#include <AM2302-Sensor.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

constexpr unsigned int SENSOR_PIN {7U};
AM2302::AM2302_Sensor am2302{SENSOR_PIN};

const int potPin = A1;

// Timing
unsigned long lastLcdUpdate = 0;
unsigned long lastSensorRead = 0;

const unsigned long lcdInterval = 1000;
const unsigned long sensorInterval = 2000;

// State
int lastMenuIndex = -1;
float temperature = NAN;
float humidity = NAN;

const int relayPin = 12;

unsigned long lastRelayToggle = 0;
const unsigned long relayInterval = 2000;

bool relayState = false;

void readSensor(unsigned long now) {
  if (now - lastSensorRead >= sensorInterval) {
    lastSensorRead = now;

    if (am2302.read() == AM2302::AM2302_READ_OK) {
      humidity = am2302.get_Humidity();
      temperature = am2302.get_Temperature();
    }
  }
}

void updateRelay(unsigned long now) {
  if (now - lastRelayToggle >= relayInterval) {
    lastRelayToggle = now;

    relayState = !relayState; // toggle state
    digitalWrite(relayPin, relayState ? HIGH : LOW);
  }
}

void updateLCD(unsigned long now) {
  int potValue = analogRead(potPin);

  int menuIndex = (potValue < 512) ? 0 : 1;

  if (menuIndex != lastMenuIndex || now - lastLcdUpdate >= lcdInterval) {
    lastMenuIndex = menuIndex;
    lastLcdUpdate = now;

    lcd.clear();

    if (menuIndex == 0) {
      lcd.setCursor(0, 0);
      lcd.print("Humidity:");

      lcd.setCursor(0, 1);
      if (!isnan(humidity)) {
        lcd.print(humidity);
        lcd.print("%");
      } else {
        lcd.print("No data");
      }
    }
    else {
      lcd.setCursor(0, 0);
      lcd.print("Temperature:");

      lcd.setCursor(0, 1);
      if (!isnan(temperature)) {
        lcd.print(temperature);
        lcd.print(" C");
      } else {
        lcd.print("No data");
      }
    }
  }
}

void setup() {

  pinMode(relayPin, OUTPUT);
  digitalWrite(relayPin, LOW); // start OFF

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

  am2302.begin();

  lcd.setCursor(0, 0);
  lcd.print("Starting...");
}

void loop() {
  unsigned long now = millis();

  readSensor(now);
  updateLCD(now);
  updateRelay(now);
}