/*

 * Copyright 2006 Sun Microsystems, Inc.  All Rights Reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

import java.net.*;

import java.io.*;

import java.util.regex.*;

import java.security.*;

import javax.net.ssl.*;

/*

 * This class handles one client connection. It will interpret and act on the

 * commands (like USER, GET, PUT etc...) sent through the socket passed to

 * the constructor.

 *

 * To function it needs to be provided 2 handlers, one for the filesystem

 * and one for authentication.

 * @see FileSystemHandler

 * @see AuthHandler

 * @see #setHandlers(FtpFileSystemHandler,FtpAuthHandler)

 */

public class FtpCommandHandler extends Thread {

    private FtpServer parent = null;

    private Socket cmd = null;

    private Socket oldCmd = null;

    private InetAddress clientAddr = null;

    private ServerSocket pasv = null;

    private BufferedReader in = null;

    private PrintStream out = null;

    private FtpFileSystemHandler fsh = null;

    private FtpAuthHandler auth = null;

    private boolean done = false;

    private String username = null;

    private String password = null;

    private String account = null;

    private boolean logged = false;

    private boolean epsvAll = false;

    private int dataPort = 0;

    private InetAddress dataAddress = null;

    private boolean pasvEnabled = true;

    private boolean portEnabled = true;

    private boolean extendedEnabled = true;

    private boolean binary = true;

    private String renameFrom = null;

    private long restart = 0;

    private boolean useCrypto = false;

    private boolean useDataCrypto = false;

    private SSLSocketFactory sslFact = null;

    private final int ERROR = -1;

    private final int QUIT = 0;

    private final int USER = 1;

    private final int PASS = 2;

    private final int CWD = 3;

    private final int CDUP = 4;

    private final int PWD = 5;

    private final int TYPE = 6;

    private final int NOOP = 7;

    private final int RETR = 8;

    private final int PORT = 9;

    private final int PASV = 10;

    private final int EPSV = 11;

    private final int EPRT = 12;

    private final int SYST = 13;

    private final int STOR = 14;

    private final int STOU = 15;

    private final int LIST = 16;

    private final int NLST = 17;

    private final int RNFR = 18;

    private final int RNTO = 19;

    private final int DELE = 20;

    private final int REST = 21;

    private final int AUTH = 22;

    private final int FEAT = 23;

    private final int CCC = 24;

    private final int PROT = 25;

    private final int PBSZ = 26;

    private String[] commands =

    { "QUIT", "USER", "PASS", "CWD", "CDUP", "PWD", "TYPE", "NOOP", "RETR",

      "PORT", "PASV", "EPSV", "EPRT", "SYST", "STOR", "STOU", "LIST", "NLST",

      "RNFR", "RNTO", "DELE", "REST", "AUTH", "FEAT", "CCC", "PROT", "PBSZ"

    };

    private boolean isPasvSet() {

        if (pasv != null && !pasvEnabled) {

            try {

                pasv.close();

            } catch ( IOException e) {

            }

            pasv = null;

        }

        if (pasvEnabled && pasv != null)

            return true;

        return false;

    }

    private OutputStream getOutDataStream() throws IOException {

        if (isPasvSet()) {

            Socket s = pasv.accept();

            if (useCrypto && useDataCrypto) {

                SSLSocket ssl = (SSLSocket) sslFact.createSocket(s, clientAddr.getHostName(), s.getPort(), true);

                ssl.setUseClientMode(false);

                s = ssl;

            }

            return s.getOutputStream();

        }

        if (dataAddress != null) {

            Socket s;

            if (useCrypto) {

                s = sslFact.createSocket(dataAddress, dataPort);

            } else

                s = new Socket(dataAddress, dataPort);

            dataAddress = null;

            dataPort = 0;

            return s.getOutputStream();

        }

        return null;

    }

    private InputStream getInDataStream() throws IOException {

        if (isPasvSet()) {

            Socket s = pasv.accept();

            if (useCrypto && useDataCrypto) {

                SSLSocket ssl = (SSLSocket) sslFact.createSocket(s, clientAddr.getHostName(), s.getPort(), true);

                ssl.setUseClientMode(false);

                s = ssl;

            }

            return s.getInputStream();

        }

        if (dataAddress != null) {

            Socket s;

            if (useCrypto) {

                s = sslFact.createSocket(dataAddress, dataPort);

            } else

                s = new Socket(dataAddress, dataPort);

            dataAddress = null;

            dataPort = 0;

            return s.getInputStream();

        }

        return null;

    }

    private void parsePort(String port_arg) throws IOException {

        if (epsvAll) {

            out.println("501 PORT not allowed after EPSV ALL.");

            return;

        }

        if (!portEnabled) {

            out.println("500 PORT command is disabled, please use PASV.");

            return;

        }

        StringBuffer host;

        int i = 0, j = 4;

        while (j > 0) {

            i = port_arg.indexOf(',', i + 1);

            if (i < 0)

                break;

            j--;

