// const int SWT1 = 22;        // the number of the pushbutton pin
// const int SWT2 = 24;
// const int SWT3 = 26;
// const int SWT4 = 28;
// const int SWT5 = 30;
// const int SWT6 = 32;
// const int SWT7 = 34;
// const int SWT8 = 36;
// const int SWT9 = 38;
// const int SWT10 = 40;
// const int SWT11 = 42;
// const int SWT12 = 44;
// const int SWT13 = 46;
// const int SWT14 = 48;
// const int SWT15 = 50;
// const int SWT16 = 52;

// const int LED1 = 23;
// const int LED2 = 25;
// const int LED3 = 27;
// const int LED4 = 29;
// const int LED5 = 31;
// const int LED6 = 33;
// const int LED7 = 35;
// const int LED8 = 37;
// const int LED9 = 39;
// const int LED10 = 41;
// const int LED11 = 43;
// const int LED12 = 45;
// const int LED13 = 47;
// const int LED14 = 49;
// const int LED15 = 51;
// const int LED16 = 53;

// int start;
// int lastMillis;

// void setup() {
//   // initialize serial communication at 9600 bits per second:
//   Serial.begin(9600);
//   pinMode(SWT1, INPUT_PULLUP);
//   pinMode(SWT2, INPUT_PULLUP);
//   pinMode(SWT3, INPUT_PULLUP);
//   pinMode(SWT4, INPUT_PULLUP);
//   pinMode(SWT5, INPUT_PULLUP);
//   pinMode(SWT6, INPUT_PULLUP);
//   pinMode(SWT7, INPUT_PULLUP);
//   pinMode(SWT8, INPUT_PULLUP);
//   pinMode(SWT9, INPUT_PULLUP);
//   pinMode(SWT10, INPUT_PULLUP);
//   pinMode(SWT11, INPUT_PULLUP);
//   pinMode(SWT12, INPUT_PULLUP);
//   pinMode(SWT13, INPUT_PULLUP);
//   pinMode(SWT14, INPUT_PULLUP);
//   pinMode(SWT15, INPUT_PULLUP);
//   pinMode(SWT16, INPUT_PULLUP);

//   pinMode(LED1, OUTPUT);
//   pinMode(LED2, OUTPUT);
//   pinMode(LED3, OUTPUT);
//   pinMode(LED4, OUTPUT);
//   pinMode(LED5, OUTPUT);
//   pinMode(LED6, OUTPUT);
//   pinMode(LED7, OUTPUT);
//   pinMode(LED8, OUTPUT);
//   pinMode(LED9, OUTPUT);
//   pinMode(LED10, OUTPUT);
//   pinMode(LED11, OUTPUT);
//   pinMode(LED12, OUTPUT);
//   pinMode(LED13, OUTPUT);
//   pinMode(LED14, OUTPUT);
//   pinMode(LED15, OUTPUT);
//   pinMode(LED16, OUTPUT);
// }

// void loop() {

//   if (!digitalRead(SWT1))
//   {
//     if (start == false)  // do we want to start the LED on/off cycle?
//     {
//       lastMillis = millis();      // initialize the timing
//       digitalWrite(LED1, HIGH);  // turn LED on
//       start = true;              // this prevents reinitializing lastMillis
//     }
//   }
//     if ( millis() - lastMillis >= 20UL)  // if we in in checking mode, has the time expired?
//     {
//       digitalWrite(LED1, LOW);  // turn led off
//       start = false;
//        while(!digitalRead(SWT1)){}
//        delay(1);              // For debouncing
//     }


//   if (!digitalRead(SWT2))
//   {
//     if (start == false)  // do we want to start the LED on/off cycle?
//     {
//       lastMillis = millis();      // initialize the timing
//       digitalWrite(LED2, HIGH);  // turn LED on
//       start = true;              // this prevents reinitializing lastMillis
//     }
//   }
//     if ( millis() - lastMillis >= 20UL)  // if we in in checking mode, has the time expired?
//     {
//       digitalWrite(LED2, LOW);  // turn led off
//       start = false;
//        while(!digitalRead(SWT2)){}
//        delay(1);              // For debouncing
//     }


//   if (!digitalRead(SWT3))
//   {
//     if (start == false)  // do we want to start the LED on/off cycle?
//     {
//       lastMillis = millis();      // initialize the timing
//       digitalWrite(LED3, HIGH);  // turn LED on
//       start = true;              // this prevents reinitializing lastMillis
//     }
//   }
//     if ( millis() - lastMillis >= 20UL)  // if we in in checking mode, has the time expired?
//     {
//       digitalWrite(LED3, LOW);  // turn led off
//       start = false;
//        while(!digitalRead(SWT3)){}
//        delay(1);              // For debouncing
//     }

  
//   if (!digitalRead(SWT4))
//   {
//     if (start == false)  // do we want to start the LED on/off cycle?
//     {
//       lastMillis = millis();      // initialize the timing
//       digitalWrite(LED4, HIGH);  // turn LED on
//       start = true;              // this prevents reinitializing lastMillis
//     }
//   }
//     if ( millis() - lastMillis >= 20UL)  // if we in in checking mode, has the time expired?
//     {
//       digitalWrite(LED4, LOW);  // turn led off
//       start = false;
//        while(!digitalRead(SWT4)){}
//        delay(1);              // For debouncing
//     }



