#define LED_PIN 21
#define BUTTON_PIN 33


int ledState = HIGH;    // make sure to initialise this in setup
int buttonState = LOW;  // button is wired : released -> LOW


void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");

  pinMode(LED_PIN, OUTPUT);  
  pinMode(BUTTON_PIN, INPUT);

  // turn on the LED to match the state var initialisation
  digitalWrite(LED_PIN, HIGH);

}


// we want to identify a new button press, 
// then when we press the button we want to toggle the button
// so we need function toggle make it HIGH if it is LOW and 
// make it LOW if it is currently HIGH
void toggleLEDState() {
  if (ledState == HIGH) {
    ledState = LOW;
  } else {
    ledState = HIGH;
  }
}

void loop() {
  // we also need to detect a button press when we press or 
  // release the button, so when the buttonState changes
  // we do not want to poll the switch and constantly toggle
  // the LED while the button is high
  
  // read in the current button state
  int newButtonState = digitalRead(BUTTON_PIN);

  // now check to see whether this newButtonState is different
  if (newButtonState != buttonState) {
    // enter this loop only if the button state has changed
    Serial.println("---");
    Serial.println("button state changed");
    
    Serial.print("old state: ");
    Serial.println(buttonState);
    
    // update the buttonState variable (our memory)
    buttonState = newButtonState;
    Serial.print("new state: ");
    Serial.println(buttonState);
    // now toggle the LED only if the button was pressed
    // this can be translated to if the button is now HIGH
    if (buttonState == HIGH) {
      Serial.print("take action code block: ledState ");
      Serial.print(ledState);
      toggleLEDState();  
      Serial.print(" -> ");
      Serial.println(ledState);
    }

  }
  
  // write the state to the LED
  digitalWrite(LED_PIN, ledState);

  delay(10);

}