#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <errno.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <pwd.h>
#include <grp.h>
#include <time.h>
#include <unistd.h>
#include <dirent.h>
#include <locale.h>
#include <langinfo.h>

static long unsigned int total_size;

int sum(const char *fpath, const struct stat *sb, int typeflag) {
	total_size += sb->st_size;
	return 0;
}

void print_perms(mode_t perms) {
	printf( (perms & S_IRUSR) ? "r" : "-" );
	printf( (perms & S_IWUSR) ? "w" : "-" );
	printf( (perms & S_IXUSR) ? "x" : "-" );
	printf( (perms & S_IRGRP) ? "r" : "-" );
	printf( (perms & S_IWGRP) ? "w" : "-" );
	printf( (perms & S_IXGRP) ? "x" : "-" );
	printf( (perms & S_IROTH) ? "r" : "-" );
	printf( (perms & S_IWOTH) ? "w" : "-" );
	printf( (perms & S_IXOTH) ? "x" : "-" );
}

int main(int argc, char *argv[])
{
	total_size = 0;

	char *dirname = "./";
	if(argc > 1) dirname = argv[1];

	DIR *dp = opendir(dirname);

	struct dirent *dirp;
	struct group *grp;
	struct passwd *pwd;
	struct tm *tm;
	struct stat statbuf;
	
	char datestring[256];

	while((dirp = readdir(dp)) != NULL) {
		if(!strcmp(dirp->d_name, ".") || !strcmp(dirp->d_name, "..")) continue;

		stat(dirp->d_name, &statbuf);

		printf(S_ISDIR(statbuf.st_mode) ? "d" : "-");

		print_perms(statbuf.st_mode);

		printf(" %4d", (int)statbuf.st_nlink);

		if( (pwd = getpwuid(statbuf.st_uid)) != NULL)
			printf(" %-8.8s", pwd->pw_name);
		else printf(" %-8d", statbuf.st_uid);

		if( (grp = getgrgid(statbuf.st_gid)) != NULL)
			printf(" %-8.8s", grp->gr_name);
		else printf(" %-8d", statbuf.st_gid);

		if(S_ISDIR(statbuf.st_mode)) {
			ftw(dirp->d_name, &sum, 1);
			printf(" %9jd", (intmax_t)total_size);
		}
		else printf(" %9jd", (intmax_t)statbuf.st_size);

		tm = localtime(&statbuf.st_mtime);
		strftime(datestring, sizeof(datestring), nl_langinfo(D_T_FMT), tm);
		printf(" %s %s\n", datestring, dirp->d_name);
	}

	return 1;
}