package hu.blint.ssldroid;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketException;
import java.security.KeyManagementException;
import java.security.KeyStore;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.UnrecoverableKeyException;

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

import android.util.Log;

public class TcpProxyServerThread extends Thread {

    String tunnelName;
    int listenPort;
    String tunnelHost;
    int tunnelPort;
    String keyFile, keyPass;
    Relay inRelay, outRelay;
    ServerSocket ss = null;
    int sessionid = 0;

    public TcpProxyServerThread(ServerSocket ss,String tunnelName, int listenPort, String tunnelHost, int tunnelPort, String keyFile, String keyPass) {
        this.tunnelName = tunnelName;
        this.listenPort = listenPort;
        this.tunnelHost = tunnelHost;
        this.tunnelPort = tunnelPort;
        this.keyFile = keyFile;
        this.keyPass = keyPass;
        this.ss = ss;
    }

    // Create a trust manager that does not validate certificate chains
    // TODO: handle this somehow properly (popup if cert is untrusted?)
    // TODO: cacert + crl should be configurable
    TrustManager[] trustAllCerts = new TrustManager[] {
    new X509TrustManager() {
        public java.security.cert.X509Certificate[] getAcceptedIssuers() {
            return null;
        }
        public void checkClientTrusted(
        java.security.cert.X509Certificate[] certs, String authType) {
        }
        public void checkServerTrusted(
        java.security.cert.X509Certificate[] certs, String authType) {
        }
    }
    };

    private static SSLSocketFactory sslSocketFactory;

    public final SSLSocketFactory getSocketFactory(String pkcsFile,
            String pwd, int sessionid) {
        if (sslSocketFactory == null) {
            try {
                KeyManagerFactory keyManagerFactory = KeyManagerFactory.getInstance("X509");
                KeyStore keyStore = KeyStore.getInstance("PKCS12");
                keyStore.load(new FileInputStream(pkcsFile), pwd.toCharArray());
                keyManagerFactory.init(keyStore, pwd.toCharArray());
                SSLContext context = SSLContext.getInstance("TLS");
                context.init(keyManagerFactory.getKeyManagers(), trustAllCerts,
                             new SecureRandom());
                sslSocketFactory = (SSLSocketFactory) context.getSocketFactory();

            } catch (FileNotFoundException e) {
                Log.d("SSLDroid", tunnelName+"/"+sessionid+": Error loading the client certificate file:"
                      + e.toString());
            } catch (KeyManagementException e) {
                Log.d("SSLDroid", tunnelName+"/"+sessionid+": No SSL algorithm support: " + e.toString());
            } catch (NoSuchAlgorithmException e) {
                Log.d("SSLDroid", tunnelName+"/"+sessionid+": No common SSL algorithm found: " + e.toString());
            } catch (KeyStoreException e) {
                Log.d("SSLDroid", tunnelName+"/"+sessionid+": Error setting up keystore:" + e.toString());
            } catch (java.security.cert.CertificateException e) {
                Log.d("SSLDroid", tunnelName+"/"+sessionid+": Error loading the client certificate:" + e.toString());
            } catch (IOException e) {
                Log.d("SSLDroid", tunnelName+"/"+sessionid+": Error loading the client certificate file:" + e.toString());
            } catch (UnrecoverableKeyException e) {
                Log.d("SSLDroid", tunnelName+"/"+sessionid+": Error loading the client certificate:" + e.toString());
            }
        }
        return sslSocketFactory;
    }

    public class Relay extends Thread {
        private InputStream in;
        private OutputStream out;
        private String side;
        private int sessionid;
        private final static int BUFSIZ = 4096;
        private byte buf[] = new byte[BUFSIZ];

        public Relay(InputStream in, OutputStream out, String side, int sessionid) {
            this.in = in;
            this.out = out;
            this.side = side;
            this.sessionid = sessionid;
        }

        public void run() {
            int n = 0;

            try {
                while ((n = in.read(buf)) > 0) {
                    if (Thread.interrupted()) {
                        // We've been interrupted: no more relaying
                        Log.d("SSLDroid", tunnelName+"/"+sessionid+": Interrupted "+side+" thread");
                        try {
                            in.close();
                            out.close();
                        } catch (IOException e) {
                            Log.d("SSLDroid", tunnelName+"/"+sessionid+": "+e.toString());
                        }
                        return;
                    }
                    out.write(buf, 0, n);
                    out.flush();

                    for (int i = 0; i < n; i++) {
                        if (buf[i] == 7)
                            buf[i] = '#';
                    }
                }
            } catch (SocketException e) {
                Log.d("SSLDroid", tunnelName+"/"+sessionid+": "+e.toString());
            } catch (IOException e) {
                Log.d("SSLDroid", tunnelName+"/"+sessionid+": "+e.toString());
            } finally {
                try {
                    in.close();
                    out.close();
                } catch (IOException e) {
                    Log.d("SSLDroid", tunnelName+"/"+sessionid+": "+e.toString());
                }
            }
            Log.d("SSLDroid", tunnelName+"/"+sessionid+": Quitting "+side+"-side stream proxy...");
        }
    }

    public void run() {
        while (true) {
            try {
                Thread fromBrowserToServer = null;
                Thread fromServerToBrowser = null;

                if (isInterrupted()) {
                    Log.d("SSLDroid", tunnelName+"/"+sessionid+": Interrupted server thread, closing sockets...");
                    ss.close();
                    return;
                }
                // accept the connection from my client
                Socket sc = null;
                try {
                    sc = ss.accept();
                    sessionid++;
                } catch (SocketException e) {
                    Log.d("SSLDroid", "Accept failure: " + e.toString());
                }

                Socket st = null;
                try {
                    st = (SSLSocket) getSocketFactory(this.keyFile, this.keyPass, this.sessionid).createSocket(this.tunnelHost, this.tunnelPort);
                    ((SSLSocket) st).startHandshake();
                } catch (IOException e) {
                    Log.d("SSLDroid", tunnelName+"/"+sessionid+": SSL failure: " + e.toString());
                    return;
                }
                catch (Exception e) {
                    Log.d("SSLDroid", tunnelName+"/"+sessionid+": SSL failure: " + e.toString());
                    sc.close();
                    return;
                }

                if (sc == null || st == null) {
                    Log.d("SSLDroid", tunnelName+"/"+sessionid+": Trying socket operation on a null socket, returning");
                    return;
                }
                Log.d("SSLDroid", tunnelName+"/"+sessionid+": Tunnelling port "
                      + listenPort + " to port "
                      + tunnelPort + " on host "
                      + tunnelHost + " ...");

                // relay the stuff through
                fromBrowserToServer = new Relay(
                    sc.getInputStream(), st.getOutputStream(), "client", sessionid);
                fromServerToBrowser = new Relay(
                    st.getInputStream(), sc.getOutputStream(), "server", sessionid);

                fromBrowserToServer.start();
                fromServerToBrowser.start();

            } catch (IOException ee) {
                Log.d("SSLDroid", tunnelName+"/"+sessionid+": Ouch: " + ee.toString());
            }
        }
    }
};