/*!
 * Date picker for pickadate.js v3.5.0
 * http://amsul.github.io/pickadate.js/date.htm
 */

(function ( factory ) {

    // Register as an anonymous module.
    if ( typeof define == 'function' && define.amd )
        define( ['picker','jquery'], factory )

    // Or using browser globals.
    else factory( Picker, jQuery )

}(function( Picker, $ ) {


/**
 * Globals and constants
 */
var DAYS_IN_WEEK = 7,
    WEEKS_IN_CALENDAR = 6,
    _ = Picker._



/**
 * The date picker constructor
 */
function DatePicker( picker, settings ) {

    var calendar = this,
        elementValue = picker.$node[ 0 ].value,
        elementDataValue = picker.$node.data( 'value' ),
        valueString = elementDataValue || elementValue,
        formatString = elementDataValue ? settings.formatSubmit : settings.format,
        isRTL = function() {
            return getComputedStyle( picker.$root[0] ).direction === 'rtl'
        }

    calendar.settings = settings
    calendar.$node = picker.$node

    // The queue of methods that will be used to build item objects.
    calendar.queue = {
        min: 'measure create',
        max: 'measure create',
        now: 'now create',
        select: 'parse create validate',
        highlight: 'parse navigate create validate',
        view: 'parse create validate viewset',
        disable: 'deactivate',
        enable: 'activate'
    }

    // The component's item object.
    calendar.item = {}

    calendar.item.clear = null
    calendar.item.disable = ( settings.disable || [] ).slice( 0 )
    calendar.item.enable = -(function( collectionDisabled ) {
        return collectionDisabled[ 0 ] === true ? collectionDisabled.shift() : -1
    })( calendar.item.disable )

    calendar.
        set( 'min', settings.min ).
        set( 'max', settings.max ).
        set( 'now' )

    // When there’s a value, set the `select`, which in turn
    // also sets the `highlight` and `view`.
    if ( valueString ) {
        calendar.set( 'select', valueString, { format: formatString })
    }

    // If there’s no value, default to highlighting “today”.
    else {
        calendar.
            set( 'select', null ).
            set( 'highlight', calendar.item.now )
    }


    // The keycode to movement mapping.
    calendar.key = {
        40: 7, // Down
        38: -7, // Up
        39: function() { return isRTL() ? -1 : 1 }, // Right
        37: function() { return isRTL() ? 1 : -1 }, // Left
        go: function( timeChange ) {
            var highlightedObject = calendar.item.highlight,
                targetDate = new Date( highlightedObject.year, highlightedObject.month, highlightedObject.date + timeChange )
            calendar.set(
                'highlight',
                [ targetDate.getFullYear(), targetDate.getMonth(), targetDate.getDate() ],
                { interval: timeChange }
            )
            this.render()
        }
    }


    // Bind some picker events.
    picker.
        on( 'render', function() {
            picker.$root.find( '.' + settings.klass.selectMonth ).on( 'change', function() {
                var value = this.value
                if ( value ) {
                    picker.set( 'highlight', [ picker.get( 'view' ).year, value, picker.get( 'highlight' ).date ] )
                    picker.$root.find( '.' + settings.klass.selectMonth ).trigger( 'focus' )
                }
            })
            picker.$root.find( '.' + settings.klass.selectYear ).on( 'change', function() {
                var value = this.value
                if ( value ) {
                    picker.set( 'highlight', [ value, picker.get( 'view' ).month, picker.get( 'highlight' ).date ] )
                    picker.$root.find( '.' + settings.klass.selectYear ).trigger( 'focus' )
                }
            })
        }).
        on( 'open', function() {
            picker.$root.find( 'button, select' ).attr( 'disabled', false )
        }).
        on( 'close', function() {
            picker.$root.find( 'button, select' ).attr( 'disabled', true )
        })

} //DatePicker


/**
 * Set a datepicker item object.
 */
DatePicker.prototype.set = function( type, value, options ) {

    var calendar = this,
        calendarItem = calendar.item

    // If the value is `null` just set it immediately.
    if ( value === null ) {
        if ( type == 'clear' ) type = 'select'
        calendarItem[ type ] = value
        return calendar
    }

