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

LiquidCrystal_I2C lcd(0x27, 20, 4);
RTC_DS3231 rtc;

#define BUTTON_HEART_RATE 2
#define BUTTON_OXYGEN 3

char daysOfTheWeek[7][12] = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};

byte smiley[8] = {
  0b00000,
  0b00000,
  0b01010,
  0b00000,
  0b10001,
  0b01110,
  0b00000,
  0b00000
};

byte sadFace[8] = {
  0b00000,
  0b01010,
  0b00000,
  0b00000,
  0b01110,
  0b10001,
  0b00000,
  0b00000
};

int heartRate = 0;
int spo2 = 0;

void setup() {
  Serial.begin(115200);
  lcd.init();
  lcd.backlight();

  lcd.createChar(1, smiley);
  lcd.createChar(2, sadFace);

  pinMode(BUTTON_HEART_RATE, INPUT_PULLUP);
  pinMode(BUTTON_OXYGEN, INPUT_PULLUP);

  if (!rtc.begin()) {
    Serial.println("Couldn't find RTC");
    while (1);
  }

  if (rtc.lostPower()) {
    rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
  }

  lcd.setCursor(0, 0);
  lcd.print("Press buttons to start");
}

void loop() {
  DateTime now = rtc.now();

  lcd.setCursor(0, 0);
  lcd.print(now.hour());
  lcd.print(":");
  lcd.print(now.minute());
  lcd.print(":");
  lcd.print(now.second());

  if (digitalRead(BUTTON_HEART_RATE) == LOW) {
    heartRate = random(40, 120);
    delay(200);
  }

  if (digitalRead(BUTTON_OXYGEN) == LOW) {
    spo2 = random(80, 100);
    delay(200);
  }

  if (heartRate > 0 && spo2 > 0) {
    lcd.setCursor(0, 1);
    lcd.print("Heart Rate: ");
    lcd.print(heartRate);
    lcd.print(" bpm ");
    lcd.write((heartRate >= 50 && heartRate <= 100) ? 1 : 2);

    lcd.setCursor(0, 2);
    lcd.print("Oxygen Saturation: ");
    lcd.print(spo2);
    lcd.print("% ");
    lcd.write((spo2 >= 90) ? 1 : 2);
  } else {
    lcd.setCursor(0, 1);
    lcd.print("Press button for HR   ");
    lcd.setCursor(0, 2);
    lcd.print("Press button for SpO2 ");
  }

  delay(1000);
}

// Try this in Wokwi and let me know! 🎯