import java.io.BufferedReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.net.Socket;
import java.util.Arrays;
import java.util.Random;
import java.util.Scanner;

public class Sender {

    Random random=new Random();
    CRC crc;
    byte[] msg= new byte[17];                   //potwierdzenie, odrzucenie

    final byte[] byteArray = new byte[] {0x41, 0x42, 0x43,0x44,0x45,0x46,0x47,0x48,
            0x49,0x4a,0x4b,0x4c,0x4d,0x4e,0x4f,0x50};

    byte[] byteArrayWithCRC = new byte[] {0x41, 0x42, 0x43,0x44,0x45,0x46,0x47,0x48,
                                          0x49,0x4a,0x4b,0x4c,0x4d,0x4e,0x4f,0x50,0x0};

    private static final byte[] ack = new byte[16];
    private static final byte[] nAck = new byte[16];
    double noise;

    static {
        //ustawia każdy bajt informacji o przyjęciu wiadomości na zera
        Arrays.fill(ack, (byte)0);
        //każdy bajt informacji o odrzuceniu na jedynki
        Arrays.fill(nAck, (byte)-1);
    }


    private Socket clientSocket;
    private PrintWriter out;
    private BufferedReader in;


    public void nextGaus(){
        noise=random.nextGaussian();
        while((noise>1)||(noise<0)){
            noise=random.nextGaussian();
        }
    }

    public void makeNoise(byte[] byteArray){

        for(int i=0; i<16;i++){

            nextGaus();
            if(noise<0.002){
                nextGaus();
                if(noise<0.5){
                    this.byteArrayWithCRC[i]+=0x5;
                }
                else{
                    this.byteArrayWithCRC[i]-=0x5;
                }
            }
        }

    }

    public void startConnection(String ip, int port) {
        Scanner scanner = new Scanner(System.in);

        try{
            clientSocket = new Socket(ip, port);
            //out = new PrintWriter(clientSocket.getOutputStream(), true);
            //in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
        }
        catch (IOException e){ }
    }

    public void sendMessage(byte[] msg) {
        try{
            clientSocket.getOutputStream().write(byteArrayWithCRC);
        }
        catch(IOException a){
        }
    }

    public void readMessage() {

        try{
            clientSocket.getInputStream().read(msg);
        }
        catch(IOException a){
            a.getMessage();
        }
    }

    public void stopConnection() {
        try{
            in.close();
            out.close();
            clientSocket.close();
        }
        catch (IOException ac){}
    }



    public static void main(String[] args) {
        int loops = 0;
        Scanner scanner = new Scanner(System.in);
        CsvWriter writer = new CsvWriter("senderErrors.csv");
        Sender sender = new Sender();
        CRC crc = new CRC();
        crc.reset();
        crc.update(sender.byteArray);
        sender.byteArrayWithCRC[16] = (byte) crc.getValue();                    //17BIT  TO CRC
        //sender.msg=null;
        System.out.println(sender.byteArrayWithCRC[16]);
        sender.startConnection("localhost", 2000);                  //WPISAC IP
        sender.sendMessage(sender.byteArrayWithCRC);


       int count = 0, incorrect = 0;


        //while
        while (true) {
            loops=0;
            count=0;
            while ((loops <= 0) && (loops % 100 != 0)) {
                System.out.println("How many loop do you want to perform. Enter x  (x mod 100==0");
                loops = scanner.nextInt();
            }

            if((count%100)==99)
            {
                writer.write(incorrect);
                System.out.println(incorrect);
                incorrect=0;

            }

            while (count < loops) {
                sender.readMessage();
                if (sender.msg != null) {
                    if (sender.msg[1] == ack[1]) {
                        sender.makeNoise(sender.byteArrayWithCRC);
                        sender.sendMessage(sender.byteArrayWithCRC);
                        System.out.println(count + ". Sending Success");


                    } else if (sender.msg[1] == nAck[1]) {
                        incorrect++;
                        for (int i = 0; i < 16; i++)
                            sender.byteArrayWithCRC[i] = sender.byteArray[i];
                        sender.makeNoise(sender.byteArrayWithCRC);
                        sender.sendMessage(sender.byteArrayWithCRC);
                        System.out.println(count + ". Sending again due to incorrect CRC");

                    } else {
                        System.out.println("ERROR: INCORRECT REPLY FROM RECEIVER");

                    }
                }
                try {
                    Thread.sleep(50);
                } catch (InterruptedException e) {

                }
                count++;

            }


        }
    }
}