#define WIRE_PIN     3
#define ARM_BTN      4
#define DISARM_BTN   5
#define SILENCE_BTN  6
#define BUZZER_PIN   2

#define LED_ARMED     10
#define LED_DISARMED  11
#define LED_ALARM     12

bool armed = false;
bool alarmTriggered = false;
bool silenced = false;

/* debounce */
unsigned long lastBtnTime = 0;
const unsigned long debounceDelay = 50;

/* alarm tone */
unsigned long lastToneTime = 0;
unsigned long lastLedBlink = 0;
const unsigned long toneInterval = 400;
const unsigned long ledBlinkInterval = 500;
bool toneState = false;
bool ledState = false;

void setup() {
  pinMode(WIRE_PIN, INPUT_PULLUP);

  pinMode(ARM_BTN, INPUT_PULLUP);
  pinMode(DISARM_BTN, INPUT_PULLUP);
  pinMode(SILENCE_BTN, INPUT_PULLUP);

  pinMode(BUZZER_PIN, OUTPUT);

  pinMode(LED_ARMED, OUTPUT);
  pinMode(LED_DISARMED, OUTPUT);
  pinMode(LED_ALARM, OUTPUT);

  noTone(BUZZER_PIN);
}

void loop() {
  handleButtons();
  monitorWire();
  alarmSound();
  updateLEDs();
}

/* ---------------- BUTTON HANDLER ---------------- */

void handleButtons() {
  if (millis() - lastBtnTime < debounceDelay) return;

  if (digitalRead(ARM_BTN) == LOW) {
    armed = true;
    alarmTriggered = false;
    silenced = false;
    noTone(BUZZER_PIN);
    lastBtnTime = millis();
  }

  if (digitalRead(DISARM_BTN) == LOW) {
    armed = false;
    alarmTriggered = false;
    silenced = false;
    noTone(BUZZER_PIN);
    lastBtnTime = millis();
  }

  if (digitalRead(SILENCE_BTN) == LOW) {
    if (alarmTriggered) {
      silenced = true;
      noTone(BUZZER_PIN);
    }
    lastBtnTime = millis();
  }
}

/* ---------------- WIRE MONITOR ---------------- */

void monitorWire() {
  if (!armed || alarmTriggered) return;

  if (digitalRead(WIRE_PIN) == HIGH) {
    alarmTriggered = true;
  }
}

/* ---------------- BUZZER ---------------- */

void alarmSound() {
  if (!alarmTriggered || silenced) return;

  if (millis() - lastToneTime >= toneInterval) {
    lastToneTime = millis();
    toneState = !toneState;

    tone(BUZZER_PIN, toneState ? 220 : 380);
  }
}

/* ---------------- LED CONTROL ---------------- */

void updateLEDs() {

  // default OFF
  digitalWrite(LED_ARMED, LOW);
  digitalWrite(LED_DISARMED, LOW);
  digitalWrite(LED_ALARM, LOW);

  if (!armed) {
    digitalWrite(LED_DISARMED, HIGH);
    return;
  }

  if (armed && !alarmTriggered) {
    digitalWrite(LED_ARMED, HIGH);
    return;
  }

  if (alarmTriggered) {
    if (silenced) {
      digitalWrite(LED_ALARM, HIGH);
    } else {
      if (millis() - lastLedBlink >= ledBlinkInterval) {
        lastLedBlink = millis();
        ledState = !ledState;
      }
      digitalWrite(LED_ALARM, ledState);
    }
  }
}