"use strict";

( function ( NS ) {

var isLeapYear = function ( year ) {
 return (
   ( ( year % 4 === 0 ) && ( year % 100 !== 0 ) ) || ( year % 400 === 0 )
 );
};
var daysInMonths = [ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 ];

var dateFormat = /^(\d{4}|[+\-]\d{6})(?:-(\d{2})(?:-(\d{2}))?)?(?:T(\d{2}):(\d{2})(?::(\d{2})(?:\.(\d{3}))?)?(?:Z|(?:([+\-])(\d{2})(?::(\d{2}))?)?)?)?$/;

Date.extend({
 fromJSON: function ( value ) {
   /*
     /^
     (\d{4}|[+\-]\d{6})      // 1. Year
     (?:
       -(\d{2})            // 2. Month
       (?:
         -(\d{2})        // 3. Day
       )?
     )?
     (?:
       T(\d{2}):(\d{2})    // 4. Hour : 5. Minutes
       (?:
         :(\d{2})        // 6. Seconds
         (?:
           \.(\d{3})   // 7. Milliseconds
         )?
       )?
       (?:
         Z|              // (UTC time)
         (?:
           ([+\-])     // 8. +/-
           (\d{2})     // 9. Hours offset
           (?:
             :(\d{2}) // 10. Minutes offset
           )?
         )?
       )?
     )?$/;
   */
   var results = value ? dateFormat.exec( value ) : null;
   return results ?
     new Date( Date.UTC(
       +results[1] || 0,            // Year
       ( +results[2] || 1 ) - 1,    // Month
       +results[3] || 1,            // Day
       +results[4] || 0,            // Hours
       +results[5] || 0,            // Minutes
       +results[6] || 0,            // Seconds
       +results[7] || 0             // MS
     ) + ( results[8] ?               // Has offset?
       // +- 1 minute in ms
       ( results[8] === '+' ? -1 : 1 ) * 60000 *
       // Offset in minutes
       ( ( ( +results[9] || 0 ) * 60 ) + ( +results[10] || 0 ) ) :
       // No offset
       0
     )) :
     null;
 },

 getDaysInMonth: function ( month, year ) {
   return ( month === 1 && isLeapYear( year ) ) ?
     29 : daysInMonths[ month ];
 },
 getDaysInYear: function ( year ) {
   return isLeapYear( year ) ? 366 : 365;
 },
 isLeapYear: isLeapYear
});

var pad = function ( num, nopad, character ) {
 return ( nopad || num > 9 ) ? num : ( character || '0' ) + num;
};

var aDay = 86400000; // milliseconds in a day

var duration = {
 second: 1000,
 minute: 60000,
 hour: 3600000,
 day: aDay,
 week: 604800000
};

Date.implement({
 isToday: function ( utc ) {
   var now = new Date(),
     date = now.getDate(),
     month = now.getMonth(),
     year = now.getFullYear();
   return utc ?
     this.getUTCFullYear() === year &&
     this.getUTCMonth() === month &&
     this.getUTCDate() === date :
     this.getFullYear() === year &&
     this.getMonth() === month &&
     this.getDate() === date;
 },

isOnSameDayAs: function ( date, utc ) {
   return utc ?
     date.getUTCFullYear() === this.getUTCFullYear() &&
     date.getUTCMonth() === this.getUTCMonth() &&
     date.getUTCDate() === this.getUTCDate() :
     date.getFullYear() === this.getFullYear() &&
     date.getMonth() === this.getMonth() &&
     date.getDate() === this.getDate();
 },

getDayName: function ( abbreviate, utc ) {
   var names = NS.i18n && NS.i18n.get(
       ( abbreviate ? 'abbreviatedD' : 'd' ) + 'ayNames' ),
     day = utc ? this.getUTCDay() : this.getDay();
   return names ? names[ day ] : day;
 },

getMonthName: function ( abbreviate, utc ) {
   var names = NS.i18n && NS.i18n.get(
       ( abbreviate ? 'abbreviatedM' : 'm' ) + 'onthNames' ),
     day = utc ? this.getUTCMonth() : this.getMonth();
   return names ? names[ day ] : day;
 },

