#include "IDGenerator.h"

#include <QDataStream>
#include <QVariant>
#include<QIODevice>

qint64 IDGenerator::new_id()
{
	if (!m_recycle_id.isEmpty())
	{
        int id = m_recycle_id.begin().key();
        m_recycle_id.erase(m_recycle_id.begin());
		return id;
	}
	
	if(!m_use_id.isEmpty())
	{ 
		while (m_use_id.contains(m_id))
		{
			m_id++;
		}
		return m_id;
	}
	return m_id++;
}

void IDGenerator::recylce_id(qint64 id)
{
	m_recycle_id.insert(id, 0);
}

qint64 IDGenerator::next_id()
{
	if (!m_recycle_id.isEmpty())
	{
		int id = m_recycle_id.cbegin().key();
		return id;
	}
	return m_id;
}

void IDGenerator::use_id(qint64 id)
{
	m_use_id.insert(id, 0);
}

QByteArray IDGenerator::to_bytes() const
{
	QByteArray bytes;
	QDataStream stream(&bytes, QIODevice::WriteOnly);
	stream << m_id << m_recycle_id;
	return bytes.toBase64();  //目的：QVariant转换成字符串时会截断'\0'
}

void IDGenerator::from_bytes(const QByteArray& bytes)
{
	QByteArray _bytes = QByteArray::fromBase64(bytes);
	QDataStream stream(&_bytes, QIODevice::ReadOnly);
	stream >> m_id >> m_recycle_id;
}