sdis1819-t7g07

package protocols;

import peer.Peer;

import utils.FileController;

import utils.Utils;

import java.io.*;

import java.net.DatagramPacket;

import java.util.ArrayList;

public class RestoreProtocol {

    String hashId;

    String name;

    int numberOfChunks;

    public RestoreProtocol(String[] args) throws IOException, InterruptedException {

        this.name = args[1];

        this.numberOfChunks = 0;

        //check in hash database

        this.hashId = Utils.hashDatabase.get(this.name);

        if(this.hashId == null) {

            System.out.println("no such file exists to restore, exiting ...");

            return;

        }

        getNumberOfChunks();

        System.out.println("RESTORE Protocol  ||  Restoring: " + this.name + "  ||  IdHashed: " + this.hashId);

        Utils.restorePeer = Peer.getSenderId();

        //send get chunck message to MC channel

        sendGetChunk(0);

        Thread.sleep(10000); //waits a bit for chunks to be stored in the folder before merging them

        System.out.println("All chunks stored, merging into one single file");

        mergeChunks();

    }

    private void getNumberOfChunks() {

        for (String name: Utils.storedChunks.keySet()){

            String [] key = name.split(":");

            if(this.hashId.equals(key[0])) this.numberOfChunks++;

        }

    }

    private void sendGetChunk(int chunkNo) throws IOException {

        if(chunkNo > this.numberOfChunks -1) return;

        System.out.println("Sending getchunk message to mc...");

        String msg = "GETCHUNK" + " " + Utils.version + " " + Peer.getSenderId() + " " + this.hashId + " " + chunkNo + Utils.crlf;

        DatagramPacket packet = new DatagramPacket(msg.getBytes(), msg.getBytes().length, Peer.getMcAddress(),Peer.getMcPort());

        Utils.mcSocket.send(packet);

        chunkNo += 1;

        sendGetChunk(chunkNo);

    }

    private void mergeChunks() throws IOException {

        File outputFile = new File("storage/Restored/Peer" + Peer.getSenderId() + "/" + this.name);

        outputFile.getParentFile().mkdirs();

        outputFile.createNewFile();

        FileOutputStream outStream = new FileOutputStream(outputFile);

        for(int i = 0; i < this.numberOfChunks; i++) {

            File inputFile = new File("storage/Restored/Peer" + Peer.getSenderId() + "/" + i);

                FileInputStream inStream = new FileInputStream(inputFile);

                byte[] buf = new byte[64000];

                int readBytes = inStream.read(buf);

                outStream.write(buf, 0, readBytes);

                inStream.close();

        }

        for(int i = 0; i < this.numberOfChunks; i++) { //delete chunks (we dont need them anymore)

            File inputFile = new File("storage/Restored/Peer" + Peer.getSenderId() + "/" + i);

            inputFile.delete();

        }

        outStream.close();

    }

}