    // Otherwise go through the queue of methods, and invoke the functions.
    // Update this as the time unit, and set the final value as this item.
    // * In the case of `enable`, keep the queue but set `disable` instead.
    //   And in the case of `flip`, keep the queue but set `enable` instead.
    calendarItem[ ( type == 'enable' ? 'disable' : type == 'flip' ? 'enable' : type ) ] = calendar.queue[ type ].split( ' ' ).map( function( method ) {
        value = calendar[ method ]( type, value, options )
        return value
    }).pop()

    // Check if we need to cascade through more updates.
    if ( type == 'select' ) {
        calendar.set( 'highlight', calendarItem.select, options )
    }
    else if ( type == 'highlight' ) {
        calendar.set( 'view', calendarItem.highlight, options )
    }
    else if ( type.match( /^(flip|min|max|disable|enable)$/ ) ) {
        if ( calendarItem.select && calendar.disabled( calendarItem.select ) ) {
            calendar.set( 'select', calendarItem.select, options )
        }
        if ( calendarItem.highlight && calendar.disabled( calendarItem.highlight ) ) {
            calendar.set( 'highlight', calendarItem.highlight, options )
        }
    }

    return calendar
} //DatePicker.prototype.set


/**
 * Get a datepicker item object.
 */
DatePicker.prototype.get = function( type ) {
    return this.item[ type ]
} //DatePicker.prototype.get


/**
 * Create a picker date object.
 */
DatePicker.prototype.create = function( type, value, options ) {

    var isInfiniteValue,
        calendar = this

    // If there’s no value, use the type as the value.
    value = value === undefined ? type : value


    // If it’s infinity, update the value.
    if ( value == -Infinity || value == Infinity ) {
        isInfiniteValue = value
    }

    // If it’s an object, use the native date object.
    else if ( $.isPlainObject( value ) && _.isInteger( value.pick ) ) {
        value = value.obj
    }

    // If it’s an array, convert it into a date and make sure
    // that it’s a valid date – otherwise default to today.
    else if ( $.isArray( value ) ) {
        value = new Date( value[ 0 ], value[ 1 ], value[ 2 ] )
        value = _.isDate( value ) ? value : calendar.create().obj
    }

    // If it’s a number or date object, make a normalized date.
    else if ( _.isInteger( value ) || _.isDate( value ) ) {
        value = calendar.normalize( new Date( value ), options )
    }

    // If it’s a literal true or any other case, set it to now.
    else /*if ( value === true )*/ {
        value = calendar.now( type, value, options )
    }

    // Return the compiled object.
    return {
        year: isInfiniteValue || value.getFullYear(),
        month: isInfiniteValue || value.getMonth(),
        date: isInfiniteValue || value.getDate(),
        day: isInfiniteValue || value.getDay(),
        obj: isInfiniteValue || value,
        pick: isInfiniteValue || value.getTime()
    }
} //DatePicker.prototype.create


/**
 * Create a range limit object using an array, date object,
 * literal “true”, or integer relative to another time.
 */
DatePicker.prototype.createRange = function( from, to ) {

    var calendar = this,
        createDate = function( date ) {
            if ( date === true || $.isArray( date ) || _.isDate( date ) ) {
                return calendar.create( date )
            }
            return date
        }

    // Create objects if possible.
    if ( !_.isInteger( from ) ) {
        from = createDate( from )
    }
    if ( !_.isInteger( to ) ) {
        to = createDate( to )
    }

    // Create relative dates.
    if ( _.isInteger( from ) && $.isPlainObject( to ) ) {
        from = [ to.year, to.month, to.date + from ];
    }
    else if ( _.isInteger( to ) && $.isPlainObject( from ) ) {
        to = [ from.year, from.month, from.date + to ];
    }

    return {
        from: createDate( from ),
        to: createDate( to )
    }
} //DatePicker.prototype.createRange


/**
 * Check if a date unit falls within a date range object.
 */
DatePicker.prototype.withinRange = function( range, dateUnit ) {
    range = this.createRange(range.from, range.to)
    return dateUnit.pick >= range.from.pick && dateUnit.pick <= range.to.pick
}


/**
 * Check if two date range objects overlap.
 */
DatePicker.prototype.overlapRanges = function( one, two ) {

    var calendar = this

    // Convert the ranges into comparable dates.
    one = calendar.createRange( one.from, one.to )
    two = calendar.createRange( two.from, two.to )

    return calendar.withinRange( one, two.from ) || calendar.withinRange( one, two.to ) ||
        calendar.withinRange( two, one.from ) || calendar.withinRange( two, one.to )
}