        }

        if (j != 0) {

            out.println("500 '" + port_arg + "': command not understood.");

            return;

        }

        try {

            host = new StringBuffer(port_arg.substring(0, i));

            for (j = 0; j < host.length(); j++)

                if (host.charAt(j) == ',')

                    host.setCharAt(j, '.');

            String ports = port_arg.substring(i + 1);

            i = ports.indexOf(',');

            dataPort = Integer.parseInt(ports.substring(0, i)) << 8;

            dataPort += (Integer.parseInt(ports.substring(i + 1)));

            dataAddress = InetAddress.getByName(host.toString());

            out.println("200 Command okay.");

        } catch (Exception ex3) {

            dataPort = 0;

            dataAddress = null;

            out.println("500 '" + port_arg + "': command not understood.");

        }

    }

    private void parseEprt(String arg) {

        if (epsvAll) {

            out.println("501 PORT not allowed after EPSV ALL");

            return;

        }

        if (!extendedEnabled || !portEnabled) {

            out.println("500 EPRT is disabled, use PASV instead");

            return;

        }

        Pattern p = Pattern.compile("\\|(\\d)\\|(.*)\\|(\\d+)\\|");

        Matcher m = p.matcher(arg);

        if (!m.find()) {

            out.println("500 '" + arg + "': command not understood.");

            return;

        }

        try {

            dataAddress = InetAddress.getByName(m.group(2));

        } catch (UnknownHostException e) {

            out.println("500 " + arg + ": invalid address.");

            dataAddress = null;

            return;

        }

        dataPort = Integer.parseInt(m.group(3));

        out.println("200 Command okay.");

    }

    private void doPasv() {

        if (!pasvEnabled) {

            out.println("500 PASV is disabled, use PORT.");

            return;

        }

        try {

            if (pasv == null)

                pasv = new ServerSocket(0);

            int port = pasv.getLocalPort();

            InetAddress rAddress = cmd.getLocalAddress();

            if (rAddress instanceof Inet6Address) {

                out.println("500 PASV illegal over IPv6 addresses, use EPSV.");

                return;

            }

            byte[] a = rAddress.getAddress();

            out.println("227 Entering Passive Mode " + a[0] + "," + a[1] + "," + a[2] + "," + a[3] + "," +

                        (port >> 8) + "," + (port & 0xff) );

        } catch (IOException e) {

            out.println("425 can't build data connection: Connection refused.");

        }

    }

    private void doEpsv(String arg) {

        if (!extendedEnabled || !pasvEnabled) {

            out.println("500 EPSV disabled, use PORT or PASV.");

            return;

        }

        if ("all".equalsIgnoreCase(arg)) {

            out.println("200 EPSV ALL Command successful.");

            epsvAll = true;

            return;

        }

        try {

            if (pasv == null)

                pasv = new ServerSocket(0);

            int port = pasv.getLocalPort();

            out.println("229 Entering Extended Passive Mode (|||" + port + "|)");

        } catch (IOException e) {

            out.println("500 Can't create data connection.");

        }

    }

    private void doRetr(String arg) {

        try {

            OutputStream dOut = getOutDataStream();

            if (dOut != null) {

                InputStream dIn = fsh.getFile(arg);

                if (dIn == null) {

                    out.println("550 File not found.");

                    dOut.close();

                    return;

                }

                out.println("150 Opening " + (binary ? "BINARY " : "ASCII ") + " data connection for file " + arg +

                            "(" + fsh.getFileSize(arg) + " bytes).");

                if (binary) {

                    byte[] buf = new byte[2048];

                    dOut = new BufferedOutputStream(dOut);

                    int count;

                    if (restart > 0) {

                        dIn.skip(restart);

                        restart = 0;

                    }

                    do {

                        count = dIn.read(buf);

                        if (count > 0)

                            dOut.write(buf, 0, count);

                    } while (count >= 0);

                    dOut.close();

                    dIn.close();

                    out.println("226 Transfer complete.");

                }

            }

        } catch (IOException e) {

        }

    }

    private void doStor(String arg, boolean unique) {

        try {

            InputStream dIn = getInDataStream();

            if (dIn != null) {

                OutputStream dOut = fsh.putFile(arg);

                if (dOut == null) {

                    out.println("500 Can't create file " + arg);

                    dIn.close();

                    return;

                }

                out.println("150 Opening " + (binary ? "BINARY " : "ASCII ") + " data connection for file " + arg);

                if (binary) {

                    byte[] buf = new byte[2048];

                    dOut = new BufferedOutputStream(dOut);

                    int count;

                    do {

                        count = dIn.read(buf);

                        if (count > 0)

                            dOut.write(buf, 0, count);

                    } while (count >= 0);

                    dOut.close();

                    dIn.close();

                    out.println("226 Transfer complete.");

