#include "dbredis.h"
#include <QDateTime>

QSqlDatabase DBRedis::m_DataBase;
QString DBRedis::m_ConnectName = "dbredis";
bool DBRedis::m_HasInit = false;


DBRedis::DBRedis()
{
	
}

DBRedis::~DBRedis()
{
	if (m_DataBase.isOpen())
	{
		m_DataBase.close();
	}
}

int DBRedis::deleteExpiredEntries()
{
	int res = init();
	if (res)
	{
		return res;
	}

	qint64 currentTimestamp = QDateTime::currentDateTime().toSecsSinceEpoch();
	QSqlQuery query(m_DataBase);
	query.prepare("DELETE FROM data_store WHERE expiry > 0 AND expiry < :currentTimestamp");
	query.bindValue(":currentTimestamp", currentTimestamp);

	if (!query.exec()) 
	{
		qDebug() << "Error deleting expired entries:" << query.lastError().text();
		return 1;
	}
	return 0;
}



int DBRedis::setData(const QString & key, const QString & value, uint32_t expiry)
{
	int res = deleteExpiredEntries();
	if (res)
	{
		return res;
	}

	QSqlQuery query(m_DataBase);
	query.prepare("SELECT COUNT(*) FROM data_store WHERE key = :key");
	query.bindValue(":key", key);
	if (!query.exec()) 
	{
		qDebug() << "Error checking existing key";
		return 1;
	}
	int count = 0;
	while (query.next())
	{
		count += query.value(0).toInt();
	}
	if (count > 0)
	{
		query.prepare("UPDATE data_store SET value = :value, expiry = :expiry WHERE key = :key");
		query.bindValue(":value", value);
		query.bindValue(":expiry", expiry > 0 ? QDateTime::currentDateTime().toSecsSinceEpoch() + expiry : 0);
		query.bindValue(":key", key);
	}
	else 
	{
		query.prepare("INSERT INTO data_store (key, value, expiry) VALUES (:key, :value, :expiry)");
		query.bindValue(":key", key);
		query.bindValue(":value", value);
		query.bindValue(":expiry", expiry > 0 ? QDateTime::currentDateTime().toSecsSinceEpoch() + expiry : 0);
	}
	if (!query.exec()) 
	{
		qDebug() << "Error setting value:" << query.lastError().text();
		return 1;
	}
	return 0;
}

int DBRedis::getData(const QString & key, QString & value)
{
	value.clear();
	int res = deleteExpiredEntries();
	if (res)
	{
		return res;
	}

	QSqlQuery query(m_DataBase);
	query.prepare("SELECT value FROM data_store WHERE key = :key");
	query.bindValue(":key", key);
	if (!query.exec()) 
	{
		qDebug() << "Error getting value:" << query.lastError().text();
		return 1;
	}
	if (!query.next())
	{
		qDebug() << "Error getting value:" << query.lastError().text();
		return 2;
	}
	value = query.value(0).toString();
	return 0;
}

int DBRedis::deleteData(const QString & key)
{
	int res = deleteExpiredEntries();
	if (res)
	{
		return res;
	}

	QSqlQuery query(m_DataBase);
	query.prepare("DELETE FROM data_store WHERE key = :key");
	query.bindValue(":key", key);
	if (!query.exec()) 
	{
		qDebug() << "Error deleting value:" << query.lastError().text();
		return 1;
	}
	return 0;
}

int DBRedis::init()
{
	if (m_HasInit)
	{
		return 0;
	}
	m_DataBase = QSqlDatabase::addDatabase("QSQLITE", m_ConnectName);
	m_DataBase.setDatabaseName("dbredis.db");
	if (m_DataBase.open())
	{
		QString table = "CREATE TABLE IF NOT EXISTS data_store(key TEXT, value TEXT, expiry INTEGER)";
		QSqlQuery query(QSqlDatabase::database(m_ConnectName));
		if (!query.exec(table.toUtf8()))
		{
			qDebug() << "Error deleting value:" << query.lastError().text();
			return 1;
		}
	}
	else
	{
		qDebug() << "Error db open fail";
		return 3;
	}
	m_HasInit = true;
	return 0;
}