#include <stdio.h>
#include <stdlib.h>
#include <termios.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>

#include "log.h"
#include "serial.h"

struct serial_port {
	int fd;
};

static speed_t baud(int speed)
{
	if (speed == 230400) return B230400; else
	if (speed == 115200) return B115200; else
	if (speed == 57600) return B57600; else
	if (speed == 38400) return B38400; else
	if (speed == 19200) return B19200; else
	if (speed == 9600) return B9600; else
	if (speed == 4800) return B4800; else
	if (speed == 2400) return B2400; else
	if (speed == 1200) return B1200; else {
		loge("Error setting baud rate: %d not recognised.", speed);
		return B0;
	}

}

port_t * serial_open(const char *name, int speed)
{
	port_t *pt = NULL;
	int fd;

	if ((fd = open(name, O_RDWR | O_NOCTTY))<0) {
		loge("Error: opening %s: %s", name, strerror(errno));
		return NULL;
	}

	struct termios adtio;
	bzero(&adtio, sizeof(adtio));

	tcgetattr(fd, &adtio);
	adtio.c_cflag = CS8 | CLOCAL | CREAD;
	adtio.c_iflag = IGNPAR | IGNBRK;
	adtio.c_oflag = 0;
	adtio.c_lflag = 0; // non-canon, no echo

	cfmakeraw(&adtio);

	adtio.c_cc[VTIME] = 0;
	adtio.c_cc[VMIN] = 1;

	cfsetispeed(&adtio, baud(speed));
	cfsetospeed(&adtio, baud(speed));

	tcsetattr(fd, TCSANOW, &adtio);

	pt = malloc(sizeof(port_t));
	pt->fd = fd;

	return pt;

}

void serial_close(port_t * pt)
{
	if (pt == NULL) return;
	if (pt->fd < 0) return;

	close(pt->fd);
	pt->fd = -1;

	return;
}

int serial_read(port_t * pt, unsigned char * buff, size_t len)
{
	if (pt == NULL || pt->fd < 0) return -1;

	int ret = 0;
	int count = 0;
	unsigned char * p = buff;
	while (count < len) {
		ret = read(pt->fd, p, len-count);
		if (ret <= 0) return ret;
		p += ret;
		count += ret;
	}
	return count;
}

int serial_write(port_t * pt, unsigned char * buff, size_t len)
{
	if (pt == NULL || pt->fd < 0) return -1;

	return write(pt->fd, buff, len);
}

int serial_break(port_t * pt, int set)
{
	if (pt == NULL || pt->fd < 0) return -1;

	if (set)
		ioctl(pt->fd, TIOCSBRK, 0);
	else
		ioctl(pt->fd, TIOCCBRK, 0);

	return 0;
}