#include "Wire.h"


int impulseArray[60];
int impulseCount = 0;
int actualHours, actualMinutes, actualSecond, actualDay, actualMonth, actualYear, DayOfW;

//BEGIN RTC CODE

//rtc variables
int second, minute, hour;
int dayOfWeek, dayOfMonth, month, year;
//end rtc variables

#define DS3231_I2C_ADDRESS 0x68

byte decToBcd(byte val) {
  return ( (val / 10 * 16) + (val % 10) );
}

// Convert binary coded decimal to decimal numbers
byte bcdToDec(byte val) {
  return ( (val / 16 * 10) + (val % 16) );
}

// Set the time
void rtc_setTime(byte second, byte minute, byte hour, byte wday, byte mday, byte mon, byte year) {
  // sets time and date data to DS3231
  Wire.beginTransmission(DS3231_I2C_ADDRESS);
  Wire.write(0); // set next input to start at the seconds register
  Wire.write(decToBcd(second)); // set seconds
  Wire.write(decToBcd(minute)); // set minutes
  Wire.write(decToBcd(hour)); // set hours

  Wire.write(decToBcd(wday)); // set day of week (1=Monday, 7=Sunday)
  Wire.write(decToBcd(mday)); // set date (1 to 31)
  Wire.write(decToBcd(mon)); // set month
  Wire.write(decToBcd(year)); // set year (0 to 99)
  
  Wire.endTransmission();
}

void rtc_readTime() {
  Wire.beginTransmission(DS3231_I2C_ADDRESS);
  Wire.write(0); // set DS3231 register pointer to 00h
  Wire.endTransmission();

  // request seven bytes of data from DS3231 starting from register 00h
  Wire.requestFrom(DS3231_I2C_ADDRESS, 7);
  second = bcdToDec(Wire.read() & 0x7f);
  minute = bcdToDec(Wire.read());
  hour = bcdToDec(Wire.read() & 0x3f);
  dayOfWeek = bcdToDec(Wire.read());
  dayOfMonth = bcdToDec(Wire.read());
  month = bcdToDec(Wire.read());
  year = bcdToDec(Wire.read());

  //leap year correction
  #define LEAP_YEAR(Y)     ( !(((Y))%4) && ( (((Y))%100) || !(((Y))%400) ) )

  if(LEAP_YEAR(year) == 0 && dayOfMonth == 29 && month == 2){
    rtc_setTime(second, minute, hour, dayOfWeek, 1, 3, year);
  }
}

void rtc_init(){
  Wire.begin(); 
}

//END RTC CODE

int dcf_out = 11;
uint32_t previous;

bool dst = false;

void setup() {
  rtc_init();
  pinMode(dcf_out, OUTPUT);
  Serial.begin(115200);
  convertDcf();

  while(second != 0){
    rtc_readTime();
    if(second == 0){
      break;
    }
  }
}

void loop() {
  rtc_readTime();
  if(millis() - previous >= 100){
    convertDcf();
    dcfOut();
    previous = millis();
  }
}

int monthVal(){
  int val = 30;

  if(month == 1){
    val = 31;
  }
  if(month == 2 && !LEAP_YEAR(year)){
    val = 28;
  }
  if(month == 2 && LEAP_YEAR(year)==1){
    val = 29;
  }
  if(month == 3){
    val = 31;
  }
  if(month == 4){
    val = 30;
  }
  if(month == 5){
    val = 31;
  }
  if(month == 6){
    val = 30;
  }
  if(month == 7){
    val = 31;
  }
  if(month == 8){
    val = 31;
  }
  if(month == 9){
    val = 30;
  }
  if(month == 10){
    val = 31;
  }
  if(month == 11){
    val = 30;
  }
  if(month == 12){
    val = 31;
  }
  return val;
}
void convertDcf() {
  rtc_readTime();
  DayOfW = dayOfWeek-1;
  if (DayOfW == 0) DayOfW = 7;
  actualDay = dayOfMonth;
  actualMonth = month;
  actualYear = year % 100;
  actualHours = hour;
  actualMinutes = minute + 1;
  actualSecond = second; 
  if (actualSecond >= 60){  actualSecond = 0;}
  if (actualMinutes >= 60){ actualMinutes = 0; actualHours += 1;}
  if (actualHours >= 24){ actualHours = 0; DayOfW += 1; actualDay += 1;}
  if (DayOfW >= 8){ DayOfW = 1;}
  if (actualDay > monthVal()){ actualDay - monthVal(); actualMonth += 1;}
  if (actualMonth >= 13){ DayOfW = 1; actualYear += 1;}
  if (actualYear >= 100){ actualYear = 0;}

