enum
{
  STATE_IDLE_INIT,
  STATE_IDLE,
  STATE_CURRENT_DETECTED,
  STATE_ON_WAIT_12_SECONDS,
  STATE_HIGH,
} state;

const int sensorPin = 2;
int currentReading = HIGH;   // pin 2 is HIGH when button is not pressed
unsigned long previousMillis;


void setup()
{
  Serial.begin( 9600);
  Serial.println( "The sketch has started.");
  pinMode( sensorPin, INPUT_PULLUP);
}


void loop()
{
  unsigned long currentMillis = millis();
  
  
  // ---------------------------------------------------
  // BUTTON
  // ---------------------------------------------------
  // Detect if the button changes, and pass
  // that information on, to the finite state machine.
  // Only the event of the change is passed on, because
  // this sketch did not need to know the state
  // of the button, only a change.
  // ---------------------------------------------------
  bool currenHigh = false;
  bool currentLow = false;

  bool readSensor(){
    //code to read from ADC pin and calculate RMS voltage and current
    //return high or low
  }

  int boilerState = readSensor();

    if( boilerState == LOW)  // low is button pressed
    {
      currenHigh = true;
    }
    else
    {
      currentLow = true;
    }
 
  
  

  // ---------------------------------------------------
  // STATE MACHINE
  // ---------------------------------------------------
  
  switch( state)
  {
    case STATE_IDLE_INIT:
      // Before going to the actual "idle" state, a message is printed.
      Serial.println( "Send State Low to DB");
      state = STATE_IDLE;
      break;
    case STATE_IDLE:
      // This "idle" state is when there is nothing to do.
      // This state is executed until a button is pressed.
      // It "waits" until a button is pressed, but it does
      // not really wait, since it is run over and over again.
      Serial.println("State: IDLE");
      if( currenHigh)
      {
        state = STATE_CURRENT_DETECTED;
              
      Serial.println( "Waiting 12s");
      }
      break;
    case STATE_CURRENT_DETECTED:
        Serial.println("State: STATE_CURRENT_DETECTED");
        previousMillis = currentMillis;
        state = STATE_ON_WAIT_12_SECONDS;
      break;
    case STATE_ON_WAIT_12_SECONDS:
      Serial.println("State: STATE_ON_WAIT_12_SECONDS");
      if( currentLow && currentMillis - previousMillisButton <= 12000)
      {
        state = STATE_IDLE;
      }
      else
      {
        if( currenHigh && currentMillis - previousMillisButton >= 12000)
        {
          state = STATE_HIGH;
          Serial.println(String(currentMillis - previousMillis));
          Serial.println("send HIGH state to DB");
        }
      }
      break;
    case STATE_HIGH:
    Serial.println("State: HIGH");
      if( currentLow){
        Serial.println(String(currentMillis - previousMillis -12000));
          Serial.println("send LOW state and time to DB");
          state = STATE_IDLE;
      }
   break;
  }
  
  
  // ---------------------------------------------------
  // BLINK WITHOUT DELAY
  // ---------------------------------------------------
  // Blinking the led is outside the final state machine.
  // The final state machine can turn the blinking on and off.
  // ---------------------------------------------------

  
}