/**
 * Get the date today.
 */
DatePicker.prototype.now = function( type, value, options ) {
    value = new Date()
    if ( options && options.rel ) {
        value.setDate( value.getDate() + options.rel )
    }
    return this.normalize( value, options )
}


/**
 * Navigate to next/prev month.
 */
DatePicker.prototype.navigate = function( type, value, options ) {

    var targetDateObject,
        targetYear,
        targetMonth,
        targetDate,
        isTargetArray = $.isArray( value ),
        isTargetObject = $.isPlainObject( value ),
        viewsetObject = this.item.view/*,
        safety = 100*/


    if ( isTargetArray || isTargetObject ) {

        if ( isTargetObject ) {
            targetYear = value.year
            targetMonth = value.month
            targetDate = value.date
        }
        else {
            targetYear = +value[0]
            targetMonth = +value[1]
            targetDate = +value[2]
        }

        // If we’re navigating months but the view is in a different
        // month, navigate to the view’s year and month.
        if ( options && options.nav && viewsetObject && viewsetObject.month !== targetMonth ) {
            targetYear = viewsetObject.year
            targetMonth = viewsetObject.month
        }

        // Figure out the expected target year and month.
        targetDateObject = new Date( targetYear, targetMonth + ( options && options.nav ? options.nav : 0 ), 1 )
        targetYear = targetDateObject.getFullYear()
        targetMonth = targetDateObject.getMonth()

        // If the month we’re going to doesn’t have enough days,
        // keep decreasing the date until we reach the month’s last date.
        while ( /*safety &&*/ new Date( targetYear, targetMonth, targetDate ).getMonth() !== targetMonth ) {
            targetDate -= 1
            /*safety -= 1
            if ( !safety ) {
                throw 'Fell into an infinite loop while navigating to ' + new Date( targetYear, targetMonth, targetDate ) + '.'
            }*/
        }

        value = [ targetYear, targetMonth, targetDate ]
    }

    return value
} //DatePicker.prototype.navigate


/**
 * Normalize a date by setting the hours to midnight.
 */
DatePicker.prototype.normalize = function( value/*, options*/ ) {
    value.setHours( 0, 0, 0, 0 )
    return value
}


/**
 * Measure the range of dates.
 */
DatePicker.prototype.measure = function( type, value/*, options*/ ) {

    var calendar = this

    // If it's anything false-y, remove the limits.
    if ( !value ) {
        value = type == 'min' ? -Infinity : Infinity
    }

    // If it's an integer, get a date relative to today.
    else if ( _.isInteger( value ) ) {
        value = calendar.now( type, value, { rel: value } )
    }

    return value
} ///DatePicker.prototype.measure


/**
 * Create a viewset object based on navigation.
 */
DatePicker.prototype.viewset = function( type, dateObject/*, options*/ ) {
    return this.create([ dateObject.year, dateObject.month, 1 ])
}


/**
 * Validate a date as enabled and shift if needed.
 */
DatePicker.prototype.validate = function( type, dateObject, options ) {

    var calendar = this,

        // Keep a reference to the original date.
        originalDateObject = dateObject,

        // Make sure we have an interval.
        interval = options && options.interval ? options.interval : 1,

        // Check if the calendar enabled dates are inverted.
        isFlippedBase = calendar.item.enable === -1,

        // Check if we have any enabled dates after/before now.
        hasEnabledBeforeTarget, hasEnabledAfterTarget,

        // The min & max limits.
        minLimitObject = calendar.item.min,
        maxLimitObject = calendar.item.max,

        // Check if we’ve reached the limit during shifting.
        reachedMin, reachedMax,

        // Check if the calendar is inverted and at least one weekday is enabled.
        hasEnabledWeekdays = isFlippedBase && calendar.item.disable.filter( function( value ) {

            // If there’s a date, check where it is relative to the target.
            if ( $.isArray( value ) ) {
                var dateTime = calendar.create( value ).pick
                if ( dateTime < dateObject.pick ) hasEnabledBeforeTarget = true
                else if ( dateTime > dateObject.pick ) hasEnabledAfterTarget = true
            }

