/*
    * Copyright 2013-2014 the original author or authors.
    *
    * Licensed 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
    *
    * https://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.springframework.security.oauth2.provider;
  
  import java.util.Collections;
  import java.util.HashSet;
  import java.util.Set;
  
  import org.springframework.security.core.Authentication;
  import org.springframework.security.core.GrantedAuthority;
  import org.springframework.security.core.context.SecurityContextHolder;
  
  /**
   * Strategy for accessing useful information about the current security context.
   * 
   * @author Dave Syer
   * 
   */
  public class DefaultSecurityContextAccessor implements SecurityContextAccessor {
  
  	@Override
  	public boolean isUser() {
  		Authentication authentication = getUserAuthentication();
  		return authentication != null;
  	}
  	
  	@Override
  	public Set<GrantedAuthority> getAuthorities() {
  		Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
  		if (authentication == null) {
  			return Collections.emptySet();
  		}
  		return Collections.unmodifiableSet(new HashSet<GrantedAuthority>(authentication.getAuthorities()));
  	}
  
  	private Authentication getUserAuthentication() {
  		Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
  		if (authentication == null) {
  			return null;
  		}
  		if (authentication instanceof OAuth2Authentication) {
  			OAuth2Authentication oauth = (OAuth2Authentication) authentication;
  			return oauth.getUserAuthentication();
  		}
  		return authentication;
  	}
  
  }