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

RTC_DS1307 rtc;

// Segment pins (A-G, DP)
const uint8_t segPins[8] = {13, 12, 14, 27, 26, 25, 33, 32};

// Digit selection pins (common cathode)
const uint8_t digitPins[6] = {19, 18, 5, 17, 16, 4};

// Standard 7-segment patterns (0-9, DP off)
const byte digitPattern[10] = {
  B00111111, // 0
  B00000110, // 1
  B01011011, // 2
  B01001111, // 3
  B01100110, // 4
  B01101101, // 5
  B01111101, // 6
  B00000111, // 7
  B01111111, // 8
  B01101111  // 9
};

void setup() {
  // Initialize segment pins
  for (int i = 0; i < 8; i++) {
    pinMode(segPins[i], OUTPUT);
    digitalWrite(segPins[i], LOW);
  }
  
  // Initialize digit pins
  for (int i = 0; i < 6; i++) {
    pinMode(digitPins[i], OUTPUT);
    digitalWrite(digitPins[i], HIGH); // Off by default
  }
  
  // Initialize RTC
  Wire.begin();
  if (!rtc.begin()) {
    while (1); // Halt if RTC not found
  }
  
  if (!rtc.isrunning()) {
    // Set to compile time if RTC not running
    rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
  }
  
  Serial.begin(115200);
}

void displayDigit(uint8_t digit, uint8_t value) {
  // Turn off all digits first
  for (int i = 0; i < 6; i++) {
    digitalWrite(digitPins[i], HIGH);
  }
  
  // Set segments
  byte pattern = digitPattern[value];
  for (int i = 0; i < 8; i++) {
    digitalWrite(segPins[i], bitRead(pattern, i));
  }
  
  // Activate current digit (common cathode)
  digitalWrite(digitPins[digit], LOW);
}

void loop() {
  static uint32_t lastUpdate = 0;
  static uint8_t digits[6] = {0};
  
  // Update time every second
  if (millis() - lastUpdate >= 1000) {
    DateTime now = rtc.now();
    digits[0] = now.hour() / 10;    // Hour tens
    digits[1] = now.hour() % 10;    // Hour ones
    digits[2] = now.minute() / 10;  // Minute tens
    digits[3] = now.minute() % 10;  // Minute ones
    digits[4] = now.second() / 10;  // Second tens
    digits[5] = now.second() % 10;  // Second ones
    lastUpdate = millis();
    
    // Serial debug output
    Serial.printf("Time: %02d:%02d:%02d\n", 
                 now.hour(), now.minute(), now.second());
  }
  
  // Display multiplexing (2ms per digit)
  for (int i = 0; i < 6; i++) {
    displayDigit(i, digits[i]);
    delay(2);
  }
}