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

// Pin configuration
#define DHT_PIN 4          // DHT22 sensor pin
#define DHT_TYPE DHT22
#define TRIG_PIN 18         // Ultrasonic sensor Trigger pin
#define ECHO_PIN 19         // Ultrasonic sensor Echo pin
#define RELAY_PIN 25        // Relay to control the pump
#define BUZZER_PIN 26       // Buzzer pin

// Sensor initialization
DHT dht(DHT_PIN, DHT_TYPE);
LiquidCrystal_I2C lcd(0x27, 20, 4);

// Variables
float temperature = 0.0;
float waterLevel = 0.0; // In liters
const float tankHeight = 20.0; // Tank height in cm (example)
bool pumpStatus = false;
bool buzzerStatus = false;

void setup() {
  // Initialize components
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(RELAY_PIN, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  
  digitalWrite(RELAY_PIN, LOW);  // Pump OFF
  noTone(BUZZER_PIN);            // Ensure buzzer is OFF

  lcd.begin(20, 4);              // 20 columns, 4 rows
  lcd.backlight();
  dht.begin();

  lcd.setCursor(0, 0);
  lcd.print("Irrigation System");
  delay(2000);
  lcd.clear();
}


void loop() {
  // Read sensors
  temperature = dht.readTemperature();
  waterLevel = getWaterLevel();

  // Display data on LCD
  displayData();

  // Control pump and buzzer
  controlPumpAndBuzzer();

  delay(1000); // Delay for readability
}

float getWaterLevel() {
  // Measure distance using ultrasonic sensor
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  
  float duration = pulseIn(ECHO_PIN, HIGH);
  float distance = (duration * 0.034) / 2; // Distance in cm (round trip divided by 2)

  // Convert distance to water height
  float waterHeight = tankHeight - distance; // Water height in cm

  // Ensure water height does not go negative
  if (waterHeight < 0) waterHeight = 0;

  // Convert water height to volume (liters)
  float tankCapacity = 2.0;                  // 2L max capacity
  return (waterHeight / tankHeight) * tankCapacity; // Approx. water volume
}

void displayData() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Temp: ");
  lcd.print(temperature);
  lcd.print("C");

  lcd.setCursor(0, 1);
  lcd.print("Water: ");
  lcd.print(waterLevel, 1);
  lcd.print(" L");

  lcd.setCursor(0, 2);
  lcd.print("Pump: ");
  lcd.print(pumpStatus ? "ON " : "OFF");

  lcd.setCursor(0, 3);
  lcd.print(buzzerStatus ? "Refill Tank!" : "Tank OK     ");
}

void controlPumpAndBuzzer() {
  // Buzzer logic
  if (waterLevel <= 0.3) {
    buzzerStatus = true;
    tone(BUZZER_PIN, 1500); // Sound buzzer at 1500 Hz
    pumpStatus = false;
    digitalWrite(RELAY_PIN, LOW); // Ensure pump is OFF
  } else if (waterLevel >= 1.0) {
    buzzerStatus = false;
    noTone(BUZZER_PIN); // Turn off buzzer
  }

  // Pump logic
  if (!buzzerStatus) {
    if (temperature >= 40.0) { // Turn pump ON at 40°C or above
      pumpStatus = true;
      digitalWrite(RELAY_PIN, HIGH);
    } else if (temperature <= 35.0) { // Turn pump OFF at 35°C or below
      pumpStatus = false;
      digitalWrite(RELAY_PIN, LOW);
    }
  }
}