sdis1819-t7g05

import java.io.File;

import java.nio.charset.StandardCharsets;

import java.security.MessageDigest;

import java.security.NoSuchAlgorithmException;

import java.util.concurrent.ConcurrentHashMap;

/**

 * BackupFile

 */

public class BackupFile {

    private File file;

    private String fileId;

    private int desiredReplicationDegree;

    private ConcurrentHashMap<Integer, Chunk> chunksMap = new ConcurrentHashMap<>();

    public BackupFile(String fileId) {

        this.fileId = fileId;

    }

    public void addChunk(int chunkNo, Chunk chunk) {

        this.chunksMap.put(chunkNo, chunk);

    }

    public BackupFile(String pathname, int desiredReplicationDegree)

            throws NoSuchAlgorithmException {

        this.file = new File(pathname);

        this.desiredReplicationDegree = desiredReplicationDegree;

        this.fileId = generateFileId(this.getPathname(), this.file.lastModified());

    }

    //Generates a unique FileId with the combined pathname & last modified info

    public static String generateFileId(String pathname, long lastModified) throws NoSuchAlgorithmException {

        String str = pathname + lastModified;

        MessageDigest digest = MessageDigest.getInstance("SHA-256");

        byte[] hash = digest.digest(str.getBytes(StandardCharsets.UTF_8));

        StringBuffer hexString = new StringBuffer();

        for (int i = 0; i < hash.length; i++) {

            String hex = Integer.toHexString(0xff & hash[i]);

            if (hex.length() == 1)

                hexString.append('0');

            hexString.append(hex);

        }

        return hexString.toString();

    }

    /**

     * @return the desiredReplicationDegree

     */

    public int getDesiredReplicationDegree() {

        return desiredReplicationDegree;

    }

    /**

     * @return the pathname

     */

    public String getPathname() {

        return this.file.getPath();

    }

    /**

     * @return the fileId

     */

    public String getFileId() {

        return fileId;

    }

    public File getFile() {

        return this.file;

    }

    public ConcurrentHashMap<Integer, Chunk> getChunksMap() {

                return this.chunksMap;

    }

    public void removeChunk(int chunkNo, Peer peer){

        this.chunksMap.remove(chunkNo);

        File chunk = new File("Peer-" + peer.getSenderId() + File.separator + "Chunks" + File.separator + this.fileId + File.separator + chunkNo);

        peer.removeStorage(chunk.length());

        chunk.delete();

    }

}