/*
input.c

Copyright © 2010 William Astle

This file is part of LWTOOLS.

LWTOOLS is free software: you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation, either version 3 of the License, or (at your option) any later
version.

This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
more details.

You should have received a copy of the GNU General Public License along with
this program. If not, see <http://www.gnu.org/licenses/>.
*/

#include <config.h>

/*
This file is used to handle reading input files. It serves to encapsulate
the entire input system to make porting to different media and systems
less difficult.
*/

#include <lw_alloc.h>
#include <lw_stringlist.h>

struct input_layer
{
	lw_stringlist_t inputlist;
	struct input_layer *nextlayer;
	
	FILE *fp;
};


static struct input_layer *layerstack = NULL;

void input_push(lw_stringlist_t list)
{
	struct input_layer *i;
	
	i = lw_alloc(sizeof(struct input_layer));
	i -> nextlayer = layerstack;
	layerstack = i;
	i -> inputlist = lw_stringlist_copy(list);
}

/* fetch a line of input from the top of the input stack */
/* return NULL if no input left */
char *input_fetchline(void)
{
again:
	if (!layerstack)
		return NULL;
	
	if (!layerstack -> fp)
	{
		// no open file
		char *fn;
		
		fn = lw_stringlist_current(layerstack -> inputlist);
		lw_stringlist_next(layerstack -> inputlist);
		if (!fn)
		{
			struct input_list *t;
			t = layerstack;
			layerstack = layerstack -> nextlayer;
			lw_stringlist_destroy(t -> inputlist);
			lw_free(t);
			goto again;
		}
		
		// open the file here
	}
	
	
}