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

// wget -S

public class ProxyServer3
{
	public static void main( String[] args )
	{
		int port = 8126;

		// TO DO: read port from argv[1]

		ProxyServer3 theServer = new ProxyServer3( port );
	}

	public ProxyServer3( int port )
	{
		System.out.println( "Server started at " + new Date() );

		try
    	{
      		// Create a server (listener) socket
		    ServerSocket serverSocket = new ServerSocket( port, 5 );
		      // Note the second arg is 5, which is the backlog....

			while ( true )
			{
				// Listen for a connection request from a client
				System.out.println( "Blocking on accept()" );
		    	Socket clientSocket = serverSocket.accept();   // BLOCK!
		    	System.out.println( "Client connection rcvd at " + new Date() );

//				StringBuilder request = new StringBuilder();
				InputStream stream = clientSocket.getInputStream();

				// ADD BUFFERED READER:
				BufferedReader in = new BufferedReader( new InputStreamReader( stream ) );

				String request = in.readLine();
				System.out.println( "Request-Line is: " + request );

		// Isolate the hostname from within the Request-Line:
		//     GET http://www.cs.rpi.edu/index.html HTTP/1.1
		//                ^             ^          ^
		//                a             b          c
		int a = request.indexOf( "://" ) + 3;
		int b = request.indexOf( "/", a );
		int c = request.indexOf( " ", b );
		String requestedHost = request.substring( a, b );
		String newRequestLine = "GET " + request.substring( b, c ) + " HTTP/1.1";
		StringBuilder newRequestHeaders = new StringBuilder();
		newRequestHeaders.append( "Host: " );
		newRequestHeaders.append( requestedHost );
		newRequestHeaders.append( "\r\n" );
		System.out.println( newRequestLine + "\r\n" + newRequestHeaders.toString() + "\r\n" );
		// e.g.
		//    GET /index.html HTTP/1.1
		//    Host: www.cs.rpi.edu





				String header;
				while ( ( header = in.readLine() ) != null )
				{
					System.out.println( "RCVD: " + header );
					//header = header.trim();
					if ( header.length() == 0 ) break;
					if (
						 header.startsWith( "User-Agent:" ) ||
						 header.startsWith( "Accept" )
						)
					{
						newRequestHeaders.append( header + "\r\n" );
					}
				}

		System.out.println();
		System.out.println();
		newRequestHeaders.append( "\r\n" );
		String newRequest = newRequestLine + "\r\n" + newRequestHeaders.toString() + "\r\n";
		System.out.println( newRequest );

      // Create a socket (socket() in C) and attempt to connect
      //  to a server at a specific port number (connect() in C)
      Socket toWebServerSocket = new Socket( requestedHost, 80 );
      OutputStream toWebServerStream = toWebServerSocket.getOutputStream();
      toWebServerStream.write( newRequest.getBytes() );
      toWebServerStream.flush();

	  InputStream fromWebServerStream = toWebServerSocket.getInputStream();
	  BufferedReader input = new BufferedReader( new InputStreamReader( fromWebServerStream ) );
      String responseLine = input.readLine();
	  System.out.println( "Response-Line is: " + responseLine );
	StringBuilder response = new StringBuilder();
	response.append( responseLine );
	response.append( "\r\n" );
	String header2;
	int contentLength = 0;
				while ( ( header2 = input.readLine() ) != null )
				{
					System.out.println( "RCVD: " + header2 );
					if ( header2.length() == 0 ) break;
					if ( header2.startsWith( "Content-Length:" ) )
					{
						String h = header2.substring( 16 );
						contentLength = Integer.parseInt( h );
						System.out.println( "content length is " + contentLength );
					}
					if ( header2.equals( "Transfer-Encoding: chunked" ) )
					{
						contentLength = 50000;
					}
					response.append( header2 );
					response.append( "\r\n" );
				}
				response.append( "Connection: close\r\n" );
				response.append( "\r\n" );

		byte[] rawData = new byte[contentLength];


		for ( int q = 0 ; q < contentLength ; q++ )
		{
			rawData[q] = (byte)input.read();
		}
		response.append( new String( rawData ) );


System.out.println( response.toString() );




				OutputStream ostream = clientSocket.getOutputStream();
				ostream.write( response.toString().getBytes() );
				ostream.flush();

				System.out.println( "Sent response" );

			}
    	}
    	catch ( IOException ex )
    	{
    		System.err.println( "ERROR: " + ex );
    	}
	}
}