#include <Wire.h>
#include "RTClib.h"
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET -1

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
RTC_DS1307 rtc;

int i = 1;
void setup() {
  Wire.begin();
  
  if (!rtc.begin()) {
    display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
    display.clearDisplay();
    display.setTextSize(1);
    display.setTextColor(SSD1306_WHITE);
    display.setCursor(0, 0);
    display.println("Couldn't find RTC!");
    display.display();
    while (1);
  }

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

  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    while (1);
  }

  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);
  display.println("Scanning I2C Bus...");
  display.display();
  delay(1000);
}

void loop() {
  display.clearDisplay();
  display.setCursor(0, 0);

  byte error, address;
  int nDevices = 0;

  for (address = 1; address < 127; address++) {
    Wire.beginTransmission(address);
    error = Wire.endTransmission();

    if (error == 0) {
      char buf[32];
      sprintf(buf, "Device: 0x%02X", address);
      display.println(buf);
      nDevices++;
      delay(10);
    } else if (error == 4) {
      char buf[32];
      sprintf(buf, "Error: 0x%02X", address);
      display.println(buf);
    }
  }

  if (nDevices == 0) {
    display.println("No I2C devices found");
  } else {
    display.println("Scan complete");
  }

  DateTime now = rtc.now();
  display.println();
  char timeBuf[32];
  sprintf(timeBuf, "%04d/%02d/%02d %02d:%02d:%02d",
          now.year(), now.month(), now.day(),
          now.hour(), now.minute(), now.second());
  display.println(timeBuf);

  if (i == 1) {
    display.println("(😭)");
  } else if (i == 2) {
    display.println("(😑)zZZ");
  } else if (i == 3) {
    display.println("(^o^)");
  }

  display.display();
  delay(1000);
  i++;
  if (i > 3) {
    i = 1;
  }
}