package prac;

/*
The purpose of the program is to build a
client based app that functions as a
Very Simple Filed Based Transfer Program.
The program is built around a Switch-case
statement. While doing research, this seemed
the mos intuitive.
*/

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

public class Clientapp {

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


        FileOutputStream fos;
        BufferedOutputStream bos;
        try (Socket socket = new Socket("localhost", 50000);
		PrintWriter outputToServer = new PrintWriter(socket.getOutputStream(), true);
		BufferedReader inputFromServer = new BufferedReader(new InputStreamReader(socket.getInputStream()));
		Scanner scanner = new Scanner(System.in))
		{
            boolean acceptedUserName = false;
            boolean acceptedPassword = false;
            boolean connected = true;
            boolean fileFound;

            int bytesRead;
            int current = 0;
            fos = null;
            bos = null;

            String currentUser = null;
            System.out.println("+Hello from VSFTP Service!");
            String[] input = scanner.nextLine().trim().split("\\s+");
            String[] command = checkInput(input);
            int numberOfFiles;
            do {
			/* This is a switch case which defines and excecutes the commands*/
                switch (command[0]) {

				//The "USER" command

                    case "USER":
                        outputToServer.println(command[0]);
                        acceptedUserName = verifyusername(inputFromServer, outputToServer, command[1]);
                        if (acceptedUserName && !acceptedPassword) {
                            currentUser = command[1];
                            System.out.println("+User-id valid, send password ");
                            input = scanner.nextLine().trim().split("\\s+");
                            command = checkInput(input);
                        } else if (acceptedUserName) {
                            System.out.println("-Already logged-in ");
                            input = scanner.nextLine().trim().split("\\s+");
                            command = checkInput(input);
                        } else {
                            System.out.println("-Invalid user-id ");
                            input = scanner.nextLine().trim().split("\\s+");
                            command = checkInput(input);
                        }
                        break;

                    case "PASS":
                        if (acceptedUserName) {

						//The "PASS" command

                            outputToServer.println(command[0]);
                            acceptedPassword = verifypassword(inputFromServer, outputToServer, currentUser, command[1]);
                            if (acceptedPassword) {
                                System.out.println("! Logged in");
                                System.out.println("+Password is ok and you can begin file transfers");
                                input = scanner.nextLine().trim().split("\\s+");
                                command = checkInput(input);
                            } else {
                                System.out.println("-Wrong password ");
                                input = scanner.nextLine().trim().split("\\s+");
                                command = checkInput(input);
                            }
                        } else {
                            System.out.println("-Must enter a valid username before password verification ");
                            input = scanner.nextLine().trim().split("\\s+");
                            command = checkInput(input);
                        }
                        break;

                    case "LIST":

					//The "LIST" command

                        if (acceptedUserName && acceptedPassword) {
                            outputToServer.println(command[0]);
                            System.out.println(inputFromServer.readLine());
                            numberOfFiles = Integer.parseInt(inputFromServer.readLine());
                            for (int i = 0; i < numberOfFiles; i++) {
                                System.out.println(inputFromServer.readLine());
                            }
                            input = scanner.nextLine().trim().split("\\s+");
                            command = checkInput(input);
                        }
						else {
                            System.out.println("-Valid credentials needed to use this command ");
                            input = scanner.nextLine().trim().split("\\s+");
                            command = checkInput(input);
                        }
                        break;

                    case "KILL":

					//The "KILL" command

                        if (acceptedUserName && acceptedPassword) {
                            outputToServer.println(command[0]);
                            outputToServer.println(command[1]);
                            System.out.println(inputFromServer.readLine());
                            input = scanner.nextLine().trim().split("\\s+");
                            command = checkInput(input);
                        }
						else {
                            System.out.println("-Valid credentials needed to use this command ");
                            input = scanner.nextLine().trim().split("\\s+");
                            command = checkInput(input);
                        }
                        break;

                    case "DONE":
                        outputToServer.println(command[0]);
                        connected = false;
                        break;

                    case "RETR":
                        if (acceptedUserName && acceptedPassword) {
                            outputToServer.println(command[0]);
                            outputToServer.println(command[1]);
                            fileFound = Boolean.parseBoolean(inputFromServer.readLine());
                            if (fileFound) {

