Glitch Date/Time calculation in JavaScript

glitch_time.js

function time_to_glitch(time){
  var year, day_of_year, month_and_day, month, day_of_month, hour, minute, sec, ts ;
  sec = Number(time) - 1238562000;

  // there are 4435200 real seconds in a game year
  // there are 14400 real seconds in a game day
  // there are 600 real seconds in a game hour
  // there are 10 real seconds in a game minute

  year = Math.floor(sec / 4435200);
  sec -= year * 4435200;

  day_of_year = Math.floor(sec / 14400);
  sec -= day_of_year * 14400;

  hour = Math.floor(sec / 600);
  sec -= hour * 600;

  minute = Math.floor(sec / 10);
  sec -= minute * 10;

  // turn the 0-based day-of-year into a day & month
  month_and_day = day_to_md(day_of_year);
  month = month_and_day[0];
  day_of_month = month_and_day[1];

  // get day-of-week
  if(month == 11) {
    day_of_week = undefined
  } else {
    day_of_week = (day_of_year + (307 * year)) % 8;
  }

  return [year, month, day_of_month, day_of_week, hour, minute, sec]
}

function day_to_md(day_of_year){
  var m,d,cd,months;
  months = [29, 3, 53, 17, 73, 19, 13, 37, 5, 47, 11, 1];
  cd = 0;

  for (var i=0; i<months.length; i++){
    cd += months[i];
    if (cd > day_of_year){
      m = i;
      d = day_of_year+1 - (cd - months[i]);
      return [m, d];
    }
  }

  return [0,0];
}

function ordinalize(number){
  if (11 <= parseInt(number) % 100 && parseInt(number) % 100 <= 13) {
    return number + "th";
  } else {
    switch (parseInt(number) % 10) {
      case  1: return number + "st";
      case  2: return number + "nd";
      case  3: return number + "rd";
      default: return number + "th";
    }
  }
}

function formatted_glitch_time(time){
  var days_of_week, months, parts, hour, ap, min;
  days_of_week = ['Hairday', 'Moonday', 'Twoday', 'Weddingday', 'Theday', 'Fryday', 'Standday', 'Fabday']
  months = ['Primuary', 'Spork', 'Bruise', 'Candy', 'Fever', 'Junuary', 'Septa', 'Remember', 'Doom', 'Widdershins', 'Eleventy', 'Recurse']
  parts = time_to_glitch(time);
  if(parts[4] > 12){
    hour = parts[4] - 12;
    ap = 'pm'
  }else if(parts[4] == 0){
    hour = 12;
    ap = 'am';
  }else{
    hour = parts[4];
    ap = 'am'
  }
  var day_and_weekday;
  if(parts[1] == 12) {
    day_and_weekday = 'Recurse'
  } else {
    day_and_weekday = days_of_week[parts[3]] + ', ' + ordinalize(parts[2]) + ' of ' + months[parts[1]]
  }
  if(parts[5] < 10){ min = '0' + String(parts[5]) }else{ min = parts[5] }
  return hour + ':' + min + ap + ', ' + day_and_weekday + ', year ' + parts[0]
}

usage.js

// The useful functions provided are:

time_to_glitch(1315001582);
// > [17, 3, 41, 3, 7, 18, 2]

// The return value is [year, month, day_of_month, day_of_week, hour, minute, sec]

formatted_glitch_time(1315001582)
// > "7:18am, Weddingday, 41st of Candy, year 17"

// Both functions take the number of seconds since epoch as an argument. The argument
// is cast to a number before being used, so don't worry about the casting if you're
// pulling it out of HTML. If you're trying to show the current time, you'll probably
// want to do something like:

formatted_glitch_time((new Date).getTime() / 1000)

// JavaScript's Date.getTime() function return milliseconds instead of seconds, so we're
// dividing by 1000 to account for that.