/*
 * 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.hadoop.fs.s3a.auth;

import java.io.IOException;
import java.net.URI;

import com.amazonaws.auth.AWSCredentials;

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.s3a.CredentialInitializationException;

import static org.apache.hadoop.util.Preconditions.checkNotNull;
import static org.apache.hadoop.fs.s3a.auth.MarshalledCredentialBinding.toAWSCredentials;

/**
 * AWS credential provider driven from marshalled session/full credentials
 * (full, simple session or role).
 * This is <i>not</i> intended for explicit use in job/app configurations,
 * instead it is returned by Delegation Token Bindings, as needed.
 * The constructor implicitly prevents explicit use.
 */
@InterfaceAudience.Private
@InterfaceStability.Unstable
@SuppressWarnings("deprecation")
public class MarshalledCredentialProvider extends
    AbstractSessionCredentialsProvider {

  /** Name: {@value}. */
  public static final String NAME
      = "org.apache.hadoop.fs.s3a.auth.MarshalledCredentialProvider";

  private final MarshalledCredentials credentials;

  private final MarshalledCredentials.CredentialTypeRequired typeRequired;

  private final String component;

  /**
   * Constructor.
   *
   * @param component component name for exception messages.
   * @param uri filesystem URI: must not be null.
   * @param conf configuration.
   * @param credentials marshalled credentials.
   * @param typeRequired credential type required.
   * @throws CredentialInitializationException validation failure
   * @throws IOException failure
   */
  public MarshalledCredentialProvider(
      final String component,
      final URI uri,
      final Configuration conf,
      final MarshalledCredentials credentials,
      final MarshalledCredentials.CredentialTypeRequired typeRequired)
      throws IOException {
    super(checkNotNull(uri, "No filesystem URI"), conf);
    this.component = component;
    this.typeRequired = typeRequired;
    this.credentials = checkNotNull(credentials);
  }

  /**
   * Perform the binding, looking up the DT and parsing it.
   * @return true if there were some credentials
   * @throws CredentialInitializationException validation failure
   * @throws IOException on a failure
   */
  @Override
  protected AWSCredentials createCredentials(final Configuration config)
      throws IOException {
    return toAWSCredentials(credentials, typeRequired, component);
  }

}