/*
 * Copyright (C) 2013 Square, Inc.
 *
 * 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
 *
 *      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 com.squareup.okhttp;

import com.squareup.okhttp.internal.Util;
import java.security.Principal;
import java.security.cert.Certificate;
import java.security.cert.X509Certificate;
import java.util.Collections;
import java.util.List;
import javax.net.ssl.SSLPeerUnverifiedException;
import javax.net.ssl.SSLSession;

/**
 * A record of a TLS handshake. For HTTPS clients, the client is <i>local</i>
 * and the remote server is its <i>peer</i>.
 *
 * <p>This value object describes a completed handshake. Use {@link
 * javax.net.ssl.SSLSocketFactory} to set policy for new handshakes.
 */
public final class Handshake {
  private final String cipherSuite;
  private final List<Certificate> peerCertificates;
  private final List<Certificate> localCertificates;

  private Handshake(
      String cipherSuite, List<Certificate> peerCertificates, List<Certificate> localCertificates) {
    this.cipherSuite = cipherSuite;
    this.peerCertificates = peerCertificates;
    this.localCertificates = localCertificates;
  }

  public static Handshake get(SSLSession session) {
    String cipherSuite = session.getCipherSuite();
    if (cipherSuite == null) throw new IllegalStateException("cipherSuite == null");

    Certificate[] peerCertificates;
    try {
      peerCertificates = session.getPeerCertificates();
    } catch (SSLPeerUnverifiedException ignored) {
      peerCertificates = null;
    }
    List<Certificate> peerCertificatesList = peerCertificates != null
        ? Util.immutableList(peerCertificates)
        : Collections.<Certificate>emptyList();

    Certificate[] localCertificates = session.getLocalCertificates();
    List<Certificate> localCertificatesList = localCertificates != null
        ? Util.immutableList(localCertificates)
        : Collections.<Certificate>emptyList();

    return new Handshake(cipherSuite, peerCertificatesList, localCertificatesList);
  }

  public static Handshake get(
      String cipherSuite, List<Certificate> peerCertificates, List<Certificate> localCertificates) {
    if (cipherSuite == null) throw new IllegalArgumentException("cipherSuite == null");
    return new Handshake(cipherSuite, Util.immutableList(peerCertificates),
        Util.immutableList(localCertificates));
  }

  /** Returns a cipher suite name like "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA". */
  public String cipherSuite() {
    return cipherSuite;
  }

  /** Returns a possibly-empty list of certificates that identify the remote peer. */
  public List<Certificate> peerCertificates() {
    return peerCertificates;
  }

  /** Returns the remote peer's principle, or null if that peer is anonymous. */
  public Principal peerPrincipal() {
    return !peerCertificates.isEmpty()
        ? ((X509Certificate) peerCertificates.get(0)).getSubjectX500Principal()
        : null;
  }

  /** Returns a possibly-empty list of certificates that identify this peer. */
  public List<Certificate> localCertificates() {
    return localCertificates;
  }

  /** Returns the local principle, or null if this peer is anonymous. */
  public Principal localPrincipal() {
    return !localCertificates.isEmpty()
        ? ((X509Certificate) localCertificates.get(0)).getSubjectX500Principal()
        : null;
  }

  @Override public boolean equals(Object other) {
    if (!(other instanceof Handshake)) return false;
    Handshake that = (Handshake) other;
    return cipherSuite.equals(that.cipherSuite)
        && peerCertificates.equals(that.peerCertificates)
        && localCertificates.equals(that.localCertificates);
  }

  @Override public int hashCode() {
    int result = 17;
    result = 31 * result + cipherSuite.hashCode();
    result = 31 * result + peerCertificates.hashCode();
    result = 31 * result + localCertificates.hashCode();
    return result;
  }
}