Message.h

#pragma once

#include "Serialize.h"
#include <cstdint>
#include <stdexcept>
#include <string>
#include <vector>

namespace P2p
{


class Message
{
public:

    class Header;

    typedef std::vector<uint8_t> Payload;

    // Constructor
    Message(char const * type, std::vector<uint8_t> const & payload);

    std::string type() const { return type_; }

    Payload payload() const { return payload_;  }

    size_t size() const { return payload_.size(); }

    uint32_t checksum() const;

private:

    std::string type_;
    Payload payload_;
};


class Message::Header : public P2p::Serializable
{
public:

    // Known magic numbers
    static uint32_t const MAGIC_MAIN    = 0xD9B4BEF9;   
    static uint32_t const MAGIC_TEST    = 0xDAB5BFFA;   
    static uint32_t const MAGIC_TEST3   = 0x0709110B;   

    // Field sizes
    static size_t const MAGIC_SIZE = 4;                 
    static size_t const TYPE_SIZE = 12;                 
    static size_t const LENGTH_SIZE = 4;                
    static size_t const CHECKSUM_SIZE = 4;              

    uint32_t magic_;                                    
    char type_[TYPE_SIZE];                              
    uint32_t length_;                                   
    uint32_t checksum_;                                 

    virtual void serialize(std::vector<uint8_t> & out) const override;
    virtual json toJson() const override;

};

struct InvalidMessageError : public std::runtime_error
{
    InvalidMessageError() : std::runtime_error("invalid message data") {}
};

} // namespace Network