/**
 * Date extensions
 * 
 * From the site: http://www.xml-blog.com/files/date_extras.js
 * @author Michael Mifsud
 * @package calendar
 */


// Global Constants
var JANUARY   = 0;
var FEBRUARY  = 1;
var MARCH     = 2;
var APRIL     = 3;
var MAY       = 4;
var JUNE      = 5;
var JULY      = 6;
var AUGUST    = 7;
var SEPTEMBER = 8;
var OCTOBER   = 9;
var NOVEMBER  = 10;
var DECEMBER  = 11;

var SUNDAY    = 0;
var MONDAY    = 1;
var TUESDAY   = 2;
var WEDNESDAY = 3;
var THURSDAY  = 4;
var FRIDAY    = 5;
var SATURDAY  = 6;


Date.prototype.getCivilianHours = function() {
  return (this.getHours() < 12) ? this.getHours() : this.getHours() - 12;
}
Date.prototype.getMeridiem = function() {
  return (this.getHours() < 12) ? "AM" : "PM";
}

Date.prototype.to_s = Date.prototype.toString;



// Non-destructive instance methods
Date.prototype.addMilliseconds = function(ms){  
  return new Date(new Date().setTime(this.getTime() + (ms)));  
}
Date.prototype.addSeconds = function(s){
  return new Date (this.getFullYear(), this.getMonth(), this.getDate(), 
                    this.getHours(), this.getMinutes(), this.getSeconds()+s);
}
Date.prototype.addMinutes = function(m){
  return new Date (this.getFullYear(), this.getMonth(), this.getDate(), 
                    this.getHours(), this.getMinutes()+m, this.getSeconds());
}
Date.prototype.addHours = function(h){
  return new Date (this.getFullYear(), this.getMonth(), this.getDate(), 
                    this.getHours()+h, this.getMinutes(), this.getSeconds());
}
Date.prototype.addDays = function(d){
  return new Date (this.getFullYear(), this.getMonth(), this.getDate()+d, 
                    this.getHours(), this.getMinutes(), this.getSeconds());
}
Date.prototype.addWeeks = function(w){
  d = w*7;
  return new Date (this.getFullYear(), this.getMonth(), this.getDate()+d, 
                    this.getHours(), this.getMinutes(), this.getSeconds());
}
Date.prototype.addMonths = function(m){
  return new Date (this.getFullYear(), this.getMonth()+m, this.getDate(), 
                    this.getHours(), this.getMinutes(), this.getSeconds());
}
Date.prototype.addYears = function(y){
  return new Date (this.getFullYear()+y, this.getMonth(), this.getDate(), 
                    this.getHours(), this.getMinutes(), this.getSeconds());
}

/**
 * Get a months long name.
 * 
 * @param integer - (optional) The month to get name for.
 */
Date.prototype.getMonthName = function() {
    var index = (0 == arguments.length) ? this.getMonth() : arguments[0];
    switch(index)
    {
        case JANUARY: 
          return "January";
        case FEBRUARY: 
          return "February";
        case MARCH: 
          return "March";
        case APRIL: 
          return "April";
        case MAY: 
          return "May";
        case JUNE: 
          return "June";
        case JULY: 
          return "July";
        case AUGUST: 
          return "August";
        case SEPTEMBER: 
          return "September";
        case OCTOBER: 
          return "October";
        case NOVEMBER: 
          return "November";
        case DECEMBER: 
          return "December";
        default:
          throw "Invalid month index: " + index.toString();
    }
}