            // Return only integers for enabled weekdays.
            return _.isInteger( value )
        }).length/*,

        safety = 100*/



    // Cases to validate for:
    // [1] Not inverted and date disabled.
    // [2] Inverted and some dates enabled.
    // [3] Not inverted and out of range.
    //
    // Cases to **not** validate for:
    // • Navigating months.
    // • Not inverted and date enabled.
    // • Inverted and all dates disabled.
    // • ..and anything else.
    if ( !options || !options.nav ) if (
        /* 1 */ ( !isFlippedBase && calendar.disabled( dateObject ) ) ||
        /* 2 */ ( isFlippedBase && calendar.disabled( dateObject ) && ( hasEnabledWeekdays || hasEnabledBeforeTarget || hasEnabledAfterTarget ) ) ||
        /* 3 */ ( !isFlippedBase && (dateObject.pick <= minLimitObject.pick || dateObject.pick >= maxLimitObject.pick) )
    ) {


        // When inverted, flip the direction if there aren’t any enabled weekdays
        // and there are no enabled dates in the direction of the interval.
        if ( isFlippedBase && !hasEnabledWeekdays && ( ( !hasEnabledAfterTarget && interval > 0 ) || ( !hasEnabledBeforeTarget && interval < 0 ) ) ) {
            interval *= -1
        }


        // Keep looping until we reach an enabled date.
        while ( /*safety &&*/ calendar.disabled( dateObject ) ) {

            /*safety -= 1
            if ( !safety ) {
                throw 'Fell into an infinite loop while validating ' + dateObject.obj + '.'
            }*/


            // If we’ve looped into the next/prev month with a large interval, return to the original date and flatten the interval.
            if ( Math.abs( interval ) > 1 && ( dateObject.month < originalDateObject.month || dateObject.month > originalDateObject.month ) ) {
                dateObject = originalDateObject
                interval = interval > 0 ? 1 : -1
            }


            // If we’ve reached the min/max limit, reverse the direction, flatten the interval and set it to the limit.
            if ( dateObject.pick <= minLimitObject.pick ) {
                reachedMin = true
                interval = 1
                dateObject = calendar.create([
                    minLimitObject.year,
                    minLimitObject.month,
                    minLimitObject.date + (dateObject.pick === minLimitObject.pick ? 0 : -1)
                ])
            }
            else if ( dateObject.pick >= maxLimitObject.pick ) {
                reachedMax = true
                interval = -1
                dateObject = calendar.create([
                    maxLimitObject.year,
                    maxLimitObject.month,
                    maxLimitObject.date + (dateObject.pick === maxLimitObject.pick ? 0 : 1)
                ])
            }


            // If we’ve reached both limits, just break out of the loop.
            if ( reachedMin && reachedMax ) {
                break
            }


            // Finally, create the shifted date using the interval and keep looping.
            dateObject = calendar.create([ dateObject.year, dateObject.month, dateObject.date + interval ])
        }

    } //endif


    // Return the date object settled on.
    return dateObject
} //DatePicker.prototype.validate


/**
 * Check if a date is disabled.
 */
DatePicker.prototype.disabled = function( dateToVerify ) {

    var
        calendar = this,

        // Filter through the disabled dates to check if this is one.
        isDisabledMatch = calendar.item.disable.filter( function( dateToDisable ) {

            // If the date is a number, match the weekday with 0index and `firstDay` check.
            if ( _.isInteger( dateToDisable ) ) {
                return dateToVerify.day === ( calendar.settings.firstDay ? dateToDisable : dateToDisable - 1 ) % 7
            }

            // If it’s an array or a native JS date, create and match the exact date.
            if ( $.isArray( dateToDisable ) || _.isDate( dateToDisable ) ) {
                return dateToVerify.pick === calendar.create( dateToDisable ).pick
            }

            // If it’s an object, match a date within the “from” and “to” range.
            if ( $.isPlainObject( dateToDisable ) ) {
                return calendar.withinRange( dateToDisable, dateToVerify )
            }
        })

    // If this date matches a disabled date, confirm it’s not inverted.
    isDisabledMatch = isDisabledMatch.length && !isDisabledMatch.filter(function( dateToDisable ) {
        return $.isArray( dateToDisable ) && dateToDisable[3] == 'inverted' ||
            $.isPlainObject( dateToDisable ) && dateToDisable.inverted
    }).length

