package com.aionemu.commons.scripting.classlistener;

import java.lang.annotation.Annotation;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.aionemu.commons.scripting.metadata.OnClassLoad;
import com.aionemu.commons.scripting.metadata.OnClassUnload;

/**
 * @author SoulKeeper
 */
public class OnClassLoadUnloadListener implements ClassListener {

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

	@Override
	public void postLoad(Class<?>[] classes) {
		for (Class<?> c : classes) {
			doMethodInvoke(c.getDeclaredMethods(), OnClassLoad.class);
		}
	}

	@Override
	public void preUnload(Class<?>[] classes) {
		for (Class<?> c : classes) {
			doMethodInvoke(c.getDeclaredMethods(), OnClassUnload.class);
		}
	}

	/**
	 * Actually invokes method where given annotation class is present. Only static methods can be invoked
	 * 
	 * @param methods
	 *          Methods to scan for annotations
	 * @param annotationClass
	 *          class of annotation to search for
	 */
	protected final void doMethodInvoke(Method[] methods, Class<? extends Annotation> annotationClass) {
		for (Method m : methods) {
			if (!Modifier.isStatic(m.getModifiers()))
				continue;

			boolean accessible = m.canAccess(null);
			m.setAccessible(true);

			if (m.getAnnotation(annotationClass) != null) {
				try {
					m.invoke(null);
				} catch (IllegalAccessException e) {
					log.error("Can't access method " + m.getName() + " of class " + m.getDeclaringClass().getName(), e);
				} catch (InvocationTargetException e) {
					log.error("Can't invoke method " + m.getName() + " of class " + m.getDeclaringClass().getName(), e);
				}
			}

			m.setAccessible(accessible);
		}
	}
}