// ------ Universal FSM Template ----------

enum State {
  STATE_IDLE,
  STATE_ACTION,
  STATE_RESULT,
  STATE_ERROR
};

State currentState = STATE_IDLE; // enum var and assigned val to it
unsigned long stateEntryTime = 0;

// -- This Switch Case is the one time action when entering the new state --
void enterState(State newState){
  
  currentState = newState; // assigning the new state to the old var
  stateEntryTime = millis(); // starting the timer (can be used to timeout from a screen going back)

  switch(newState)
  {
    case STATE_IDLE:
      // One time action when entering IDLE
      break;
    case STATE_ACTION:
      // One time action when entering ACTION
      break;
    case STATE_RESULT:
      // One time action when entering RESULT
      break;
    case STATE_ERROR:
      // One time action when entering ERROR
      break;
  }
}

// -- This Switch case handles transistion logic and the running logic --
void fsmUpdate()
{
  unsigned long now = millis();

  switch (currentState)
  {
    case STATE_IDLE:
      //check cond for transistion
      // if(button pressed) -> enterState(STATE_ACTION);
      break;

    case STATE_ACTION:
      // Monitor ongoing stuff
      // if(timeout) -> enterState(STATE_RESULT)
      // if(error) -> enterState(STATE_ERROR)
      break;
    
    case STATE_RESULT:
      // stay here for some time or until reset
      // if (now - stateEntryTime > 3000) -> enterState(IDLE)
      break; 

    case STATE_ERROR:
      // Recover or reset
      // if (reset_cond) -> enterState(IDLE)
      break;
  }
}


void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  enterState(STATE_IDLE); // starting here 
}

void loop() {
  fsmUpdate();  //always running 

}