debouncer.h

#pragma once
 
#ifndef _EMAKEFUN_DEBOUNCER_H_
#define _EMAKEFUN_DEBOUNCER_H_
 
#include <Arduino.h>
#include <stdint.h>
 
namespace emakefun {
template <typename T>
class Debouncer {
 public:
  static constexpr uint64_t kDefaultDebounceDurationMs = 20;
 
  Debouncer(const T& value, uint64_t debounce_duration_ms = kDefaultDebounceDurationMs)
      : debouncing_value_(value), last_value_(value), debounce_duration_ms_(debounce_duration_ms) {
  }
 
  const T& Debounce(const T& value) {
    if (start_debounce_time_ == UINT64_MAX || value != debouncing_value_) {
      debouncing_value_ = value;
      start_debounce_time_ = millis();
    } else if (last_value_ != debouncing_value_ && millis() - start_debounce_time_ >= debounce_duration_ms_) {
      last_value_ = debouncing_value_;
    }
 
    return last_value_;
  }
 
  inline const T& operator()(const T& value) {
    return Debounce(value);
  }
 
  inline const T& operator=(const T& value) {
    return Debounce(value);
  }
 
  inline const T& operator()() const {
    return last_value_;
  }
 
 private:
  T debouncing_value_;
  T last_value_;
  const uint64_t debounce_duration_ms_ = kDefaultDebounceDurationMs;
  uint64_t start_debounce_time_ = UINT64_MAX;
};
}  // namespace emakefun
 
#endif