                                System.out.println(inputFromServer.readLine());
                                input = scanner.nextLine().trim().split("\\s+");
                                command = checkInputForRetrieveFunction(input);
                                outputToServer.println(command[0]);
                                String xlt = inputFromServer.readLine();

                                if (command[0].equals("SEND")) {
//                                    byte[] mybytearray = new byte[10000];
//                                    InputStream is = socket.getInputStream();
                                	System.out.println("Enter the desired filename: ");
                                    Scanner fln = new Scanner(System.in);
                                 String  xpz = fln.nextLine();




                                     fos = new FileOutputStream(xpz);
//                                    bos = new BufferedOutputStream(fos);
//                                    bytesRead = is.read(mybytearray, 0, mybytearray.length);
//                                    current = bytesRead;
                                    PrintWriter out = new PrintWriter(xpz);

                                    xlt = xlt.replace("+File sent","");
                                    String[] xltDel = xlt.split("xyz");

                                    for (int i = 0; i<xltDel.length;i++)
                                    out.println(xltDel[i]);
                                    System.out.println("test2");
                                    out.close();
//                                    do {
//                                        bytesRead = is.read(mybytearray, current, (mybytearray.length - current));
//                                        if (bytesRead >= 0) current += bytesRead;
//                                    } while (bytesRead > -1);

//                                    bos.write(inputFromServer);
//                                    bos.flush();


                                    input = scanner.nextLine().trim().split("\\s+");
                                    command = checkInput(input);
                                } else {
                                    System.out.println("-File not found ");
                                    input = scanner.nextLine().trim().split("\\s+");
                                    command = checkInput(input);
                                }
                }
                        }
						else{
                            System.out.println("-Correct credentials needed");
							input = scanner.nextLine().trim().split("\\s+");
							command = checkInput(input);
						}
                break;

                default:
                    System.out.println("-Command not found ");
                    input = scanner.nextLine().trim().split("\\s+");
                    command = checkInput(input);
                    break;
            } }
            while (connected);
        }
			catch (IOException e) {
            System.out.println("-Connection Error");
			}
    }//close main



    private static boolean verifyusername(BufferedReader inputFromServer, PrintWriter outputToServer, String username) throws IOException {
        outputToServer.println(username);
        return Boolean.parseBoolean(inputFromServer.readLine());
    }//close verifyusername



    private static boolean verifypassword(BufferedReader inputFromServer, PrintWriter outputToServer, String username, String password) throws IOException {
        outputToServer.println(username);
        outputToServer.println(password);
        return Boolean.parseBoolean(inputFromServer.readLine());
    }//close verifypassword



    private static String[] checkInput(String[] command){

        Scanner scanner = new Scanner(System.in);

        do{
            switch (command[0]) {
                case "USER":
                case "PASS":
                case "KILL":
                case "RETR":
                    if (command.length < 2) {
                        System.out.println("-This command requires additional input.");
                        command = scanner.nextLine().trim().split("\\s+");
                    } else if (command.length > 2) {
                        System.out.println("-Too much input.");
                        command = scanner.nextLine().trim().split("\\s+");
                    } else {
                        return command;
                    }
                    break;
                case "LIST":
                case "DONE":
                    if (command.length > 1) {
                        System.out.println("-This command does not accept any additional input.");
                        command = scanner.nextLine().trim().split("\\s+");
                    } else {
                        return command;
                    }
                    break;
                default:
                    return command;
            }
        }while(true);

    }//close checkInput


    private static String[] checkInputForRetrieveFunction(String[] command) {
        Scanner scanner = new Scanner(System.in);
        do{
            if(command[0].equals("SEND") || command[0].equals("STOP")){
                if(command.length > 1){
                    System.out.println("-This command does not accept any additional input.");
                    command = scanner.nextLine().trim().split("\\s+");
                }
                else
                    return command;
            }
            else{
                System.out.println("-Only SEND and STOP commands available within RETR function ");
                command = scanner.nextLine().trim().split("\\s+");
            }


        }while(true);
    }//close checkInputForRetrieveFunction



}//close Client