/**
 * @file    shellmatta_transport.h
 * @brief   transport layer functions of shellmatta
 * @author  Simon Fischer <fischer.simon.1991@gmail.com>
 */

#include "shellmatta_transport.h"

shellmatta_retCode_t shellmatta_init_transport_inst()
{
    transportLayerInst.h2s_sequenceCnt = 0;
    transportLayerInst.s2h_sequenceCnt = 0;
    transportLayerInst.state = STATE_GET_SOH;
    transportLayerInst.mandatory = false;
    transportLayerInst.active = false;

    return SHELLMATTA_OK;
}

shellmatta_retCode_t shellmatta_handle_transport_fsm(shellmatta_transport_layer_t *transportLayer, char *data)
{
    switch (transportLayer->state)
    {
    case STATE_GET_SOH:
        if (SHELLMATTA_START_OF_HEADER == *data)
        {
            transportLayer->state = STATE_GET_PROTOCOL_VERSION;
            transportLayer->active = true;
        }
        else
        {
            transportLayer->active = false;
            transportLayer->state = STATE_GET_PAYLOAD;
        }
        break;
    case STATE_GET_PROTOCOL_VERSION:
        transportLayer->state = STATE_GET_PACKET_TYPE;
        break;
    case STATE_GET_PACKET_TYPE:
        transportLayer->state = STATE_GET_PAYLOAD_LENGTH;
        break;
    case STATE_GET_PAYLOAD_LENGTH:
        transportLayer->state = STATE_GET_SOURCE;
        break;
    case STATE_GET_SOURCE:
        transportLayer->state = STATE_GET_DESTINATION;
        break;
    case STATE_GET_DESTINATION:
        transportLayer->state = STATE_GET_H2S_SEQUENCE_CNT;
        break;
    case STATE_GET_H2S_SEQUENCE_CNT:
        transportLayer->state = STATE_GET_S2H_SEQUENCE_CNT;
        break;
    case STATE_GET_S2H_SEQUENCE_CNT:
        transportLayer->state = STATE_GET_PAYLOAD;
        break;
    case STATE_GET_PAYLOAD:
        if (    (payloadLength == payloadCounter)
            &&  (true == transportLayer->active))
        {
            transportLayer->state = STATE_GET_CRC;
        }
        break;
    case STATE_GET_CRC:
        if (SHELLMATTA_LENGTH_CRC == crcCounter)
        {
            transportLayer->state = STATE_GET_SOH;
            protocolVersion = 0u;
            packetType      = 0u;
            payloadLength   = 0u;
            source          = 0u;
            destination     = 0u;
            crc32           = 0u;
            payloadCounter  = 0u;
            crcCounter      = 0u;
            transportLayer->active = false;
        }
        break;
    
    default:
        break;
    }

    return SHELLMATTA_OK;
}