/*
 * Copyright (C) 2024  Tristan Riehs
 *
 * This program 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"

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

#include "disp.h"

#define dlsym_and_check(dest, name)			\
	dest->name = dlsym(dest->dl_handle, #name);	\
	if (!dest->name) {				\
		dlclose(dest->dl_handle);		\
		free(dest);				\
		return NULL;				\
	}

struct disp *
get_disp(char *disp_name)
{
#ifndef NDEBUG
	/* displays are shared libraries */
	char so_path[16] = {0};
	strcpy(so_path, "./");
	strcat(so_path, disp_name);
	strcat(so_path, ".la");
	void *handle = dlopen(so_path, RTLD_LAZY);

	if (!handle)
	{
		char *msg = dlerror();
		fprintf(stderr, "calculer: %s\n", msg);
		exit(1);
	}

	struct disp *disp = malloc(sizeof(*disp));
	disp->dl_handle = handle;
	dlsym_and_check(disp, display_calc);
	dlsym_and_check(disp, read_input);
	dlsym_and_check(disp, display_res);
	dlsym_and_check(disp, destroy);

	return disp;
#else
#  error "not available yet"
#endif
	return NULL;
}