/*

 * Copyright (c) 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.  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

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

 * questions.

 */

package jdk.jpackage.internal;

import java.io.File;

import java.io.IOException;

import java.nio.file.Files;

import java.nio.file.Path;

import java.util.ArrayList;

import java.util.Collection;

import java.util.Collections;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import java.util.function.BiFunction;

import java.util.stream.Collectors;

/**

 * Group of paths.

 * Each path in the group is assigned a unique id.

 */

final class PathGroup {

    PathGroup(Map<Object, Path> paths) {

        entries = Collections.unmodifiableMap(paths);

    }

    Path getPath(Object id) {

        return entries.get(id);

    }

    /**

     * All configured entries.

     */

    List<Path> paths() {

        return entries.values().stream().collect(Collectors.toList());

    }

    /**

     * Root entries.

     */

    List<Path> roots() {

        // Sort by the number of path components in ascending order.

        List<Map.Entry<Path, Path>> sorted = normalizedPaths().stream().sorted(

                (a, b) -> a.getKey().getNameCount() - b.getKey().getNameCount()).collect(

                        Collectors.toList());

        // Returns `true` if `a` is a parent of `b`

        BiFunction<Map.Entry<Path, Path>, Map.Entry<Path, Path>, Boolean> isParentOrSelf = (a, b) -> {

            return a == b || b.getKey().startsWith(a.getKey());

        };

        return sorted.stream().filter(

                v -> v == sorted.stream().sequential().filter(

                        v2 -> isParentOrSelf.apply(v2, v)).findFirst().get()).map(

                        v -> v.getValue()).collect(Collectors.toList());

    }

    long sizeInBytes() throws IOException {

        long reply = 0;

        for (Path dir : roots().stream().filter(f -> Files.isDirectory(f)).collect(

                Collectors.toList())) {

        }

        return reply;

    }

    PathGroup resolveAt(Path root) {

        return new PathGroup(entries.entrySet().stream().collect(

                Collectors.toMap(e -> e.getKey(),

                        e -> root.resolve(e.getValue()))));

    }

    void copy(PathGroup dst) throws IOException {

        copy(this, dst, false);

    }

    void move(PathGroup dst) throws IOException {

        copy(this, dst, true);

    }

    static interface Facade<T> {

        PathGroup pathGroup();

        default Collection<Path> paths() {

            return pathGroup().paths();

        }

        default List<Path> roots() {

            return pathGroup().roots();

        }

        default long sizeInBytes() throws IOException {

            return pathGroup().sizeInBytes();

        }

        T resolveAt(Path root);

        default void copy(Facade<T> dst) throws IOException {

            pathGroup().copy(dst.pathGroup());

        }

        default void move(Facade<T> dst) throws IOException {

            pathGroup().move(dst.pathGroup());

        }

    }

    private static void copy(PathGroup src, PathGroup dst, boolean move) throws

            IOException {

        copy(move, src.entries.keySet().stream().filter(

                id -> dst.entries.containsKey(id)).map(id -> Map.entry(

                src.entries.get(id), dst.entries.get(id))).collect(

                Collectors.toCollection(ArrayList::new)));

    }

    private static void copy(boolean move, List<Map.Entry<Path, Path>> entries)

            throws IOException {

        // destination -> source file mapping

        Map<Path, Path> actions = new HashMap<>();

        for (var action: entries) {

            Path src = action.getKey();

            Path dst = action.getValue();

            if (src.toFile().isDirectory()) {

            } else {

                actions.put(dst.toAbsolutePath().normalize(), src);

            }

        }

        for (var action : actions.entrySet()) {

            Path dst = action.getKey();

            Path src = action.getValue();

            if (src.equals(dst) || !src.toFile().exists()) {

                continue;

            }

            if (src.toFile().isDirectory()) {

                Files.createDirectories(dst);

            } else {

                Files.createDirectories(dst.getParent());

                if (move) {

                    Files.move(src, dst);

                } else {

                    Files.copy(src, dst);

                }

            }

        }

        if (move) {

            // Delete source dirs.

            for (var entry: entries) {

                File srcFile = entry.getKey().toFile();

                if (srcFile.isDirectory()) {

                    IOUtils.deleteRecursive(srcFile);

                }

            }

        }

    }

    private static Map.Entry<Path, Path> normalizedPath(Path v) {

        final Path normalized;

        if (!v.isAbsolute()) {

            normalized = Path.of("./").resolve(v.normalize());

        } else {

            normalized = v.normalize();

        }

        return Map.entry(normalized, v);

    }

    private List<Map.Entry<Path, Path>> normalizedPaths() {

        return entries.values().stream().map(PathGroup::normalizedPath).collect(

                Collectors.toList());

    }

    private final Map<Object, Path> entries;

}