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

LiquidCrystal_I2C lcd(0x27, 16, 2);

#define DHTPIN 2     
#define DHTTYPE DHT22   
#define DHTPIN1 3
#define DHTTYPE1 DHT22
#define joyX A0
#define joyY A1

DHT dht(DHTPIN, DHTTYPE);
DHT dht1(DHTPIN1, DHTTYPE1);

const int relayPin= 4;

float relHumOut;
float tempOut;
float relHumIn;
float tempIn;

float absHumOut;
float absHumIn;
double satVaporPressureOut;
float satVaporPressureIn;
double powerNumOut;
float powerNumIn;
double altitude = 30;
double universal_gas_constant = 8.314;
double molecular_weight_water_vapor = 18.016;

double actual_vapor_pressure(double temperature, double relative_humidity) {
  const double hPa = 6.11;
  const double a = 17.27;
  const double b = 237.7;
  return (relative_humidity / 100) * (hPa * exp(a * temperature / (temperature + b)));
}

double dew_point(double temperature, double relative_humidity) {
  double actual_vap = actual_vapor_pressure(temperature, relative_humidity);
  return (237.3 * log(actual_vap / 6.11)) / (17.27 - log(actual_vap / 6.11));
}

double absolute_humidity(double temperature, double humidity, double dew_point){

  double satVapPre = (6.1078 * pow(10, ((7.5 * temperature) / (237.3 + dew_point))));
  double actVapPre = (satVapPre * (humidity / 100));
  double firstPart = 216.7 * actVapPre;
  double secondPart = temperature + 273.15;
  return firstPart / secondPart;

}

void dew_point_scrn(){

  lcd.setCursor(0, 0);
  lcd.print("DPOut: ");
  lcd.setCursor(0, 1);
  lcd.print(String(dew_point(tempOut, relHumOut)));
  lcd.setCursor(10, 0);
  lcd.print("DPin: ");
  lcd.setCursor(10, 1);
  lcd.print(String(dew_point(tempIn, relHumIn)));

}

void temp_scrn(){

  lcd.setCursor(0, 0);
  lcd.print("TempOut: ");
  lcd.setCursor(0, 1);
  lcd.print(tempOut);
  lcd.setCursor(10, 0);
  lcd.print("TempIn: ");
  lcd.setCursor(10, 1);
  lcd.print(tempIn);

}

void hum_scrn(){

  lcd.setCursor(0, 0);
  lcd.print("HumOut: ");
  lcd.setCursor(0, 1);
  lcd.print(relHumOut);
  lcd.setCursor(10, 0);
  lcd.print("HumIn: ");
  lcd.setCursor(10, 1);
  lcd.print(relHumIn);

}

void abs_hum_scrn(){

  lcd.setCursor(0, 0);
  lcd.print("AbsOut: ");
  lcd.setCursor(0, 1);
  lcd.print(absolute_humidity(tempOut, relHumOut, dew_point(tempOut, relHumOut)));
  lcd.setCursor(10, 0);
  lcd.print("AbsIn: ");
  lcd.setCursor(10, 1);
  lcd.print(absolute_humidity(tempIn, relHumIn, dew_point(tempIn, relHumIn)));

}

void lueften(double afau, double afin, double tau, double tin){

  Serial.println(afau);
  Serial.println(afin);
  double afdiff = afau - afin;
  Serial.println(afdiff);
  
  if(tau < 3.0){
    lcd.print("Nicht lueften");
    
  }else if( -1 < afdiff < 1){
    lcd.print("Kleine Diff.");
    
  }else if(afau > afin){
    lcd.print("Nicht lueften");
    
  }else{
    lcd.print("Bitte lueften");
    
  }
}

//int display_mode = 0;
//int prev_x_value = 0;

/*void scrn_change() {
  int xValue = analogRead(joyX);
  if (xValue != prev_x_value) {
    // Update the display mode based on the value of xValue
    if (xValue == 1023) {
      display_mode = 0;
    } else if (xValue < 768 && xValue > 0) {
      display_mode = 1;
    } else {
      display_mode = 2;
    }
    // Call the appropriate function based on the display mode
    switch (display_mode) {
      case 0:
        temp_scrn();
        break;
      case 1:
        hum_scrn();
        break;
      case 2:
        dew_point_scrn();
        break;
    }
    // Update the prev_x_value variable with the current xValue
    prev_x_value = xValue;
  }
}*/

void setup() {

Serial.begin(9600);

dht.begin(); 
dht1.begin();
lcd.init();
lcd.backlight();
lcd.clear();

pinMode(buttonPin, INPUT);
pinMode(buttonPin1, INPUT_PULLUP);
pinMode(relayPin, OUTPUT);

}


void loop() {
  

relHumOut = dht.readHumidity();
tempOut = dht.readTemperature();
relHumIn = dht1.readHumidity();
tempIn = dht1.readTemperature();

double x = 0;

lueften(absolute_humidity(tempOut, relHumOut, dew_point(tempOut, relHumOut)), absolute_humidity(tempIn, relHumIn, dew_point(tempIn, relHumIn)), tempOut, tempIn);
digitalWrite(relayPin, HIGH);
delay(3000);

}