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

unsigned int a_flag;
unsigned int l_flag;

void PrintPerm(struct stat sb) {
	printf("%c", (S_ISDIR(sb.st_mode)) ? 'd' : '-');
	printf("%c%c%c", (sb.st_mode & S_IRUSR) ? 'r' : '-', (sb.st_mode & S_IWUSR) ? 'w' : '-', (sb.st_mode & S_IXUSR) ? 'x' : '-');
	printf("%c%c%c", (sb.st_mode & S_IRGRP) ? 'r' : '-', (sb.st_mode & S_IWGRP) ? 'w' : '-', (sb.st_mode & S_IXGRP) ? 'x' : '-');
	printf("%c%c%c", (sb.st_mode & S_IROTH) ? 'r' : '-', (sb.st_mode & S_IWOTH) ? 'w' : '-', (sb.st_mode & S_IXOTH) ? 'x' : '-');
}

int list(const char *path, int label) {
	struct stat sb;
	if (stat(path, &sb)) {
		fprintf(stderr, "ls: unable to stat %s: %s\n", path, strerror(errno));
		return 1;
	}

	/* If its file */
	if (!S_ISDIR(sb.st_mode)) {
		puts(path);
		return 0;
	}

	/* Make label */
	if (label)
		printf("\n%s: \n", path);

	if (chdir(path)) {
		fprintf(stderr, "ls: %s: %s\n", path, strerror(errno));
		return 1;
	}

	/* Open and print dir */
	DIR *dp = opendir(".");
	if (dp == NULL)
		return 1;

	struct dirent *ep;
	while ((ep = readdir(dp)) != NULL) {
		if (ep->d_name[0] == '.' && !a_flag)
			continue;

		if (l_flag) {
			if (lstat(ep->d_name, &sb) == -1) {
				fprintf(stderr, "ls: lstat()\n");
				return 1;
			}

			/* Permissions */
			PrintPerm(sb);

			/* Date */
			struct tm *tm = localtime(&sb.st_mtime);

			char date[14];
			if (strftime(date, sizeof(date), "%b %d %H:%M", tm) == 0) {
				fprintf(stderr, "ls: strftime()\n");
				return 1;
			}

			/* Group and user name */
			struct passwd *pw = getpwuid(sb.st_uid);
			struct group *gr = getgrgid(sb.st_gid);

			printf("  %s  %s  %jd  %s  %s\n", (pw != 0) ? pw->pw_name : "nobody", (gr != 0) ? gr->gr_name : "nobody", (uintmax_t)sb.st_size, date, ep->d_name);
		}

		else
			printf("%s ", ep->d_name);
	}

	closedir(dp);
	printf("\n");
	return 0;
}



int main(const int argc, const char **argv) {
	int i;
	for (i = 1; i < argc; i++) {
		if (argv[i][0] != '-')
			break;

		else if (!strcmp(argv[i], "-a"))
			a_flag = 1;

		else if (!strcmp(argv[i], "-l"))
			l_flag = 1;

		else if (!strcmp(argv[i], "-h")) {
			printf("ls [-a (Show hidden files)] [-l (use a long listing format (month / day / hour:min))] [Path]\n");
			return 0;
		}
	}

	if (i == argc)
		return list(".", 0);

	if (i == argc - 1)
		return list(argv[i], 0);

	else
		for (int i = 1; i < argc; i++)
			if (list(argv[i], 1))
				return 1;

	return 0;
}