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

// Pin definitions
#define DHTPIN1 2
#define DHTPIN2 3
#define DHTTYPE DHT22

DHT dht1(DHTPIN1, DHTTYPE);
DHT dht2(DHTPIN2, DHTTYPE);

LiquidCrystal_I2C lcd(0x27, 20, 4);

unsigned long lastUpdate = 0;
const unsigned long updateInterval = 2000; // DHT22 timing

// Helper to prevent leftover digits
void printPadded(float value, int width, int decimals) {
  if (isnan(value)) {
    lcd.print("Err");
    for (int i = 0; i < width - 3; i++) lcd.print(" ");
  } else {
    String s = String(value, decimals);
    lcd.print(s);
    for (int i = s.length(); i < width; i++) lcd.print(" ");
  }
}

void setup() {
  Serial.begin(9600);
  dht1.begin();
  dht2.begin();

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

  lcd.setCursor(0, 0);
  lcd.print("Temp Monitor Ready");
  delay(2000);
  lcd.clear();

  // Static labels (printed once)
  lcd.setCursor(0, 0); lcd.print("S1:       F       %");
  lcd.setCursor(0, 1); lcd.print("S2:       F       %");
  lcd.setCursor(0, 2); lcd.print("AVG:      F       %");
}

void loop() {
  if (millis() - lastUpdate >= updateInterval) {
    lastUpdate = millis();

    float t1C = dht1.readTemperature();
    float h1  = dht1.readHumidity();
    float t2C = dht2.readTemperature();
    float h2  = dht2.readHumidity();

    float t1F = t1C * 1.8 + 32;
    float t2F = t2C * 1.8 + 32;
    float avgTF = (t1F + t2F) / 2.0;
    float avgH  = (h1 + h2) / 2.0;

    // S1
    lcd.setCursor(4, 0);   // Temp
    printPadded(t1F, 6, 1);
    lcd.setCursor(12, 0);  // Humidity
    printPadded(h1, 6, 1);

    // S2
    lcd.setCursor(4, 1);
    printPadded(t2F, 6, 1);
    lcd.setCursor(12, 1);
    printPadded(h2, 6, 1);

    // AVG
    lcd.setCursor(5, 2);
    printPadded(avgTF, 6, 1);
    lcd.setCursor(13, 2);
    printPadded(avgH, 5, 1);
  }
}