#include "nbus_app.h"

nBus_TypeDef nBus;


static uint8_t const crc8x_table[] = {
    0x00, 0x31, 0x62, 0x53, 0xc4, 0xf5, 0xa6, 0x97, 0xb9, 0x88, 0xdb, 0xea, 0x7d,
    0x4c, 0x1f, 0x2e, 0x43, 0x72, 0x21, 0x10, 0x87, 0xb6, 0xe5, 0xd4, 0xfa, 0xcb,
    0x98, 0xa9, 0x3e, 0x0f, 0x5c, 0x6d, 0x86, 0xb7, 0xe4, 0xd5, 0x42, 0x73, 0x20,
    0x11, 0x3f, 0x0e, 0x5d, 0x6c, 0xfb, 0xca, 0x99, 0xa8, 0xc5, 0xf4, 0xa7, 0x96,
    0x01, 0x30, 0x63, 0x52, 0x7c, 0x4d, 0x1e, 0x2f, 0xb8, 0x89, 0xda, 0xeb, 0x3d,
    0x0c, 0x5f, 0x6e, 0xf9, 0xc8, 0x9b, 0xaa, 0x84, 0xb5, 0xe6, 0xd7, 0x40, 0x71,
    0x22, 0x13, 0x7e, 0x4f, 0x1c, 0x2d, 0xba, 0x8b, 0xd8, 0xe9, 0xc7, 0xf6, 0xa5,
    0x94, 0x03, 0x32, 0x61, 0x50, 0xbb, 0x8a, 0xd9, 0xe8, 0x7f, 0x4e, 0x1d, 0x2c,
    0x02, 0x33, 0x60, 0x51, 0xc6, 0xf7, 0xa4, 0x95, 0xf8, 0xc9, 0x9a, 0xab, 0x3c,
    0x0d, 0x5e, 0x6f, 0x41, 0x70, 0x23, 0x12, 0x85, 0xb4, 0xe7, 0xd6, 0x7a, 0x4b,
    0x18, 0x29, 0xbe, 0x8f, 0xdc, 0xed, 0xc3, 0xf2, 0xa1, 0x90, 0x07, 0x36, 0x65,
    0x54, 0x39, 0x08, 0x5b, 0x6a, 0xfd, 0xcc, 0x9f, 0xae, 0x80, 0xb1, 0xe2, 0xd3,
    0x44, 0x75, 0x26, 0x17, 0xfc, 0xcd, 0x9e, 0xaf, 0x38, 0x09, 0x5a, 0x6b, 0x45,
    0x74, 0x27, 0x16, 0x81, 0xb0, 0xe3, 0xd2, 0xbf, 0x8e, 0xdd, 0xec, 0x7b, 0x4a,
    0x19, 0x28, 0x06, 0x37, 0x64, 0x55, 0xc2, 0xf3, 0xa0, 0x91, 0x47, 0x76, 0x25,
    0x14, 0x83, 0xb2, 0xe1, 0xd0, 0xfe, 0xcf, 0x9c, 0xad, 0x3a, 0x0b, 0x58, 0x69,
    0x04, 0x35, 0x66, 0x57, 0xc0, 0xf1, 0xa2, 0x93, 0xbd, 0x8c, 0xdf, 0xee, 0x79,
    0x48, 0x1b, 0x2a, 0xc1, 0xf0, 0xa3, 0x92, 0x05, 0x34, 0x67, 0x56, 0x78, 0x49,
    0x1a, 0x2b, 0xbc, 0x8d, 0xde, 0xef, 0x82, 0xb3, 0xe0, 0xd1, 0x46, 0x77, 0x24,
    0x15, 0x3b, 0x0a, 0x59, 0x68, 0xff, 0xce, 0x9d, 0xac};


uint8_t crc8x_fast(uint8_t crc, void const *mem, uint16_t len) {
	uint8_t const *data = mem;
    if (data == NULL)
        return 0xff;
    crc &= 0xff;
    while (len--)
        crc = crc8x_table[crc ^ *data++];
    return crc;
}

void nbus_init(Peripheral_typeDef *periph){
  nBus.periph = periph;

  HAL_TIM_RegisterCallback(nBus.periph->uart_timer, HAL_TIM_PERIOD_ELAPSED_CB_ID, nbus_cb_TIM_periodElapsed);
  HAL_UART_RegisterCallback(nBus.periph->huart, HAL_UART_RX_COMPLETE_CB_ID, nbus_cb_UART_RX);

  nBus.rx_length = 0;

  // init restart timer
  nBus.uart_state = UART_RX_1B;
  HAL_TIM_Base_Start_IT(periph->uart_timer);
  HAL_TIM_Base_Stop_IT(periph->uart_timer);

