/*

 * Copyright (c) 2017, 2019, 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.

 *

 * 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package jdk.tools.jaotc.collect;

import java.io.IOException;

import java.net.MalformedURLException;

import java.net.URI;

import java.net.URISyntaxException;

import java.net.URL;

import java.net.URLClassLoader;

import java.nio.file.DirectoryStream;

import java.nio.file.FileSystem;

import java.nio.file.FileSystems;

import java.nio.file.Files;

import java.nio.file.Path;

import java.util.HashMap;

public class FileSupport {

    public boolean exists(Path path) {

        return Files.exists(path);

    }

    public boolean isDirectory(Path path) {

        return Files.isDirectory(path);

    }

    private static FileSystem makeJarFileSystem(Path path) {

        try {

            return FileSystems.newFileSystem(makeJarFileURI(path), new HashMap<>());

        } catch (IOException e) {

            throw new InternalError(e);

        }

    }

    private static URI makeJarFileURI(Path path) {

        try {

            String name = path.toAbsolutePath().toString();

            name = name.replace('\\', '/');

            return new URI("jar:file", null, "///" + name + "!/", null);

        } catch (URISyntaxException e) {

            throw new InternalError(e);

        }

    }

    public ClassLoader createClassLoader(Path path, ClassLoader parent) {

        try {

            return URLClassLoader.newInstance(buildUrls(path), parent);

        } catch (MalformedURLException e) {

            throw new InternalError(e);

        }

    }

    public ClassLoader createClassLoader(Path path) throws MalformedURLException {

        return URLClassLoader.newInstance(buildUrls(path));

    }

    private static URL[] buildUrls(Path path) throws MalformedURLException {

        return new URL[]{path.toUri().toURL()};

    }

    public Path getJarFileSystemRoot(Path jarFile) {

        FileSystem fileSystem = makeJarFileSystem(jarFile);

        return fileSystem.getPath("/");

    }

    public boolean isAbsolute(Path entry) {

        return entry.isAbsolute();

    }

    public Path getSubDirectory(FileSystem fileSystem, Path root, Path path) throws IOException {

        DirectoryStream<Path> paths = fileSystem.provider().newDirectoryStream(root, null);

        for (Path entry : paths) {

            Path relative = root.relativize(entry);

            if (relative.equals(path)) {

                return entry;

            }

        }

        return null;

    }

}