/**
 * Get a months Abbreviated name.
 * 
 * @param integer - (optional) The month to get name for.
 */
Date.prototype.getMonthAbbreviation = function() {
    var index = (0 == arguments.length) ? this.getMonth() : arguments[0];
    switch(index)
    {
        case JANUARY: 
          return "Jan";
        case FEBRUARY: 
          return "Feb";
        case MARCH: 
          return "Mar";
        case APRIL: 
          return "Apr";
        case MAY: 
          return "May";
        case JUNE: 
          return "Jun";
        case JULY: 
          return "Jul";
        case AUGUST: 
          return "Aug";
        case SEPTEMBER: 
          return "Sep";
        case OCTOBER: 
          return "Oct";
        case NOVEMBER: 
          return "Nov";
        case DECEMBER: 
          return "Dec";
        default:
          throw "Invalid month index: " + index.toString();
    }
}

/**
 * Get a day name.
 * 
 * @param integer - (optional) The day to get name for.
 */
Date.prototype.getDayName = function() {
    var index = (0 == arguments.length) ? this.getDay() : arguments[0];
    switch(index)
    {
        case SUNDAY: 
          return "Sunday";
        case MONDAY: 
          return "Monday";
        case TUESDAY: 
          return "Tuesday";
        case WEDNESDAY: 
          return "Wednesday";
        case THURSDAY: 
          return "Thursday";
        case FRIDAY: 
          return "Friday";
        case SATURDAY: 
          return "Saturday";    
        default:
          throw "Invalid day index: " + index.toString();
    }
}

/**
 * Get a day Abbreviated name.
 * 
 * @param integer - (optional) The day to get name for.
 */
Date.prototype.getDayAbbreviation = function() {
    var index = (0 == arguments.length) ? this.getDay() : arguments[0];
    switch(index)
    {
        case SUNDAY: 
          return "Sun";
        case MONDAY: 
          return "Mon";
        case TUESDAY: 
          return "Tue";
        case WEDNESDAY: 
          return "Wed";
        case THURSDAY: 
          return "Thu";
        case FRIDAY: 
          return "Fri";
        case SATURDAY: 
          return "Sat";
        default:
          throw "Invalid day index: " + index.toString();
    }
}

/**
 * Get the number of days in this month or given month.
 * 
 * @param integer - (optional) The month to get value for
 */
Date.prototype.getDaysInMonth = function () {
    var index = arguments[0] != null ? arguments[0] : this.getMonth();
    
    switch(this.getMonth())
    {
        case JANUARY:
          return 31;
        case FEBRUARY:
          return this.isLeapYear() ? 29 : 28;
        case MARCH:
          return 31;
        case APRIL:
          return 30;
        case MAY:
          return 31;
        case JUNE:
          return 30;
        case JULY:
          return 31;
        case AUGUST:
          return 31;
        case SEPTEMBER:
          return 30;
        case OCTOBER:
          return 31;
        case NOVEMBER:
          return 30;
        case DECEMBER:
          return 31;
        default:
          throw "Invalid month index: " + index.toString();
    }
}

/** 
 * Test if this month is a leap year.
 * 
 */
Date.prototype.isLeapYear = function() {
    if (0 == this.getFullYear() % 400) return true;
    if (0 == this.getFullYear() % 100) return false;
    return (0 == this.getFullYear() % 4) ? true : false;
}

/**
 * Get a DAte object of the first day of this objects month.
 * @return Date
 */
Date.prototype.getFirstDayOfMonth = function() {  
    return new Date(this.getFullYear(), this.getMonth(), 1, 12, 0, 0);
}

/**
 * Get a Date object of the last day of this objects month.
 * @return Date
 */
Date.prototype.getLastDayOfMonth = function() {  
    return new Date(this.getFullYear(), this.getMonth(), this.getDaysInMonth(), 12, 0, 0);
}

/**
 * Return a clone of this date
 * @return Date
 */
Date.prototype.clone = function() {
  var dt = new Date();
  dt.setTime(this.getTime());  
  return dt;
}

/**
 * Return a clone date that has a zero value time.
 * @return Date
 */
Date.prototype.zeroTime = function() {
  var dt = this.clone();
  dt.setHours(0);
  dt.setMinutes(0);
  dt.setSeconds(0);
  dt.setMilliseconds(0);
  return dt;
}

