#include <Wire.h>
#include <RTClib.h>
#include <TM1637Display.h>

#define CLK_PIN 9
#define DIO_PIN 8
TM1637Display display(CLK_PIN, DIO_PIN);

#define SET_PIN 2
#define DOWN_PIN 3
#define UP_PIN 4

byte hour, minute;
bool settingMode = false;
bool updateTime = false;

bool setButtonState = HIGH;
bool upButtonState = HIGH;
bool downButtonState = HIGH;

bool lastSetButtonState = HIGH;
bool lastUpButtonState = HIGH;
bool lastDownButtonState = HIGH;

RTC_DS1307 rtc;

void setup() {
  display.setBrightness(7);

  Wire.begin();
  rtc.begin();

  if (rtc.isrunning()) {
    DateTime now = rtc.now();
    hour = now.hour();
    minute = now.minute();
  } else {
    hour = 12;
    minute = 0;
  }

  pinMode(SET_PIN, INPUT_PULLUP);
  pinMode(DOWN_PIN, INPUT_PULLUP);
  pinMode(UP_PIN, INPUT_PULLUP);

  displayTime();
}

void loop() {
  setButtonState = digitalRead(SET_PIN);
  upButtonState = digitalRead(UP_PIN);
  downButtonState = digitalRead(DOWN_PIN);

  if (settingMode) {
    if (upButtonState != lastUpButtonState) {
      lastUpButtonState = upButtonState;
      if (upButtonState == LOW) {
        if (hour < 12) {
          hour++;
        } else {
          hour = 0;
        }
        updateTime = true;
      }
    } else if (downButtonState != lastDownButtonState) {
      lastDownButtonState = downButtonState;
      if (downButtonState == LOW) {
        if (minute < 59) {
          minute++;
        } else {
          minute = 0;
        }
        updateTime = true;
      }
    }

    if (setButtonState != lastSetButtonState) {
      lastSetButtonState = setButtonState;
      if (setButtonState == LOW || updateTime) {
        settingMode = false;
        updateTime = false;
        displayTime();

        DateTime now = rtc.now();
        rtc.adjust(DateTime(now.year(), now.month(), now.day(), hour, minute, now.second()));
        delay(100);
      }
    }
  } else {
    if (setButtonState != lastSetButtonState) {
      lastSetButtonState = setButtonState;
      if (setButtonState == LOW) {
        settingMode = true;
        display.clear();

        delay(200);
      }
    }
  }

  if (!settingMode || (millis() % 500 < 250)) {
    displayTime();
  } else {
    display.clear();
  }

  delay(10);
}

void displayTime() {
  int displayHour = hour;
  if (displayHour > 12) {
    displayHour -= 12;
  }
  display.showNumberDecEx(displayHour * 100 + minute, 0b01000000, true);
  delay(200);
}