                }

            }

        } catch (IOException e) {

        }

    }

    private void doList() {

        try {

            OutputStream dOut = getOutDataStream();

            if (dOut != null) {

                InputStream dIn = fsh.listCurrentDir();

                if (dIn == null) {

                    out.println("550 File not found.");

                    dOut.close();

                    return;

                }

                out.println("150 Opening ASCII data connection for file list");

                byte[] buf = new byte[2048];

                dOut = new BufferedOutputStream(dOut);

                int count;

                do {

                    count = dIn.read(buf);

                    if (count > 0)

                        dOut.write(buf, 0, count);

                } while (count >= 0);

                dOut.close();

                dIn.close();

                out.println("226 Transfer complete.");

            }

        } catch (IOException e) {

        }

    }

    private boolean useTLS() {

        if (sslFact == null) {

            sslFact = (SSLSocketFactory) SSLSocketFactory.getDefault();

        }

        if (sslFact == null)

            return false;

        return true;

    }

    private void stopTLS() {

        if (useCrypto) {

            SSLSocket ssl = (SSLSocket) cmd;

            try {

                ssl.close();

            } catch (IOException e) {

                // nada

            }

            cmd = oldCmd;

            oldCmd = null;

            try {

                in = new BufferedReader(new InputStreamReader(cmd.getInputStream()));

                out = new PrintStream(cmd.getOutputStream(), true, "ISO8859_1");

            } catch (Exception ex) {

            }

        }

    }

    public void setHandlers(FtpFileSystemHandler f, FtpAuthHandler a) {

        fsh = f;

        auth = a;

    }

    public FtpCommandHandler(Socket cl, FtpServer p) {

        parent = p;

        cmd = cl;

        clientAddr = cl.getInetAddress();

    }

    public void terminate() {

        done = true;

    }

    private int parseCmd(StringBuffer cmd) {

        if (cmd == null || cmd.length() < 3) // Shortest command is 3 char long

            return ERROR;

        int blank = cmd.indexOf(" ");

        if (blank < 0)

            blank = cmd.length();

        if (blank < 3)

            return ERROR;

        String s = cmd.substring(0,blank);

        cmd.delete(0, blank + 1);

        System.out.println("parse: cmd = " + s + " arg = " +cmd.toString());

        for (int i = 0; i < commands.length; i++)

            if (s.equalsIgnoreCase(commands[i]))

                return i;

        // Unknown command

        return ERROR;

    }

    private boolean checkLogged() {

        if (!logged) {

            out.println("530 Not logged in.");

            return false;

        }

        return true;

    }

    public void run() {

        try {

            // cmd.setSoTimeout(2000);

            in = new BufferedReader(new InputStreamReader(cmd.getInputStream()));

            out = new PrintStream(cmd.getOutputStream(), true, "ISO8859_1");

            out.println("220 Java FTP test server (j2se 6.0) ready.");

            out.flush();

            if (auth.authType() == 0) // No auth needed

                logged = true;

        } catch (IOException e) {

            e.printStackTrace();

            return;

        }

        String str;

        StringBuffer buf;

        int res;

        while (!done) {

            try {

                str = in.readLine();

                System.out.println("line: " + str);

                buf = new StringBuffer(str);

                res = parseCmd(buf);

                switch (res) {

                case ERROR:

                    out.println("500 '" + str +"': command not understood.");

                    break;

                case QUIT:

                    out.println("221 Goodbye.");

                    done = true;

                    break;

                case USER:

                    logged = false;

                    username = buf.toString();

                    if (auth.authType() > 1)

                        out.println("331 User name okay, need password.");

                    else {

                        if (auth.authenticate(username, null)) {

                            out.println("230 User logged in, proceed.");

                            logged = true;

                        } else {

                            out.println("331 User name okay, need password.");

                        }

                    }

                    break;

                case PASS:

                    if (logged || (username == null)) {

                        out.println("503 Login with USER first.");

                        break;

                    }

                    password = buf.toString();

                    if (auth.authType() == 3) {

                        out.println("332 Need account for login.");

                        break;

                    }

                    if (auth.authenticate(username, password)) {

                        logged = true;

                        out.println("230 User " + username + " logged in.");

                        break;

                    }

                    out.println("530 Login incorrect.");

                    username = null;

                    break;

                case CWD:

                    if (checkLogged()) {

                        String path = buf.toString();

                        if (fsh.cd(path)) {

                            out.println("250 CWD command successful.");

                        } else {

                            out.println("550 " + path + ": no such file or directory.");

                        }

                    }

                    break;

                case CDUP:

                    if (checkLogged()) {

                        if (fsh.cdUp())

                            out.println("250 CWD command successful.");

                        else

                            out.println("550 invalid path.");

                    }

                    break;

                case PWD:

                    if (checkLogged()) {

                        String s = fsh.pwd();

                        out.println("257 \"" + s + "\" is current directory");

                    }

                    break;

                case NOOP:

                    if (checkLogged()) {

                        out.println("200 NOOP command successful.");