import java.io.*;
import java.nio.*;
import java.net.*;
import java.nio.channels.*;

/**
 *
 * Classe Server ouvant une socket TCP et envoyant un flux de bytes au client qui s'y connecte
 */
public class StreamServer {
	
  /** Socket pour la mise en attente des connexions. */
  ServerSocketChannel variableServerSocketChannel = ServerSocketChannel.open(); // ServerSocketChannel is an abstract class
  
  /** port par defaut d'ecoute */
  final static int portByDefault = 1000;
  
  /** port effectif d'ecoute */
  int portEffectif;
  
  /** Fichier a transferer */
  static File fileSource;
  
  /** Capacite du buffer */	
  int MAX_PACKET_SIZE = 1000000;
  
  

  
//**********************************************************************************************************************
//														CONSTRUCTEUR
//**********************************************************************************************************************
   
  /** Constructeur, qui attache la socket a la channel, la socket au port, le file au fileInputStream et le fileChannel au fileInputStream */
  public StreamServer(int portArg,String fileSrcArg) throws IOException {
	  
	  portEffectif = portArg;
	  fileSource = new File(fileSrcArg);
	  
	  ServerSocket socket = variableServerSocketChannel.socket(); // necessary to manipulate the SocketChannel
	  try {socket.bind(new InetSocketAddress(portEffectif));} //TCP connection listening on the port portEffectif
	  catch(BindException ex){
		  System.err.println("port used by another processus");
		  System.exit(1);
	  }
	  
  }
	  

//************************************************************************************************************************
// 														METHODES
//************************************************************************************************************************
	  
  

  /** Demarre le server. */
  public void startingServer(){
	  System.out.println("Server TCP ecoutant sur le port : " + portEffectif);

	  try {
		  FileInputStream fileSrcInputStream = new FileInputStream(fileSource);


		  // Allocation du tampon pour l'ecriture
		  ByteBuffer byteB = ByteBuffer.allocate(MAX_PACKET_SIZE);
		  FileChannel fileChannelsrc = fileSrcInputStream.getChannel();


		  System.out.println("En attente de nouvelles connections...");
		  SocketChannel sc = variableServerSocketChannel.accept();//Now connections are accepted ;blocking until one connection is established
			  
			  String scString = sc.toString();		//information on SocketChannel
			  String subStringsc = scString.substring(72,scString.length()-1); //obtemir l'ip du client, ne marche pas tres bien
			  System.out.println("Le client " + subStringsc + " vient de se connecter");
			  
			 // while (byteB.hasRemaining()) {
				  int start = byteB.remaining(); 
				  fileChannelsrc.read(byteB); //ecrit le contenu du fichier sur byteB
				  
				  int afterRead = byteB.remaining();
				  int difference = start - afterRead;
				  System.out.println("Il a été ecrit " + difference + " bytes du fichier vers le buffer.");
				  byteB.flip(); //position set to zero and limit is set to last element, If the mark is defined then it is discarded. 
				  ByteBuffer byteBufferTemp = ByteBuffer.allocate(1); //temp buffer used to receive from the client
				  sc.read(byteBufferTemp); //wait the client to be ready
				  sc.write(byteB); //envoi byteB sur la socket
			 // }
			  variableServerSocketChannel.close();
	  }
			  catch (FileNotFoundException ex) {System.err.println("Error, file not accessible");}
			  
			  catch (IOException ex) {
				  System.err.println("Probleme d'ecriture sur la socket");
				  System.exit(1);}
			 
			//  catch (InterruptedException iex){System.out.println("Interrupt Exception");}		  
	  
  }
	  
	
  
	  
     
//*********************************************************************************************************************
//																MAIN
//*********************************************************************************************************************
      
  public static void main(String[] args) throws IOException{

	  
	  if (args.length != 2) {
		  System.err.println("usage : portServer,file ");
		  System.exit(1);
	  }
	  
	  
	 
	  int port = portByDefault;  
	  try {
		  port = Integer.parseInt(args[0]);
	  } catch (NumberFormatException e) {
		  System.err.println("Le numero de port doit etre un entier");
		  System.exit(1);
	  }
	
	  StreamServer myStreamServer = new StreamServer(port,args[1]);
	  myStreamServer.startingServer();
    		
  }
}