#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <time.h>

#include "messages.h"

void error(char *msg)
{
	printf("Error: %s\n", msg);
	exit(0);
}

void dump(const char *label, uint8_t *data, int len)
{
	int i;
	printf("%s: ", label);
	for (i = 0; i < len; i++)
		printf("%02hhx ", data[i]);
	printf("\n");
}

int main(int argc, char **argv)
{
	if (argc < 3)
		error("usage: control /dev/ttyACM0 0 sync");

	// Parse args
	char *opt_tty    = argv[1];
	int   opt_device = atoi(argv[2]);
	int   opt_sync   = argv[3] && !strcmp(argv[3], "sync") ?
	                   MSG_CTL_VALID_SYNC : 0;
	int   opt_relay  = opt_device == 2;

	// Lookup current wall-clock time
	struct timespec ts;
	clock_gettime(CLOCK_REALTIME, &ts);

	// Message buffers
	header_t   head = {};
	init_msg_t body = {};

	// Set message header
	head.header  = MSG_HEADER;
	head.msgid   = MSG_ID_INIT;
	head.length  = sizeof(init_msg_t);
	head.cksum   = 0; // todo

	// Set valid flags
	body.control = MSG_CTL_VALID_DEVICE
	             | MSG_CTL_VALID_START
	             | MSG_CTL_VALID_PERIOD
	             | MSG_CTL_VALID_WORLD
	             | opt_relay
	             | opt_sync;

	// Set message body
	body.device         = opt_device;
	body.world.seconds  = ts.tv_sec;
	body.world.nanosec  = ts.tv_nsec;
	body.start.seconds  = ts.tv_sec;
	body.start.nanosec  = 0; //ts.tv_nsec;
	body.period.seconds = 0;
	body.period.nanosec =  100000000;
	//                  [s][m][u][n]

	// Transmit message
	FILE *fd = fopen(opt_tty, "a+");
	if (!fd) error("opening device");
	int len = 0;
	len += fwrite(&head, 1, sizeof(head), fd);
	len += fwrite(&body, 1, sizeof(body), fd);
	fclose(fd);

	// Debug output
	dump("head", (uint8_t*)&head, sizeof(head));
	dump("body", (uint8_t*)&body, sizeof(body));

	printf("wrote %d bytes\n", len);

	return 0;
}