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

// ----- Pin definitions -----
#define DHTPIN 4
#define DHTTYPE DHT22

#define RED_PIN 26
#define GREEN_PIN 27
#define BLUE_PIN 14

#define RELAY_PIN 33
#define BUZZER_PIN 25

// ----- Temperature thresholds (°C) -----
#define TOO_COLD 2
#define SAFE_MAX 5
#define CRITICAL_TEMP 8

// ----- Humidity thresholds (%) -----
#define LOW_HUMIDITY 70
#define OPTIMAL_HUMIDITY_MIN 80
#define OPTIMAL_HUMIDITY_MAX 90
#define HIGH_HUMIDITY 95

// ----- Objects -----
DHT dht(DHTPIN, DHTTYPE);
LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
  Serial.begin(115200);
  dht.begin();

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

  pinMode(RED_PIN, OUTPUT);
  pinMode(GREEN_PIN, OUTPUT);
  pinMode(BLUE_PIN, OUTPUT);
  pinMode(RELAY_PIN, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);
}

void loop() {
  float temp = dht.readTemperature();
  float hum = dht.readHumidity();

  if (isnan(temp) || isnan(hum)) {
    Serial.println("Sensor Error!");
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Sensor Failure");

    digitalWrite(RED_PIN, LOW);
    digitalWrite(GREEN_PIN, LOW);
    digitalWrite(BLUE_PIN, LOW);
    digitalWrite(RELAY_PIN, LOW);
    digitalWrite(BUZZER_PIN, LOW);

    delay(2000);
    return;
  }

  // ----- TEMPERATURE CHECK -----
  if (temp <= TOO_COLD) {
    digitalWrite(RED_PIN, LOW);
    digitalWrite(GREEN_PIN, LOW);
    digitalWrite(BLUE_PIN, HIGH);
    digitalWrite(RELAY_PIN, LOW);
    digitalWrite(BUZZER_PIN, HIGH);
  }
  else if (temp > SAFE_MAX && temp <= CRITICAL_TEMP) {
    digitalWrite(RED_PIN, HIGH);
    digitalWrite(GREEN_PIN, LOW);
    digitalWrite(BLUE_PIN, LOW);
    digitalWrite(RELAY_PIN, HIGH);
    digitalWrite(BUZZER_PIN, HIGH);
  }
  else if (temp > CRITICAL_TEMP) {
    digitalWrite(RED_PIN, HIGH);
    digitalWrite(GREEN_PIN, LOW);
    digitalWrite(BLUE_PIN, LOW);
    digitalWrite(RELAY_PIN, HIGH);
    digitalWrite(BUZZER_PIN, HIGH);
    delay(500);
    digitalWrite(RED_PIN, LOW);
    delay(500);
  }

  // ----- HUMIDITY CHECK -----
  if (hum < LOW_HUMIDITY) {
    digitalWrite(RED_PIN, HIGH);
    digitalWrite(GREEN_PIN, HIGH);
    digitalWrite(BLUE_PIN, LOW);
  }
  else if (hum >= OPTIMAL_HUMIDITY_MIN && hum <= OPTIMAL_HUMIDITY_MAX) {
    digitalWrite(RED_PIN, LOW);
    digitalWrite(GREEN_PIN, HIGH);
    digitalWrite(BLUE_PIN, HIGH);
  }
  else if (hum > OPTIMAL_HUMIDITY_MAX && hum <= HIGH_HUMIDITY) {
    digitalWrite(RED_PIN, HIGH);
    digitalWrite(GREEN_PIN, LOW);
    digitalWrite(BLUE_PIN, HIGH);
  }
  else if (hum > HIGH_HUMIDITY) {
    digitalWrite(RED_PIN, HIGH);
    digitalWrite(BLUE_PIN, HIGH);
    delay(500);
    digitalWrite(RED_PIN, LOW);
    digitalWrite(BLUE_PIN, LOW);
    delay(500);
  }

  // ----- LCD Alternating Display -----
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Temp: ");
  lcd.print(temp);
  lcd.print("C");
  delay(2000); // Show temperature for 2 seconds

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Hum: ");
  lcd.print(hum);
  lcd.print("%");
  delay(2000); // Show humidity for 2 seconds
}