/*
 * 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.catalina.util;

import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.security.AccessController;
import java.security.PrivilegedAction;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import javax.annotation.Resource;
import javax.ejb.EJB;
import javax.naming.NamingException;
import javax.persistence.PersistenceContext;
import javax.persistence.PersistenceUnit;
import javax.xml.ws.WebServiceRef;

import org.apache.AnnotationProcessor;
import org.apache.catalina.Globals;


/**
 * Verify the annotation and Process it.
 *
 * @author Fabien Carrion
 * @author Remy Maucherat
 *
 */
public class DefaultAnnotationProcessor implements AnnotationProcessor {
    
    protected javax.naming.Context context = null;
    
    public DefaultAnnotationProcessor(javax.naming.Context context) {
        this.context = context;
    }


    /**
     * Call postConstruct method on the specified instance.
     */
    public void postConstruct(Object instance)
        throws IllegalAccessException, InvocationTargetException {
        
        Class<?> clazz = instance.getClass();
        
        while (clazz != null) {
            Method[] methods = null;
            if (Globals.IS_SECURITY_ENABLED) {
                final Class<?> clazz2 = clazz;
                methods = AccessController.doPrivileged(
                        new PrivilegedAction<Method[]>(){
                    public Method[] run(){
                        return clazz2.getDeclaredMethods();
                    }
                });
            } else {
                methods = clazz.getDeclaredMethods();
            }
            Method postConstruct = null;
            for (int i = 0; i < methods.length; i++) {
                if (methods[i].isAnnotationPresent(PostConstruct.class)) {
                    if ((postConstruct != null) 
                            || (methods[i].getParameterTypes().length != 0)
                            || (Modifier.isStatic(methods[i].getModifiers())) 
                            || (methods[i].getExceptionTypes().length > 0)
                            || (!methods[i].getReturnType().getName().equals("void"))) {
                        throw new IllegalArgumentException("Invalid PostConstruct annotation");
                    }
                    postConstruct = methods[i];
                }
            }
    
            // At the end the postconstruct annotated 
            // method is invoked
            if (postConstruct != null) {
                boolean accessibility = postConstruct.isAccessible();
                postConstruct.setAccessible(true);
                postConstruct.invoke(instance);
                postConstruct.setAccessible(accessibility);
            }
        
            clazz = clazz.getSuperclass();
        }
    }
    
    
    /**
     * Call preDestroy method on the specified instance.
     */
    public void preDestroy(Object instance)
        throws IllegalAccessException, InvocationTargetException {
        
        Class<?> clazz = instance.getClass();
        
        while (clazz != null) {
            Method[] methods;
            // Hack so PrivilegedAction can access clazz object
            final Class<?> clazz2 = clazz;
            if (Globals.IS_SECURITY_ENABLED) {
                methods = AccessController.doPrivileged(
                        new PrivilegedAction<Method[]>(){
                            public Method[] run(){
                                return clazz2.getDeclaredMethods();
                            }
                        });
            } else {
                methods = clazz.getDeclaredMethods();
            }

            Method preDestroy = null;
            for (int i = 0; i < methods.length; i++) {
                if (methods[i].isAnnotationPresent(PreDestroy.class)) {
                    if ((preDestroy != null) 
                            || (methods[i].getParameterTypes().length != 0)
                            || (Modifier.isStatic(methods[i].getModifiers())) 
                            || (methods[i].getExceptionTypes().length > 0)
                            || (!methods[i].getReturnType().getName().equals("void"))) {
                        throw new IllegalArgumentException("Invalid PreDestroy annotation");
                    }
                    preDestroy = methods[i];
                }
            }
    
            // At the end the postconstruct annotated 
            // method is invoked
            if (preDestroy != null) {
                boolean accessibility = preDestroy.isAccessible();
                preDestroy.setAccessible(true);
                preDestroy.invoke(instance);
                preDestroy.setAccessible(accessibility);
            }

            clazz = clazz.getSuperclass();
        }
    }
    
    
    /**
     * Inject resources in specified instance.
     */
    public void processAnnotations(Object instance)
        throws IllegalAccessException, InvocationTargetException, NamingException {
        
        if (context == null) {
            // No resource injection
            return;
        }
        