    // Check the calendar “enabled” flag and respectively flip the
    // disabled state. Then also check if it’s beyond the min/max limits.
    return calendar.item.enable === -1 ? !isDisabledMatch : isDisabledMatch ||
        dateToVerify.pick < calendar.item.min.pick ||
        dateToVerify.pick > calendar.item.max.pick

} //DatePicker.prototype.disabled


/**
 * Parse a string into a usable type.
 */
DatePicker.prototype.parse = function( type, value, options ) {

    var calendar = this,
        parsingObject = {}

    // If it’s already parsed, we’re good.
    if ( !value || typeof value != 'string' ) {
        return value
    }

    // We need a `.format` to parse the value with.
    if ( !( options && options.format ) ) {
        options = options || {}
        options.format = calendar.settings.format
    }

    // Convert the format into an array and then map through it.
    calendar.formats.toArray( options.format ).map( function( label ) {

        var
            // Grab the formatting label.
            formattingLabel = calendar.formats[ label ],

            // The format length is from the formatting label function or the
            // label length without the escaping exclamation (!) mark.
            formatLength = formattingLabel ? _.trigger( formattingLabel, calendar, [ value, parsingObject ] ) : label.replace( /^!/, '' ).length

        // If there's a format label, split the value up to the format length.
        // Then add it to the parsing object with appropriate label.
        if ( formattingLabel ) {
            parsingObject[ label ] = value.substr( 0, formatLength )
        }

        // Update the value as the substring from format length to end.
        value = value.substr( formatLength )
    })

    // Compensate for month 0index.
    return [
        parsingObject.yyyy || parsingObject.yy,
        +( parsingObject.mm || parsingObject.m ) - 1,
        parsingObject.dd || parsingObject.d
    ]
} //DatePicker.prototype.parse


/**
 * Various formats to display the object in.
 */
DatePicker.prototype.formats = (function() {

    // Return the length of the first word in a collection.
    function getWordLengthFromCollection( string, collection, dateObject ) {

        // Grab the first word from the string.
        var word = string.match( /\w+/ )[ 0 ]

        // If there's no month index, add it to the date object
        if ( !dateObject.mm && !dateObject.m ) {
            dateObject.m = collection.indexOf( word ) + 1
        }

        // Return the length of the word.
        return word.length
    }

    // Get the length of the first word in a string.
    function getFirstWordLength( string ) {
        return string.match( /\w+/ )[ 0 ].length
    }

    return {

        d: function( string, dateObject ) {

            // If there's string, then get the digits length.
            // Otherwise return the selected date.
            return string ? _.digits( string ) : dateObject.date
        },
        dd: function( string, dateObject ) {

            // If there's a string, then the length is always 2.
            // Otherwise return the selected date with a leading zero.
            return string ? 2 : _.lead( dateObject.date )
        },
        ddd: function( string, dateObject ) {

            // If there's a string, then get the length of the first word.
            // Otherwise return the short selected weekday.
            return string ? getFirstWordLength( string ) : this.settings.weekdaysShort[ dateObject.day ]
        },
        dddd: function( string, dateObject ) {

            // If there's a string, then get the length of the first word.
            // Otherwise return the full selected weekday.
            return string ? getFirstWordLength( string ) : this.settings.weekdaysFull[ dateObject.day ]
        },
        m: function( string, dateObject ) {

            // If there's a string, then get the length of the digits
            // Otherwise return the selected month with 0index compensation.
            return string ? _.digits( string ) : dateObject.month + 1
        },
        mm: function( string, dateObject ) {

            // If there's a string, then the length is always 2.
            // Otherwise return the selected month with 0index and leading zero.
            return string ? 2 : _.lead( dateObject.month + 1 )
        },
        mmm: function( string, dateObject ) {

            var collection = this.settings.monthsShort

            // If there's a string, get length of the relevant month from the short
            // months collection. Otherwise return the selected month from that collection.
            return string ? getWordLengthFromCollection( string, collection, dateObject ) : collection[ dateObject.month ]
        },
        mmmm: function( string, dateObject ) {

            var collection = this.settings.monthsFull

            // If there's a string, get length of the relevant month from the full
            // months collection. Otherwise return the selected month from that collection.
            return string ? getWordLengthFromCollection( string, collection, dateObject ) : collection[ dateObject.month ]
        },
        yy: function( string, dateObject ) {

