#include <stdlib.h>
#include <dirent.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdint.h>
#include <inttypes.h>
#include <string.h>

enum
{
    DIR_SIZE = 20
};

int
cmp(const void *a, const void *b)
{
    return strcasecmp(*(const char **)a, *(const char **)b);
}

char *
name(char *path) {
    int len = strlen(path);

    int ind;
    for (ind = len - 1; ind >= 0; --ind) {
        if (path[ind] == '/') {
            return path + ind + 1;
        }
    }

    return path;
}

void
check_dir(char *dir_path)
{
    DIR *dir = opendir(dir_path);

    if (dir == NULL) {
        return;
    }

    printf("cd %s\n", name(dir_path));

    char files[DIR_SIZE][PATH_MAX];
    int size = 0;

    struct dirent *dirent;
    while ((dirent = readdir(dir)) != NULL) {
        struct stat st;

        if (!strcmp(dirent->d_name, "..") ||
                !strcmp(dirent->d_name, ".")) {
            continue;
        }

        char name[PATH_MAX];
        snprintf(name, sizeof(name), "%s/%s", dir_path, dirent->d_name);
        stat(name, &st);

        if (S_ISDIR(st.st_mode)) {
            strcpy(files[size], name);
            ++size;
        }
    }

    for (int i = 0; i < size; ++i)
        printf("%s\n", files[i]);

    qsort(files, size, sizeof(char[PATH_MAX]), cmp);

    for (int i = 0; i < size; ++i) {
        check_dir(files[i]);
    }

    printf("cd ..\n");
}

int
main(int argc, char *argv[])
{
    check_dir(argv[1]);
    return 0;
}