/*******************************************************************************
 * Copyright (C) 2013 JMaNGOS <http://jmangos.org/>
 * 
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 * 
 * You should have received a copy of the GNU General Public License along
 * with this program. If not, see <http://www.gnu.org/licenses/>.
 ******************************************************************************/
package org.jmangos.commons.configuration;

import java.io.IOException;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.Properties;

import org.jmangos.commons.utils.PropertiesUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public abstract class AbstractConfig {

    /**
     * Logger.
     */
    private static final Logger log = LoggerFactory.getLogger(AbstractConfig.class);

    protected AbstractConfig(final String configFileName) {

        Properties properties;
        try {
            properties = PropertiesUtils.load(configFileName);
        } catch (final IOException e) {
            throw new RuntimeException(e);
        }
        process(this, properties);
    }

    protected static void process(final Object obj, final Properties... properties) {

        for (final Field field : obj.getClass().getDeclaredFields()) {
            if (Modifier.isStatic(field.getModifiers()) || Modifier.isFinal(field.getModifiers())) {
                continue;
            }
            if (field.isAnnotationPresent(Property.class)) {
                processField(obj, field, properties);
            }
        }
    }

    private static void processField(final Object obj, final Field field,
            final Properties... properties) {

        final Property property = field.getAnnotation(Property.class);
        final boolean isAccessible = field.isAccessible();
        field.setAccessible(true);
        String value = findPropertyByKey(property.key(), properties);
        if (value == null) {
            value = property.defaultValue();
        }
        try {
            field.set(obj, TypeTransformer.castFromString(value, field.getType()));
        } catch (final IllegalAccessException e) {
            throw new RuntimeException(e);
        }
        field.setAccessible(isAccessible);
        if (log.isDebugEnabled()) {
            log.debug("Field " +
                field.getName() +
                " of class " +
                field.getDeclaringClass().getName() +
                " is " +
                value);
        }
    }

    private static String findPropertyByKey(final String key, final Properties... properties) {

        for (final Properties current : properties) {
            if (current.containsKey(key)) {
                return current.getProperty(key);
            }
        }
        return null;
    }
}