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

#include <paper.h>

typedef struct Offtab Offtab;
struct Offtab
{
	char	*member;
	uintptr	offset;
};

Offtab tmofftab[] = {
	{"hour", offsetof(Tm, hour)},
	{"mday", offsetof(Tm, mday)},
	{"min", offsetof(Tm, min)},
	{"mon", offsetof(Tm, mon)},
	{"sec", offsetof(Tm, sec)},
	{"wday", offsetof(Tm, wday)},
	{"yday", offsetof(Tm, yday)},
	{"year", offsetof(Tm, year)},
};

#define OFFNIL ((uintptr)-1ULL)

uintptr
offsearch(Offtab *tab, int nel, char *member)
{
	int lo, mid, hi, rv;

	lo = 0;
	hi = nel;

	while(lo <= hi){
		mid = (lo + hi) / 2;
		rv = strcmp(tab[mid].member, member);
		if(rv > 0)
			hi = mid - 1;
		else if(rv < 0)
			lo = mid + 1;
		else
			return tab[mid].offset;
	}

	return OFFNIL;
}

void
pptime(Node *r, Node **av, int na)
{
	long *t;

	USED(av);
	USED(na);

	r->op = OCONST;
	r->store.type = TINT;
	r->store.ival = time(nil);
}

void
timegetset(Node *v, char *nam, Node *res, int *val)
{
	int *iptr;
	Tm *t;
	uintptr off;

	assert(v != nil);
	assert(nam != nil);
	assert(res != nil);

	t = v->store.pval->v;

	off = offsearch(tmofftab, nelem(tmofftab), nam);
	if(off == OFFNIL)
		pperror("unknown member %q", nam);

	iptr = (int*)((char*)t + off);

	/* set */
	if(val != nil)
		*iptr = *val;

	res->op = OCONST;
	res->store.type = TINT;
	res->store.ival = *iptr;
}

void
timeindex(Node *v, char *nam, Node *res)
{
	timegetset(v, nam, res, nil);
}

void
timenewindex(Node *v, char *nam, Node *res)
{
	int val;

	if(res->store.type != TINT)
		pperror("expected int in assignment");

	val = res->store.ival;

	timegetset(v, nam, res, &val);
}

void
timegc(Pointer *p)
{
	USED(p);
}

static Metatable timetable = {
.index		= timeindex,
.newindex	= timenewindex,
.gc			= timegc,
};

void
pplocaltime(Node *r, Node **av, int na)
{
	Node res;
	Tm *t;

	if(na != 1)
		pperror("localtime(long clock): expected argument");

	ppexpr(av[0], &res);
	if(res.store.type != TINT)
		pperror("localtime(long clock): expected TINT)");

	t = localtime((long)res.store.ival);

	r->op = OCONST;
	r->store.type = TPOINTER;
	r->store.pval = pppointernode(t, &timetable);
}

void
usage(void)
{
	fprint(2, "usage: %s\n", argv0);
	exits("usage");
}

void
main(int argc, char *argv[])
{
	ARGBEGIN{
	default:
		usage();
	}ARGEND

	ppsetup();

	ppbind("time", pptime);
	ppbind("localtime", pplocaltime);

	/*
	char ppcode[] = "\
loop 0, 10 do { \
	t0 = time(); \
	tm = localtime(t0); \
	print(tm.hour, \":\", tm.min, \":\", itoa(tm.sec, \"%.02d\"), \"\\n\"); \
}";

	ppcall("interpret", as(ppcode));
	ppcall("interpret", as("t0=time(); tm=localtime(t0); print(tm.sec, \"\\n\");"));

	for(i = 0; i < 100; i++){
		ppcall("interpret", as("assert(localtime(time()).sec >= 0);"));
	}
	*/

	ppcall("interpret", ppstring("defn checktime(t){ assert(tm.hour == 6); assert(tm.min == 6); assert(tm.sec == 6); };"), nil);
	ppcall("interpret", ppstring("tm = localtime(time()); tm.hour = 6; tm.min = 6; tm.sec = 6; checktime(tm); tm = {};"), nil);

	exits(nil);
}