/**********************************************************************
 * LeechCraft - modular cross-platform feature rich internet client.
 * Copyright (C) 2006-2014  Georg Rudoy
 *
 * Boost Software License - Version 1.0 - August 17th, 2003
 *
 * Permission is hereby granted, free of charge, to any person or organization
 * obtaining a copy of the software and accompanying documentation covered by
 * this license (the "Software") to use, reproduce, display, distribute,
 * execute, and transmit the Software, and to prepare derivative works of the
 * Software, and to permit third-parties to whom the Software is furnished to
 * do so, all subject to the following:
 *
 * The copyright notices in the Software and this entire statement, including
 * the above license grant, this restriction and the following disclaimer,
 * must be included in all copies of the Software, in whole or in part, and
 * all derivative works of the Software, unless such copies or derivative
 * works are solely in the form of machine-executable object code generated by
 * a source language processor.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
 * SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
 * FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 **********************************************************************/

#include "dirwatcher.h"
#include <QFileSystemWatcher>
#include <QTimer>
#include <QUrl>

namespace LeechCraft
{
namespace SB2
{
	namespace
	{
		QSet<QString> ScanQuarks (const QDir& dir)
		{
			QSet<QString> result;
			for (const auto& entry : dir.entryList (QDir::Dirs | QDir::NoDotAndDotDot | QDir::Readable))
			{
				QDir quarkDir { dir };
				quarkDir.cd (entry);
				if (quarkDir.exists (entry + ".qml"))
					result << entry;
			}
			return result;
		}
	}

	DirWatcher::DirWatcher (const QDir& dir, QObject *parent)
	: QObject { parent }
	, Watched_ { dir }
	, Watcher_ { new QFileSystemWatcher (parent) }
	, LastQuarksList_ { ScanQuarks (dir) }
	{
		Watcher_->addPath (Watched_.absolutePath ());

		connect (Watcher_,
				SIGNAL (directoryChanged (QString)),
				this,
				SLOT (handleDirectoryChanged ()));
	}

	void DirWatcher::handleDirectoryChanged ()
	{
		if (NotifyScheduled_)
			return;

		QTimer::singleShot (1000,
				this,
				SLOT (notifyChanges ()));
	}

	void DirWatcher::notifyChanges ()
	{
		auto current = ScanQuarks (Watched_);
		const auto& newQuarks = current - LastQuarksList_;
		const auto& removedQuarks = LastQuarksList_ - current;
		LastQuarksList_.swap (current);

		auto toUrlList = [this] (const QSet<QString>& filenames) -> QList<QUrl>
		{
			QList<QUrl> result;
			for (const auto& name : filenames)
				result << QUrl::fromLocalFile (Watched_.absoluteFilePath (name + '/' + name + ".qml"));
			return result;
		};

		if (!newQuarks.isEmpty ())
			emit quarksAdded (toUrlList (newQuarks));
		if (!removedQuarks.isEmpty ())
			emit quarksRemoved (toUrlList (removedQuarks));
	}
}
}
