import java.lang.*;
import java.io.*;
import java.net.*;
import java.util.*;


// this thread will handle each connection

class handler extends Thread {
    
    // our local server's names and IP addresses
    String localhosts = new String("localhost  127.0.0.1  julia  11.22.33.1  11.22.44.1");
    int localport = 80;

    // our WinGate proxy's address
    String proxy = new String ("11.22.33.10");
    int proxyport = 80;
        
    Socket sock = null;
    Socket f_sock = null;
    
    DataOutputStream os = null;
    DataInputStream is = null;
    
    PrintStream f_os = null;
    DataInputStream f_is = null;
    
    StringTokenizer st = null;
    
    
    // see if s2 contains s1
    static boolean containsString (String s1, String s2) {
	
	boolean found = false;
	StringTokenizer st;
	String token = new String ();
	
	if (s2.length() > 0) {
	    st = new StringTokenizer (s2);
	    try {
		while (!found) {
		    token = st.nextToken ();
		    found = (token.compareTo (s1) == 0);
		}
	    } catch (NoSuchElementException e) {
	    }
	}
	
	return (found);
    }
    
    // see if s2 contains the parameter string defined by tag s1
    String getParam (String s1, String s2) {
	
	StringTokenizer st;
	String token1 = new String ("");
	String token2 = new String ();
	
	if (s2.length() > 0) {
	    st = new StringTokenizer (s2);
	    try {
		token2 = st.nextToken ();
		if (token2.compareTo (s1) == 0)
		    token1 = st.nextToken ();
	    } catch (NoSuchElementException e) {
	    }
	    st = null;
	}
	
	return (token1);
    }
    
    
    // parent threads gives us our client socket number
    public void setSocket (Socket so) {
	sock = so;
    }
    
    
    public void run () {
	
	String host = new String ("");
	String request = new String ("");
	String s[];
	s = new String[20];
	int ns;            
	int i;
	
	byte buffer[] = new byte[1024];
	int lbuffer;
	String aux = new String ();
	
	try {

	    is = new DataInputStream (sock.getInputStream ());
	    os = new DataOutputStream (sock.getOutputStream ());
	    
	    for (i = 0; i < 20; i++)
		s[i] = new String(" ");
	    ns = 0;
	    while (s[ns].length() > 0) {
		ns++;
		s[ns] = is.readLine();

       		aux = getParam ("Host:", s[ns]); if (aux.length() > 0) host = new String(aux);
	     	aux = getParam ("GET", s[ns]); if (aux.length() > 0) request = new String (aux);
	    }
	    
	    System.out.print ("host: ");
	    System.out.print (host);
	    System.out.print ("  request: ");
	    System.out.print (request);
	    if (containsString (host, localhosts)) {
		System.out.println ("  -  Sent to localhost");
		f_sock = new Socket ("127.0.0.1", localport);
	    } else {
		System.out.println ("  -  Sent to proxy");
		f_sock = new Socket (proxy, proxyport);
	    }
	    
	    f_is = new DataInputStream (f_sock.getInputStream ());
	    f_os = new PrintStream (f_sock.getOutputStream ());
	    
	    for (i = 1; i <= ns; i++) {
		f_os.print (s[i]);
		f_os.print ("\r\n");
	    }
	    
	    try {
		while ((lbuffer = f_is.read (buffer, 1, 512)) > 0) 
		    os.write (buffer, 1, lbuffer);
		
	    } catch (IOException e) {
	    }
	    
	    f_is.close ();
	    f_os.close ();
	    f_sock.close ();
	    
	    is.close ();
	    os.close ();
	    sock.close ();
	} catch (IOException e) {
	    System.out.println ("Caught socket IO exception");
	}
	
    }
}
    

// main class: listens on port myport, and when a connection comes in 
// creates a new handler thread for it

public class proxy {   

    static int myport = 8080;
    
    static public void main (String argv[]) {
	
       	ServerSocket serv = null;
	Socket sock = null;
	handler h = null;
	
	try {
	    serv = new ServerSocket (myport);
	} catch (IOException e) {
	    System.out.println ("Caught server IO exception");
	    System.exit (1);
	}
	
	while (true) {
	    try {
		sock = serv.accept ();
		
		h = new handler ();
		h.setSocket (sock);
		h.start ();
		
	    } catch (IOException e) {
		System.out.println ("Caught IO exception closing server");
		System.exit (1);
	    }
	    
	    
	}
	
    }
    
}