/* ****************************************************************************
 * Copyright 2019 Open Systems Development BV                                 *
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 * Software is furnished to do so, subject to the following conditions:       *
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 * The above copyright notice and this permission notice shall be included in *
 * all copies or substantial portions of the Software.                        *
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 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,   *
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 * DEALINGS IN THE SOFTWARE.                                                  *
 * ***************************************************************************/
#include "timestamp.h"

using namespace osdev::components;

Timestamp::Timestamp()
    : m_msecsSinceEpoch(0)
    , m_seqNr(0)
{
}

Timestamp::Timestamp(unsigned long long msecsSinceEpoch)
    : m_msecsSinceEpoch(msecsSinceEpoch)
    , m_seqNr(1)
{
}

bool Timestamp::operator<(const Timestamp& rhs) const
{
    if (m_msecsSinceEpoch < rhs.m_msecsSinceEpoch)
    {
        return true;
    }

    if (m_msecsSinceEpoch == rhs.m_msecsSinceEpoch)
    {
        return m_seqNr < rhs.m_seqNr;
    }
    return false;
}

Timestamp& Timestamp::operator++() // prefix
{
    if (!valid())
    {
        return *this; // an invalid timestamp can only be made valid by assigning a valid timestamp to it.
    }

    if (m_seqNr < std::numeric_limits<decltype(m_seqNr)>::max())
    {
        ++m_seqNr;
    }
    else
    {
        // The idea is to never reach this point by choosing a large datatype.
        // Overflowing is not an option because then the < relation doesn't hold anymore.
        throw std::out_of_range("sequence number overflow");
    }
    return *this;
}

Timestamp Timestamp::operator++(int) // postfix
{
    auto cpy(*this);
    ++(*this);
    return cpy;
}

QString Timestamp::toString() const
{
    return QString("%1:%2").arg(m_msecsSinceEpoch).arg(m_seqNr);
}