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

#define DHTPIN 2
#define DHTTYPE DHT22

#define LIGHT_SENSOR_PIN A0
#define PIR_SENSOR_PIN 3

#define RED_LED_PIN 4
#define GREEN_LED_PIN 5
#define BLUE_LED_PIN 6
#define BUZZER_PIN 7

#define TEMP_HIGH 30
#define TEMP_LOW 20

#define NIGHT_MODE_START 22 // 10 PM
#define NIGHT_MODE_END 6 // 6 AM

DHT dht(DHTPIN, DHTTYPE); // Initialize the DHT sensor

LiquidCrystal_I2C lcd(0x27, 16, 2); // Initialize LCD with I2C address

unsigned long lastDisplayUpdate = 0;
unsigned long lastSerialUpdate = 0;
unsigned long lastMotionDetection = 0;

bool motionDetected = false;
bool nightModeActive = false;

void setup() {
  Serial.begin(9600);

  dht.begin(); // Initialize the DHT sensor
  lcd.begin(16, 2); // Initialize the LCD with columns and rows
  lcd.backlight(); // Turn on the backlight

  pinMode(RED_LED_PIN, OUTPUT);
  pinMode(GREEN_LED_PIN, OUTPUT);
  pinMode(BLUE_LED_PIN, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(PIR_SENSOR_PIN, INPUT);

  digitalWrite(RED_LED_PIN, LOW);
  digitalWrite(GREEN_LED_PIN, LOW);
  digitalWrite(BLUE_LED_PIN, LOW);
  digitalWrite(BUZZER_PIN, LOW);
}

void loop() {
  unsigned long currentMillis = millis();
  int lightLevel = analogRead(LIGHT_SENSOR_PIN);
  motionDetected = digitalRead(PIR_SENSOR_PIN);

  float temperature = dht.readTemperature();
  float humidity = dht.readHumidity();

  if (isnan(temperature) || isnan(humidity)) {
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Error");
    return;
  }

  if (currentMillis - lastDisplayUpdate >= 5000) {
    updateDisplay(temperature, humidity, lightLevel);
    lastDisplayUpdate = currentMillis;
  }

  if (currentMillis - lastSerialUpdate >= 10000) {
    sendSerialData(temperature, humidity, lightLevel);
    lastSerialUpdate = currentMillis;
  }

  if (motionDetected && lightLevel < 100) { // Assuming light level < 100 is considered dark
    tone(BUZZER_PIN, 1000); // Activate buzzer
    delay(3000); // Alarm duration
    noTone(BUZZER_PIN); // Stop buzzer
  }

  if (currentMillis - lastMotionDetection >= 30000 && !motionDetected) {
    lcd.noBacklight();
  } else {
    lcd.backlight();
  }

  updateTemperatureLED(temperature);

  if (currentMillis % 86400000 < (24 - NIGHT_MODE_START) * 3600000 || currentMillis % 86400000 >= NIGHT_MODE_END * 3600000) {
    nightModeActive = false;
  } else {
    nightModeActive = true;
  }
}

void updateDisplay(float temperature, float humidity, int lightLevel) {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Temp: ");
  lcd.print(temperature);
  lcd.print(" C");
  lcd.setCursor(0, 1);
  lcd.print("Hum: ");
  lcd.print(humidity);
  lcd.print("% Lght: ");
  lcd.print(lightLevel);
}

void sendSerialData(float temperature, float humidity, int lightLevel) {
  String jsonData = "{";
  jsonData += "\"temperature\": " + String(temperature) + ",";
  jsonData += "\"humidity\": " + String(humidity) + ",";
  jsonData += "\"light_level\": " + String(lightLevel);
  jsonData += "}";
  Serial.println(jsonData);
}

void updateTemperatureLED(float temperature) {
  if (temperature > TEMP_HIGH) {
    digitalWrite(RED_LED_PIN, HIGH);
    digitalWrite(GREEN_LED_PIN, LOW);
    digitalWrite(BLUE_LED_PIN, LOW);
  } else if (temperature < TEMP_LOW) {
    digitalWrite(RED_LED_PIN, LOW);
    digitalWrite(GREEN_LED_PIN, LOW);
    digitalWrite(BLUE_LED_PIN, HIGH);
  } else {
    digitalWrite(RED_LED_PIN, LOW);
    digitalWrite(GREEN_LED_PIN, HIGH);
    digitalWrite(BLUE_LED_PIN, LOW);
  }
}