/**
 * Return a clone date that has a time of noon
 * @return Date
 */
Date.prototype.noon = function() {
  var dt = this.clone();
  dt.setHours(12);
  dt.setMinutes(0);
  dt.setSeconds(0);
  dt.setMilliseconds(0);
  return dt;
}
/** 
 *  Ultra-flexible date formatting
 *
 *  %YYYY = 4 digit year         (2005)
 *  %YY   = 2 digit year         (05)
 *  %MMMM = Month name           (March)
 *  %MMM  = Month abbreviation   (March becomes Mar)
 *  %MM   = 2 digit month number (March becomes 03)
 *  %M    = 1 or 2 digit month   (March becomes 3)
 *  %DDDD = Day name             (Thursday)
 *  %DDD  = Day abbreviation     (Thu)
 *  %DD   = 2 digit day          (09) 
 *  %D    = 1 or 2 digit day     (9)
 *  %HH   = 2 digit 24 hour      (13)
 *  %H    = 1 or 2 digit 24 hour (9)
 *  %hh   = 2 digit 12 Hour      (01)
 *  %h    = 1 or 2 digit 12 Hour (01)
 *  %mm   = 2 digit minute       (02)
 *  %m    = 1 or 2 digit minute  (2)
 *  %ss   = 2 digit second       (59)
 *  %s    = 1 or 2 digit second  (1)
 *  %nnn  = milliseconds
 *  %p    = AM/PM indicator
 * 
 * @param string fs - A string to format the date (eg: '%DD-%MM-%YYYY' = '02-25-2003')
 * @return string
 */
Date.prototype.format = function(fs) {

   fs = fs.replace(/%YYYY/, this.getFullYear().toString());
   fs = fs.replace(/%YY/, this.getFullYear().toString().substr(2,2));
   
   fs = fs.replace(/%MMMM/, this.getMonthName(this.getMonth()).toString());
   fs = fs.replace(/%MMM/, this.getMonthAbbreviation(this.getMonth()).toString());
   fs = fs.replace(/%MM/, (this.getMonth() + 1) > 9 ? (this.getMonth() + 1).toString() : "0" + (this.getMonth() + 1).toString());
   fs = fs.replace(/%M/, (this.getMonth() + 1).toString());
   
   fs = fs.replace(/%DDDD/, this.getDayName(this.getDay()).toString());
   fs = fs.replace(/%DDD/, this.getDayAbbreviation(this.getDay()).toString());
   fs = fs.replace(/%DD/, this.getDate() > 9 ? this.getDate().toString() : "0" + this.getDate().toString());
   fs = fs.replace(/%D/, this.getDate().toString());
   
   fs = fs.replace(/%HH/, this.getHours() > 9 ? this.getHours().toString() : "0" + this.getHours().toString());
   fs = fs.replace(/%H/, this.getHours().toString());
   fs = fs.replace(/%hh/, this.getCivilianHours() > 9 ? this.getCivilianHours().toString() : "0" + this.getCivilianHours().toString());
   fs = fs.replace(/%h/, this.getCivilianHours());

   fs = fs.replace(/%mm/, this.getMinutes() > 9 ? this.getMinutes().toString() : "0" + this.getMinutes().toString());
   fs = fs.replace(/%m/, this.getMinutes().toString());

   fs = fs.replace(/%ss/, this.getSeconds() > 9 ? this.getSeconds().toString() : "0" + this.getSeconds().toString());
   fs = fs.replace(/%s/, this.getSeconds().toString());

   fs = fs.replace(/%nnn/, this.getMilliseconds().toString());
   fs = fs.replace(/%p/, this.getMeridiem());
   return fs;
}

// Give toString more flexibility
Date.prototype.toString = function() {
  if (0 == arguments.length || 1 < arguments.length) return this.to_s();
  return this.format(arguments[0].toString());
}