getDayOfYear: function ( utc ) {
   var beginningOfYear = utc ?
     Date.UTC( this.getUTCFullYear(), 0, 1 ) :
     +new Date( this.getFullYear(), 0, 1 );
   return ~~( ( this.getTime() - beginningOfYear ) / aDay ) + 1;
 },

getWeekNumber: function ( firstDayOfWeek, utc ) {
   var day = utc ? this.getUTCDay() : this.getDay(),
     dayOfYear = this.getDayOfYear( utc ) - 1, // Day of the year 0-index
     daysToNext = ( ( firstDayOfWeek || 0 ) - day ).mod( 7 ) || 7;
   return Math.floor( ( dayOfYear + daysToNext ) / 7 );
 },

getISOWeekNumber: function ( firstDayOfWeek, utc ) {
   // The week number of the year (Monday as the first day of
   // the week) as a decimal number [01,53]. If the week containing
   // 1 January has four or more days in the new year, then it is
   // considered week 1. Otherwise, it is the last week of the
   // previous year, and the next week is week 1.
   if ( firstDayOfWeek == null ) { firstDayOfWeek = 1; }

   // 4th January is always in week 1.
   var jan4 = utc ?
       new Date( Date.UTC( this.getUTCFullYear(), 0, 4 ) ) :
       new Date( this.getFullYear(), 0, 4 ),
     jan4WeekDay = utc ? jan4.getUTCDay() : jan4.getDay(),
     // Find Monday before 4th Jan
     wk1Start = jan4 - ( jan4WeekDay - firstDayOfWeek ).mod( 7 ) * aDay,
     // Week No == How many weeks have past since then, + 1.
     week = Math.floor( ( this - wk1Start ) / 604800000 ) + 1,
     date, day;
   if ( week === 53 ) {
     date = utc ? this.getUTCDate() : this.getDate();
     day = utc ? this.getUTCDay() : this.getDay();
     // First day of week must be no greater than 28th December
     if ( date - ( day - firstDayOfWeek ).mod( 7 ) > 28 ) {
       week = 1;
     }
   }
   return week || new Date(
     ( utc ? this.getUTCFullYear() : this.getFullYear() ) - 1, 11, 31, 12
   ).getISOWeekNumber( firstDayOfWeek, false );
 },

add: function ( number, unit ) {
   if ( unit === 'year' ) {
     this.setFullYear( this.getFullYear() + number );
   } else if ( unit === 'month' ) {
     this.setMonth( this.getMonth() + number );
   } else {
     this.setTime(
       this.getTime() + number * ( duration[ unit || 'day' ] || 0 ) );
   }
   return this;
 },

