package sendBackAndForth;

import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.*;
import java.nio.ByteBuffer;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

public class OpSysClientSendRecieve {
    public static int B = 1000;
    private BufferedReader bin = new BufferedReader(new InputStreamReader(System.in));
    private int serverport = 5432;
    private int bufsize = 512;
    private int MAX = (int) Math.floor(Math.pow(2, 4 * 8) - 1);
    private int R = (int) Math.floor(Math.random() * MAX);
    private boolean[] ackArray;
    private boolean init = true;


    /**
     * VÆR OPMÆRKSOM PÅ
     * timeout
     * package lost
     */
    static public void main(String args[]) {
        new OpSysClientSendRecieve().run(args);
    }

    private void run(String[] args) {
        String desthost = "localhost";

        if (args.length >= 1) {
            desthost = args[0];
        }

        InetAddress dest; // DNS query
        DatagramSocket s = null;
        try {
            dest = InetAddress.getByName(desthost);
            s = new DatagramSocket();
            System.err.println("Our own port is " + s.getLocalPort());
            System.out.println("R IS: " + R);

            DatagramPacket receiveMsg = new DatagramPacket(new byte[bufsize], bufsize);
            /*************************************************
             *                     LOOP
             *************************************************/
            while (true) {
                handleSend(s, dest);
                handleReceive(s, receiveMsg);
            } // while
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (s != null) {
                s.close();
            }
        }
    }


    private void handleSend(DatagramSocket s, InetAddress dest) throws IOException {
        Path path = Paths.get("/home/datstorm/IdeaProjects/Opsys-BFTP/src/testerFiles/test.txt");
        File file =new File("/home/datstorm/IdeaProjects/Opsys-BFTP/src/testerFiles/test.txt");

        if(file.exists()) {
            long S = file.length();
            byte[] fileInBytes = Files.readAllBytes(path);


//            long S = fileInBytes.length;
            if (init) {
                int blocksOfSizeB = (int) (Math.ceil((double) S / B)); // FIXME Removed -1 HERE
                ackArray = new boolean[blocksOfSizeB];
                init = false;
            }


            // TODO: SEND ONLY NOT SENT PACKAGES
            int T = (int) (Math.ceil((double) S / B) ); // FIXME ADD -1
//            int blockNum = 0;
            ByteBuffer bb = ByteBuffer.wrap(fileInBytes);
            for (int blockNum = 0; blockNum < T; blockNum++) {
                byte b = bb.get(blockNum);

                // We have recieved ACK here
                if (ackArray[blockNum]) {
                    continue;
                }
                //Creating packet
                ByteBuffer bufAllocate = ByteBuffer.allocate(16 + B);
                bufAllocate.putInt(R);
                bufAllocate.putLong(S);
                bufAllocate.putInt(blockNum);
                bufAllocate.put(b);
                DatagramPacket sendMsg = new DatagramPacket(bufAllocate.array(), bufAllocate.capacity(), dest, serverport);
                s.send(sendMsg);
            }
        }

    }

    private void handleReceive(DatagramSocket s, DatagramPacket receive) throws IOException {
        receive.setLength(bufsize); // max received packet size
        s.receive(receive); // the actual receive operation

        ByteBuffer buffer = ByteBuffer.wrap(receive.getData());
        int recieveR = buffer.getInt();
        int receiveI = buffer.getInt();
        // we got our ACK
        if (recieveR == R) {
            ackArray[receiveI] = true;
            System.out.println("R: " + recieveR + ". i: " + receiveI);
        }
    }

}



/* FRAKLIP

    //        String buf;
//        buf = bin.readLine();
//        if (buf == null) {
//            buf = "null"; // user typed EOF character
//        }
//        buf = buf + "\n"; // append newline character
//        int slen = buf.length();
//        byte[] bbuf = buf.getBytes();
//        msg.setData(bbuf);
//        msg.setLength(slen);


 */