#include <iostream>
#include <dirent.h>
#include <string>
#include <cstring>
#include <list>
#include <algorithm>

int rec_dir(const char *dirfirst, std::string viewstr)
{
    DIR *dir;
    struct dirent *entry;

    dir = opendir(dirfirst);
    if (!dir)
    {
        perror("diropen");
        exit(1);
    }

    std::list<std::string> *files = new std::list<std::string>;
    std::list<std::string> *dirs = new std::list<std::string>;
    std::list<std::string>::iterator iter;
    std::string *str1 = new std::string;
    std::string *str2 = new std::string;
    while ((entry = readdir(dir)) != NULL)
    {
        *str2 = entry->d_name;
        std::transform(str2->begin(), str2->end(), str2->begin(), [](unsigned char c){return std::tolower(c);});
        if (entry->d_type == DT_DIR)
        {
            iter = dirs->begin();
            do
            {
                if (dirs->empty())
                {
                    dirs->push_back(entry->d_name);
                    break;
                }
                if (entry->d_name < *iter)
                {
                    dirs->insert(iter, entry->d_name);
                    break;
                }
                iter++;
                if (iter == dirs->end()) dirs->push_back(entry->d_name);
            } while (iter != dirs->end());
        }
        else
        {
            iter = files->begin();
            do
            {
                if (files->empty())
                {
                    files->push_back(entry->d_name);
                    break;
                }
                *str1 = *iter;
                std::transform(str1->begin(), str1->end(), str1->begin(), [](unsigned char c){return std::tolower(c);});
                if (*str1 > *str2)
                {
                    files->insert(iter, entry->d_name);
                    break;
                }
                iter++;
                if (iter == files->end()) files->push_back(entry->d_name);
            } while (iter != files->end());
        }
    }

    std::list<std::string>::iterator iter1;
    iter = dirs->begin();
    iter++;
    iter++;
    std::string *dirnext = new std::string;

    while (iter != dirs->end())
    {
        iter1 = iter;
        if (++iter1 == dirs->end() && files->empty()) viewstr.replace(viewstr.length()-9, 3, "┗");
        std::cout << viewstr << " " << *iter << '\n';
        viewstr.replace(viewstr.length()-9, 3, "┣");
        *dirnext = dirfirst;
        *dirnext += "/";
        *dirnext += *iter;
        rec_dir(dirnext->c_str(), "┃   " + viewstr);
        iter++;
    }
    viewstr.replace(viewstr.length()-9, 3, "┣");
    iter = files->begin();
    while (iter != files->end())
    {
        iter1 = iter;
        if (++iter1 == files->end()) viewstr.replace(viewstr.length()-9, 3, "┗");
        std::cout << viewstr<< " " << *iter << '\n';
        iter++;
    }
    delete dirnext;
    delete str1;
    delete str2;
    delete dirs;
    delete files;
    closedir(dir);
}

int main(int argc, char *argv[])
{
    if (argc > 1) rec_dir(argv[1], "┣━━");
    else
    {
        std::string path = argv[0];
        int i = path.rfind("/");
        rec_dir(path.substr(0, i).c_str(), "┣━━");
    }
    return(0);
}