/*
 * Copyright (c) 2020, Itamar S. <itamar8910@gmail.com>
 * Copyright (c) 2021, the SerenityOS developers.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#pragma once

#include <AK/Function.h>
#include <AK/Noncopyable.h>
#include <AK/NonnullRefPtr.h>
#include <AK/RefCounted.h>
#include <AK/Result.h>
#include <AK/String.h>
#include <LibCore/Notifier.h>

namespace Core {

struct FileWatcherEvent {
    enum class Type {
        Modified,
        ChildAdded,
        ChildRemoved,
    };
    Type type;
    String child_path;
};

class BlockingFileWatcher {
    AK_MAKE_NONCOPYABLE(BlockingFileWatcher);

public:
    explicit BlockingFileWatcher(const String& path);
    ~BlockingFileWatcher();

    Optional<FileWatcherEvent> wait_for_event();

private:
    String m_path;
    int m_watcher_fd { -1 };
};

class FileWatcher : public RefCounted<FileWatcher> {
    AK_MAKE_NONCOPYABLE(FileWatcher);

public:
    static Result<NonnullRefPtr<FileWatcher>, String> watch(const String& path);
    ~FileWatcher();

    Function<void(FileWatcherEvent)> on_change;

private:
    FileWatcher(NonnullRefPtr<Notifier>, const String& path);

    NonnullRefPtr<Notifier> m_notifier;
    String m_path;
};

}