}

inline void receiveOneByte(){
	HAL_UART_Receive_IT(nBus.periph->huart, nBus.rx_buffer, 1);
	nBus.uart_state = UART_RX_1B;
}

inline static void receiveNBytes(uint8_t n){
	nBus.rx_length = n;
	HAL_UART_Receive_IT(nBus.periph->huart, nBus.rx_buffer, nBus.rx_length);
	nBus.uart_state = UART_RX_PAYLOAD;
}

inline static void send_response(){
	if(nBus.send_response == SEND_RESPONSE) {
		nBus.tx_buffer[0] -= 1;
		HAL_UART_Transmit_DMA(nBus.periph->huart, nBus.tx_buffer, nBus.tx_length);
	}
}

void nbus_cb_UART_RX(UART_HandleTypeDef *huart){
	if(nBus.uart_state == UART_RX_PAYLOAD) {
		nBus.uart_state = UART_RECEIVED;
		HAL_GPIO_WritePin(nBus.periph->led->port, nBus.periph->led->pin, GPIO_PIN_RESET);
		HAL_TIM_Base_Stop_IT(nBus.periph->uart_timer);
	}

	if(nBus.uart_state == UART_RX_1B) {
		HAL_GPIO_WritePin(nBus.periph->led->port, nBus.periph->led->pin, GPIO_PIN_SET);
		receiveNBytes(nBus.rx_buffer[0]);

		HAL_TIM_Base_Stop_IT(nBus.periph->uart_timer);
		nBus.periph->uart_timer->Instance->CNT = 1;
		HAL_TIM_Base_Start_IT(nBus.periph->uart_timer);
	}

}

void nbus_cb_TIM_periodElapsed(TIM_HandleTypeDef *htim) {
	if(nBus.uart_state == UART_RX_PAYLOAD) {
		HAL_TIM_Base_Stop_IT(nBus.periph->uart_timer);
		HAL_UART_AbortReceive_IT(nBus.periph->huart);
		receiveOneByte();
	}
}

static nBusCommandType_t get_request_type(){

	nBus.addressModule = nBus.rx_buffer[0];
	nBus.sensorInfo = *(const nBus_sensorByte_t*)&nBus.rx_buffer[1];
	nBus.function_code = *(const nBus_functionCode_t*)&nBus.rx_buffer[2];

	if(nBus.sensorInfo.address != 0 && nBus.addressModule !=0 ){
		nBus.request_type = UNICAST_TO_SENSOR;
		return UNICAST_TO_SENSOR;
	}

	if(nBus.sensorInfo.address == 0 && nBus.addressModule !=0 ){
		nBus.request_type = UNICAST_TO_MODULE;
		return UNICAST_TO_MODULE;
	}

	if(nBus.sensorInfo.address != 0 && nBus.addressModule == 0 ){
		nBus.request_type = BROADCAST_SPECIFIC_SENSORS;
		return BROADCAST_SPECIFIC_SENSORS;
	}

	nBus.request_type = BROADCAST_GLOBAL;
	return BROADCAST_GLOBAL;
}

void process_request(){
	nBusCommandType_t request_type = get_request_type();
	nBus_functionCode_t *fc = &nBus.function_code;
	nBus.send_response = SEND_RESPONSE;

	nBus.tx_buffer[0] = 0;
	nBus.tx_buffer[1] = nBus.rx_buffer[0];	// Module address
	nBus.tx_buffer[2] = nBus.rx_buffer[1];	// Sensor address

	uint8_t crcC = crc8x_fast(0x00, nBus.rx_buffer, nBus.rx_length-1);
	if(crcC != nBus.rx_buffer[nBus.rx_length-1]){
		nBus.send_response = NO_RESPONSE;
		return;
	}

	// paket nie je adresovany tomuto modulu
	if(nBus.addressModule != MODULE_ADDRESS) {
		nBus.send_response = NO_RESPONSE;
		return;
	}

	// spracovanie broadcast komunikacie
	if((request_type == BROADCAST_SPECIFIC_SENSORS || request_type == BROADCAST_GLOBAL)) {
		nbus_broadcast(&nBus, request_type);
		return;
	}

	if(nBus.function_code.notReadWrite == REQUEST_GET) {
		fc->error = 1;
		nBus.tx_length = META_SIZE;

		if(request_type == UNICAST_TO_SENSOR) {

		}

		if(request_type == UNICAST_TO_MODULE) {
			fc = nbus_unicastToModule(&nBus, fc);
		}

		nBus.tx_buffer[3] = *(uint8_t*)&fc;
		nBus.tx_buffer[nBus.tx_length-1] = crc8x_fast(0x00, &nBus.tx_buffer[1], nBus.tx_length-2);
		nBus.tx_buffer[0] = nBus.tx_length;

	} else {

	}

}

void nbus_stack(void){
	receiveOneByte();

	while(1){
		if(nBus.uart_state == UART_RECEIVED){
			//HAL_TIM_Base_Stop_IT(nBus.periph->uart_timer);

			process_request();

			// ready for next receiving
			receiveOneByte();

			send_response();
		}
	}

}