// File: SimpleWebServer.java
// T Balls : Oct 1999

// The basic web server program, with local buffering
// Uses objects to handle the connections.
// Each Handler object "signs in" with a serial number to
// allow simple tracing of the server's operation.

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

public class SimpleWebServer
{  public static void main( String[] args )
   {  if( args.length == 1 )
      {  new SimpleWebServer( args[0] ).run();
      }
      else
      {  new SimpleWebServer( "44444" ).run();
      }
   }

   private ServerSocket ss = null;
   public SimpleWebServer( String portNum )
   {  int port = new Integer( portNum ).intValue();
      try
      {  ss = new ServerSocket( port );
      }
      catch( IOException ioe )
      {  System.out.println( "Can't create server socket on port : " + port );
         System.exit( -1 );
      }
   }

   public void run()
   {  Socket sock = null;
      int handlerCount = 0;
      while( true )
      {  try
         {  sock = ss.accept();
         }
         catch( IOException ioe )
         {  System.out.println( "Accept failed" );
            System.exit( -1 );
         }
         handlerCount++;
         new ConnectionHandler( sock, handlerCount ).run();
      }
   }
}

class ConnectionHandler
{  public ConnectionHandler( Socket s, int id )
   {  this.s = s;
      this.id = id;
   }
   
   private Socket s;
   private int id;
   public void run()
   {  BufferedReader in = null;
      OutputStream os = null;
      try
      {  in = new BufferedReader( new InputStreamReader( s.getInputStream() ) );
         os = s.getOutputStream();
      }
      catch( IOException ioe )
      {  System.out.println( "#" + id +" Can't get streams" );
         System.exit( -1 );
      }

      String firstLine = "";
      String line = "";
      try
      {  firstLine = in.readLine();
         System.out.println( "\n\n#" + id + " *** " + firstLine );
         line = in.readLine();
         while( !line.equals( "" ) )
         {  System.out.println( "#" + id + " " + line );
            line = in.readLine();
         }
      }
      catch( IOException ioe )
      {  System.out.println( "#" + id + " Error reading data from client" );
         System.exit( -1 );
      }

      StringTokenizer st = new StringTokenizer( firstLine );
      String command = st.nextToken();
      String filename = st.nextToken();

      if( command.equals( "GET" ) )
      {  sendFile( os, filename );
      }
      else
      {  sendError( os, 501, "NOT IMPLEMENTED" );
      }

      // This object should close the socket when it's finished with it
      try
      {  s.close();
      }
      catch( IOException ioe )
      {  System.out.println( "Error closing socket" );
      }
   }

   public void sendFile( OutputStream os, String filename )
   {  filename = filename.substring( 1, filename.length() );
      File f = new File( filename );
      if( !f.exists() )
      {  sendError( os, 404, "NOT FOUND" );
      }
      else
      {  String extension = filename.substring( filename.lastIndexOf( "." )+1,
                                                filename.length() );

         // Send header
         PrintStream ps = new PrintStream( os );
         ps.println( "HTTP/1.0 200 OK" );
         ps.print( "Content-Type: " );
         if( extension.equals( "html" ) )
         {  ps.println( "text/html" );
         }
         else if( extension.equals( "gif" ) )
         {  ps.println( "image/gif" );
         }
         else if( extension.equals( "jpeg" ) || extension.equals( "jpg" ) )
         {  ps.println( "image/jpeg" );
         }
         else
         {  ps.println( "text/plain" );
         }
         ps.println( "Connection: close" );
         ps.println();
         ps.flush();

         // send file body
         try
         {  InputStream is = new FileInputStream( filename );
            // Faster read/write than in first example
            // using a local buffer
            byte[] buffer = new byte[1024];
            int bytesRead;       
            while( (bytesRead = is.read( buffer )) !=  -1 )
            {  os.write( buffer, 0, bytesRead );
               System.out.print( "#" + id + " " );
            }
            os.flush();
         }
         catch( IOException ioe )
         {  System.out.println( "#" + id + " Error sending file body " );
         }
      }
   }

   public void sendError( OutputStream os, int errorNo, String errorText )
   {  PrintStream ps = new PrintStream( os );
      ps.println( "HTTP/1.0 " + errorNo + " " + errorText );
      ps.println( "Content-Type: text/html" );
      ps.println( "Connection: close" );
      ps.println();
      ps.println( "<HTML><HEAD><TITLE>Error " + errorNo + "</TITLE>" );
      ps.println( "<BODY><H2>HTTP Error " + errorNo + " " + errorText + "</H2>" );
      ps.println( "</BODY></HTML>" );
      ps.flush();
   }

}