package net.sourceforge.jsocks;
import java.io.IOException;
import java.io.InputStream;
import java.io.InterruptedIOException;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;

/**
  Abstract class Proxy, base for classes Socks4Proxy and Socks5Proxy.
  Defines methods for specifying default proxy, to be
  used by all classes of this package.
*/

public abstract class Proxy {

//Data members
    //protected InetRange directHosts = new InetRange();

    protected InetAddress proxyIP = null;
    protected String proxyHost = null;
    protected int proxyPort;
    protected Socket proxySocket = null;

    protected InputStream in;
    protected OutputStream out;

    protected int version;

    protected Proxy chainProxy = null;


//Protected static/class variables
    protected static Proxy defaultProxy = null;

//Constructors
//====================
    Proxy(String proxyHost, int proxyPort) throws UnknownHostException {
        this.proxyHost = proxyHost;
        this.proxyIP = InetAddress.getByName(proxyHost);
        this.proxyPort = proxyPort;
    }

    Proxy(Proxy chainProxy, InetAddress proxyIP, int proxyPort) {
        this.chainProxy = chainProxy;
        this.proxyIP = proxyIP;
        this.proxyPort = proxyPort;
    }

    Proxy(InetAddress proxyIP, int proxyPort) {
        this.proxyIP = proxyIP;
        this.proxyPort = proxyPort;
    }

    Proxy(Proxy p) {
        this.proxyIP = p.proxyIP;
        this.proxyPort = p.proxyPort;
        this.version = p.version;
    }

//Public instance methods
//========================

    /**
       Get the port on which proxy server is running.
     * @return Proxy port.
     */
    public int getPort() {
        return proxyPort;
    }
    /**
       Get the ip address of the proxy server host.
     * @return Proxy InetAddress.
     */
    public InetAddress getInetAddress() {
        return proxyIP;
    }

    /**
       Get string representation of this proxy.
     * @returns string in the form:proxyHost:proxyPort \t Version versionNumber
     */
    public String toString() {
        return ("" + proxyIP.getHostName() + ":" + proxyPort + "\tVersion " + version);
    }


//Public Static(Class) Methods
//==============================

    /**
     * Sets SOCKS4 proxy as default.
       @param hostName Host name on which SOCKS4 server is running.
       @param port Port on which SOCKS4 server is running.
       @param user Username to use for communications with proxy.
     */
    public static void setDefaultProxy(String hostName, int port, String user)
    throws UnknownHostException {
        defaultProxy = new Socks4Proxy(hostName, port, user);
    }

    /**
     * Sets SOCKS4 proxy as default.
       @param ipAddress Host address on which SOCKS4 server is running.
       @param port Port on which SOCKS4 server is running.
       @param user Username to use for communications with proxy.
     */
    public static void setDefaultProxy(InetAddress ipAddress, int port,
                                       String user) {
        defaultProxy = new Socks4Proxy(ipAddress, port, user);
    }
    /**
     * Sets SOCKS5 proxy as default.
     * Default proxy only supports no-authentication.
       @param hostName Host name on which SOCKS5 server is running.
       @param port Port on which SOCKS5 server is running.
     */
    public static void setDefaultProxy(String hostName, int port)
    throws UnknownHostException {
        defaultProxy = new Socks5Proxy(hostName, port);
    }
    /**
     * Sets SOCKS5 proxy as default.
     * Default proxy only supports no-authentication.
       @param ipAddress Host address on which SOCKS5 server is running.
       @param port Port on which SOCKS5 server is running.
     */
    public static void setDefaultProxy(InetAddress ipAddress, int port) {
        defaultProxy = new Socks5Proxy(ipAddress, port);
    }
    /**
     * Sets default proxy.
       @param p Proxy to use as default proxy.
     */
    public static void setDefaultProxy(Proxy p) {
        defaultProxy = p;
    }

    /**
       Get current default proxy.
     * @return Current default proxy, or null if none is set.
     */
    public static Proxy getDefaultProxy() {
        return defaultProxy;
    }

