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


public class Ftpclient extends Thread 
{

	static int keepgoing = 0;
	DatagramSocket dataSock;
	public static	
	String filename;

	public static void main(String[] args) throws Exception
	{	

		//TCP connection variables:
  		  Socket clientSocket = null; 
  		  DataInputStream is = null;
  		  DataOutputStream outToServer = null;
  		  BufferedReader inFromUser = null;
  		  BufferedReader inFromServer = null;
  		  String host = null;
  		  int port, i, code;
  		  char[] line;
  		  String instring;
  		  host =  new String(args[0]);
  		  port =  5180;
		//

		//loggedin = 1 if user logged in or loggedin = 0 if user not logged in
  		  int loggedin = 0;
		//

		//retrieve variables:
  		  long before=System.currentTimeMillis(); //gets the time before the transfer begins
  		  int MAX_WIRE_LENGTH = 16000;    
  		  int datalength = 9;
  		  DatagramPacket packet = null;
  		  DatagramSocket dataSock = null;
  		  String filetoRead = null;
		//

		//store variables:
  		  String filetoWrite = null;
  		  int availableBytes = 1;
		//


		try 
		{//try 1
			//open streams and socket for TCP connection
			inFromUser = new BufferedReader(new InputStreamReader(System.in));
			clientSocket = new Socket(host, port);
			outToServer = new DataOutputStream(clientSocket.getOutputStream());
			inFromServer = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
		}//end try 1
		catch (UnknownHostException e) {
			System.err.println("Don't know about host: " + host);
		} catch (IOException e) {
			System.err.println("Couldn't get I/O for the connection to: hostname");
		}

		try {//try 2

 			String responseLine; //variable used to store the line the server responds to the client with 
 			responseLine = inFromServer.readLine(); //read the response line from the server
  			System.out.println("Server: " + responseLine);

		while(true) //executes FTP commands until the user quits  
		{ //while 1
	
			instring = inFromUser.readLine(); //read the FTP command the client enters
			outToServer.writeBytes(instring + '\n'); //send the command to the server
			responseLine = inFromServer.readLine(); //read the servers respnse line
 
			//retrieve code---works only if user is logged in
			if((instring.substring(0,4).equals("RETR")) && loggedin == 1) 
			{ 		
				filename = instring.substring(5, instring.length()); //read the file the client wishes to retrieve
				dataSock = new DatagramSocket(3500); //create datagram socket for udp connection				
				Ftpclient udpin = new Ftpclient(dataSock); //dataSock variable of class Ftpclient
        			udpin.start();  //execute run method
				responseLine = inFromServer.readLine(); 				
				responseLine = inFromServer.readLine();
				udpin.stop(); //stop the run method
		
				//if file doesn't exist erase it from directory 		
				if(responseLine.equals("450"))
				{
					System.out.println("The file requested does not exist!");
					File deleteFile = new File(filename);
					deleteFile.delete();
				}
	
        			dataSock.close(); // close data sock 
 
			}// end of retrieve command

			//break out of while loop if the client types QUIT
			if (instring.equals("QUIT"))
			{
				break;
			}

			//store code
			if(instring.substring(0,4).equals("STOR"))
			{

				filetoWrite = new String(instring.substring(5, instring.length())); //get file from the client and store in filetoWrite

				try
				{ 
					InetAddress addr = clientSocket.getInetAddress();
					DatagramSocket outNet = new DatagramSocket(); //create datagram socket for udp connection

					//Open the File And Send it
					FileInputStream iStream = new FileInputStream(filetoWrite);
					System.out.println("Now Sending: " + filetoWrite);
		
					availableBytes = iStream.available();  //get # of available bytes
 					Thread.sleep(1000); // pause program for 1 second to allow the program receiving data to get ready 					
					  		
					while(availableBytes > 0)  //while there is still available bytes send the file to server 
					{	
						//create datagram packet called message and send the message to the server
						if(availableBytes <= 16000)
						{
							byte [] bytes = new byte [availableBytes];
							int j = iStream.read(bytes);
							DatagramPacket message = new DatagramPacket(bytes, bytes.length, addr, 3500);
							outNet.send(message);
						}
						else
						{
							byte [] bytes = new byte [16000];
							int j = iStream.read(bytes);
							DatagramPacket message = new DatagramPacket(bytes, bytes.length, addr, 3500);
							outNet.send(message);
						}

						//find the new value of available bytes
						availableBytes = iStream.available();

