#pragma once
#include <iterator>

#include <LittleFS.h>

struct filename_iterator: public std::iterator<std::input_iterator_tag, const char*> {
  public:
    filename_iterator();
    filename_iterator(const char* path, const char* suffix);
    void next();
    filename_iterator& operator++();
    filename_iterator& operator++(int) {filename_iterator ret = *this; ++(*this); return ret;}
    bool operator==(const filename_iterator &other) const { return valid == other.valid;}
    bool operator!=(const filename_iterator &other) const { return !(*this == other); }
    const char* operator*() const {
      if (!valid) {
        return NULL;
      }
      return ret.c_str();
    }

  private:
    String ret;
    bool valid;
    const char* suffix;

#ifdef ESP8266
    Dir dir;
#endif
#ifdef ESP32
    File dir;
#endif
};