/*
 * 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));
    }
}
