/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at
 * trunk/opends/resource/legal-notices/OpenDS.LICENSE
 * or https://OpenDS.dev.java.net/OpenDS.LICENSE.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at
 * trunk/opends/resource/legal-notices/OpenDS.LICENSE.  If applicable,
 * add the following below this CDDL HEADER, with the fields enclosed
 * by brackets "[]" replaced with your own identifying information:
 *      Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 *
 *
 *      Copyright 2010 Sun Microsystems, Inc.
 */

package org.opends.sdk;



import java.security.GeneralSecurityException;
import java.security.Provider;
import java.security.SecureRandom;

import javax.net.ssl.KeyManager;
import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManager;



/**
 * An SSL context builder provides an interface for incrementally constructing
 * {@link SSLContext} instances for use when securing connections with SSL or
 * the StartTLS extended operation. The {@link #getSSLContext()} should be
 * called in order to obtain the {@code SSLContext}.
 */
public final class SSLContextBuilder
{

  /**
   * SSL protocol: supports some version of SSL; may support other versions.
   */
  public static final String PROTOCOL_SSL = "SSL";

  /**
   * SSL protocol: supports SSL version 2 or higher; may support other versions.
   */
  public static final String PROTOCOL_SSL2 = "SSLv2";

  /**
   * SSL protocol: supports SSL version 3; may support other versions.
   */
  public static final String PROTOCOL_SSL3 = "SSLv3";

  /**
   * SSL protocol: supports some version of TLS; may support other versions.
   */
  public static final String PROTOCOL_TLS = "TLS";

  /**
   * SSL protocol: supports RFC 2246: TLS version 1.0 ; may support other
   * versions.
   */
  public static final String PROTOCOL_TLS1 = "TLSv1";

  /**
   * SSL protocol: supports RFC 4346: TLS version 1.1 ; may support other
   * versions.
   */
  public static final String PROTOCOL_TLS1_1 = "TLSv1.1";

  private TrustManager trustManager = null;
  private KeyManager keyManager = null;
  private String protocol = PROTOCOL_TLS1;
  private SecureRandom random = null;

  // These are mutually exclusive.
  private Provider provider = null;
  private String providerName = null;



  /**
   * Creates a new SSL context builder using default parameters.
   */
  public SSLContextBuilder()
  {
    // Do nothing.
  }



  /**
   * Creates a {@code SSLContext} using the parameters of this SSL context
   * builder.
   *
   * @return A {@code SSLContext} using the parameters of this SSL context
   *         builder.
   * @throws GeneralSecurityException
   *           If the SSL context could not be created, perhaps due to missing
   *           algorithms.
   */
  public SSLContext getSSLContext() throws GeneralSecurityException
  {
    TrustManager[] tm = null;
    if (trustManager != null)
    {
      tm = new TrustManager[] { trustManager };
    }

    KeyManager[] km = null;
    if (keyManager != null)
    {
      km = new KeyManager[] { keyManager };
    }

    SSLContext sslContext;
    if (provider != null)
    {
      sslContext = SSLContext.getInstance(protocol, provider);
    }
    else if (providerName != null)
    {
      sslContext = SSLContext.getInstance(protocol, providerName);
    }
    else
    {
      sslContext = SSLContext.getInstance(protocol);
    }
    sslContext.init(km, tm, random);

    return sslContext;
  }



  /**
   * Sets the key manager which the SSL context should use. By default, no key
   * manager is specified indicating that no certificates will be used.
   *
   * @param keyManager
   *          The key manager which the SSL context should use, which may be
   *          {@code null} indicating that no certificates will be used.
   * @return This SSL context builder.
   */
  public SSLContextBuilder setKeyManager(final KeyManager keyManager)
  {
    this.keyManager = keyManager;
    return this;
  }



  /**
   * Sets the protocol which the SSL context should use. By default, TLSv1 will
   * be used.
   *
   * @param protocol
   *          The protocol which the SSL context should use, which may be
   *          {@code null} indicating that TLSv1 will be used.
   * @return This SSL context builder.
   */
  public SSLContextBuilder setProtocol(final String protocol)
  {
    this.protocol = protocol;
    return this;
  }



  /**
   * Sets the provider which the SSL context should use. By default, the default
   * provider associated with this JVM will be used.
   *
   * @param provider
   *          The provider which the SSL context should use, which may be
   *          {@code null} indicating that the default provider associated with
   *          this JVM will be used.
   * @return This SSL context builder.
   */
  public SSLContextBuilder setProvider(final Provider provider)
  {
    this.provider = provider;
    this.providerName = null;
    return this;
  }



  /**
   * Sets the provider which the SSL context should use. By default, the default
   * provider associated with this JVM will be used.
   *
   * @param providerName
   *          The name of the provider which the SSL context should use, which
   *          may be {@code null} indicating that the default provider
   *          associated with this JVM will be used.
   * @return This SSL context builder.
   */
  public SSLContextBuilder setProvider(final String providerName)
  {
    this.provider = null;
    this.providerName = providerName;
    return this;
  }



  /**
   * Sets the secure random number generator which the SSL context should use.
   * By default, the default secure random number generator associated with this
   * JVM will be used.
   *
   * @param random
   *          The secure random number generator which the SSL context should
   *          use, which may be {@code null} indicating that the default secure
   *          random number generator associated with this JVM will be used.
   * @return This SSL context builder.
   */
  public SSLContextBuilder setSecureRandom(final SecureRandom random)
  {
    this.random = random;
    return this;
  }



  /**
   * Sets the trust manager which the SSL context should use. By default, no
   * trust manager is specified indicating that only certificates signed by the
   * authorities associated with this JVM will be accepted.
   *
   * @param trustManager
   *          The trust manager which the SSL context should use, which may be
   *          {@code null} indicating that only certificates signed by the
   *          authorities associated with this JVM will be accepted.
   * @return This SSL context builder.
   */
  public SSLContextBuilder setTrustManager(final TrustManager trustManager)
  {
    this.trustManager = trustManager;
    return this;
  }
}