// Smart Water Leak Detection System — with OLED + tone() buzzer
#include <Arduino.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SENSOR_PIN    4
#define LED_RED       18
#define LED_GREEN     19
#define BUZZER_PIN    5
#define RELAY_PIN     23

#define SCREEN_WIDTH  128
#define SCREEN_HEIGHT 64
#define OLED_RESET    -1
#define OLED_ADDRESS  0x3C

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

bool leakDetected = false;
unsigned long lastUpdateTime = 0;
unsigned long lastBuzzTime = 0;
bool buzzState = false;

void updateDisplay(bool leak);

void setup() {
  Serial.begin(115200);
  pinMode(SENSOR_PIN, INPUT_PULLUP);
  pinMode(LED_RED,    OUTPUT);
  pinMode(LED_GREEN,  OUTPUT);
  pinMode(RELAY_PIN,  OUTPUT);

  digitalWrite(LED_RED,   LOW);
  digitalWrite(LED_GREEN, HIGH);
  digitalWrite(RELAY_PIN, HIGH);
  noTone(BUZZER_PIN);

  if (!display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDRESS)) {
    Serial.println("OLED init failed!");
    while (true);
  }
  display.clearDisplay();
  display.setTextColor(WHITE);
  display.setTextSize(2);
  display.setCursor(10, 10);
  display.println("WaterGuard");
  display.setTextSize(1);
  display.setCursor(20, 38);
  display.println("Leak Detection v1.0");
  display.setCursor(28, 52);
  display.println("Initializing...");
  display.display();
  delay(2000);
  Serial.println("WaterGuard ready. Monitoring started.");
}

void loop() {
  int sensorValue = digitalRead(SENSOR_PIN);
  unsigned long now = millis();

  if (sensorValue == LOW) {
    if (!leakDetected) {
      leakDetected = true;
      Serial.println("LEAK DETECTED! Triggering alerts...");
    }
    activateAlerts(now);
  } else {
    if (leakDetected) {
      leakDetected = false;
      Serial.println("Leak cleared. Resuming normal operation.");
    }
    normalOperation();
  }

  if (now - lastUpdateTime >= 500) {
    lastUpdateTime = now;
    updateDisplay(leakDetected);
    Serial.print("[STATUS] Sensor: ");
    Serial.print(sensorValue == LOW ? "WET" : "DRY");
    Serial.print("  Valve: ");
    Serial.print(leakDetected ? "CLOSED" : "OPEN");
    Serial.print("  Alert: ");
    Serial.println(leakDetected ? "ACTIVE" : "OFF");
  }
}

void activateAlerts(unsigned long now) {
  digitalWrite(LED_RED,   HIGH);
  digitalWrite(LED_GREEN, LOW);
  digitalWrite(RELAY_PIN, LOW);

  // Non-blocking beep: 200ms on / 200ms off using tone()
  if (now - lastBuzzTime >= 200) {
    lastBuzzTime = now;
    buzzState = !buzzState;
    if (buzzState) {
      tone(BUZZER_PIN, 1000); // 1000 Hz beep
    } else {
      noTone(BUZZER_PIN);
    }
  }
}

void normalOperation() {
  digitalWrite(LED_RED,   LOW);
  digitalWrite(LED_GREEN, HIGH);
  digitalWrite(RELAY_PIN, HIGH);
  noTone(BUZZER_PIN);
}

void updateDisplay(bool leak) {
  display.clearDisplay();
  if (leak) {
    display.fillRect(0, 0, 128, 16, WHITE);
    display.setTextColor(BLACK);
    display.setTextSize(1);
    display.setCursor(20, 4);
    display.println("!! LEAK DETECTED !!");
    display.setTextColor(WHITE);
    display.setTextSize(2);
    display.setCursor(28, 20);
    display.println("ALERT!");
    display.setTextSize(1);
    display.setCursor(0, 42);
    display.println("Valve:  CLOSED");
    display.setCursor(0, 52);
    display.println("Buzzer: ACTIVE");
  } else {
    display.fillRect(0, 0, 128, 16, WHITE);
    display.setTextColor(BLACK);
    display.setTextSize(1);
    display.setCursor(28, 4);
    display.println("WaterGuard v1.0");
    display.setTextColor(WHITE);
    display.setTextSize(1);
    display.setCursor(0, 22);
    display.println("Status: NORMAL");
    display.setCursor(0, 32);
    display.println("Sensor: DRY");
    display.setCursor(0, 42);
    display.println("Valve:  OPEN");
    display.setCursor(0, 52);
    display.println("Alert:  OFF");
  }
  display.display();
}