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

#include "apl9.h"

Symtab *globalsymtab;
DfnFrame *currentdfn;

Symtab *newsymtab(void);
void freesymtab(Symtab *);

Symbol *
getsym(Rune *name, int fresh)
{
	DfnFrame *dfn = currentdfn;
	Symtab *tab;
	int done = 0;
	do{
		if(dfn != nil)
			tab = dfn->symtab;
		else
			tab = globalsymtab;

		for(int i = 0; i < tab->nsyms; i++)
			if(runestrcmp(tab->syms[i]->name, name) == 0)
				return tab->syms[i];
		if(dfn)
			dfn = dfn->prev;
		else
			done = 1;
	}while(!done && !fresh);

	tab->nsyms++;
	tab->syms = realloc(tab->syms, sizeof(Symbol *) * tab->nsyms);
	tab->syms[tab->nsyms-1] = emalloc(sizeof(Symbol));
	tab->syms[tab->nsyms-1]->name = runestrdup(name);
	tab->syms[tab->nsyms-1]->undefined = 1;
	tab->syms[tab->nsyms-1]->getfn = nil;
	tab->syms[tab->nsyms-1]->setfn = nil;
	return tab->syms[tab->nsyms-1];
}

Symtab *
newsymtab(void)
{
	Symtab *tab = emalloc(sizeof(Symtab));
	tab->nsyms = 0;
	tab->syms = nil;
	tab->io = globalIO();
	tab->div = globalDIV();

	return tab;
}

void
freesymtab(Symtab *tab)
{
	int i;
	for(i = 0; i < tab->nsyms; i++){
		Symbol *s = tab->syms[i];
		if(s->undefined == 0 && s->value.tag == ArrayTag)
			freearray(s->value.array);
	}
	free(tab->syms);
	free(tab);
}

void
initsymtab(void)
{
	globalsymtab = newsymtab();
}

DfnFrame *
getcurrentdfn(void)
{
	return currentdfn;
}

DfnFrame *
pushdfnframe(Rune *code)
{
	DfnFrame *new = malloc(sizeof(DfnFrame));
	new->code = code;
	new->symtab = newsymtab();
	new->prev = currentdfn;
	currentdfn = new;
	return new;
}

void
popdfnframe(void)
{
	if(currentdfn != nil){
		DfnFrame *prev = currentdfn->prev;
		freesymtab(currentdfn->symtab);
		free(currentdfn);
		currentdfn = prev;
	}
}

vlong
globalIO(void)
{
	if(currentdfn)
		return currentdfn->symtab->io;
	else if(globalsymtab)
		return globalsymtab->io;
	else
		return 1;
}

void
globalIOset(vlong io)
{
	if(currentdfn)
		currentdfn->symtab->io = io;
	else
		globalsymtab->io = io;
}

int
globalDIV(void)
{
	if(currentdfn)
		return currentdfn->symtab->div;
	else if(globalsymtab)
		return globalsymtab->div;
	else
		return 0;
}

void
globalDIVset(int div)
{
	if(currentdfn)
		currentdfn->symtab->div = div;
	else
		globalsymtab->div = div;
}