/**
 * 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.activemq.transport.amqp.client.sasl;

import javax.security.sasl.SaslException;
import java.util.Map;

/**
 * Interface for all SASL authentication mechanism implementations.
 */
public interface Mechanism extends Comparable<Mechanism> {

   /**
    * Relative priority values used to arrange the found SASL
    * mechanisms in a preferred order where the level of security
    * generally defines the preference.
    */
   enum PRIORITY {
      LOWEST(0),
      LOW(1),
      MEDIUM(2),
      HIGH(3),
      HIGHEST(4);

      private final int value;

      PRIORITY(int value) {
         this.value = value;
      }

      public int getValue() {
         return value;
      }
   }

   /**
    * @return return the relative priority of this SASL mechanism.
    */
   int getPriority();

   /**
    * @return the well known name of this SASL mechanism.
    */
   String getName();

   /**
    * @return the response buffer used to answer the initial SASL cycle.
    * @throws SaslException if an error occurs computing the response.
    */
   byte[] getInitialResponse() throws SaslException;

   /**
    * Create a response based on a given challenge from the remote peer.
    *
    * @param challenge the challenge that this Mechanism should response to.
    * @return the response that answers the given challenge.
    * @throws SaslException if an error occurs computing the response.
    */
   byte[] getChallengeResponse(byte[] challenge) throws SaslException;

   /**
    * Sets the user name value for this Mechanism.  The Mechanism can ignore this
    * value if it does not utilize user name in it's authentication processing.
    *
    * @param username The user name given.
    */
   void setUsername(String username);

   /**
    * Returns the configured user name value for this Mechanism.
    *
    * @return the currently set user name value for this Mechanism.
    */
   String getUsername();

   /**
    * Sets the password value for this Mechanism.  The Mechanism can ignore this
    * value if it does not utilize a password in it's authentication processing.
    *
    * @param password The password given.
    */
   void setPassword(String password);

   /**
    * Returns the configured password value for this Mechanism.
    *
    * @return the currently set password value for this Mechanism.
    */
   String getPassword();

   /**
    * Sets any additional Mechanism specific properties using a Map&lt;String, Object&gt;
    *
    * @param options the map of additional properties that this Mechanism should utilize.
    */
   void setProperties(Map<String, Object> options);

   /**
    * The currently set Properties for this Mechanism.
    *
    * @return the current set of configuration Properties for this Mechanism.
    */
   Map<String, Object> getProperties();

   /**
    * Using the configured credentials, check if the mechanism applies or not.
    *
    * @param username The user name that will be used with this mechanism
    * @param password The password that will be used with this mechanism
    * @return true if the mechanism works with the provided credentials or not.
    */
   boolean isApplicable(String username, String password);

   /**
    * Get the currently configured Authentication ID.
    *
    * @return the currently set Authentication ID.
    */
   String getAuthzid();

   /**
    * Sets an Authentication ID that some mechanism can use during the
    * challenge response phase.
    *
    * @param authzid The Authentication ID to use.
    */
   void setAuthzid(String authzid);

}
