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

// Pin definitions
#define DHTPIN 2
#define DHTTYPE DHT22  // DHT 22
#define LDRPIN A0
#define PIRPIN 3
#define BUTTONPIN 13
#define LED1 5  // LED to indicate the active sensor display
#define LED2 6  // LED to indicate a specific condition (e.g., motion detected)

// Initializations
LiquidCrystal_I2C lcd(0x27, 16, 2);
RTC_DS1307 rtc;
DHT dht(DHTPIN, DHTTYPE);

// Variables
int sensorState = 0;  // Tracks the current sensor being displayed
unsigned long lastUpdate = 0;
const unsigned long updateInterval = 500;  // 1 second update interval
int buzzer = 7;


void setup() {
  pinMode(BUTTONPIN, INPUT_PULLUP);
  pinMode(LED1, OUTPUT);
  pinMode(LED2, OUTPUT);
  pinMode(buzzer,OUTPUT);

  lcd.begin(16, 2);
  lcd.backlight();
  dht.begin();

  if (!rtc.begin() || !rtc.isrunning()) {
    lcd.print("RTC error");
    while (1);
  }

  digitalWrite(LED1, HIGH);
  digitalWrite(LED2, LOW);

  updateDisplay();  // Initial display
}

void loop() {
  checkButton();
  updateDisplay();  // Continuous display update based on interval
  checkMotion();    // Real-time motion detection
}

void checkButton() {
  static bool buttonPressed = false;
  if (digitalRead(BUTTONPIN) == LOW && !buttonPressed) {
    delay(50);  // Debounce
    buttonPressed = true;
    sensorState = (sensorState + 1) % 4;
    updateDisplay();
  }
  buttonPressed = digitalRead(BUTTONPIN) == LOW;
}

void updateDisplay() {
  if (millis() - lastUpdate >= updateInterval) {
    lastUpdate = millis();
    lcd.clear();
    switch (sensorState) {
      case 0: displayTemperatureHumidity(); break;
      case 1: displayLightLevel(); break;
      case 2: displayMotionStatus(); break;
      case 3: displayTimeDate(); break;
    }
  }
}

unsigned char i;
void checkMotion() {
  if (digitalRead(PIRPIN) == HIGH) {
    digitalWrite(LED2, HIGH);
    delay(50);
    digitalWrite(LED2,LOW);
    delay(15);

    for(i=0;i<80;i++) {
      digitalWrite(buzzer,HIGH);
      delay(3);//wait for 1ms
      digitalWrite(buzzer,LOW);
      delay(4);//wait for 1ms
    }
    if (sensorState == 2) displayMotionStatus();
  } else {
    digitalWrite(LED2, LOW);
    //digitalWrite(buzzer,LOW);
  }
}

void displayTemperatureHumidity() {
  lcd.setCursor(0, 0);
  lcd.print("Temp: " + String(dht.readTemperature()) + " C");
  lcd.setCursor(0, 1);
  lcd.print("Humidity: " + String(dht.readHumidity()) + " %");
}

void displayLightLevel() {
  lcd.setCursor(0, 0);
  lcd.print("Light Level:");
  lcd.setCursor(0, 1);
  lcd.print(analogRead(LDRPIN));
}

void displayMotionStatus() {
  lcd.setCursor(0, 0);
  lcd.print("Motion: ");
  lcd.setCursor(0, 1);
  lcd.print(digitalRead(PIRPIN) == HIGH ? "Detected" : "None");
}

void displayTimeDate() {
  DateTime now = rtc.now();
  lcd.setCursor(0, 0);
  lcd.print(now.hour(), DEC);
  lcd.print(':');
  lcd.print(now.minute(), DEC);
  lcd.print(':');
  lcd.print(now.second(), DEC);

  lcd.setCursor(0, 1);
  lcd.print(now.day(), DEC);
  lcd.print('/');
  lcd.print(now.month(), DEC);
  lcd.print('/');
  lcd.print(now.year(), DEC);
}