/* -*- C -*-
 * FILE: "/home/y1zln/pub/zimg/path.c"
 * LAST MODIFICATION: "Fr, 29 Okt 2004 15:30:21 CEST (y1zln)"
 * (C) 2003 - 2004 by Johannes Zellner, <johannes@zellner.org>
 * $Id: path.c,v 1.3 2004/10/30 12:22:49 joze Exp $
 */

#ifdef HAVE_CONFIG_H
#   include "config.h"
#endif

#include "path.h"

#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <stdio.h>

#if defined HAVE_SYS_STAT_H && defined HAVE_SYS_STAT_H
#   include <sys/types.h>
#   include <sys/stat.h>
#endif


static char*
path_cat(const char* filename, const char* subdir, const char* path_prefix)
{
    char* path = (char*)malloc(strlen(path_prefix) + (subdir ? strlen(subdir) : 0) + strlen(filename) + 4);
    if (!path) {
	perror("path_cat->path");
	exit(2);
    }
    strcpy(path, path_prefix);
    strcat(path, "/");
    if (subdir) {
	strcat(path, subdir);
	strcat(path, "/");
    }
    strcat(path, filename);
    return path;
}

/* returns 0 on success */
static int access_file(char* path)
{
    int status;

    if ((status = access(path, R_OK)))
	return status;

#if defined HAVE_SYS_STAT_H && defined HAVE_SYS_STAT_H
    {
	struct stat buf;
	stat(path, &buf);
	if (S_ISDIR(buf.st_mode))
	    return 1; /* directory */
    }
#endif

    return 0; /* success, not a directory */
}

char*
search_file(const char* filename, const char* subdir, const char* path_prefix, unsigned char absolute)
{
    char* path = (char*)0;
    static char* path_home_zimg = (char*)0;
    static char* path_cwd = (char*)0;

    if (filename && '/' == filename[0]) {
	return strdup(filename);
    }

    if (!path_home_zimg) {
	char* home = getenv("HOME");
	if (home) {
	    path_home_zimg = malloc(sizeof (char) * (strlen(home) + 8));
	    strcpy(path_home_zimg, home);
	    strcat(path_home_zimg, "/.zimg");
	}
    }

    if (absolute) {
	if (!path_cwd) {
	    int i;
	    for (i = 1; i < 10; i++) {
		path_cwd = (char*)malloc(sizeof (char) * 0x100 * i);
		if (!path_cwd) {
		    perror("search_file->path_cwd");
		    exit(2);
		}
		if (getcwd(path_cwd, 0x100 * i))
		    break;
		else {
		    free(path_cwd);
		    path_cwd = (char*)0;
		}
	    }
	}
	path = path_cat(filename, (char*)0, path_cwd);
    } else {
	path = strdup(filename);
    }

    if (access_file(path)) {
	if (path_home_zimg) {
	    if (path)
		free(path);
	    /* e.g. ~/.zimg/expr/<filename> */
	    path = path_cat(filename, subdir, path_home_zimg);
	}
	if (access_file(path)) {
	    if (path)
		free(path);
	    /* e.g. /usr/local/lib/zimg-4.7.7/expr/<filename> */
	    path = path_cat(filename, subdir, path_prefix);
	    if (access_file(path)) {
		if (path)
		    free(path);
		path = (char*)0;
	    }
	}
    }
    return path;
}