//     if (!digitalRead(SWT5))
//   {
//     if (start == false)  // do we want to start the LED on/off cycle?
//     {
//       lastMillis = millis();      // initialize the timing
//       digitalWrite(LED5, HIGH);  // turn LED on
//       start = true;              // this prevents reinitializing lastMillis
//     }
//   }
//     if ( millis() - lastMillis >= 20UL)  // if we in in checking mode, has the time expired?
//     {
//       digitalWrite(LED5, LOW);  // turn led off
//       start = false;
//        while(!digitalRead(SWT5)){}
//        delay(1);              // For debouncing
//     }


//   if (!digitalRead(SWT6))
//   {
//     if (start == false)  // do we want to start the LED on/off cycle?
//     {
//       lastMillis = millis();      // initialize the timing
//       digitalWrite(LED6, HIGH);  // turn LED on
//       start = true;              // this prevents reinitializing lastMillis
//     }
//   }
//     if ( millis() - lastMillis >= 20UL)  // if we in in checking mode, has the time expired?
//     {
//       digitalWrite(LED6, LOW);  // turn led off
//       start = false;
//        while(!digitalRead(SWT6)){}
//        delay(1);              // For debouncing
//     }


//   if (!digitalRead(SWT7))
//   {
//     if (start == false)  // do we want to start the LED on/off cycle?
//     {
//       lastMillis = millis();      // initialize the timing
//       digitalWrite(LED7, HIGH);  // turn LED on
//       start = true;              // this prevents reinitializing lastMillis
//     }
//   }
//     if ( millis() - lastMillis >= 20UL)  // if we in in checking mode, has the time expired?
//     {
//       digitalWrite(LED7, LOW);  // turn led off
//       start = false;
//        while(!digitalRead(SWT7)){}
//        delay(1);              // For debouncing
//     }


//   //   if (!digitalRead(SWT8))
//   // {
//   //   if (start == false)  // do we want to start the LED on/off cycle?
//   //   {
//   //     lastMillis = millis();      // initialize the timing
//   //     digitalWrite(LED8, HIGH);  // turn LED on
//   //     start = true;              // this prevents reinitializing lastMillis
//   //   }
//   // }
//   //   if ( millis() - lastMillis >= 20UL)  // if we in in checking mode, has the time expired?
//   //   {
//   //     digitalWrite(LED8, LOW);  // turn led off
//   //     start = false;
//   //      while(!digitalRead(SWT8)){}
//   //      delay(1);              // For debouncing
//   //   }


  
// }














































//https://forum.arduino.cc/t/one-shot-without-delay/1225555
//https://europe1.discourse-cdn.com/arduino/original/4X/7/e/0/7e0ee1e51f1df32e30893550c85f0dd33244fb0e.jpeg
#define ProjectName "One Shot without DELAY"
#define NotesOnRelease "Arduino MEGA tested"
// make names
enum TimerEvent {NotExpired, Expired};
enum TimerControl {Halt, Run};
enum ButtonControl {Released, Pressed};
enum OnOff {Off, On};
// make variables
constexpr uint8_t ButtonPins[] {22, 24, 26, 28};
constexpr uint8_t LedPins[] {23, 25, 27, 29};
constexpr uint32_t FlashTimes[] {10, 20, 30, 40};
constexpr uint32_t TestLedDelay {250};
uint32_t currentMillis = millis();
// make structures
struct TIMER
{
  uint32_t interval;
  uint8_t control;
  uint32_t now;
  uint8_t expired(uint32_t currentMillis)
  {
    uint8_t timerEvent = currentMillis - now >= interval and control;
    if (timerEvent == Expired) now = currentMillis;
    return timerEvent;
  }
};
struct LEDFLASH
{
  uint8_t button;
  uint8_t stateOld;
  uint8_t led;
  TIMER   flash;
  TIMER   debounce;
  void make(uint8_t button_, uint8_t led_, uint32_t delay_)
  {
    button = button_;
    pinMode(button, INPUT_PULLUP);
    stateOld = digitalRead(button) ? LOW : HIGH;
    led = led_,
    pinMode(led, OUTPUT);
    digitalWrite(led, On);
    delay(TestLedDelay);
    digitalWrite(led, Off);
    delay(TestLedDelay);
    flash.interval = delay_;
    debounce.interval = 20;
    debounce.control = Run;
  }
  void run()
  {
    if (debounce.expired(currentMillis) == Expired)
    {
      uint8_t stateNew = digitalRead(button) ? LOW : HIGH;
      if (stateOld != stateNew)
      {
        stateOld = stateNew;
        if (stateNew == Pressed)
        {
          digitalWrite(led, On);
          flash.control = Run;
          flash.now = currentMillis;
        }
      }
    }
    if (flash.expired(currentMillis) == Expired)
    {
      digitalWrite(led, Off);
      flash.control = Halt;
    }
  }
} ledFlashs[sizeof(LedPins)];
// make support
void heartBeat(const uint8_t LedPin, uint32_t currentMillis)
{
  static bool setUp = false;
  if (setUp == false) pinMode (LedPin, OUTPUT), setUp = true;
  digitalWrite(LedPin, (currentMillis / 500) % 2);
}
// make application
void setup()
{
  Serial.begin(9600);
  Serial.print("Source: "), Serial.println(__FILE__);
  Serial.print(ProjectName), Serial.print(" - "), Serial.println(NotesOnRelease);
  uint8_t element = 0;
  for (auto &ledFlash : ledFlashs)
  {
    ledFlash.make(ButtonPins[element], LedPins[element], FlashTimes[element]);
    element++;
  }
  Serial.println(" =-> and off we go\n");
}
void loop()
{
  currentMillis = millis();
  heartBeat(LED_BUILTIN, currentMillis);
  for (auto &ledFlash : ledFlashs) ledFlash.run();
}