// --- Pins ---
const int LDR_PIN = A0;

const int PIR_PIN  = 2;
const int TRIG_PIN = 3;
const int ECHO_PIN = 4;

const int BTN_PIN = 7;

const int LED_R = 9;
const int LED_Y = 10;
const int LED_G = 11;

const int BUZZ = 6;

// -------- Параметры (разрешено менять) --------
int nightThreshold      = 512;  // ниже -> считаем "ночь"
int nearDistanceCm      = 40;   // ближе -> "подошел к зоне"
int blinkPeriodMs       = 150;  // скорость мигания LED
int alarmToneHz         = 2000; // частота тревоги
int alarmBeepDurationMs = 200;  // длительность звука в тревоге
// ----------------------------------------------

// monitoring on/off
bool armed = true;

// button edge
int prevBtn = HIGH;

// blink
bool blinkState = false;
unsigned long lastBlinkMs = 0;

// distance
long readDistanceCm() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  long duration = pulseIn(ECHO_PIN, HIGH, 30000UL); // up to ~5m
  if (duration == 0) return -1; // invalid
  long cm = duration / 58;       // standard conversion
  return cm;
}

void setLeds(bool r, bool y, bool g) {
  digitalWrite(LED_R, r);
  digitalWrite(LED_Y, y);
  digitalWrite(LED_G, g);
}

void setup() {
  pinMode(LDR_PIN, INPUT);

  pinMode(PIR_PIN, INPUT);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);

  pinMode(BTN_PIN, INPUT_PULLUP);

  pinMode(LED_R, OUTPUT);
  pinMode(LED_Y, OUTPUT);
  pinMode(LED_G, OUTPUT);

  pinMode(BUZZ, OUTPUT);

  Serial.begin(9600);
  Serial.println("Animal Pen Monitor (PIR + HC-SR04 + LDR)");
}

void loop() {
  // --- Button: arm/disarm ---
  int btn = digitalRead(BTN_PIN);
  if (btn == LOW && prevBtn == HIGH) {
    armed = !armed;
    delay(150);
  }
  prevBtn = btn;

  // --- Blink tick ---
  unsigned long now = millis();
  if (now - lastBlinkMs >= (unsigned long)blinkPeriodMs) {
    lastBlinkMs = now;
    blinkState = !blinkState;
  }

  // --- Read sensors ---
  int  lightRaw = analogRead(LDR_PIN);
  bool motion   = (digitalRead(PIR_PIN) == HIGH);
  long distCm   = readDistanceCm();

  bool night = (lightRaw < nightThreshold);
  bool near  = (distCm > 0 && distCm <= nearDistanceCm);

  // --- Decide state ---
  // If disarmed -> all OFF, no buzzer.
  // If armed:
  // ALARM = night AND (motion OR near)
  // WARNING = day AND near
  // OK = otherwise
  bool alarm   = false;
  bool warning = false;

  if (armed) {
    if (night && (motion || near)) alarm = true;
    else if (!night && near) warning = true;
  }

  // --- Output / Indication ---
  if (!armed) {
    setLeds(false, false, false);
    noTone(BUZZ);
  } else if (alarm) {
    setLeds(blinkState, false, false);
    if (blinkState) tone(BUZZ, alarmToneHz, alarmBeepDurationMs);
  } else if (warning) {
    setLeds(false, blinkState, false);
    noTone(BUZZ);
  } else {
    setLeds(false, false, blinkState);
    noTone(BUZZ);
  }

  // --- Serial diagnostics ---
  Serial.print("Light=");
  Serial.print(lightRaw);
  Serial.print(night ? " (NIGHT)" : " (DAY)");
  Serial.print("  Dist=");
  Serial.print(distCm);
  Serial.print("cm");
  Serial.print(near ? " (NEAR)" : " (FAR)");
  Serial.print("  Motion=");
  Serial.print(motion ? "YES" : "NO");
  Serial.print("  Armed=");
  Serial.print(armed ? "ON" : "OFF");
  Serial.print("  State=");
  if (!armed) Serial.println("DISARM");
  else if (alarm) Serial.println("ALARM");
  else if (warning) Serial.println("WARNING");
  else Serial.println("OK");

  delay(80);
}