// https://wokwi.com/projects/404496189354172417
// State Change detection with verbose serial output

/*
  State change detection (edge detection)

  Often, you don't need to know the state of a digital input all the time, but
  you just need to know when the input changes from one state to another.
  For example, you want to know when a button goes from OFF to ON. This is called
  state change detection, or edge detection.

  This example shows how to detect when a button or button changes from off to on
  and on to off.

  The circuit:
  - pushbutton attached to pin 2 and Ground
  - LED attached from pin 13 to ground through 220 ohm resistor (or use the
    built-in LED on most Arduino boards)

  created  27 Sep 2005
  modified 30 Aug 2011
  by Tom Igoe

  This example code is in the public domain.

  https://docs.arduino.cc/built-in-examples/digital/StateChangeDetection/
*/

// this constant won't change:
const int buttonPin = 2;  // the pin that the pushbutton is attached to
const int ledPin = 13;    // the pin that the LED is attached to

// Variables will change:
int buttonPushCounter = 0;  // counter for the number of button presses
int buttonState = 0;        // current state of the button
int lastButtonState = 0;    // previous state of the button

void setup() {
  // initialize the button pin as a input:
  pinMode(buttonPin, INPUT_PULLUP);
  // initialize the LED as an output:
  pinMode(ledPin, OUTPUT);
  // initialize serial communication:
  Serial.begin(115200);
}


void loop() {
  // read the pushbutton input pin:
  buttonState = digitalRead(buttonPin);
  uint32_t currentMillis = millis();
  static uint32_t lastChangeMs = 0;
  bool changed = false,rose=false, fell = false;

  // compare the buttonState to its previous state
  if (buttonState != lastButtonState && currentMillis - lastChangeMs > 5 ) { // changed?
    changed = true;
    // if the state has changed, increment the counter
    if (buttonState == LOW) { // fell?
      fell = true;
      // if the current state is LOW then the button went from off to on:
      buttonPushCounter++;
      Serial.print("b#");
      Serial.print(buttonPushCounter);
      Serial.print(":");
    } else { // RISE

      rose = true;
      // if the current state is HIGH then the button went from on to off:
      Serial.print("B");
    }
    // record last change and time to limit bouncing
    lastButtonState = buttonState;
    lastChangeMs = currentMillis;
  }

  // turns on the LED every four button pushes by checking the modulo of the
  // button push counter. the modulo function gives you the remainder of the
  // division of two numbers:
  if (fell) {
    if (buttonPushCounter % 4 == 0) {
      digitalWrite(ledPin, HIGH);
      Serial.print("\nLedOn");
    } else {
      digitalWrite(ledPin, LOW);
      Serial.print("LedOff, ");
    }
  }
  report();
  // save the current state as the last state, for next time through the loop
  // lastButtonState = buttonState;
}


void report(void) {
  const unsigned interval = 500;
  static uint32_t lastReport = 0;
  static int lastState = -1;
  uint32_t now = millis();
  if (now - lastReport > interval) {
    lastReport = now;
    Serial.print("");
  }

}