/*
    * Copyright 2008 Web Cohesion
    *
    * 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.oauth.provider;
  
  import org.springframework.security.core.AuthenticationException;
  import org.springframework.security.oauth.common.signature.UnsupportedSignatureMethodException;
  import org.springframework.security.web.AuthenticationEntryPoint;
  
  import javax.servlet.ServletException;
  import javax.servlet.http.HttpServletResponse;
  import javax.servlet.http.HttpServletRequest;
  import java.io.IOException;
  
  /**
   * Entry point for OAuth authentication requests.
   *
   * @author Ryan Heaton
   */
  public class OAuthProcessingFilterEntryPoint implements AuthenticationEntryPoint {
  
    private String realmName;
  
    public void commence(HttpServletRequest request, HttpServletResponse response, AuthenticationException authException) throws IOException, ServletException {
  	  if (authException instanceof InvalidOAuthParametersException) {
  		  response.sendError(400, authException.getMessage());
  	  }
  	  else if (authException.getCause() instanceof UnsupportedSignatureMethodException) {
  		  response.sendError(400, authException.getMessage());
  	  }
  	  else {
  		  StringBuilder headerValue = new StringBuilder("OAuth");
  		  if (realmName != null) {
  			  headerValue.append(" realm=\"").append(realmName).append('"');
  		  }
  		  response.addHeader("WWW-Authenticate", headerValue.toString());
  		  response.sendError(HttpServletResponse.SC_UNAUTHORIZED, authException.getMessage());
  	  }
    }
  
    public String getRealmName() {
      return realmName;
    }
  
    public void setRealmName(String realmName) {
      this.realmName = realmName;
    }
  
  }