#include <LiquidCrystal.h>        // Include the LCD library
#include <DHT.h>                  // Include the DHT sensor library
#include <Arduino.h>              // For Arduino-specific functions

LiquidCrystal lcd(12, 11, 5, 4, 3, 2);    // LCD pins (for 20x4 LCD)
#define DHTPIN 7
#define DHTTYPE DHT22   // DHT 22 (AM2302)

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

const int relayPin = 6;  // Digital pin connected to relay module

class HVACSystem {
  private:
    float temperature;
    float target_temperature;
    String hvac_mode;
    String fan_speed;
    int iterations;

  public:
    HVACSystem() {
      temperature = 0.0;
      target_temperature = 0.0;
      hvac_mode = "off";
      fan_speed = "auto";
      iterations = 0;
      lcd.begin(20, 4);    // Initialize the LCD for 20x4 display
      pinMode(relayPin, OUTPUT);  // Set relay pin as output
      dht.begin();  // Start DHT sensor
    }

    void set_hvac_mode(String mode) {
      hvac_mode = mode;
      if (mode == "off") {
        digitalWrite(relayPin, LOW);  // Turn off HVAC system
      } else {
        digitalWrite(relayPin, HIGH);  // Turn on HVAC system
      }
    }

    void set_fan_speed(String speed) {
      fan_speed = speed;
    }

    void read_temperature() {
      temperature = dht.readTemperature(); // Read real-time temperature from DHT22 sensor
    }

    void update_target_temperature() {
      if (temperature >= 23) {
        target_temperature = random(max(18, temperature - 5), min(22, temperature - 1));
      } else if (temperature <= 20) {
        target_temperature = random(max(18, temperature + 1), min(22, temperature + 1));
      } else {
        target_temperature = temperature; // Set target temperature equal to current temperature
      }
    }

    void run() {
      iterations = 0; // Reset iterations to 0
      lcd.clear();   // Clear LCD screen
      lcd.setCursor(0, 0);   // Set cursor to beginning of first line
      lcd.print("Custom HVAC ON");

      delay(2000);   // Wait for 2 seconds

      int sleep_time;
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("Sleep time (s):");
      while (!Serial.available());   // Wait for input from Serial Monitor
      sleep_time = Serial.parseInt();   // Read the input as integer
      Serial.println(sleep_time);

      while (iterations < 20) {
        read_temperature();
        update_target_temperature();

        // Ensure target temperature is within the range of 18 to 22 degrees Celsius
        if (target_temperature > 22) {
          target_temperature = 22;
        } else if (target_temperature < 18) {
          target_temperature = 18;
        }

        lcd.clear();
        lcd.setCursor(0, 0);
        lcd.print("Current Temp: ");
        lcd.print((int)temperature); // Cast temperature to integer
        lcd.print("*C");

        lcd.setCursor(0, 1);
        lcd.print("Target Temp: ");
        lcd.print((int)target_temperature); // Cast target_temperature to integer
        lcd.print("*C");

        if (temperature >= 23) {
          set_hvac_mode("cooling");
          set_fan_speed("auto"); // Set fan speed to auto if cooling is required
        } else if (temperature <= 18) {
          set_hvac_mode("heating");
          set_fan_speed("auto"); // Set fan speed to auto if heating is required
        } else {
          set_hvac_mode("off");
          set_fan_speed("off"); // Set fan speed to off if temperature is within range
        }

        lcd.setCursor(0, 2);  // Move cursor to the beginning of the third line
        lcd.print("HVAC Mode: ");
        lcd.print(hvac_mode);

        lcd.setCursor(0, 3); // Move cursor to the beginning of the fourth line
        lcd.print("Fan Speed: ");
        lcd.print(fan_speed);

        delay(1000 * sleep_time);   // Delay in seconds

        iterations++;
      }

      Serial.println("This is a demo of the Custom Climate Controlled HVAC System.");
    }
};

HVACSystem hvac;

void setup() 
{
  Serial.begin(9600);
  Serial.println("Welcome to the Serial Monitor!");
  Serial.println("---------------------------------");
}


void loop() {
  hvac.run();
}