    /**
      Parses strings in the form: host[:port:user:password], and creates
      proxy from information obtained from parsing.
      <p>
      Defaults: port = 1080.<br>
      If user specified but not password, creates Socks4Proxy, if user
      not specified creates Socks5Proxy, if both user and password are
      speciefied creates Socks5Proxy with user/password authentication.
      @param proxy_entry String in the form host[:port:user:password]
      @return Proxy created from the string, null if entry was somehow
              invalid(host unknown for example, or empty string)
    */
    public static Proxy parseProxy(String proxy_entry) {
        String proxy_host;
        int proxy_port = 1080;
        String proxy_user = null;
        String proxy_password = null;
        Proxy proxy;
        java.util.StringTokenizer st = new java.util.StringTokenizer(
            proxy_entry, ":");

        if (st.countTokens() < 1) return null;

        proxy_host = st.nextToken();

        if (st.hasMoreTokens())
            try {
                proxy_port = Integer.parseInt(st.nextToken().trim());
            }
            catch (NumberFormatException nfe) {}

        if (st.hasMoreTokens())
            proxy_user = st.nextToken();

        if (st.hasMoreTokens())
            proxy_password = st.nextToken();

        try {
            if (proxy_user == null)
                proxy = new Socks5Proxy(proxy_host, proxy_port);
            else if (proxy_password == null)
                proxy = new Socks4Proxy(proxy_host, proxy_port, proxy_user);
            else {
                proxy = new Socks5Proxy(proxy_host, proxy_port);
                /*
                UserPasswordAuthentication upa = new UserPasswordAuthentication(
                                                 proxy_user, proxy_password);

                ((Socks5Proxy)proxy).setAuthenticationMethod(upa.METHOD_ID,upa);
                */
            }
        }
        catch (UnknownHostException uhe) {
            return null;
        }

        return proxy;
    }


//Protected Methods
//=================

    protected void startSession()throws SocksException {
        try {
            proxySocket = new Socket(proxyIP, proxyPort);
            in = proxySocket.getInputStream();
            out = proxySocket.getOutputStream();
        }
        catch (SocksException se) {
            throw se;
        }
        catch (IOException io_ex) {
            throw new SocksException(SOCKS_PROXY_IO_ERROR, "" + io_ex);
        }
    }

    protected abstract Proxy copy();
    protected abstract ProxyMessage formMessage(int cmd, InetAddress ip, int port);
    protected abstract ProxyMessage formMessage(int cmd, String host, int port)
    throws UnknownHostException;
    protected abstract ProxyMessage formMessage(InputStream in)
    throws SocksException,
        IOException;


    protected ProxyMessage connect(InetAddress ip, int port)
    throws SocksException {
        try {
            startSession();
            ProxyMessage request  = formMessage(SOCKS_CMD_CONNECT,
                                                ip, port);
            return exchange(request);
        }
        catch (SocksException se) {
            endSession();
            throw se;
        }
    }
    protected ProxyMessage connect(String host, int port)
    throws UnknownHostException, SocksException {
        try {
            startSession();
            ProxyMessage request  = formMessage(SOCKS_CMD_CONNECT,
                                                host, port);
            return exchange(request);
        }
        catch (SocksException se) {
            endSession();
            throw se;
        }
    }

    protected ProxyMessage bind(InetAddress ip, int port)
    throws SocksException {
        try {
            startSession();
            ProxyMessage request  = formMessage(SOCKS_CMD_BIND,
                                                ip, port);
            return exchange(request);
        }
        catch (SocksException se) {
            endSession();
            throw se;
        }
    }
    protected ProxyMessage bind(String host, int port)
    throws UnknownHostException, SocksException {
        try {
            startSession();
            ProxyMessage request  = formMessage(SOCKS_CMD_BIND,
                                                host, port);
            return exchange(request);
        }
        catch (SocksException se) {
            endSession();
            throw se;
        }
    }

    protected ProxyMessage accept()
    throws IOException, SocksException {
        ProxyMessage msg;