  int n, Tmp, TmpIn;
  int ParityCount = 0;

  //we put the first 20 bits of each minute at a logical zero value
  for (n = 0; n < 20; n++) impulseArray[n] = 1;
  
  // set DST bit
  if (dst == false) {
    impulseArray[18] = 2; // CET or DST OFF
  } else {
    impulseArray[17] = 2; // CEST or DST ON
  }
  
  //bit 20 must be 1 to indicate active time
  impulseArray[20] = 2;

  //calculates the bits for the minutes
  TmpIn = Bin2Bcd(actualMinutes);
  for (n = 21; n < 28; n++) {
    Tmp = TmpIn & 1;
    impulseArray[n] = Tmp + 1;
    ParityCount += Tmp;
    TmpIn >>= 1;
  }
  if ((ParityCount & 1) == 0)
    impulseArray[28] = 1;
  else
    impulseArray[28] = 2;

  //calculates bits for the hours
  ParityCount = 0;
  TmpIn = Bin2Bcd(actualHours);
  for (n = 29; n < 35; n++) {
    Tmp = TmpIn & 1;
    impulseArray[n] = Tmp + 1;
    ParityCount += Tmp;
    TmpIn >>= 1;
  }
  if ((ParityCount & 1) == 0)
    impulseArray[35] = 1;
  else
    impulseArray[35] = 2;
  ParityCount = 0;

  //calculate the bits for the actual Day of Month
  TmpIn = Bin2Bcd(actualDay);
  for (n = 36; n < 42; n++) {
    Tmp = TmpIn & 1;
    impulseArray[n] = Tmp + 1;
    ParityCount += Tmp;
    TmpIn >>= 1;
  }
  TmpIn = Bin2Bcd(DayOfW);
  for (n = 42; n < 45; n++) {
    Tmp = TmpIn & 1;
    impulseArray[n] = Tmp + 1;
    ParityCount += Tmp;
    TmpIn >>= 1;
  }
  //calculates the bits for the actualMonth
  TmpIn = Bin2Bcd(actualMonth);
  for (n = 45; n < 50; n++) {
    Tmp = TmpIn & 1;
    impulseArray[n] = Tmp + 1;
    ParityCount += Tmp;
    TmpIn >>= 1;
  }
  //calculates the bits for actual year
  TmpIn = Bin2Bcd(actualYear);   // 2 digit year
  for (n = 50; n < 58; n++) {
    Tmp = TmpIn & 1;
    impulseArray[n] = Tmp + 1;
    ParityCount += Tmp;
    TmpIn >>= 1;
  }
  //equal date
  if ((ParityCount & 1) == 0)
    impulseArray[58] = 1;
  else
    impulseArray[58] = 2;

  //last missing pulse
  impulseArray[59] = 0; // No pulse
}

int Bin2Bcd(int dato) {
  int msb, lsb;
  if (dato < 10)
    return dato;
  msb = (dato / 10) << 4;
  lsb = dato % 10;
  return msb + lsb;
}

void dcfOut(){
  for(int i = 0; i < 60; i++){
    if(impulseArray[i] == 1){
      digitalWrite(dcf_out,1);
      delay(100);
      digitalWrite(dcf_out,0);
      delay(900);
    }
    if(impulseArray[i] == 2){
      digitalWrite(dcf_out,1);
      delay(200);
      digitalWrite(dcf_out,0);
      delay(800);
    }
    if(impulseArray[i] == 0){
      digitalWrite(dcf_out,0);
      delay(901);
    }
  }
}