/*  Starshatter: The Open Source Project
    Copyright (c) 2021-2024, Starshatter: The Open Source Project Contributors
    Copyright (c) 2011-2012, Starshatter OpenSource Distribution Contributors
    Copyright (c) 1997-2006, Destroyer Studios LLC.

    AUTHOR:       John DiCamillo


    OVERVIEW
    ========
    Datagram (UDP) packet that implements the basic
    packet-oriented network protocol.
*/

#ifndef NetGram_h
#define NetGram_h

#include <cstdint>

#include "NetAddr.h"
#include "Text.h"


const std::uint32_t NET_GRAM_ACK           = 0x80000000;
const std::uint32_t NET_GRAM_RELIABLE      = 0x40000000;
const std::uint32_t NET_GRAM_SEQ_MASK      = 0x3fffffff;

const std::uint32_t NET_GRAM_HEADER_SIZE   = 4;
const std::uint32_t NET_GRAM_MAX_SIZE      = 1024;


class NetGram
{
public:
    static const char* TYPENAME() { return "NetGram"; }

    // for receiving packets from remote hosts:
    NetGram(const NetAddr& src, Text msg);

    // for composing packets to send to remote hosts:
    NetGram(const NetAddr& dst, Text user_data, int retries);

    int operator == (const NetGram& g) const { return packet_id == g.packet_id &&
                                                      addr      == g.addr;        }
    int operator <  (const NetGram& g) const { return Sequence() < g.Sequence();  }

    std::uint32_t  PacketID()  const { return packet_id;                                   }
    std::uint32_t  Sequence()  const { return packet_id & NET_GRAM_SEQ_MASK;               }
    std::uint32_t  SendTime()  const { return send_time;                                   }
    std::uint8_t*  Data()      const { return (std::uint8_t*) body.data();                 }
    std::uint8_t*  UserData()  const { return (std::uint8_t*) body.data() + NET_GRAM_HEADER_SIZE;  }
    int            Size()      const { return body.length();                               }
    const Text&    Body()      const { return body;                                        }
    const NetAddr& Address()   const { return addr;                                        }

    bool        IsAck()        const { return packet_id & NET_GRAM_ACK      ? true : false; }
    bool        IsReliable()   const { return packet_id & NET_GRAM_RELIABLE ? true : false; }
    int         Retries()      const { return retries; }

    void        Retry();
    NetGram     Ack();
    void        ClearAck()           { packet_id &= ~NET_GRAM_ACK;                         }

protected:
    NetGram();

    NetAddr  addr;       // network address of remote host
    int      retries;    // number of retries remaining (reliable packets only)
    std::uint32_t send_time;  // time in msec of most recent send attempt
    std::uint32_t packet_id;  // copy of packet id from header in body
    Text     body;       // header plus user data
};


#endif  // NetGram_h