// ================= Configuration Variables =================
const int buzzerPin = 27;
const int pumpRelayPin = 16;

const unsigned long pumpOnTimeMs = 20000;   // 20 seconds
const unsigned long beepIntervalMs = 300;   // beep delay

// ================= Internal State Variables =================
bool pumpActive = false;
unsigned long pumpStartTime = 0;
unsigned long lastBeepTime = 0;
bool buzzerState = false;

// ================= Function Prototypes =================
void handlePumpCycle();
void handleBuzzerBeep();

/*
 * Function: handlePumpCycle
 * I/O: Controls pump relay (output)
 * Working: Turns ON pump for fixed duration, then turns OFF
 */
void handlePumpCycle() {
  // Start pump if not active
  if (!pumpActive) {
    digitalWrite(pumpRelayPin, HIGH);
    pumpActive = true;
    pumpStartTime = millis();
  }

  // Turn OFF after 20 seconds
  if (pumpActive && (millis() - pumpStartTime >= pumpOnTimeMs)) {
    digitalWrite(pumpRelayPin, LOW);
    pumpActive = false;
  }
}

/*
 * Function: handleBuzzerBeep
 * I/O: Controls buzzer (output)
 * Working: Creates beep-beep sound while pump is ON
 */
void handleBuzzerBeep() {
  // Error handling: if pump is OFF, ensure buzzer OFF
  if (!pumpActive) {
    digitalWrite(buzzerPin, LOW);
    buzzerState = false;
    return;
  }

  // Toggle buzzer for beep effect
  if (millis() - lastBeepTime >= beepIntervalMs) {
    lastBeepTime = millis();
    buzzerState = !buzzerState;
    digitalWrite(buzzerPin, buzzerState ? HIGH : LOW);
  }
}

void setup() {
  pinMode(buzzerPin, OUTPUT);
  pinMode(pumpRelayPin, OUTPUT);

  // Ensure everything OFF at start
  digitalWrite(pumpRelayPin, LOW);
  digitalWrite(buzzerPin, LOW);
}

void loop() {
  handlePumpCycle();
  handleBuzzerBeep();
}