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

// Pin definitions for LCD (Parallel connection)
#define LCD_RS    A0
#define LCD_E     A1
#define LCD_D4    A2
#define LCD_D5    A3
#define LCD_D6    A4
#define LCD_D7    A5

// Pin definitions for sensors
#define DHT_PIN   PB0  // DHT22 (Temperature & Humidity)
#define MQ2_PIN   A6   // MQ2 (Gas sensor)
#define PIR_PIN   A7   // PIR (Motion detection)
#define TRIG_PIN  PB1  // Ultrasonic Trigger
#define ECHO_PIN  PB10 // Ultrasonic Echo

// Constants for RGB LEDs
#define LED_RED    PB12  // Red LED
#define LED_GREEN  PB13  // Green LED
#define LED_BLUE   PB14  // Blue LED

// Initialize LCD
LiquidCrystal lcd(LCD_RS, LCD_E, LCD_D4, LCD_D5, LCD_D6, LCD_D7);

// Initialize DHT22 sensor
#define DHT_TYPE DHT22
DHT dht(DHT_PIN, DHT_TYPE);

void setup() {
  // LCD setup
  lcd.begin(16, 2);
  lcd.print("Env Monitor");
  delay(2000);

  // Initialize sensors
  dht.begin();
  pinMode(PIR_PIN, INPUT);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(LED_RED, OUTPUT);
  pinMode(LED_GREEN, OUTPUT);
  pinMode(LED_BLUE, OUTPUT);

  // Serial for debugging
  Serial.begin(9600);
}

// Function to read distance from the Ultrasonic sensor
long readDistance() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  
  long duration = pulseIn(ECHO_PIN, HIGH, 30000);  // timeout 30ms
  if (duration == 0) {
    return 400;  // Default max distance in cm
  }
  return duration * 0.034 / 2;
}

void loop() {
  // Read sensor values
  float temperature = dht.readTemperature();
  float humidity    = dht.readHumidity();
  int gasLevel      = analogRead(MQ2_PIN);
  long distance     = readDistance();
  bool motion       = digitalRead(PIR_PIN);

  // Display temperature and humidity
  if (isnan(temperature) || isnan(humidity)) {
    lcd.setCursor(0, 0);
    lcd.print("DHT Error       ");
    lcd.setCursor(0, 1);
    lcd.print("Check Sensor    ");
  } else {
    lcd.setCursor(0, 0); 
    lcd.print("Temp: ");
    lcd.print(temperature, 1); // Display with 1 decimal
    lcd.print(" C  ");
    
    lcd.setCursor(0, 1);
    lcd.print("Hum: ");
    lcd.print(humidity, 1); // Display with 1 decimal
    lcd.print(" %   ");
  }

  // Serial output for debugging
  Serial.print("Temp: "); Serial.print(temperature);
  Serial.print(" C, Hum: "); Serial.print(humidity);
  Serial.print(" %, Gas: "); Serial.print(gasLevel);
  Serial.print(", Dist: "); Serial.print(distance);
  Serial.print(" cm, Motion: "); Serial.println(motion ? "Yes" : "No");

  // RGB LED Logic for alerting based on different conditions

  // Condition 1: High Temperature
  if (temperature > 30) {
    lcd.setCursor(0, 0);
    lcd.print("High Temp!      ");
    lcd.setCursor(0, 1);
    lcd.print("Temp: ");
    lcd.print(temperature, 1);  // Display the temperature
    digitalWrite(LED_RED, HIGH);  // Turn Red LED on
    digitalWrite(LED_GREEN, LOW);  // Turn Green LED off
    digitalWrite(LED_BLUE, LOW);   // Turn Blue LED off
  }
  // Condition 2: Gas level too high (MQ2)
  else if (gasLevel > 400) {
    lcd.setCursor(0, 0);
    lcd.print("High Gas Level  ");
    lcd.setCursor(0, 1);
    lcd.print("Gas: ");
    lcd.print(gasLevel);  // Display the gas level
    digitalWrite(LED_RED, HIGH);  // Turn Red LED on
    digitalWrite(LED_GREEN, HIGH);  // Turn Green LED off
    digitalWrite(LED_BLUE, HIGH);   // Turn Blue LED off
  }
  // Condition 3: Distance too short (proximity alert)
  else if (distance < 20) {
    lcd.setCursor(0, 0);
    lcd.print("Close Object!   ");
    lcd.setCursor(0, 1);
    lcd.print("Dist: ");
    lcd.print(distance);  // Display the distance
    digitalWrite(LED_RED, HIGH);  // Turn Red LED on
    digitalWrite(LED_GREEN, LOW);  // Turn Green LED off
    digitalWrite(LED_BLUE, LOW);   // Turn Blue LED off
  }
  // Condition 4: Motion detected
  else if (motion) {
    lcd.setCursor(0, 0);
    lcd.print("Motion Detected ");
    lcd.setCursor(0, 1);
    lcd.print("Dist: ");
    lcd.print(distance);  // Display the distance
    digitalWrite(LED_RED, HIGH);  // Turn Red LED on
    digitalWrite(LED_GREEN, LOW);  // Turn Green LED off
    digitalWrite(LED_BLUE, LOW);   // Turn Blue LED off
  }
  // Condition 5: Distance is being monitored (mid-range)
  else if (distance > 20 && distance < 400) {
    lcd.setCursor(0, 0);
    lcd.print("Monitoring Dist ");
    lcd.setCursor(0, 1);
    lcd.print("Dist: ");
    lcd.print(distance);  // Display the distance
    digitalWrite(LED_RED, LOW);  // Turn Red LED off
    digitalWrite(LED_GREEN, LOW);  // Turn Green LED off
    digitalWrite(LED_BLUE, HIGH);   // Turn Blue LED on
  }
  // Default condition: Normal status
  else {
    lcd.setCursor(0, 0);
    lcd.print("All OK          ");
    lcd.setCursor(0, 1);
    lcd.print("Temp: ");
    lcd.print(temperature, 1);  // Display the temperature
    lcd.print(" C  ");
    digitalWrite(LED_RED, LOW);  // Turn Red LED off
    digitalWrite(LED_GREEN, HIGH);  // Turn Green LED on
    digitalWrite(LED_BLUE, LOW);   // Turn Blue LED off
  }

  delay(1000);  // 1-second delay to update readings
}