// Copyright (c) 2011-2024 Squall Line Software, LLC
// Distributed under the terms of the MIT License
// See accompanying LICENSE.txt file or
// http://www.opensource.org/licenses/mit-license.php

#ifndef DISORDER_PDU_PDU_HPP
#define DISORDER_PDU_PDU_HPP

#include <disorder/dso_api.hpp>

#include <disorder/pdu/record/header.hpp>

#include <disorder/time/time_point.hpp>

namespace disorder
{

namespace pdu
{

/**
* PDU serves as the abstract base class for all Protocol Data Units (PDUs).
*/
struct DISORDER_DSO_PUBLIC PDU: public record::Record
{
    /// header that appears at the beginning of all PDUs
    record::Header header;

    /**
    * Prepares the PDU for sending by filling out various fields in the header
    * and any automatic fields within the PDU itself such as event id fields.
    *
    * This method is automatically called by the system when PDU::send or
    * Exercise::send is called, so disorder users will probably not need to
    * invoke this method directly.
    */
    virtual void finalize_for_sending();

    /**
    * Instructs this PDU to finalize its header fields and send itself using
    * all the transports that have been registered with disorder::Exercise.
    */
    void send();

    /**
    * Traverses all the fields that makeup this PDU including the header
    * portion.
    *
    * @param visitor visitor that operates on the traversed fields
    */
    void accept(field::Visitor& visitor) override;

    /**
    * Traverses the fields that makeup this PDU without the header portion.
    *
    * @param visitor visitor that operates on the traversed fields
    */
    virtual void accept_without_header(field::Visitor& visitor) = 0;

    /**
    * This method returns the time at which this PDU was received.
    *
    * Obviously, this method only returns something reasonable for PDUs that
    * have been received from other simulation applications.
    *
    * @return time at which this PDU was received
    */
    const time::TimePoint& received_at() const
    {
        return received_at_;
    }

    /**
    * This method sets the time at which this PDU was received.
    *
    * @param time time at which this PDU was received
    */
    void received_at(const time::TimePoint& time)
    {
        received_at_ = time;
    }

protected:
    /**
    * Constructor.
    *
    * @param type type of this PDU
    * @param family protocol family of this PDU
    */
    PDU(siso::DISPDUType type, siso::DISProtocolFamily family);

private:
    /// local reference and simulation times at which this PDU was received.
    /// This field is only valid for received PDUs and is zeroed otherwise.
    time::TimePoint received_at_;
};

}

}

#endif