subtract: function ( number, unit ) {
   return this.add( -number, unit );
 },

format: function ( format, utc ) {
   var date = this;
   return format ?
     format.replace(/%(\-)?([%A-Za-z])/g,
       function ( string, nopad, character ) {
     var num, str;
     switch ( character ) {
     case 'a':
       // Abbreviated day of the week, e.g. 'Mon'.
       return date.getDayName( true, utc );
     case 'A':
       // Full day of the week, e.g. 'Monday'.
       return date.getDayName( false, utc );
     case 'b':
       // Abbreviated month name, e.g. 'Jan'.
       return date.getMonthName( true, utc );
     case 'B':
       // Full month name, e.g. 'January'.
       return date.getMonthName( false, utc );
     case 'c':
       // The locale's appropriate date and time representation.
       return NS.i18n ?
         NS.i18n.date( date, 'fullDateAndTime' ) :
         date.toLocaleString();
     case 'C':
       // Century number (00-99).
       return pad( ~~(
         ( utc ? date.getUTCFullYear() : date.getFullYear() ) / 100
       ), nopad );
     case 'd':
       // Day of the month (01-31).
       return pad( utc ? date.getUTCDate() : date.getDate(), nopad );
     case 'D':
       // Same as '%m/%d/%y'
       return date.format( '%m/%d/%y', utc );
     case 'e':
       // Day of the month (' 1'-'31'), padded with a space if single
       // digit.
       return pad(
         utc ? date.getUTCDate() : date.getDate(), nopad, ' ' );
     case 'h':
       // Same as '%b'.
       return date.getMonthName( true, utc );
     case 'H':
       // Hour of the day in 24h clock (00-23).
       return pad( utc ? date.getUTCHours() : date.getHours(), nopad );
     case 'I':
       // Hour of the day in 12h clock (01-12).
       num = utc ? date.getUTCHours() : date.getHours();
       return num ? pad( num < 13 ? num : num - 12, nopad ) : 12;
     case 'j':
       // Day of the year as a decimal number (001-366).
       num = date.getDayOfYear( utc );
       return nopad ? num : num < 100 ? '0' + pad( num ) : pad( num );
     case 'm':
       // Month of the year (01-12).
       return pad(
         ( utc ? date.getUTCMonth() : date.getMonth() ) + 1, nopad );
     case 'M':
       // Minute of the hour (00-59).
       return pad(
         ( utc ? date.getUTCMinutes() : date.getMinutes() ), nopad );
     case 'n':
       // Newline character.
       return '\n';
     case 'p':
       // Localised equivalent of AM or PM.
       str = ( utc ? date.getUTCHours() : date.getHours() ) < 12 ?
         'am' : 'pm';
       return NS.i18n ?
         NS.i18n.get( str + 'Designator' ) : str.toUpperCase();
     case 'r':
       // The time in AM/PM notation: '%I:%M:%S %p'.
       return date.format( '%I:%M:%S %p', utc );
     case 'R':
       // The time in 24h notation: '%H:%M'.
       return date.format( '%H:%M', utc );
     case 'S':
       // The second of the minute (00-61)
       return pad(
         utc ? date.getUTCSeconds() : date.getSeconds(), nopad );
     case 't':
       // Tab character.
       return '\t';
     case 'T':
       // The time: '%H:%M:%S'.
       return date.format( '%H:%M:%S', utc );
     case 'u':
       // Weekday (1-7) where Monday is 1.
       return ( utc ? date.getUTCDay() : date.getDay() ) || 7;
     case 'U':
       // The week number of the year (Sunday as the first day of
       // the week) as a decimal number [00,53]. First Sunday in the
       // year is the start of week 1.
       return pad( this.getWeekNumber( 0, utc ), nopad );
     case 'V':
       // The week number of the year (Monday as the first day of
       // the week) as a decimal number [01,53]. If the week containing
       // 1 January has four or more days in the new year, then it is
       // considered week 1. Otherwise, it is the last week of the
       // previous year, and the next week is week 1.
       return pad( this.getISOWeekNumber( 1, utc ), nopad );
     case 'w':
       // Weekday (0-6) where Sunday is 0.
       return utc ? date.getUTCDay() : date.getDay();
     case 'W':
       // The week number of the year (Monday as the first day of
       // the week) as a decimal number [00,53]. All days in a new year
       // preceding the first Monday are considered to be in week 0.
       return pad( this.getWeekNumber( 1, utc ), nopad );
     case 'x':
       // The locale's appropriate date representation.
       return NS.i18n ?
         NS.i18n.date( date, 'date' ) :
         date.format( '%d/%m/%y', utc );
     case 'X':
       // The locale's appropriate time representation.
       return NS.i18n ?
         NS.i18n.date( date, 'time' ) : date.format( '%H:%M', utc );
     case 'y':
       // Year without century (00-99).
       return ( utc ?
         date.getUTCFullYear() : date.getFullYear()
       ).toString().slice( 2 );
     case 'Y':
       // Year with century (0-9999).
       return utc ? date.getUTCFullYear() : date.getFullYear();
     case 'Z':
       // Timezone name or abbreviation.
       return ( /\((.*)\)/.exec( date.toString() ) || [ '' ] ).pop();
     case '%':
       // A '%' character.
       return character;
     default:
       return string;
     }
   }) : this.toString();
 }
});

}( O ) );