        try {
            msg = formMessage(in);
        }
        catch (InterruptedIOException iioe) {
            throw iioe;
        }
        catch (IOException io_ex) {
            endSession();
            throw new SocksException(SOCKS_PROXY_IO_ERROR, "While Trying accept:"
                                     + io_ex);
        }

        return msg;
    }

    protected ProxyMessage udpAssociate(InetAddress ip, int port)
    throws SocksException {
        try {
            startSession();
            ProxyMessage request  = formMessage(SOCKS_CMD_UDP_ASSOCIATE,
                                                ip, port);

            if (request != null)
                return exchange(request);
        }
        catch (SocksException se) {
            endSession();
            throw se;
        }

        //Only get here if request was null
        endSession();
        throw new SocksException(SOCKS_METHOD_NOTSUPPORTED,
                                 "This version of proxy does not support UDP associate, use version 5");
    }
    protected ProxyMessage udpAssociate(String host, int port)
    throws UnknownHostException, SocksException {
        try {
            startSession();
            ProxyMessage request  = formMessage(SOCKS_CMD_UDP_ASSOCIATE,
                                                host, port);

            if (request != null) return exchange(request);
        }
        catch (SocksException se) {
            endSession();
            throw se;
        }

        //Only get here if request was null
        endSession();
        throw new SocksException(SOCKS_METHOD_NOTSUPPORTED,
                                 "This version of proxy does not support UDP associate, use version 5");
    }


    protected void endSession() {
        try {
            if (proxySocket != null) proxySocket.close();

            proxySocket = null;
        }
        catch (IOException io_ex) {
        }
    }

    /**
     *Sends the request to SOCKS server
     */
    protected void sendMsg(ProxyMessage msg)throws SocksException,
        IOException {
        msg.write(out);
    }

    /**
     * Reads the reply from the SOCKS server
     */
    protected ProxyMessage readMsg()throws SocksException,
        IOException {
        return formMessage(in);
    }
    /**
     *Sends the request reads reply and returns it
     *throws exception if something wrong with IO
     *or the reply code is not zero
     */
    protected ProxyMessage exchange(ProxyMessage request)
    throws SocksException {
        ProxyMessage reply;

        try {
            request.write(out);
            reply = formMessage(in);
        }
        catch (SocksException s_ex) {
            throw s_ex;
        }
        catch (IOException ioe) {
            throw(new SocksException(SOCKS_PROXY_IO_ERROR, "" + ioe));
        }

        return reply;
    }


//Private methods
//===============


//Constants

    public static final int SOCKS_SUCCESS        = 0;
    public static final int SOCKS_FAILURE        = 1;
    public static final int SOCKS_BADCONNECT     = 2;
    public static final int SOCKS_BADNETWORK     = 3;
    public static final int SOCKS_HOST_UNREACHABLE   = 4;
    public static final int SOCKS_CONNECTION_REFUSED = 5;
    public static final int SOCKS_TTL_EXPIRE     = 6;
    public static final int SOCKS_CMD_NOT_SUPPORTED  = 7;
    public static final int SOCKS_ADDR_NOT_SUPPORTED = 8;

    public static final int SOCKS_NO_PROXY       = 1 << 16;
    public static final int SOCKS_PROXY_NO_CONNECT   = 2 << 16;
    public static final int SOCKS_PROXY_IO_ERROR     = 3 << 16;
    public static final int SOCKS_AUTH_NOT_SUPPORTED = 4 << 16;
    public static final int SOCKS_AUTH_FAILURE       = 5 << 16;
    public static final int SOCKS_JUST_ERROR     = 6 << 16;

    public static final int SOCKS_DIRECT_FAILED      = 7 << 16;
    public static final int SOCKS_METHOD_NOTSUPPORTED    = 8 << 16;


    public static final int SOCKS_CMD_CONNECT        = 0x1;
    static final int SOCKS_CMD_BIND      = 0x2;
    static final int SOCKS_CMD_UDP_ASSOCIATE = 0x3;

}