#include <QtCore/QCryptographicHash>
#include <QtCore/QDir>
#include <QtCore/QEventLoop>
#include <QtCore/QUrl>
#include <QtCore/QDebug>
#include <QtNetwork/QNetworkRequest>
#include <QtNetwork/QNetworkReply>

#include "global.h"
#include "imageprovider.h"

// Warning: QML might call requestImage() from another thread. Be careful.

ImageProvider::ImageProvider() :
    QDeclarativeImageProvider(Image),
    _cachePath(board_manager->getCachePath() + "/images"),
    _manager(new QNetworkAccessManager)
{
	QDir dir;
	if (!dir.mkpath(_cachePath)) {
		qWarning() << "Could not create image cache path";
	}
}

ImageProvider::~ImageProvider()
{
	delete _manager;
}

QImage ImageProvider::requestImage(const QString &id, QSize *size, const QSize &requestedSize)
{
	QString remoteUrl = QUrl::fromPercentEncoding(id.toUtf8());
	QString localPath = getCachedImagePath(remoteUrl);

	qDebug() << "Loading image for " << remoteUrl;

	if (!QFile::exists(localPath)) {
		if (!fetchImage(remoteUrl)) {
			qWarning() << "Failed to fetch remote image" << remoteUrl;
		}
	} else {
		qDebug() << "Local file exists" << localPath;
	}

	QImage image(localPath);
	QImage result;

	if (image.isNull()) {
		qWarning() << "Failed to load local image" << localPath;
	}

	if (requestedSize.isValid()) {
		result = image.scaled(requestedSize, Qt::KeepAspectRatio);
	} else {
		result = image;
	}
	if (size) {
		*size = result.size();
	}

	return result;
}

QString ImageProvider::getProviderImageUrl(const QString &remoteUrl)
{
	return "image://tapasboard/" + QString::fromUtf8(QUrl::toPercentEncoding(remoteUrl));
}

QString ImageProvider::getCachedImagePath(const QString &remoteUrl)
{
	static const QRegExp regexp("[^a-z0-9]+");
	QString url = remoteUrl.toLower();

	// Grab the extension before applying the regexp
	QString extension;
	int dot_pos = url.lastIndexOf('.');

	if (dot_pos != -1) {
		extension = url.mid(dot_pos);
	}

	url.replace(regexp, "_");

	return _cachePath + "/" + url + extension;
}

bool ImageProvider::fetchImage(const QString &remoteUrl)
{
	QString localPath = getCachedImagePath(remoteUrl);

	QNetworkRequest request(remoteUrl);
	QNetworkReply *reply = _manager->get(request);
	qDebug() << "Start download of" << remoteUrl;

	QEventLoop loop;
	loop.connect(reply, SIGNAL(finished()), &loop, SLOT(quit()));

	loop.exec();

	qDebug() << "End download of" << remoteUrl;
	QFile localFile(localPath);
	if (localFile.open(QIODevice::WriteOnly | QIODevice::Truncate)) {
		localFile.write(reply->readAll());
		localFile.close();
	}

	reply->deleteLater();

	return true;
}