/*
    * 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.shiro.web.jaxrs;
  
  
  import org.apache.shiro.authz.annotation.RequiresAuthentication;
  import org.apache.shiro.authz.annotation.RequiresGuest;
  import org.apache.shiro.authz.annotation.RequiresPermissions;
  import org.apache.shiro.authz.annotation.RequiresRoles;
  import org.apache.shiro.authz.annotation.RequiresUser;
  import org.apache.shiro.authz.aop.AuthenticatedAnnotationHandler;
  import org.apache.shiro.authz.aop.AuthorizingAnnotationHandler;
  import org.apache.shiro.authz.aop.GuestAnnotationHandler;
  import org.apache.shiro.authz.aop.PermissionAnnotationHandler;
  import org.apache.shiro.authz.aop.RoleAnnotationHandler;
  import org.apache.shiro.authz.aop.UserAnnotationHandler;
  
  import javax.ws.rs.container.ContainerRequestContext;
  import javax.ws.rs.container.ContainerRequestFilter;
  import javax.ws.rs.ext.Provider;
  import java.io.IOException;
  import java.lang.annotation.Annotation;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.Map;
  
  /**
   * A filter that grants or denies access to a JAX-RS resource based on the Shiro annotations on it.
   *
   * @see org.apache.shiro.authz.annotation
   * @since 1.4
   */
  public class AnnotationAuthorizationFilter implements ContainerRequestFilter {
  
      private final Map<AuthorizingAnnotationHandler, Annotation> authzChecks;
  
      public AnnotationAuthorizationFilter(Collection<Annotation> authzSpecs) {
          Map<AuthorizingAnnotationHandler, Annotation> authChecks = new HashMap<AuthorizingAnnotationHandler, Annotation>(authzSpecs.size());
          for (Annotation authSpec : authzSpecs) {
              authChecks.put(createHandler(authSpec), authSpec);
          }
          this.authzChecks = Collections.unmodifiableMap(authChecks);
      }
  
      private static AuthorizingAnnotationHandler createHandler(Annotation annotation) {
          Class<?> t = annotation.annotationType();
          if (RequiresPermissions.class.equals(t)) return new PermissionAnnotationHandler();
          else if (RequiresRoles.class.equals(t)) return new RoleAnnotationHandler();
          else if (RequiresUser.class.equals(t)) return new UserAnnotationHandler();
          else if (RequiresGuest.class.equals(t)) return new GuestAnnotationHandler();
          else if (RequiresAuthentication.class.equals(t)) return new AuthenticatedAnnotationHandler();
          else throw new IllegalArgumentException("Cannot create a handler for the unknown for annotation " + t);
      }
  
      @Override
      public void filter(ContainerRequestContext requestContext) throws IOException {
  
          for (Map.Entry<AuthorizingAnnotationHandler, Annotation> authzCheck : authzChecks.entrySet()) {
              AuthorizingAnnotationHandler handler = authzCheck.getKey();
              Annotation authzSpec = authzCheck.getValue();
              handler.assertAuthorized(authzSpec);
          }
      }
  
  }