					}	
		 
					outToServer.writeBytes("DONE" + '\n'); //let the server know the client is done transfering the file 
				}
				catch (IOException e)
				{ outToServer.writeBytes("NE" + '\n');
				  System.out.println("The file does not exist!");
	  			}
	
				responseLine = inFromServer.readLine(); 

			}// end of STORE


			////If statements to determine definition for codes of which the server responds
			////Read print statement to find definition of each code

			if(responseLine.equals("221"))
			{ 
				System.out.println( responseLine + " " + " Service closing control connection." );
				System.out.println( "  Logged out if appropriate." );
			}
			else if(responseLine.equals("230"))
			{
				System.out.println( responseLine + " " + " User logged in proceed." ); 	
				loggedin = 1; //server logged in user therefor set loggedin to 1
			}
			else if(responseLine.equals("150"))
			{
				System.out.println( responseLine + " " + " File status OK - about to open file." );
			}
			else if(responseLine.equals("530"))	
			{
				System.out.println( responseLine + " " + " Not logged in." ); 	
				loggedin = 0;  //server did not log in user therefore set loggedin to 0
			}
			else if(responseLine.equals("331"))
			{
				System.out.println( responseLine + " " + " User name okay, need password." ); 	
				loggedin = 0; //server needs a password for user name therefore not logged in and loggedin is 0
			}
			else if(responseLine.equals("250"))
			{
				System.out.println( responseLine + " " + " Requested file action okay, completed.");
			} 
			else if(responseLine.equals("450"))
			{
				System.out.println( responseLine + " " + " Requested file action not taken.");
			}
			else if(responseLine.equals("226"))
			{
				System.out.println( responseLine + " " + " Closing data connection. \n Requested file action successful.");
			}  
			else if(responseLine.equals("500"))
			{
				System.out.println( responseLine + " " + " Syntax error, command unrecognized.");
			}
			else if(responseLine.equals("501"))
			{
				System.out.println( responseLine + " " + " Syntax error in parameters or arguments.");
			}
			else if(responseLine.equals("425"))
			{
				System.out.println( responseLine + " " + " Can't open data connection.");
			}
			else if(responseLine.equals("550"))
			{
				System.out.println( responseLine + " " + " Requested action not taken.");
			}
			else if(responseLine.substring(0, 3).equals("999"))
			{
			System.out.println( responseLine.substring(0, 3) + " " + responseLine.substring(4, responseLine.length()));
			}
			else if(responseLine.substring(0, 3).equals("998"))	
			{
				System.out.println( responseLine.substring(0, 3) + " " + responseLine.substring(4, responseLine.length()));
			}
			else
			{
				System.out.println( " Invalid Command" );
			}
	
		}// while 1

		clientSocket.close();

		}//try 2
		catch (UnknownHostException e) {
		System.err.println("Trying to connect to unknown host: " + e);}
		catch (IOException e) {
		System.err.println("IOException: " + e);}

	}// main

	//
	public Ftpclient(DatagramSocket dataSock) 
	{ 	
		this.dataSock = dataSock; 	
	}  

	public void run() 
	{  		
		long before=System.currentTimeMillis(); //gets the time before the transfer begins 		
		int datalength = 9;         
		DatagramPacket packet = new DatagramPacket(new byte[16000], 16000); //create datagram packet              
		try             
		{                         
			System.out.println("Retrieving " + filename);                       
			FileOutputStream outtoFile = new FileOutputStream(filename);                                              
			datalength = 9;   
           
			while(true)  	    
			{          			
				dataSock.receive(packet); //retrieve the data sock packet      
       			
				datalength = packet.getLength(); //get the length of the packet      	
				byte [] theData = new byte [datalength];  //create byte array with size datalength        			
				byte [] packetBuf = new byte [16000]; //create byte array with size 16000        			
				packetBuf = packet.getData(); //get data from packet and store in packetBuf
           			
				//if data is equal to 16000 send the packetBuf to the server         			
				if (datalength == 16000)                 		
				{                  			
					outtoFile.write(packetBuf);                 		
				}  
				//otherwise get the data from each byte of packetBuf up to datalength and send to sever              		
				else                 		
				{                  			
					for(int i=0;i<datalength;i++)                         		
					{                                 		
						theData[i] = packetBuf[i];                         		
					}                
         		                         		
					outtoFile.write(theData);                 		
				}       	        
			}  
               	                 
            
		} catch (UnknownHostException e)              
		{ System.out.println(e); }              
		catch (IOException e)              
		{ System.out.println(e); }  
  
	}// run method 


}// class