#include <time.h>
#include <string.h>
#include <malloc.h>
#include <errno.h>

#include <unistd.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <linux/spi/spidev.h>

//#include <wiringPi.h>

#include "logger.h"
#include "ws2801.h"

static const char    *spi_dev   = "/dev/spidev0.0";
static const uint32_t spi_speed = 1000000; // clock freq in Hz
static const uint16_t spi_delay = 0; // us
static const uint8_t  spi_bits  = 8; // bits per word

uint32_t  numModules;
uint8_t *message;

int spi_fd = 0;

void send_message(void)
{
	struct spi_ioc_transfer tr = {
		.tx_buf = (unsigned long)message,
		.rx_buf = (unsigned long)NULL,
		.len = 3 * numModules,
		.delay_usecs = spi_delay,
		.speed_hz = spi_speed,
		.bits_per_word = 8
	};

	if(ioctl(spi_fd, SPI_IOC_MESSAGE(1), &tr) < 0) {
		LOG(LVL_ERR, "ws2801: could not send SPI message: %s", strerror(errno));
	}
}

int ws2801_init(uint32_t nMod)
{
	// Initialize SPI
	// We need to have stable data at falling edge of the spi interface (this
	// means rising edge at the led strip, as the signal is inverted.
	uint8_t spi_mode = SPI_NO_CS; // | SPI_CPOL;

	spi_fd = open(spi_dev, O_RDWR);
	if(spi_fd < 0) {
		LOG(LVL_ERR, "ws2801: cannot open %s: %s", spi_dev, strerror(errno));
		return -1;
	}

	if(ioctl(spi_fd, SPI_IOC_WR_MODE, &spi_mode) == -1) {
		LOG(LVL_ERR, "ws2801: cannot change SPI mode: %s", strerror(errno));
		return -1;
	}

	if(ioctl(spi_fd, SPI_IOC_WR_BITS_PER_WORD, &spi_bits) == -1) {
		LOG(LVL_ERR, "ws2801: cannot change SPI bits per word: %s", strerror(errno));
		return -1;
	}

	if(ioctl(spi_fd, SPI_IOC_WR_MAX_SPEED_HZ, &spi_speed) == -1) {
		LOG(LVL_ERR, "ws2801: cannot change SPI speed: %s", strerror(errno));
		return -1;
	}

	// create the message array
	numModules = nMod;
	message = malloc(3 * nMod * sizeof(uint8_t));

	if(!message) {
		LOG(LVL_ERR, "ws2801: could not allocate the message array!");
		return -1;
	}

	return 0;
}

void ws2801_shutdown(void)
{
	close(spi_fd);

	if(message != NULL) { free(message); message = NULL; }
}

void ws2801_set_colour(uint32_t module, uint8_t red, uint8_t green, uint8_t blue)
{
	//message[3*module + 0] = ~red;
	//message[3*module + 1] = ~green;
	//message[3*module + 2] = ~blue;
	message[3*module + 0] = red;
	message[3*module + 1] = blue;
	message[3*module + 2] = green;
}

void ws2801_send_update(void)
{
	send_message();

	static const struct timespec sleepval = {0, 550000};
	nanosleep(&sleepval, NULL);
}