package org.tn5250j.framework.transport.SSL;

/*
 * @(#)SSLImplementation.java
 * @author Stephen M. Kennedy
 *
 * Copyright:    Copyright (c) 2001
 *
 * 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; either version 2, or (at your option)
 * any later version.
 *
 * 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 software; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307 USA
 *
 */

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.net.Socket;
import java.security.KeyStore;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;

import javax.net.ssl.KeyManagerFactory;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSocket;
import javax.net.ssl.TrustManager;
import javax.net.ssl.TrustManagerFactory;
import javax.net.ssl.X509TrustManager;

import com.five_ten_sg.connectbot.R;
import com.five_ten_sg.connectbot.service.TerminalBridge;
import com.five_ten_sg.connectbot.service.TerminalManager;

import org.tn5250j.framework.transport.SSLInterface;
import android.util.Log;


/**
 * <p>
 * This class implements the SSLInterface and is used to create SSL socket
 * instances.
 * </p>
 *
 * @author Stephen M. Kennedy <skennedy@tenthpowertech.com>
 *
 */
public class SSLImplementation implements SSLInterface, X509TrustManager {
    private static final String TAG = "SSLImplementation";
    SSLContext sslContext = null;
    KeyStore userks = null;
    private String userKsPath;
    private char[] userksPassword = "changeit".toCharArray();

    TerminalBridge  bridge = null;
    TerminalManager manager = null;
    String          target  = null;     // destination:port

    KeyManagerFactory userkmf = null;

    TrustManagerFactory usertmf = null;

    TrustManager[] userTrustManagers = null;

    X509Certificate[] acceptedIssuers;

    public SSLImplementation(TerminalBridge bridge, TerminalManager manager) {
        this.bridge  = bridge;
        this.manager = manager;
    }

    public void init(String sslType, String homeDirectory) {
        try {
            Log.d(TAG, "Initializing User KeyStore");
            userKsPath = homeDirectory + File.separator + "keystore";
            File userKsFile = new File(userKsPath);
            userks = KeyStore.getInstance(KeyStore.getDefaultType());
            userks.load(userKsFile.exists() ? new FileInputStream(userKsFile)
                        : null, userksPassword);
            Log.d(TAG, "Initializing User Key Manager Factory");
            userkmf = KeyManagerFactory.getInstance(KeyManagerFactory
                                                    .getDefaultAlgorithm());
            userkmf.init(userks, userksPassword);
            Log.d(TAG, "Initializing User Trust Manager Factory");
            usertmf = TrustManagerFactory.getInstance(TrustManagerFactory
                      .getDefaultAlgorithm());
            usertmf.init(userks);
            userTrustManagers = usertmf.getTrustManagers();
            Log.d(TAG, "Initializing SSL Context");
            sslContext = SSLContext.getInstance(sslType);
            sslContext.init(userkmf.getKeyManagers(), new TrustManager[] {this}, null);
        }
        catch (Exception ex) {
            Log.e(TAG, "Error initializing SSL [" + ex.getMessage() + "]");
        }
    }

    public Socket createSSLSocket(String destination, int port) {
        if (sslContext == null)
            throw new IllegalStateException("SSL Context Not Initialized");

        SSLSocket socket = null;

        try {
            target = destination + ":" + String.valueOf(port);
            socket = (SSLSocket) sslContext.getSocketFactory().createSocket(
                         destination, port);
        }
        catch (Exception e) {
            Log.e(TAG, "Error creating ssl socket [" + e.getMessage() + "]");
        }

        return socket;
    }

    // X509TrustManager Methods

    /*
     * (non-Javadoc)
     *
     * @see javax.net.ssl.X509TrustManager#getAcceptedIssuers()
     */
    public X509Certificate[] getAcceptedIssuers() {
        return acceptedIssuers;
    }

    /*
     * (non-Javadoc)
     *
     * @see
     * javax.net.ssl.X509TrustManager#checkClientTrusted(java.security.cert.
     * X509Certificate[], java.lang.String)
     */
    public void checkClientTrusted(X509Certificate[] arg0, String arg1)
    throws CertificateException {
        throw new SecurityException("checkClientTrusted unsupported");
    }

    /*
     * (non-Javadoc)
     *
     * @see
     * javax.net.ssl.X509TrustManager#checkServerTrusted(java.security.cert.
     * X509Certificate[], java.lang.String)
     */
    public void checkServerTrusted(X509Certificate[] chain, String type)
    throws CertificateException {
        try {
            for (int i = 0; i < userTrustManagers.length; i++) {
                if (userTrustManagers[i] instanceof X509TrustManager) {
                    X509TrustManager trustManager = (X509TrustManager) userTrustManagers[i];
                    X509Certificate[] calist = trustManager
                                               .getAcceptedIssuers();

                    if (calist.length > 0) {
                        trustManager.checkServerTrusted(chain, type);
                    }
                    else {
                        throw new CertificateException(
                            "Empty list of accepted issuers (a.k.a. root CA list).");
                    }
                }
            }

            return;
        }
        catch (CertificateException ce) {
            X509Certificate cert = chain[0];
            String certInfo =          manager.res.getString(R.string.host_cert_version)   + cert.getVersion() + "\r\n";
            certInfo = certInfo.concat(manager.res.getString(R.string.host_cert_serial)    + cert.getSerialNumber() + "\r\n");
            certInfo = certInfo.concat(manager.res.getString(R.string.host_cert_algorithm) + cert.getSigAlgName() + "\r\n");
            certInfo = certInfo.concat(manager.res.getString(R.string.host_cert_issuer)    + cert.getIssuerDN().getName() + "\r\n");
            certInfo = certInfo.concat(manager.res.getString(R.string.host_cert_from)      + cert.getNotBefore() + "\r\n");
            certInfo = certInfo.concat(manager.res.getString(R.string.host_cert_to)        + cert.getNotAfter() + "\r\n");
            certInfo = certInfo.concat(manager.res.getString(R.string.host_cert_dn)        + cert.getSubjectDN().getName() + "\r\n");
            certInfo = certInfo.concat(manager.res.getString(R.string.host_cert_publickey) + cert.getPublicKey().getFormat() + "\r\n");
            bridge.outputLine(manager.res.getString(R.string.host_authenticity_warning, target));
            bridge.outputLine(manager.res.getString(R.string.host_certificate, certInfo));
            Boolean result = bridge.promptHelper.requestBooleanPrompt(null, manager.res.getString(R.string.prompt_accept_certificate));

            if ((result == null) || (!result.booleanValue())) {
                throw new java.security.cert.CertificateException(
                    "Certificate Rejected");
            }

            result = bridge.promptHelper.requestBooleanPrompt(null, manager.res.getString(R.string.prompt_save_certificate));

            if ((result != null) && (result.booleanValue())) {
                try {
                    userks.setCertificateEntry(cert.getSubjectDN().getName(),
                                               cert);
                    userks.store(new FileOutputStream(userKsPath),
                                 userksPassword);
                }
                catch (Exception e) {
                    Log.e(TAG, "Error saving certificate [" + e.getMessage()
                          + "]");
                    e.printStackTrace();
                }
            }
        }
    }
}