SDIS1819-T6G05-P2

package files;

import chord.ConnectionInfo;

import messages.BackupMessage;

import messages.MessageForwarder;

import chord.ChordManager;

import peer.Peer;

import java.io.File;

import java.io.IOException;

import java.math.BigInteger;

import java.net.InetAddress;

import java.nio.ByteBuffer;

import java.nio.channels.*;

import java.nio.charset.StandardCharsets;

import java.nio.file.*;

import java.nio.file.attribute.BasicFileAttributes;

import java.security.MessageDigest;

import java.security.NoSuchAlgorithmException;

import java.util.Comparator;

import java.util.List;

import java.util.concurrent.ExecutionException;

import java.util.concurrent.Future;

import java.util.concurrent.atomic.AtomicLong;

import java.util.stream.Collectors;

public class FileHandler {

    public static byte[] readFromFile(String filename) throws IOException, ExecutionException, InterruptedException {

        Path path = Paths.get(filename);

        AsynchronousFileChannel fileChannel = AsynchronousFileChannel.open(path, StandardOpenOption.READ);

        int fileSize = (int) new File(filename).length();

        ByteBuffer buffer = ByteBuffer.allocate(fileSize);

        Future<Integer> operation = fileChannel.read(buffer, 0);

        operation.get();

        buffer.rewind();

        byte[] byteArray = new byte[buffer.remaining()];

        buffer.get(byteArray);

        return byteArray;

    }

    public static boolean checkFileExists(String filename) {

        Path path = Paths.get(filename);

        return Files.exists(path);

    }

    public static void writeFile(String filename, byte[] fileContent) throws IOException, ExecutionException, InterruptedException {

        Path path = Paths.get(filename);

        if (!checkFileExists(filename))

            Files.createFile(path);

        AsynchronousFileChannel fileChannel = AsynchronousFileChannel.open(path, StandardOpenOption.WRITE);

        int fileSize = fileContent.length;

        ByteBuffer buffer = ByteBuffer.allocate(fileSize);

        buffer.put(fileContent);

        buffer.flip();

        Future<Integer> operation = fileChannel.write(buffer, 0);

        buffer.clear();

        operation.get();

    }

    public static String getFileSize(String filename) throws IOException {

        Path path = Paths.get("./testFiles/" + filename);

        return String.valueOf(Files.size(path));

    }

    public static void createDir(String type) {

        String typeDirName = "./peerDisk/peer" + Peer.getPeerAccessPoint() + "-" + ChordManager.peerHash + "/" + type;

        Path dirPath = Paths.get(typeDirName);

        boolean backupExists = Files.exists(dirPath);

        if (backupExists) {

            System.out.println("Directory already exists");

        } else {

            try {

                Files.createDirectories(dirPath);

            } catch (IOException ioExceptionObj) {

                System.out.println("Problem creating directory");

            }

        }

    }

    public static void clearStorageSpace() throws IOException {

        Path rootPath = Paths.get("./peerDisk/peer" + Peer.getPeerAccessPoint() + "-" + ChordManager.peerHash);

        final List<Path> pathsToDelete = Files.walk(rootPath).sorted(Comparator.reverseOrder()).collect(Collectors.toList());

        for(Path path : pathsToDelete) {

            if(Peer.storage.getSpaceReserved() < Peer.storage.getSpaceOcupied()) {

                    if(Files.isRegularFile(path)){

                    System.out.println("\n \n \n \n" + path);

                    if(Files.exists(path)){

                        if(!Files.isDirectory(path))

                            handleDeleteFile(path);

                    Files.deleteIfExists(path);

                    }

                    }

            }

        }

    }

    private static void handleDeleteFile(Path path) throws IOException {

        byte[] content = Files.readAllBytes(path);

        long filename; 

        try {

           filename = Long.parseLong(path.getFileName().toString());

           DeleteHandler handler = new DeleteHandler(new ConnectionInfo(ChordManager.peerHash, InetAddress.getLocalHost().getHostAddress(), Peer.port), new BigInteger(path.getFileName().toString()), 1, content);

            Peer.executor.submit(handler);

        } catch(Exception e) {

        }

    }

    public static long getSize(Path startPath) throws IOException {

        final AtomicLong size = new AtomicLong(0);

        Files.walkFileTree(startPath, new SimpleFileVisitor<Path>() {

            @Override

            public FileVisitResult visitFile(Path file,

                                             BasicFileAttributes attrs) throws IOException {

                size.addAndGet(attrs.size());

                return FileVisitResult.CONTINUE;

            }

            @Override

            public FileVisitResult visitFileFailed(Path file, IOException exc)

                    throws IOException {

                return FileVisitResult.CONTINUE;

            }

        });

        return size.get();

    }

}