/**
 * @file can_sensor.c
 * @brief Однокадровый транспорт SETCAN SETTINGS для локаций DS18B20.
 */

#include "can_sensor.h"

/** Возвращает 1, если все восемь байтов ROM равны нулю. */
static uint8_t can_sensor_rom_is_zero(const uint8_t *rom)
{
    uint8_t index;

    for (index = 0U; index < CAN_SENSOR_ID_SIZE; index++) {
        if (rom[index] != 0U) {
            return 0U;
        }
    }
    return 1U;
}

/** Передаёт уже собранный кадр с ограниченным числом повторов. */
static uint8_t can_sensor_send_frame(CanSensor *link, const CanSensor_Frame *frame)
{
    uint8_t attempt;

    for (attempt = 0U; attempt < link->config.retries; attempt++) {
        if (link->io.send(link->io.context, frame) != 0U) {
            link->sent_messages++;
            return 1U;
        }
    }
    link->send_errors++;
    return 0U;
}

void CanSensor_ConfigDefault(CanSensor_Config *config)
{
    if (config == 0) {
        return;
    }
    config->tx_id = CAN_SENSOR_DEFAULT_TX_ID;
    config->rx_id = CAN_SENSOR_DEFAULT_RX_ID;
    config->extended = 1U;
    config->retries = CAN_SENSOR_DEFAULT_RETRIES;
}

uint8_t CanSensor_Init(CanSensor *link, const CanSensor_Io *io,
                       const CanSensor_Config *config)
{
    if ((link == 0) || (io == 0) || (io->send == 0)) {
        return 0U;
    }
    link->io = *io;
    if (config != 0) {
        link->config = *config;
    } else {
        CanSensor_ConfigDefault(&link->config);
    }
    if (link->config.tx_id == 0U) {
        link->config.tx_id = CAN_SENSOR_DEFAULT_TX_ID;
    }
    if (link->config.rx_id == 0U) {
        link->config.rx_id = CAN_SENSOR_DEFAULT_RX_ID;
    }
    link->config.tx_id &= CAN_SENSOR_HEADER_MASK;
    link->config.rx_id &= CAN_SENSOR_HEADER_MASK;
    link->config.extended = 1U;
    if (link->config.retries == 0U) {
        link->config.retries = CAN_SENSOR_DEFAULT_RETRIES;
    }
    link->sent_messages = 0U;
    link->send_errors = 0U;
    link->received_messages = 0U;
    link->dropped_frames = 0U;
    return 1U;
}

uint8_t CanSensor_BuildFrame(const CanSensor_Config *config, CanSensor_Frame *frame,
                             uint8_t response, uint8_t position,
                             uint8_t assembly_serial, const uint8_t *data,
                             uint8_t length)
{
    uint8_t index;
    uint32_t base;

    if ((config == 0) || (frame == 0) || (length > CAN_SENSOR_MAX_DATA)
        || ((length != 0U) && (data == 0))) {
        return 0U;
    }
    base = (response != 0U) ? config->tx_id : config->rx_id;
    frame->id = (base & CAN_SENSOR_HEADER_MASK)
                | ((uint32_t)assembly_serial << 8U) | (uint32_t)position;
    frame->extended = 1U;
    frame->length = length;
    for (index = 0U; index < CAN_SENSOR_MAX_DATA; index++) {
        frame->data[index] = (index < length) ? data[index] : 0U;
    }
    return 1U;
}

uint8_t CanSensor_SendId(CanSensor *link, uint8_t position,
                         uint8_t assembly_serial, const uint8_t *id)
{
    CanSensor_Frame frame;

    if ((link == 0) || (id == 0) || (link->io.send == 0)) {
        return 0U;
    }
    if (CanSensor_BuildFrame(&link->config, &frame, 1U, position,
                             assembly_serial, id, CAN_SENSOR_ID_SIZE) == 0U) {
        link->send_errors++;
        return 0U;
    }
    return can_sensor_send_frame(link, &frame);
}

uint8_t CanSensor_SendError(CanSensor *link, uint8_t position,
                            uint8_t assembly_serial, uint8_t result)
{
    CanSensor_Frame frame;

    if ((link == 0) || (link->io.send == 0) || (result == CAN_SENSOR_RESULT_OK)) {
        return 0U;
    }
    if (CanSensor_BuildFrame(&link->config, &frame, 1U, position,
                             assembly_serial, &result, 1U) == 0U) {
        link->send_errors++;
        return 0U;
    }
    return can_sensor_send_frame(link, &frame);
}

uint8_t CanSensor_HandleFrame(CanSensor *link, const CanSensor_Frame *frame,
                              CanSensor_Message *out)
{
    CanSensor_Message message;
    uint32_t header;
    uint8_t index;

    if ((link == 0) || (frame == 0)) {
        return 0U;
    }
    if (frame->extended == 0U) {
        return 0U;
    }
    header = frame->id & CAN_SENSOR_HEADER_MASK;
    if (header == (link->config.rx_id & CAN_SENSOR_HEADER_MASK)) {
        message.request = 1U;
    } else if (header == (link->config.tx_id & CAN_SENSOR_HEADER_MASK)) {
        message.request = 0U;
    } else {
        return 0U;
    }

    message.assembly_serial = (uint8_t)((frame->id >> 8U) & 0xFFU);
    message.position = (uint8_t)(frame->id & 0xFFU);
    message.result = CAN_SENSOR_RESULT_OK;
    for (index = 0U; index < CAN_SENSOR_ID_SIZE; index++) {
        message.id[index] = (index < frame->length) ? frame->data[index] : 0U;
    }

    if (message.request != 0U) {
        if (frame->length == 0U) {
            message.operation = CAN_SENSOR_OPERATION_GET;
        } else if (frame->length == CAN_SENSOR_ID_SIZE) {
            message.operation = (can_sensor_rom_is_zero(message.id) != 0U)
                                    ? CAN_SENSOR_OPERATION_CLEAR
                                    : CAN_SENSOR_OPERATION_WRITE;
        } else {
            message.operation = CAN_SENSOR_OPERATION_INVALID;
            message.result = CAN_SENSOR_RESULT_INVALID_DLC;
        }
    } else if (frame->length == CAN_SENSOR_ID_SIZE) {
        message.operation = CAN_SENSOR_OPERATION_RESPONSE;
    } else if (frame->length == 1U) {
        message.operation = CAN_SENSOR_OPERATION_ERROR;
        message.result = frame->data[0];
    } else {
        link->dropped_frames++;
        return 0U;
    }

    link->received_messages++;
    if (out != 0) {
        *out = message;
    }
    return 1U;
}

uint8_t CanSensor_Poll(CanSensor *link, CanSensor_Message *out)
{
    CanSensor_Frame frame;

    if ((link == 0) || (link->io.receive == 0)) {
        return 0U;
    }
    while (link->io.receive(link->io.context, &frame) != 0U) {
        if (CanSensor_HandleFrame(link, &frame, out) != 0U) {
            return 1U;
        }
    }
    return 0U;
}