#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// -------- PIN DEFINITIONS --------
#define TRIG 5
#define ECHO 18
#define RELAY 19
#define BUZZER 23
#define SERVO_PIN 4
#define LEAK_SENSOR 34
#define BUTTON 14

LiquidCrystal_I2C lcd(0x27, 16, 2);

// PWM channel (still needed for writing)
#define PWM_CHANNEL 0

long duration;
float distance;
int waterLevel;

// -------- SERVO FUNCTION --------
void setServoAngle(int angle) {
  int duty = map(angle, 0, 180, 1638, 8192);
  ledcWrite(PWM_CHANNEL, duty);
}

// -------- WATER LEVEL --------
int getWaterLevel() {
  digitalWrite(TRIG, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG, LOW);

  duration = pulseIn(ECHO, HIGH);
  distance = duration * 0.034 / 2;

  int level = map(distance, 20, 0, 0, 100);
  return constrain(level, 0, 100);
}

// -------- SETUP --------
void setup() {
  Serial.begin(115200);

  pinMode(TRIG, OUTPUT);
  pinMode(ECHO, INPUT);
  pinMode(RELAY, OUTPUT);
  pinMode(BUZZER, OUTPUT);
  pinMode(BUTTON, INPUT_PULLUP);

  // ✅ New API
  ledcAttach(SERVO_PIN, 50, 16);

  lcd.init();
  lcd.backlight();

  lcd.setCursor(0, 0);
  lcd.print("SMART WATER SYS");
  delay(2000);
  lcd.clear();
}

// -------- LOOP --------
void loop() {

  waterLevel = getWaterLevel();
  int leakValue = analogRead(LEAK_SENSOR);
  bool leakDetected = (leakValue > 2000);
  bool emergencyPressed = (digitalRead(BUTTON) == LOW);

  lcd.clear();

  if (leakDetected || emergencyPressed) {

    digitalWrite(RELAY, LOW);
    digitalWrite(BUZZER, HIGH);
    setServoAngle(0);

    lcd.setCursor(0, 0);
    lcd.print("!!! ALERT !!!");

    lcd.setCursor(0, 1);
    if (leakDetected)
      lcd.print("Leak Detected");
    else
      lcd.print("Emergency Stop");

  } else {

    digitalWrite(BUZZER, LOW);
    setServoAngle(90);

    if (waterLevel < 30) {
      digitalWrite(RELAY, HIGH);
    } else if (waterLevel > 90) {
      digitalWrite(RELAY, LOW);
    }

    lcd.setCursor(0, 0);
    lcd.print("Level:");
    lcd.print(waterLevel);
    lcd.print("%");

    lcd.setCursor(0, 1);
    lcd.print("Pump:");
    lcd.print(digitalRead(RELAY) ? "ON " : "OFF");
  }

  delay(800);
}