/* Copyright (c) 2019, Anthony Latorre <tlatorre at uchicago>
 *
 * 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 <https://www.gnu.org/licenses/>.
 */

#include "util.h"
#include <unistd.h> /* for access() */
#include <stdlib.h> /* for getenv() */
#include <stdio.h> /* for sprintf(), fopen() */

/* Equivalent to fopen() but uses find_file() to find the path to the filename. */
FILE *open_file(const char *filename, const char *mode)
{
    char *path;

    path = find_file(filename);

    if (!path) return NULL;

    return fopen(path,mode);
}

/* Returns the full path to `filename` by searching the current working
 * directory and the path specified by the environment variables SDDM_DATA and
 * DQXX_DIR.
 *
 * Returns a pointer to the full path on success or NULL if the file isn't
 * found. */
char *find_file(const char *filename)
{
    static char path[256];
    char *dir;

    /* First check in the current working directory. */
    sprintf(path, "%s", filename);
    if (access(path, F_OK) == 0) return path;

    /* Now check in the directory specified by the environment variable
     * SDDM_DATA. */
    dir = getenv("SDDM_DATA");
    if (dir) {
        sprintf(path, "%s/%s", dir,filename);
        if (access(path, F_OK) == 0) return path;
    }

    /* Now check in the directory specified by the environment variable
     * DQXX_DIR. */
    dir = getenv("DQXX_DIR");
    if (dir) {
        sprintf(path, "%s/%s", dir,filename);
        if (access(path, F_OK) == 0) return path;
    }

    return NULL;
}