#include "RTClib.h"

const int dataPin = 12;   // DS
const int latchPin = 11;  // ST_CP
const int clockPin = 13;  // SH_CP

const int amPin = 10;     // LED green for AM
const int pmPin = 9;      // LED red for PM

const int dataPin2 = 8;  // DS do 5º 74HC595 (para o dia da semana)
const int latchPin2 = 7; // ST_CP do 5º 74HC595
const int clockPin2 = 6; // SH_CP do 5º 74HC595

// Segment table for numbers 0-9 (common cathode)
const byte digits[10] = {
  B00111111, // 0
  B00000110, // 1
  B01011011, // 2
  B01001111, // 3
  B01100110, // 4
  B01101101, // 5
  B01111101, // 6
  B00000111, // 7
  B01111111, // 8
  B01101111  // 9
};

RTC_DS1307 rtc;

void setup() {
  pinMode(dataPin, OUTPUT);
  pinMode(latchPin, OUTPUT);
  pinMode(clockPin, OUTPUT);

  pinMode(dataPin2, OUTPUT);  // Para o 5º 74HC595 (dia da semana)
  pinMode(latchPin2, OUTPUT);
  pinMode(clockPin2, OUTPUT);

  Serial.begin(9600);
  
  if (!rtc.begin()) {
    Serial.println("Could not find RTC");
    while (1);
  }

  pinMode(amPin, OUTPUT);  // LED AM
  pinMode(pmPin, OUTPUT);  // LED PM
}

void loop() {
  DateTime now = rtc.now();  // Gets the current time from the RTC
  
  // Convert to 12h format
  int hour = now.hour();
  int minute = now.minute();
  bool isPM = false;
  
  // Check if it's PM
  if (hour >= 12) {
    isPM = true;
    if (hour > 12) hour -= 12;  // Convert to 12h format
  }

  // For 12h format, if the time is 0, we consider it as 12 AM (midnight)
  if (hour == 0) {
    hour = 12;
  }
  // Exibe o dia da semana com LEDs
  displayDayOfWeek(now.dayOfTheWeek());

  // Displays in hh:mm format (hours and minutes)
  displayNumber(hour, minute);

  // Turn on the AM or PM LED
  if (isPM) {
    digitalWrite(pmPin, HIGH); // Red LED lights up for PM
    digitalWrite(amPin, LOW);  // Turn off green LED for AM
  } else {
    digitalWrite(amPin, HIGH); // Green LED lights up for AM
    digitalWrite(pmPin, LOW);  // Turn off red LED for PM
  }

  delay(1000); // Updates every 1 second
}

void displayNumber(int hours, int minutes) {
  byte displayBuffer[4];

  // Extracts the digits from the hours and minutes
  displayBuffer[0] = digits[(hours / 10) % 10]; // First hour house
  displayBuffer[1] = digits[hours % 10];        // Second hour house
  displayBuffer[2] = digits[(minutes / 10) % 10]; // First minute house
  displayBuffer[3] = digits[minutes % 10];      // Second minute house

  digitalWrite(latchPin, LOW);
  
  // Sends to the 4 ICs (displays)
  for (int i = 0; i < 4; i++) {
    shiftOut(dataPin, clockPin, MSBFIRST, displayBuffer[i]);
  }
  
  digitalWrite(latchPin, HIGH);
}

void displayDayOfWeek(int day) {
  // Mapeia os dias da semana para LEDs (0 = Domingo, 1 = Segunda, etc)
  byte dayOfWeek = 1 << day;  // Cria um byte onde o bit correspondente ao dia é 1 (ex: 1<<0 para Domingo, 1<<1 para Segunda, etc)

  digitalWrite(latchPin2, LOW);
  
  // Envia para o 74HC595 (dias da semana)
  shiftOut(dataPin2, clockPin2, MSBFIRST, dayOfWeek);
  
  digitalWrite(latchPin2, HIGH);
}