/*************************************************************************
 * Copyright 2013-2014 Eucalyptus Systems, Inc.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 3 of the License.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see http://www.gnu.org/licenses/.
 *
 * Please contact Eucalyptus Systems, Inc., 6755 Hollister Ave., Goleta
 * CA 93117, USA or visit http://www.eucalyptus.com/licenses/ if you need
 * additional information or have any questions.
 ************************************************************************/

package com.eucalyptus.objectstorage.client;

import java.util.Date;

import javax.annotation.Nonnull;

import com.amazonaws.ClientConfiguration;
import com.amazonaws.Protocol;
import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.services.s3.AmazonS3Client;
import com.amazonaws.services.s3.S3ClientOptions;

/**
 * A convenience wrapper for an AWS Java SDK S3 Client that sets default timeouts etc, options, etc
 *
 * This is specifically as needed for the OSG's internal use to various backends
 */
public class OsgInternalS3Client {
  private static final int CONNECTION_TIMEOUT_MS = 500; // 500ms connection timeout, fail fast
  private static final int OSG_SOCKET_TIMEOUT_MS = 10 * 1000; // 10 sec socket timeout if no data
  private static final int OSG_MAX_CONNECTIONS = 512; // Lots of connections since this is for the whole OSG
  private static final String SIGNER_OVERRIDE =
      System.getProperty( "com.eucalyptus.objectstorage.client.signerType", "S3SignerType" );

  private S3ClientOptions ops;
  private AmazonS3Client s3Client;
  private ClientConfiguration clientConfig;
  private Date instantiated;
  private volatile String endpoint;
  private volatile AWSCredentials currentCredentials;

  public OsgInternalS3Client(AWSCredentials credentials, String endpoint, boolean https, boolean useDns) {
    update(credentials, endpoint, https, useDns);
  }

  public void setUsePathStyle(boolean usePathStyle) {
    ops.setPathStyleAccess(usePathStyle);
    s3Client.setS3ClientOptions(ops);
  }

  public AmazonS3Client getS3Client() {
    return s3Client;
  }

  public synchronized String getS3Endpoint() {
    return this.endpoint;
  }

  public synchronized void setS3Endpoint(String s3Endpoint) {
    this.endpoint = s3Endpoint;
    s3Client.setEndpoint(s3Endpoint);
  }

  /**
   * Basically an .equals() call for AWSCreds
   * 
   * @param c1
   * @param c2
   * @return
   */
  private static boolean credentialsEqual(AWSCredentials c1, AWSCredentials c2) {
    return (c1 == null && c2 == null)
        || (c1 == null || c2 == null)
        || (c1.getAWSSecretKey() != null && c1.getAWSSecretKey().equals(c2.getAWSSecretKey()) && c1.getAWSAccessKeyId() != null && c1
            .getAWSAccessKeyId().equals(c2.getAWSAccessKeyId()));
  }

  private synchronized void initializeNewClient(@Nonnull AWSCredentials credentials, @Nonnull String endpoint, @Nonnull Boolean https,
      @Nonnull Boolean useDns) {
    ClientConfiguration config = new ClientConfiguration();
    config.setConnectionTimeout(CONNECTION_TIMEOUT_MS); // very short timeout
    config.setSocketTimeout(OSG_SOCKET_TIMEOUT_MS);
    config.setUseReaper(true);
    config.setMaxConnections(OSG_MAX_CONNECTIONS);
    Protocol protocol = https ? Protocol.HTTPS : Protocol.HTTP;
    config.setProtocol(protocol);
    config.setSignerOverride(SIGNER_OVERRIDE);
    this.clientConfig = config;
    this.s3Client = new AmazonS3Client(credentials, config);
    this.ops = new S3ClientOptions().withPathStyleAccess(!useDns);
    this.s3Client.setS3ClientOptions(ops);
    this.instantiated = new Date();
    this.currentCredentials = credentials;
    this.setS3Endpoint(endpoint);
  }

  public void update(@Nonnull AWSCredentials credentials, @Nonnull String latestEndpoint, @Nonnull Boolean https, @Nonnull Boolean useDns) {
    // Credentials changes require new client instance (for now)
    if (this.s3Client == null || !credentialsEqual(this.currentCredentials, credentials)) {
      this.initializeNewClient(credentials, latestEndpoint, https, useDns);
      return;
    }

    // They have opposite semantics, so any equality means it must be updated
    if (this.ops.isPathStyleAccess() == useDns) {
      this.ops.setPathStyleAccess(!useDns);
      this.s3Client.setS3ClientOptions(this.ops);
    }

    Protocol tmpProto = https ? Protocol.HTTPS : Protocol.HTTP;
    if (!tmpProto.equals(this.clientConfig.getProtocol())) {
      this.clientConfig.setProtocol(tmpProto);
    }

    if (this.getS3Endpoint() == null || !this.getS3Endpoint().equals(latestEndpoint)) {
      this.setS3Endpoint(latestEndpoint);
    }
  }

  public Date getInstantiated() {
    return instantiated;
  }
}