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

RTC_DS1307 rtc;
SevSeg sevseg;

// Variables for timing update
unsigned long prevMillis = 0;
const long interval = 1000; // Update every 1 second

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

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

  // If the RTC is not running, set it to the time this sketch was compiled
  if (!rtc.isrunning()) {
    rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
  }

  // --- 7-Segment Display Configuration ---
  byte numDigits = 4;
  
  // Digit Pins (D1, D2, D3, D4 mapped to pins 10, 11, 12, 13)
  byte digitPins[] = {10, 11, 12, 13}; 
  
  // Segment Pins (A, B, C, D, E, F, G, DP mapped to pins 2 to 9)
  byte segmentPins[] = {2, 3, 4, 5, 6, 7, 8, 9}; 
  
  bool resistorsOnSegments = false; // Set true if using physical resistors on segments
  byte hardwareConfig = COMMON_ANODE; // Change to COMMON_CATHODE if display shows inverted/blank logic
  bool updateWithDelays = false; 
  bool leadingZeros = true; 
  bool disableDecPoint = false; 

  // Initialize the display
  sevseg.begin(hardwareConfig, numDigits, digitPins, segmentPins, resistorsOnSegments,
               updateWithDelays, leadingZeros, disableDecPoint);
  sevseg.setBrightness(90);
}

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

  // Read the RTC time periodically
  if (currentMillis - prevMillis >= interval) {
    prevMillis = currentMillis;
    
    DateTime now = rtc.now();
    
    // Format time as HHMM (e.g., 14:30 becomes integer 1430)
    int displayTime = (now.hour() * 100) + now.minute();
    
    // Send the integer to the display buffer, lighting up the second decimal point as a colon
    sevseg.setNumber(displayTime, 2); 
  }

  // Must be called continuously to refresh the multiplexed display
  sevseg.refreshDisplay(); 
}