/*

 * Copyright 2008-2009 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

import java.nio.file.*;

import java.io.IOException;

import java.util.*;

/**

 * Creates a file tree with possible cycles caused by symbolic links

 * to ancestor directories.

 */

public class CreateFileTree {

    static final Random rand = new Random();

    public static Path createTemporaryDirectory() throws IOException {

        Path tmpdir = Paths.get(System.getProperty("java.io.tmpdir"));

        Path dir;

        do {

            dir = tmpdir.resolve("name" + rand.nextInt());

        } while (dir.exists());

        dir.createDirectory();

        return dir;

    }

    public static void main(String[] args) throws IOException {

        Path top = createTemporaryDirectory();

        if (!top.isAbsolute())

            top = top.toAbsolutePath();

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

        // create tree

        Queue<Path> queue = new ArrayDeque<Path>();

        queue.add(top);

        int total = 1 + rand.nextInt(20);

        int n = 0;

        Path dir;

        while (((dir = queue.poll()) != null) && (n < total)) {

            int r = Math.min((total-n), (1+rand.nextInt(3)));

            for (int i=0; i<r; i++) {

                String name = "dir" + (++n);

                Path subdir = dir.resolve(name).createDirectory();

                queue.offer(subdir);

                dirs.add(subdir);

            }

        }

        assert dirs.size() >= 2;

        // create a few regular files in the file tree

        int files = dirs.size() * 3;

        for (int i=0; i<files; i++) {

            String name = "file" + (i+1);

            int x = rand.nextInt(dirs.size());

            dirs.get(x).resolve(name).createFile();

        }

        // create a few sym links in the file tree so as to create cycles

        int links = 1 + rand.nextInt(5);

        for (int i=0; i<links; i++) {

            int x = rand.nextInt(dirs.size());

            int y;

            do {

                y = rand.nextInt(dirs.size());

            } while (y != x);

            String name = "link" + (i+1);

            Path link = dirs.get(x).resolve(name);

            Path target = dirs.get(y);

            link.createSymbolicLink(target);

        }

        // done

        System.out.println(top);

    }

}