        Class<?> clazz = instance.getClass();
        
        while (clazz != null) {
            // Initialize fields annotations
            Field[] fields = null;
            if (Globals.IS_SECURITY_ENABLED) {
                final Class<?> clazz2 = clazz;
                fields = AccessController.doPrivileged(
                        new PrivilegedAction<Field[]>(){
                    public Field[] run(){
                        return clazz2.getDeclaredFields();
                    }
                });
            } else {
                fields = clazz.getDeclaredFields();
            }
            for (int i = 0; i < fields.length; i++) {
                if (fields[i].isAnnotationPresent(Resource.class)) {
                    Resource annotation =
                        fields[i].getAnnotation(Resource.class);
                    lookupFieldResource(context, instance, fields[i],
                            annotation.name(), clazz);
                }
                if (fields[i].isAnnotationPresent(EJB.class)) {
                    EJB annotation = fields[i].getAnnotation(EJB.class);
                    lookupFieldResource(context, instance, fields[i],
                            annotation.name(), clazz);
                }
                if (fields[i].isAnnotationPresent(WebServiceRef.class)) {
                    WebServiceRef annotation =
                        fields[i].getAnnotation(WebServiceRef.class);
                    lookupFieldResource(context, instance, fields[i],
                            annotation.name(), clazz);
                }
                if (fields[i].isAnnotationPresent(PersistenceContext.class)) {
                    PersistenceContext annotation = 
                        fields[i].getAnnotation(PersistenceContext.class);
                    lookupFieldResource(context, instance, fields[i],
                            annotation.name(), clazz);
                }
                if (fields[i].isAnnotationPresent(PersistenceUnit.class)) {
                    PersistenceUnit annotation = 
                        fields[i].getAnnotation(PersistenceUnit.class);
                    lookupFieldResource(context, instance, fields[i],
                            annotation.name(), clazz);
                }
            }
            
            // Initialize methods annotations
            Method[] methods = null;
            if (Globals.IS_SECURITY_ENABLED) {
                final Class<?> clazz2 = clazz;
                methods = AccessController.doPrivileged(
                        new PrivilegedAction<Method[]>(){
                    public Method[] run(){
                        return clazz2.getDeclaredMethods();
                    }
                });
            } else {
                methods = clazz.getDeclaredMethods();
            }
            for (int i = 0; i < methods.length; i++) {
                if (methods[i].isAnnotationPresent(Resource.class)) {
                    Resource annotation = methods[i].getAnnotation(Resource.class);
                    lookupMethodResource(context, instance, methods[i],
                            annotation.name(), clazz);
                }
                if (methods[i].isAnnotationPresent(EJB.class)) {
                    EJB annotation = methods[i].getAnnotation(EJB.class);
                    lookupMethodResource(context, instance, methods[i],
                            annotation.name(), clazz);
                }
                if (methods[i].isAnnotationPresent(WebServiceRef.class)) {
                    WebServiceRef annotation = 
                        methods[i].getAnnotation(WebServiceRef.class);
                    lookupMethodResource(context, instance, methods[i],
                            annotation.name(), clazz);
                }
                if (methods[i].isAnnotationPresent(PersistenceContext.class)) {
                    PersistenceContext annotation = 
                        methods[i].getAnnotation(PersistenceContext.class);
                    lookupMethodResource(context, instance, methods[i],
                            annotation.name(), clazz);
                }
                if (methods[i].isAnnotationPresent(PersistenceUnit.class)) {
                    PersistenceUnit annotation = 
                        methods[i].getAnnotation(PersistenceUnit.class);
                    lookupMethodResource(context, instance, methods[i],
                            annotation.name(), clazz);
                }
            }
            
            clazz = clazz.getSuperclass();
        }
    }
    
    
    /**
     * Inject resources in specified field.
     */
    protected static void lookupFieldResource(javax.naming.Context context, 
            Object instance, Field field, String name, Class<?> clazz)
        throws NamingException, IllegalAccessException {
    
        Object lookedupResource = null;
        boolean accessibility = false;
        
        if ((name != null) &&
                (name.length() > 0)) {
            lookedupResource = context.lookup(name);
        } else {
            lookedupResource = context.lookup(
                    clazz.getName() + "/" + field.getName());
        }
        
        accessibility = field.isAccessible();
        field.setAccessible(true);
        field.set(instance, lookedupResource);
        field.setAccessible(accessibility);
    }


    /**
     * Inject resources in specified method.
     */
    protected static void lookupMethodResource(javax.naming.Context context, 
            Object instance, Method method, String name, Class<?> clazz)
        throws NamingException, IllegalAccessException, InvocationTargetException {
        
        if (!method.getName().startsWith("set") 
                || method.getParameterTypes().length != 1
                || !method.getReturnType().getName().equals("void")) {
            throw new IllegalArgumentException("Invalid method resource injection annotation");
        }
        
        Object lookedupResource = null;
        boolean accessibility = false;
        
        if ((name != null) &&
                (name.length() > 0)) {
            lookedupResource = context.lookup(name);
        } else {
            lookedupResource = context.lookup(
                    clazz.getName() + "/" + method.getName().substring(3));
        }
        
        accessibility = method.isAccessible();
        method.setAccessible(true);
        method.invoke(instance, lookedupResource);
        method.setAccessible(accessibility);
    }
    

}
