter out) {
	printOptions(out, Logger.getRootLogger());

	Enumeration cats = LogManager.getCurrentLoggers();
	while (cats.hasMoreElements()) {
	    printOptions(out, (Logger) cats.nextElement());
	}
    }

    /**
     * @since 1.2.15
     */
    protected void printOptions(PrintWriter out, Category cat) {
	Enumeration appenders = cat.getAllAppenders();
	Level prio = cat.getLevel();
	String appenderString = (prio == null ? "" : prio.toString());

	while (appenders.hasMoreElements()) {
	    Appender app = (Appender) appenders.nextElement();
	    String name;

	    if ((name = (String) appenderNames.get(app)) == null) {

		// first assign name to the appender
		if ((name = app.getName()) == null || isGenAppName(name)) {
		    name = genAppName();
		}
		appenderNames.put(app, name);

		printOptions(out, app, "log4j.appender." + name);
		if (app.getLayout() != null) {
		    printOptions(out, app.getLayout(), "log4j.appender." + name + ".layout");
		}
	    }
	    appenderString += ", " + name;
	}
	String catKey = (cat == Logger.getRootLogger()) ? "log4j.rootLogger" : "log4j.logger." + cat.getName();
	if (appenderString != "") {
	    out.println(catKey + "=" + appenderString);
	}
	if (!cat.getAdditivity() && cat != Logger.getRootLogger()) {
	    out.println("log4j.additivity." + cat.getName() + "=false");
	}
    }

    protected void printOptions(PrintWriter out, Logger cat) {
	printOptions(out, (Category) cat);
    }

    protected void printOptions(PrintWriter out, Object obj, String fullname) {
	out.println(fullname + "=" + obj.getClass().getName());
	PropertyGetter.getProperties(obj, this, fullname + ".");
    }

    public void foundProperty(Object obj, String prefix, String name, Object value) {
	// XXX: Properties encode value.toString()
	if (obj instanceof Appender && "name".equals(name)) {
	    return;
	}
	if (doCapitalize) {
	    name = capitalize(name);
	}
	out.println(prefix + name + "=" + value.toString());
    }

    public static String capitalize(String name) {
	if (Character.isLowerCase(name.charAt(0))) {
	    if (name.length() == 1 || Character.isLowerCase(name.charAt(1))) {
		StringBuilder newname = new StringBuilder(name);
		newname.setCharAt(0, Character.toUpperCase(name.charAt(0)));
		return newname.toString();
	    }
	}
	return name;
    }

    // for testing
    public static void main(String[] args) {
	new PropertyPrinter(new PrintWriter(System.out));
    }
}
