/**
 * 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.cxf.interceptor.security;

import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;

import org.apache.cxf.common.classloader.ClassLoaderUtils;
import org.apache.cxf.common.logging.LogUtils;
import org.apache.cxf.common.util.ClassHelper;


public class SecureAnnotationsInterceptor extends SimpleAuthorizingInterceptor {

    private static final Logger LOG = LogUtils.getL7dLogger(SecureAnnotationsInterceptor.class);
    private static final String DEFAULT_ANNOTATION_CLASS_NAME = "javax.annotation.security.RolesAllowed";
    
    private static final Set<String> SKIP_METHODS;
    static {
        SKIP_METHODS = new HashSet<String>();
        SKIP_METHODS.addAll(Arrays.asList(
            new String[] {"wait", "notify", "notifyAll", 
                          "equals", "toString", "hashCode"}));
    }
    
    private String annotationClassName = DEFAULT_ANNOTATION_CLASS_NAME;
    
    public void setAnnotationClassName(String name) {
        try {
            ClassLoaderUtils.loadClass(name, SecureAnnotationsInterceptor.class);
            annotationClassName = name;
        } catch (Throwable ex) {
            ex.printStackTrace();
            throw new IllegalArgumentException("Annotation class " + name + " is not available");
        }
    }
    
    public void setSecuredObject(Object object) {
        Class<?> cls = ClassHelper.getRealClass(object);
        Map<String, String> rolesMap = new HashMap<String, String>();
        findRoles(cls, rolesMap);
        if (rolesMap.isEmpty()) {
            LOG.warning("The roles map is empty, the service object is not protected");
        } else if (LOG.isLoggable(Level.FINE)) {
            for (Map.Entry<String, String> entry : rolesMap.entrySet()) {
                LOG.fine("Method: " + entry.getKey() + ", roles: " + entry.getValue());
            }
        }
        super.setMethodRolesMap(rolesMap);
    }

    protected void findRoles(Class<?> cls, Map<String, String> rolesMap) {
        if (cls == null || cls == Object.class) {
            return;
        }
        String classRolesAllowed = getRoles(cls.getAnnotations(), annotationClassName);
        for (Method m : cls.getMethods()) {
            if (SKIP_METHODS.contains(m.getName())) {
                continue;
            }
            String methodRolesAllowed = getRoles(m.getAnnotations(), annotationClassName);
            String theRoles = methodRolesAllowed != null ? methodRolesAllowed : classRolesAllowed;
            if (theRoles != null) {
                rolesMap.put(m.getName(), theRoles);
            }
        }
        if (!rolesMap.isEmpty()) {
            return;
        }
        
        findRoles(cls.getSuperclass(), rolesMap);
        
        if (!rolesMap.isEmpty()) {
            return;
        }
        
        for (Class<?> interfaceCls : cls.getInterfaces()) {
            findRoles(interfaceCls, rolesMap);
        }
    }
    
    private String getRoles(Annotation[] anns, String annName) {
        for (Annotation ann : anns) {
            if (ann.annotationType().getName().equals(annName)) {
                try {
                    Method valueMethod = ann.annotationType().getMethod("value", new Class[]{});
                    String[] roles = (String[])valueMethod.invoke(ann, new Object[]{});
                    StringBuilder sb = new StringBuilder();
                    for (int i = 0; i < roles.length; i++) {
                        sb.append(roles[i]);
                        if (i + 1 < roles.length) {
                            sb.append(" ");
                        }
                    }
                    return sb.toString();
                } catch (Exception ex) {
                    // ignore    
                }
                break;
            }
        }
        return null;
    }
}
