/* Timer with 4 LEDs and 3 Buttons
    https://forum.arduino.cc/t/delay-issue-millis-usage/1264070

   2024-05-25 by noiasca

   to be deleted 2024-09 
   https://wokwi.com/projects/398844668015443969
*/

class Button {                                // a simple class for buttons based on the "Debounce" example
    const uint8_t buttonPin;                  // the GPIO / pin for the button
    static constexpr byte debounceDelay = 30; // the debounce time; Static because we only need one value for all buttons
    const bool active;                        // is the pin active HIGH or active LOW (will also activate the pullups!)
    bool lastButtonState = HIGH;              // the previous reading from the input pin
    uint32_t lastDebounceTime = 0;            // the last time the output pin was toggled

  public:
    /**
       \brief constructor for a button

       The constructor takes the GPIO as parameter.
       If you omit the second parameter, the class will activate the internal pullup resistor
       and the button should connect to GND.
       If you set the second parameter to HIGH, the button is active HIGH.
       The button should connect to VCC.
       The internal pullups will not be used but you will need an external pulldown resistor.

       \param buttonPin the GPIO for the button
       \param active LOW (default) - if button connects to GND, HIGH if button connects to VCC
    */
    Button(uint8_t buttonPin, bool active = LOW) : buttonPin(buttonPin), active(active) {}

    /**
       \brief set the pin to the proper state

       Call this function in your setup().
       The pinMode will be set according to your constructor.
    */
    void begin() {
      if (active == LOW)
        pinMode(buttonPin, INPUT_PULLUP);
      else
        pinMode(buttonPin, INPUT);
    }

    /**
        \brief indicate if button was pressed since last call

        @return HIGH if button was pressed since last call - debounce
    */
    bool wasPressed() {
      bool buttonState = LOW;                                        // the current reading from the input pin
      byte reading = LOW;                                            // "translated" state of button LOW = released, HIGH = pressed, despite the electrical state of the input pint
      if (digitalRead(buttonPin) == active) reading = HIGH;          // if we are using INPUT_PULLUP we are checking invers to LOW Pin
      if ((millis()  - lastDebounceTime) > debounceDelay) { // If the switch changed, AFTER any pressing or noise
        if (reading != lastButtonState && lastButtonState == LOW) {  // If there was a change and and last state was LOW (= released)
          buttonState = HIGH;
        }
        lastDebounceTime = millis();
        lastButtonState = reading;
      }
      return buttonState;
    }
};

const uint8_t ledPin[4] = {8, 9, 10, 11};        // indicator LEDs
const uint8_t interval[4] = {5, 10, 15, 20};     // interval for each LED
const uint32_t factor = 1000;                    // 60 * 1000UL for minutes
const uint8_t relayPin = 7;                      // GPIO for the output
const uint8_t buttonPin1 = 12;                   // Min Select
const uint8_t buttonPin2 = 13;	                 // Start
const uint8_t buttonPin3 = 6;                    // Stop Test

enum State {IDLE, RUNNING} state;
int8_t presses = 0;                              // counts how often the select button was pressed
uint32_t previousMillis;                         // time management

Button selectBtn{buttonPin1};
Button startBtn{buttonPin2};
Button stopBtn{buttonPin3};

// switches some indicator LEDs on:
void indicate(byte count = state) {
  for (size_t i = 0; i < sizeof(ledPin) / sizeof(ledPin[0]); i++ ) {
    if (count >= i)
      digitalWrite(ledPin[i], HIGH);
    else
      digitalWrite(ledPin[i], LOW);
  }
}

void runFSM() {
  switch (state) {
    case IDLE :
      if (selectBtn.wasPressed()) {
        presses = ++presses % (sizeof(ledPin) / sizeof(ledPin[0]));
        indicate(presses);
        Serial.println(presses);
      }
      if (startBtn.wasPressed()) {
        Serial.print("start for "); Serial.print(interval[presses] * factor); Serial.println(" ms");
        state = RUNNING;
        previousMillis = millis();
        digitalWrite(relayPin, HIGH);
      }
      break;

    case RUNNING :
      if ((millis() - previousMillis > (interval[presses] * factor)) || stopBtn.wasPressed() ) {
        Serial.println("stop");
        state = IDLE;
        digitalWrite(relayPin, LOW);
        presses = 0;
        indicate(state);
      }
      // optional update indicator
      break;
  }
}

void setup() {
  Serial.begin(115200);
  selectBtn.begin();
  startBtn.begin();
  stopBtn.begin();
  pinMode(relayPin, OUTPUT);
  indicate(state);
}

void loop() {
  runFSM();
}