#include "wallpapercache.hpp"

#include <QCryptographicHash>
#include <QDir>
#include <QFileInfo>
#include <QImageReader>
#include <QJsonDocument>
#include <QJsonObject>
#include <QSqlDatabase>
#include <QSqlError>
#include <QSqlQuery>
#include <QThread>

namespace ZShell::wallpaper {

namespace {

QString connectionName() {
	return QStringLiteral("wallpaper-cache-%1")
		.arg(quintptr(QThread::currentThreadId()));
}

QSqlDatabase openDatabase(const QString& databasePath) {
	const QString connection = connectionName();

	QSqlDatabase database =
		QSqlDatabase::contains(connection)
			? QSqlDatabase::database(connection, false)
			: QSqlDatabase::addDatabase("QSQLITE", connection);

	if (database.databaseName() != databasePath) {
		if (database.isOpen()) database.close();
		database.setDatabaseName(databasePath);
	}

	if (!database.isOpen() && !database.open()) return {};
	return database;
}

} // namespace

void WallpaperCache::setDbPath(const QString& path) {
	std::lock_guard<std::mutex> lock(m_mtx);
	m_dbPath = path;
}

QString WallpaperCache::dbPath() const {
	std::lock_guard<std::mutex> lock(m_mtx);
	return m_dbPath;
}

QByteArray WallpaperCache::cachedBlob(const QString& path) const {
	if (path.isEmpty()) return {};

	const QString databasePath = dbPath();
	if (databasePath.isEmpty()) return {};

	const QFileInfo info(path);

	QSqlDatabase database = openDatabase(databasePath);
	if (!database.isOpen()) return {};

	QSqlQuery query(database);
	query.prepare("SELECT cache, size, mtime FROM wallpapers WHERE path = ?");
	query.addBindValue(info.absoluteFilePath());
	if (!query.exec() || !query.next()) return {};

	const QByteArray blob = query.value(0).toByteArray();
	if (blob.isEmpty()) return {};

	const qint64 mtime = info.lastModified().toMSecsSinceEpoch() / 1000;
	if (query.value(1).toLongLong() != info.size() ||
		query.value(2).toLongLong() != mtime) {
		return {};
	}

	return blob;
}

QImage WallpaperCache::decodeImage(
	const QString& path, const QSize& decodeSize) const {
	if (path.isEmpty()) return {};

	QImageReader probe(path);
	const QSize source = probe.size();
	QSize required = source.isEmpty() ? decodeSize : source;
	if (!source.isEmpty() && !decodeSize.isEmpty()) {
		const QSize cover =
			source.scaled(decodeSize, Qt::KeepAspectRatioByExpanding);
		if (cover.width() <= source.width() &&
			cover.height() <= source.height())
			required = cover;
	}

	const QByteArray blob = cachedBlob(path);
	if (!blob.isEmpty()) {
		QImage image = QImage::fromData(blob, "JPEG");
		if (!image.isNull() && image.width() >= required.width() &&
			image.height() >= required.height()) {
			return image.convertToFormat(QImage::Format_RGBA8888);
		}
	}

	QImageReader reader(path);
	reader.setAutoTransform(true);

	if (!decodeSize.isEmpty() && !source.isEmpty())
		reader.setScaledSize(
			source.scaled(decodeSize, Qt::KeepAspectRatioByExpanding));

	QImage image = reader.read();
	if (image.isNull()) return {};

	return image.convertToFormat(QImage::Format_RGBA8888);
}

QByteArray WallpaperCache::posterBlob(const QString& path) const {
	if (path.isEmpty()) return {};

	const QString databasePath = dbPath();
	if (databasePath.isEmpty()) return {};

	const QFileInfo info(path);

	QSqlDatabase database = openDatabase(databasePath);
	if (!database.isOpen()) return {};

	QSqlQuery query(database);
	query.prepare("SELECT poster, size, mtime FROM wallpapers WHERE path = ?");
	query.addBindValue(info.absoluteFilePath());
	if (!query.exec() || !query.next()) return {};

	const QByteArray blob = query.value(0).toByteArray();
	if (blob.isEmpty()) return {};

	const qint64 mtime = info.lastModified().toMSecsSinceEpoch() / 1000;
	if (query.value(1).toLongLong() != info.size() ||
		query.value(2).toLongLong() != mtime) {
		return {};
	}

	return blob;
}

QVariantMap WallpaperCache::cropsForPath(const QString& path) const {
	if (path.isEmpty()) return {};

	const QString databasePath = dbPath();
	if (databasePath.isEmpty()) return {};

	const QFileInfo info(path);

	QSqlDatabase database = openDatabase(databasePath);
	if (!database.isOpen()) return {};

	QSqlQuery query(database);
	query.prepare("SELECT crop FROM wallpapers WHERE path = ?");
	query.addBindValue(info.absoluteFilePath());
	if (!query.exec() || !query.next()) return {};

	const QByteArray json = query.value(0).toByteArray();
	if (json.isEmpty()) return {};

	const auto doc = QJsonDocument::fromJson(json);
	if (!doc.isObject()) return {};

	return doc.object().toVariantMap();
}

} // namespace ZShell::wallpaper