package prac;

import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
import java.nio.file.Files;
import java.util.ArrayList;
import java.util.*;


/*
The purpose of the program is to build a
server application.
*/


class User {

    private String username;
    private String password;

    User(String x, String y){
        this.username = x;
        this.password = y;
    }

    //boolean values
    public boolean usernameAuthentication(String x) {
        return x.equals(this.username);
    }

    public boolean passwordAuthentication(String y) {
        return y.equals(this.password);
    }

}



public class Serverapp {

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

        ArrayList<User> userNameAndPassword = null;

        try {
            File inputFile = new File("users.txt");
            userNameAndPassword = array_Of_Users(inputFile);
        }

        catch (FileNotFoundException e) {
            System.out.println("File not found. Make sure the user txt and root folder are located with the Server executable");
            System.exit(1);
        }

        File rootFolder = new File("root");
        File[] rootFiles = rootFolder.listFiles();
        BufferedReader inputFromClient = null;
        PrintWriter outputToClient = null;
        Socket socket = null;

        //The actual connection method
        try (ServerSocket serverSocket = new ServerSocket(50000))
        {
            socket = serverSocket.accept();
            inputFromClient = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            outputToClient = new PrintWriter(socket.getOutputStream(), true);

            String fileName;

            System.out.println("Connected");

            boolean connected = true;
                do {
                    String command = inputFromClient.readLine();
                    switch (command) {
                        case "USER":
                            verifyusername(inputFromClient, outputToClient, userNameAndPassword);
                            break;
                        case "PASS":
                            verifypassword(inputFromClient, outputToClient, userNameAndPassword);
                            break;
                        case "LIST":
                            sendFileList(outputToClient, rootFolder);
                            break;
                        case "KILL":
                            fileName = inputFromClient.readLine();
                            rootFiles = deleteFile(outputToClient, rootFolder, rootFiles, fileName);
                            break;
                        case "DONE":
                            connected = false;
                            System.out.println("Client Disconnected");
                            break;
                        case "RETR":
                            fileName = inputFromClient.readLine();
                            retrieveFile(inputFromClient, outputToClient, rootFiles, fileName, socket);
                            break;
                        default:

                            break;
                    }
                } while (connected);
            }
          catch (IOException e) {
            System.out.println(e.getMessage());
            e.printStackTrace();
        } finally {
            if (inputFromClient != null) {
                inputFromClient.close();
            }
            if (outputToClient != null) {
                outputToClient.close();
            }
            if (socket != null) {
                socket.close();
            }
        }
    }//close main

    private static void retrieveFile(BufferedReader inputFromClient, PrintWriter outputToClient, File[] rootFiles, String fileToRetrieve, Socket socket) throws IOException {








        String input;
        boolean found = false;

        for (File x : rootFiles) {
            String fileName = x.getName();
            if (fileToRetrieve.equals(fileName)) {
                found = true;
                outputToClient.println(true);
                outputToClient.println("#" + x.length());
                input = inputFromClient.readLine();
                if (input.equals("SEND")) {
                    File fileToSend = new File(fileToRetrieve);

                    byte[] byteArray = new byte[(int)x.length()];

                    FileInputStream fis = new FileInputStream("root/"+fileToSend);

//                    BufferedInputStream inputStream = new BufferedInputStream(fis);
//                    inputStream.read(byteArray, 0, byteArray.length);
//                    OutputStream outputStream = null;
//                    outputStream = socket.getOutputStream();
//                    outputStream.write(byteArray, 0, byteArray.length);




            		Scanner fileSeek = new Scanner(new File("root/"+fileToSend));
            		String inf = "";
					while (fileSeek.hasNextLine())
						inf += fileSeek.nextLine() + "xyz";


						 outputToClient.println(inf);








fis.close();
                    outputToClient.println("+File sent");
                    break;
                } else if (input.equals("STOP")) {
                    outputToClient.println("+ok, RETR aborted");
                    break;
                }
            }
        }

        if(!found){
            outputToClient.println(false);
        }


    }//close retrieveFile


    private static File[] deleteFile(PrintWriter outputToClient, File rootFolder, File[] rootFiles, String fileToDelete) {

        boolean deleted = false;

        for(File x: rootFiles){

            String fileName = x.getName();

            if(fileToDelete.equals(fileName)){
                deleted = x.delete();
                outputToClient.println("+" + fileToDelete + " deleted");
                break;
            }
        }

        if(!deleted){
            outputToClient.println("-" + fileToDelete + " does not exist");
        }

        return rootFolder.listFiles();

    }


    private static void sendFileList(PrintWriter outputToClient, File folder) {
        String[] fileList = folder.list();
        outputToClient.println("+root");

        outputToClient.println(fileList.length);

        for(String x: fileList){
            outputToClient.println(x);
        }
    }

    //This splits the line into username and password
    //trimmedString[0] is the username, trimmedString[1] is the password.

    private static ArrayList<User> array_Of_Users(File file) throws IOException {
        String inputString;
        BufferedReader br = null;
        ArrayList<User> userArr = new ArrayList<>();
        try {
            br = new BufferedReader(new FileReader(file));
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        while ((inputString = br.readLine()) != null) {
            String[] trimmedString = inputString.trim().split("\\s+");
            userArr.add(new User(trimmedString[0], trimmedString[1]));
            }
        return userArr;
    }//close array_Of_Users


    private static void verifypassword(BufferedReader inputFromServer, PrintWriter outputToServer, ArrayList<User> userNameAndPassword) throws IOException {

        String username = inputFromServer.readLine();
        String password = inputFromServer.readLine();

        for (User list : userNameAndPassword) {
            boolean findUser = list.usernameAuthentication(username);

            if (findUser) {
                boolean checkPassword = list.passwordAuthentication(password);

                if(checkPassword){
                    outputToServer.println(true);
                    return;
                }
            }
        }

        outputToServer.println(false);
    }

    //Verifying the username

    private static void verifyusername(BufferedReader inputFromServer, PrintWriter outputToServer, ArrayList<User> userNameAndPassword) throws IOException {
        //read the username from the server
        String username = inputFromServer.readLine();
        //for each user
        for (User list : userNameAndPassword) {
            boolean check = list.usernameAuthentication(username);
            //if the username was found, send true.
            if (check) {
                outputToServer.println(true);
                return;
            }
        }
        //if username not found, send false
        outputToServer.println(false);
    }

}//close Server