#include <Wire.h> // Include the Wire library for I2C communication
#include <Adafruit_Sensor.h>  // Include the Adafruit Sensor library for the DHT22 sensor
#include <DHT.h> // Include the DHT library for the DHT22 sensor
#include <LiquidCrystal_I2C.h> // Include the Liquid Crystal I2C library for the LCD display

#define DHTPIN 7  // Define the pin that the DHT22 sensor is connected to
#define DHTTYPE DHT22  // Define the type of the DHT22 sensor
#define RELAY_PIN 4 // Define the pin that the relay is connected to
#define BUTTON_UP_PIN 2 // Define the pin for the "UP" button
#define BUTTON_DOWN_PIN 3 // Define the pin for the "DOWN" button

#define MIN_SETPOINT 10.0 // Define the minimum allowed temperature setpoint in degrees Celsius
#define MAX_SETPOINT 50.0 // Define the maximum allowed temperature setpoint in degrees Celsius
#define HYSTERESIS 0.1 // Define the temperature hysteresis in degrees Celsius
#define HUMIDIFIER_PIN 13 // Define the pin that the humidifier is connected to
#define HUMIDITY_SETPOINT 50.0 // Define the desired humidity level

DHT dht(DHTPIN, DHTTYPE); // Create a DHT object with the defined pin and type

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

float temperature_setpoint = 37.0; // Set the initial temperature setpoint in degrees Celsius

void setup() {
  // Initialize I2C communication
  Wire.begin();

  // Initialize the DHT22 sensor
  dht.begin();

  // Set the relay and humidifier pins as outputs
  pinMode(RELAY_PIN, OUTPUT);
  pinMode(HUMIDIFIER_PIN, OUTPUT);

  // Set the button pins as inputs with pull-up resistors enabled
  pinMode(BUTTON_UP_PIN, INPUT_PULLUP);
  pinMode(BUTTON_DOWN_PIN, INPUT_PULLUP);

  // Initialize the LCD display
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0,0);
  lcd.print("Temp: ");
  lcd.setCursor(0,1);
  lcd.print("Setpoint: ");
  lcd.print(temperature_setpoint);
  lcd.print(" C");
}

void loop() {
  // Read the temperature and humidity from the DHT22 sensor
  float temperature = dht.readTemperature();
  float humidity = dht.readHumidity();

  // If the DHT22 sensor failed to read data, print an error message to the LCD display
  if (isnan(temperature) || isnan(humidity)) {
    lcd.setCursor(0,0);
    lcd.print("Error: DHT22 fail");
  }
  // Otherwise, print the temperature and relay status to the LCD display
  else {
    lcd.setCursor(6,0);
    lcd.print(temperature);
    lcd.print(" C");
    lcd.setCursor(0,1);
    lcd.print("Relay: ");
    if (digitalRead(RELAY_PIN) == HIGH) {
      lcd.print("ON ");
    }
    else {
      lcd.print("OFF");
    }
  }

  // Control the relay based on the temperature reading and setpoint
  if (temperature < (temperature_setpoint - HYSTERESIS)) {
    digitalWrite(RELAY_PIN, HIGH); // Turn on the relay
  }
  else if (temperature > (temperature_setpoint + HYSTERESIS)) {
    digitalWrite(RELAY_PIN, LOW); // Turn off the relay
  }

  // Check if the "UP" button is pressed and increase the setpoint if it is
  if (digitalRead(BUTTON_UP_PIN) == LOW && temperature_setpoint < MAX_SETPOINT) {
    temperature_setpoint += 0.1; // Increase the setpoint by 0.1 degrees Celsius
    lcd.setCursor(11,1);
    lcd.print(temperature_setpoint);
    lcd.print(" C");
    delay(100); // Add a small delay to debounce the button
  }

  // Check if the "DOWN" button is pressed and decrease the setpoint if it is
  if (digitalRead(BUTTON_DOWN_PIN) == LOW && temperature_setpoint > MIN_SETPOINT) {
    temperature_setpoint -= 0.1; // Decrease the setpoint by 0.1 degrees Celsius
    lcd.setCursor(11,1);
    lcd.print(temperature_setpoint);
    lcd.print(" C");
    delay(100); // Add a small delay to debounce the button
  }
  
  // Control the humidifier based on the humidity reading and setpoint
  if (humidity < HUMIDITY_SETPOINT) {
    digitalWrite(HUMIDIFIER_PIN, HIGH); // Turn on the humidifier
  }
  else {
    digitalWrite(HUMIDIFIER_PIN, LOW); // Turn off the humidifier
  }
  
  delay(100); // Wait for 0.1 second before repeating the loop
}