/* Thyracont smartline vaccum gauge */

#include <u.h>
#include <libc.h>

typedef struct thct thct;
typedef struct tcg tcg;

struct thct {
	char	port[128];
	int		fd;
};

struct tcg {
	thct *t;
	char addr[4];
	char name[32];
};

thct*
newtc(char *p)
{
	thct *t;
	if((t = mallocz(sizeof(thct), 1)) == nil)
		sysfatal("%r: newtc mallocz failed");
	strcpy(t->port, p);
	return t;
}

tcg*
newtcg(thct *t, char *ad, char *n)
{
	tcg *g;
	if( ad == nil || n == nil)
		return nil;

	if( (g = mallocz(8, 1)) == nil)
		sysfatal("%r: newtcg mallocz failed");
	g->t = t;
	strcpy(g->addr, ad);
	strcpy(g->name, n);

	return g;
}

int
chksum(char *s)
{
	int t = 0;
	while(*s)
		t += *s++;
	return t % 64 + 64;
}

/*-=WIP=-*/
char*
mkheader(char *ad, char *ac, char *cm, char *ln)
{
	if(ad == 0 | ac == 0 || cm == 0 || ln == 0)
		return 0;
	char *buf = mallocz(11, 1);
	strncpy(buf, ad, 3);
	strncpy(buf+3, ac, 1);
	strncpy(buf+4, cm, 2);
	strncpy(buf+6, ln, 2);
	buf[8] = (char)chksum(buf);
	buf[9] = '\r';
	return buf;
}

char*
mkold(char *ad, char *cm)
{
	if(ad == 0 | cm == 0)
		return 0;
	
	char *buf = mallocz(11, 1);
	strncpy(buf, ad, 3);
	strncpy(buf+3, cm, 1);
	buf[4] = (char)chksum(buf);
	buf[5] = '\r';
	return buf;
}

int
contc(thct *t)
{
	if( (t->fd = open(t->port, ORDWR)) == 0 ) 
		return 1;
	else return 0;
}

int
closetc(thct *t)
{
	return close(t->fd);
}

long
sendmsg(tcg *g, char *m)
{
	return write(g->t->fd, m, strlen(m));
}

long
readmsg(tcg *g, char *b, long n)
{
	return pread(g->t->fd, b, n, 0);
}

void
freetc(thct *t)
{
	free(t);
}

int
verify(char *s)
{
	char b[4] = {0};
	int n;
	memcpy(b, s+4, 2);
	n = atoi(b);
	print("accesscode: %d\n", n);
	return n;
}

int
loopctl(int i)
{
	static int g = 0;
	switch(i){
	case -1:
		g = 0;
		return g;
	case 0:
		return g;
	case 1:
		g = 1;
		return g;
	default :
		return 0;
	}
}

int 
cleanbreak(void *, char *n) /* Note handler */
{
	if(strcmp(n,"interrupt") != 0)
		return 0;
	print("Note received: %s\n",n);
	loopctl(-1);
	return 1;
}

/* test code loop read should fork off */
void
loop(tcg *g)
{
	int pid, rl;
	char *buf;
	char reply[32];
	buf = mkheader(g->addr, "0", "MV", "00");

	/*buf = mkold(g->addr, "M");*/

	print("mkheader: %s\n", buf);
	print("checksum: %d\n", buf[8]);

	/*-=WIP=-*/
	loopctl(1);

	pid = rfork(RFPROC|RFMEM);

	if (pid < 0)
		exits("%r");

	else if (pid == 0) {
		while(loopctl(0)){
			rl = readmsg(g, reply, 13);
			if(rl == 13) print("%s\n",reply);
			memset(reply, 0, 32);
		}
		exits("%r");
	}

	else
		while(loopctl(0)){
			sendmsg(g, buf);
			sleep(1000);
		}
}

void
main(int argc, char *argv[])
{
	if(argc < 2){
		print("missing serial port.\n ");
		exits("missing argument");
	}
	
	int atn;
	thct *t = newtc(argv[1]);
	tcg *g;

	atn = atnotify((*cleanbreak), 2);

	g = newtcg(t, "001", "chamber");
	print("gauge addr: %s, name: %s\n", g->addr, g->name);

	contc(t);
	loop(g);

	closetc(t);
	freetc(t);

	print("Done.\n");

	exits(nil);
}