#include "periph28335.h"

#include <string.h>

#include "set_crc.h"

typedef struct {
    const char *project;
    const char *commands[PERIPH28335_COMMAND_COUNT];
} periph28335_project_t;

static const periph28335_project_t projects[] = {
    { "По умолчанию", { "Test", "Def", "Save", "Load", "Calibr", "Calcul", "Secret", "Light", "Raw", "-", "-", "-", "-", "-", "-", "Reset", "Nothing at all" } },
    { "23470", { "Test", "Def", "Save", "Load", "Calibr", "Read", "Secret", "-", "-", "-", "-", "-", "-", "-", "-", "Reset", "Nothing at all" } },
    { "23550", { "Test", "Def", "Save", "Load", "Calibr", "Read", "Secret", "Send", "-", "-", "-", "-", "-", "-", "-", "Reset", "Nothing at all" } },
    { "23550.2", { "Test", "Def", "Save", "Load", "Calibr", "Calcul", "Secret", "Send", "Raw", "Beep", "", "", "", "", "Log", "Reset", "Nothing at all" } },
    { "ICE 22220.1-3", { "Test", "Zero", "Save", "Def", "Calibr", "Read", "ExtLamp", "ExtLite", "-", "-", "-", "-", "-", "-", "-", "Reset", "Nothing at all" } },
    { "ICE 22220.4-5", { "Test", "Def", "Save", "Load", "Raw", "Read", "ExtLamp", "ExtLite", "No log", "-", "-", "-", "-", "-", "-", "Reset", "Nothing at all" } },
    { "Бальзам 161", { "Test", "Zero", "Save", "Def", "Calibr", "Clbr 400", "Stop", "Start", "Init", "Secret", "-", "-", "-", "-", "-", "Reset", "Nothing at all" } },
    { "Бальзам 162", { "Test", "Def", "Save", "Load", "Calibr", "Secret", "Stop", "Start", "Init", "Tune", "-", "-", "-", "-", "-", "Reset", "Nothing at all" } },
    { "Бальзам 163", { "Test", "Def", "Save", "Load", "Calibr", "Calcul", "Stop", "Start", "Init", "Tune", "Secret", "-", "-", "-", "-", "Reset", "Nothing at all" } }
};

static void put_be16(uint8_t *output, uint16_t value)
{
    output[0] = (uint8_t)(value >> 8);
    output[1] = (uint8_t)value;
}

static uint16_t get_be16(const uint8_t *input)
{
    return (uint16_t)(((uint16_t)input[0] << 8) | input[1]);
}

uint16_t periph28335_crc16_modbus(const uint8_t *data, size_t size)
{
    return set_crc16_modbus(data, size);
}

size_t periph28335_append_crc(const uint8_t *payload, size_t payload_size,
                              uint8_t *output, size_t output_size)
{
    uint16_t crc;
    if ((output == NULL) || ((payload == NULL) && (payload_size != 0U)) ||
        (payload_size > output_size) || (output_size - payload_size < 2U)) {
        return 0U;
    }
    if (payload_size != 0U) memcpy(output, payload, payload_size);
    crc = periph28335_crc16_modbus(payload, payload_size);
    output[payload_size] = (uint8_t)crc;
    output[payload_size + 1U] = (uint8_t)(crc >> 8);
    return payload_size + 2U;
}

size_t periph28335_build_read_registers(
    uint8_t controller, uint16_t start, uint16_t count,
    uint8_t *output, size_t output_size)
{
    uint8_t payload[6];
    if ((count == 0U) || (count > PERIPH28335_REGISTER_COUNT) ||
        (start >= PERIPH28335_REGISTER_COUNT) ||
        ((uint32_t)start + count > PERIPH28335_REGISTER_COUNT)) return 0U;
    payload[0] = controller;
    payload[1] = 3U;
    put_be16(&payload[2], start);
    put_be16(&payload[4], count);
    return periph28335_append_crc(payload, sizeof payload, output, output_size);
}

size_t periph28335_build_write_register(
    uint8_t controller, uint16_t address, uint16_t value,
    uint8_t *output, size_t output_size)
{
    uint8_t payload[6];
    if (address >= PERIPH28335_REGISTER_COUNT) return 0U;
    payload[0] = controller;
    payload[1] = 6U;
    put_be16(&payload[2], address);
    put_be16(&payload[4], value);
    return periph28335_append_crc(payload, sizeof payload, output, output_size);
}

size_t periph28335_build_command(
    uint8_t controller, uint8_t command_index,
    uint8_t *output, size_t output_size)
{
    uint16_t value;
    if (command_index >= PERIPH28335_COMMAND_COUNT) return 0U;
    value = command_index < 16U ? (uint16_t)(1UL << command_index) : 0U;
    return periph28335_build_write_register(
        controller, PERIPH28335_REGISTER_COUNT - 1U, value,
        output, output_size);
}

size_t periph28335_expected_read_response_size(uint16_t count)
{
    return (count >= 1U && count <= PERIPH28335_REGISTER_COUNT)
        ? (size_t)count * 2U + 5U : 0U;
}

int periph28335_decode_read_response(
    const uint8_t *data, size_t size, uint8_t controller, uint16_t count,
    uint16_t *output, size_t output_count)
{
    size_t expected = periph28335_expected_read_response_size(count);
    uint16_t crc;
    size_t index;
    if ((data == NULL) || (output == NULL)) return PERIPH28335_ERROR_ARGUMENT;
    if (expected == 0U) return PERIPH28335_ERROR_RANGE;
    if (size != expected) return PERIPH28335_ERROR_LENGTH;
    if (output_count < count) return PERIPH28335_ERROR_CAPACITY;
    crc = periph28335_crc16_modbus(data, size - 2U);
    if ((data[size - 2U] != (uint8_t)crc) ||
        (data[size - 1U] != (uint8_t)(crc >> 8))) {
        return PERIPH28335_ERROR_CRC;
    }
    if ((data[0] != controller) || (data[1] != 3U) ||
        (data[2] != (uint8_t)(count * 2U))) {
        return PERIPH28335_ERROR_HEADER;
    }
    for (index = 0U; index < count; ++index) {
        output[index] = get_be16(&data[3U + index * 2U]);
    }
    return PERIPH28335_OK;
}

int periph28335_validate_write_response(
    const uint8_t *response, size_t response_size,
    const uint8_t *request, size_t request_size)
{
    uint16_t crc;
    if ((response == NULL) || (request == NULL)) return PERIPH28335_ERROR_ARGUMENT;
    if ((response_size != PERIPH28335_REQUEST_SIZE) ||
        (request_size != PERIPH28335_REQUEST_SIZE)) return PERIPH28335_ERROR_LENGTH;
    crc = periph28335_crc16_modbus(response, response_size - 2U);
    if ((response[response_size - 2U] != (uint8_t)crc) ||
        (response[response_size - 1U] != (uint8_t)(crc >> 8))) {
        return PERIPH28335_ERROR_CRC;
    }
    return memcmp(response, request, PERIPH28335_REQUEST_SIZE) == 0
        ? PERIPH28335_OK : PERIPH28335_ERROR_HEADER;
}

size_t periph28335_project_count(void)
{
    return sizeof projects / sizeof projects[0];
}

const char *periph28335_project_name(size_t project_index)
{
    return project_index < periph28335_project_count()
        ? projects[project_index].project : NULL;
}

const char *periph28335_command_name(size_t project_index,
                                     size_t command_index)
{
    return project_index < periph28335_project_count() &&
           command_index < PERIPH28335_COMMAND_COUNT
        ? projects[project_index].commands[command_index] : NULL;
}