/*
 * HipMessage.cpp
 *
 *  Created on: 4 мар. 2020 г.
 *      Author: user
 */

#include "HipMessage.hh"

#include <cstring>

unsigned short driver::Message::calcControlSumm( const char* data,
                                                 std::size_t data_len ) {

    unsigned short csumm = 0;
    for( unsigned short i = 0; i < data_len; i++ ) csumm ^= data[i];
    return csumm & 0xff;

}

driver::Message & driver::Message::operator=( const Header & header ) {

    data[0] = header.bytes_2[0];
    data[1] = header.bytes_2[1];

    return *this;

}

bool driver::Message::pack_message( const MessageControl* message ) {

    std::size_t data_len = 0;
    const unsigned short csumm_byte_pos = (data_len = message->send_data_size + 3) - 1;

    if( data_size < data_len ) return data_len = 0, false; else {
        operator=(Header(message->address, message->code));

        static void * const message_data_start = &data[first_data_byte_pos];
        std::memcpy( message_data_start, message->send_data, message->send_data_size );

        data[csumm_byte_pos] = calcControlSumm(data, data_len - 1);
    }

    return true;

}

driver::HipResult driver::Message::unpack_message(
        const MessageControl * message ) {

    std::size_t data_len = 0;
    const unsigned short csumm_byte_pos = (data_len = message->rec_data_size + 3) - 1;

    if( data_size < data_len ) return driver::internal_error; else {
        if( (data[csumm_byte_pos] & 0xff) != calcControlSumm(data, data_len - 1) )
            return driver::csumm_error;

        if( ( Header(*this).command_value + 0x40 ) != message->code )
            return driver::unexpected_answer;

        static const void * const message_data_start = &data[first_data_byte_pos];
        std::memcpy( message->rec_data, message_data_start, message->rec_data_size );
    }

    return driver::OK;

}