/*
  MoonPhase Calendar
  Description:
  Author: Axel "Okura" MONTZAMIR
  Date: 26/01/2024
*/

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

RTC_DS1307 RTC;

void setup() {
  Serial.begin(9600);
  RTC.begin();
  
  if (!RTC.isrunning()) {
    Serial.println("RTC is NOT running!");
  }
}

void loop() {
  displayMoonPhaseCalendar();
  delay(1000); // Delay for better readability in the serial monitor
}

void displayMoonPhaseCalendar() {
  DateTime now = RTC.now();
  int daysInMonth = 30;
  
  Serial.println("\nMoon Phase Calendar for the Current Month:");
  Serial.println("=======================================");
  
  for (int day = 1; day <= daysInMonth; day++) {
    int mp = moon_phase(now.year(), now.month(), day);
    
    Serial.print("Day ");
    Serial.print(day);
    Serial.print(": ");
    
    switch (mp) {
      case 0:
        Serial.println("Full Moon");
        break;
      case 1:
        Serial.println("Waning Gibbous");
        break;
      case 2:
        Serial.println("Last Quarter");
        break;
      case 3:
        Serial.println("Old Crescent");
        break;
      case 4:
        Serial.println("New Moon");
        break;
      case 5:
        Serial.println("New Crescent");
        break;
      case 6:
        Serial.println("First Quarter");
        break;
      case 7:
        Serial.println("Waxing Gibbous");
        break;
    }
  }
}

int moon_phase(int year, int month, int day) {
  double jd = julianDate(year, month, day);
  jd = int(jd - 2244116.75);
  jd /= 29.53;
  int b = jd;
  jd -= b;
  b = jd * 8 + 0.5;
  b = b & 7;
  return b;
}

int daysInMonth(int month, int year) {
  switch (month) {
    case 4:
    case 6:
    case 9:
    case 11:
      return 30;
    case 2:
      if ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0)) {
        return 29; // Leap year
      } else {
        return 28;
      }
    default:
      return 31;
  }
}

double julianDate(int year, int month, int day) {
  int mm, yy;
  double k1, k2, k3, j;
  
  yy = year - int((12 - month) / 10);
  mm = month + 9;
  if (mm >= 12) {
    mm = mm - 12;
  }
  
  k1 = 365.25 * (yy + 4172);
  k2 = int((30.6001 * mm) + 0.5);
  k3 = int((((yy / 100) + 4) * 0.75) - 38);
  j = k1 + k2 + day + 59;
  j = j - k3;
  
  return j;
}