/*

 * Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package jdk.jfr.internal.tool;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.PrintStream;

import java.nio.channels.FileChannel;

import java.nio.file.DirectoryStream;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.Paths;

import java.util.ArrayList;

import java.util.Collections;

import java.util.Deque;

import java.util.List;

final class Assemble extends Command {

    @Override

    public String getName() {

        return "assemble";

    }

    @Override

    public List<String> getOptionSyntax() {

        return Collections.singletonList("<repository> <file>");

    }

    @Override

    public String getDescription() {

        return "Assemble leftover chunks from a disk repository into a recording file";

    }

    @Override

    public void displayOptionUsage(PrintStream stream) {

        stream.println("  <repository>   Directory where the repository is located");

        stream.println();

        stream.println("  <file>         Name of the recording file (.jfr) to create");

    }

    @Override

    public void execute(Deque<String> options) throws UserSyntaxException, UserDataException {

        ensureMinArgumentCount(options, 2);

        ensureMaxArgumentCount(options, 2);

        Path repository = getDirectory(options.pop());

        Path file = Paths.get(options.pop());

        ensureFileDoesNotExist(file);

        ensureJFRFile(file);

        try (FileOutputStream fos = new FileOutputStream(file.toFile())) {

            List<Path> files = listJFRFiles(repository);

            if (files.isEmpty()) {

                throw new UserDataException("no *.jfr files found at " + repository);

            }

            println();

            println("Assembling files... ");

            println();

            transferTo(files, file, fos.getChannel());

            println();

            println("Finished.");

        } catch (IOException e) {

            throw new UserDataException("could not open destination file " + file + ". " + e.getMessage());

        }

    }

    private List<Path> listJFRFiles(Path path) throws UserDataException {

        try {

            List<Path> files = new ArrayList<>();

            if (Files.isDirectory(path)) {

                try (DirectoryStream<Path> stream = Files.newDirectoryStream(path, "*.jfr")) {

                    for (Path p : stream) {

                        if (!Files.isDirectory(p) && Files.isReadable(p)) {

                            files.add(p);

                        }

                    }

                }

            }

            files.sort((u, v) -> u.getFileName().compareTo(v.getFileName()));

            return files;

        } catch (IOException ioe) {

            throw new UserDataException("could not list *.jfr for directory " + path + ". " + ioe.getMessage());

        }

    }

    private void transferTo(List<Path> sourceFiles, Path output, FileChannel out) throws UserDataException {

        long pos = 0;

        for (Path p : sourceFiles) {

            println(" " + p.toString());

            try (FileChannel sourceChannel = FileChannel.open(p)) {

                long rem = Files.size(p);

                while (rem > 0) {

                    long n = Math.min(rem, 1024 * 1024);

                    long w = out.transferFrom(sourceChannel, pos, n);

                    pos += w;

                    rem -= w;

                }

            } catch (IOException ioe) {

                throw new UserDataException("could not copy recording chunk " + p + " to new file. " + ioe.getMessage());

            }

        }

    }

}