            // If there's a string, then the length is always 2.
            // Otherwise return the selected year by slicing out the first 2 digits.
            return string ? 2 : ( '' + dateObject.year ).slice( 2 )
        },
        yyyy: function( string, dateObject ) {

            // If there's a string, then the length is always 4.
            // Otherwise return the selected year.
            return string ? 4 : dateObject.year
        },

        // Create an array by splitting the formatting string passed.
        toArray: function( formatString ) { return formatString.split( /(d{1,4}|m{1,4}|y{4}|yy|!.)/g ) },

        // Format an object into a string using the formatting options.
        toString: function ( formatString, itemObject ) {
            var calendar = this
            return calendar.formats.toArray( formatString ).map( function( label ) {
                return _.trigger( calendar.formats[ label ], calendar, [ 0, itemObject ] ) || label.replace( /^!/, '' )
            }).join( '' )
        }
    }
})() //DatePicker.prototype.formats




/**
 * Check if two date units are the exact.
 */
DatePicker.prototype.isDateExact = function( one, two ) {

    var calendar = this

    // When we’re working with weekdays, do a direct comparison.
    if (
        ( _.isInteger( one ) && _.isInteger( two ) ) ||
        ( typeof one == 'boolean' && typeof two == 'boolean' )
     ) {
        return one === two
    }

    // When we’re working with date representations, compare the “pick” value.
    if (
        ( _.isDate( one ) || $.isArray( one ) ) &&
        ( _.isDate( two ) || $.isArray( two ) )
    ) {
        return calendar.create( one ).pick === calendar.create( two ).pick
    }

    // When we’re working with range objects, compare the “from” and “to”.
    if ( $.isPlainObject( one ) && $.isPlainObject( two ) ) {
        return calendar.isDateExact( one.from, two.from ) && calendar.isDateExact( one.to, two.to )
    }

    return false
}


/**
 * Check if two date units overlap.
 */
DatePicker.prototype.isDateOverlap = function( one, two ) {

    var calendar = this,
        firstDay = calendar.settings.firstDay ? 1 : 0

    // When we’re working with a weekday index, compare the days.
    if ( _.isInteger( one ) && ( _.isDate( two ) || $.isArray( two ) ) ) {
        one = one % 7 + firstDay
        return one === calendar.create( two ).day + 1
    }
    if ( _.isInteger( two ) && ( _.isDate( one ) || $.isArray( one ) ) ) {
        two = two % 7 + firstDay
        return two === calendar.create( one ).day + 1
    }

    // When we’re working with range objects, check if the ranges overlap.
    if ( $.isPlainObject( one ) && $.isPlainObject( two ) ) {
        return calendar.overlapRanges( one, two )
    }

    return false
}


/**
 * Flip the “enabled” state.
 */
DatePicker.prototype.flipEnable = function(val) {
    var itemObject = this.item
    itemObject.enable = val || (itemObject.enable == -1 ? 1 : -1)
}


/**
 * Mark a collection of dates as “disabled”.
 */
DatePicker.prototype.deactivate = function( type, datesToDisable ) {

    var calendar = this,
        disabledItems = calendar.item.disable.slice(0)


    // If we’re flipping, that’s all we need to do.
    if ( datesToDisable == 'flip' ) {
        calendar.flipEnable()
    }

    else if ( datesToDisable === false ) {
        calendar.flipEnable(1)
        disabledItems = []
    }

    else if ( datesToDisable === true ) {
        calendar.flipEnable(-1)
        disabledItems = []
    }

    // Otherwise go through the dates to disable.
    else {

        datesToDisable.map(function( unitToDisable ) {

            var matchFound

            // When we have disabled items, check for matches.
            // If something is matched, immediately break out.
            for ( var index = 0; index < disabledItems.length; index += 1 ) {
                if ( calendar.isDateExact( unitToDisable, disabledItems[index] ) ) {
                    matchFound = true
                    break
                }
            }

            // If nothing was found, add the validated unit to the collection.
            if ( !matchFound ) {
                if (
                    _.isInteger( unitToDisable ) ||
                    _.isDate( unitToDisable ) ||
                    $.isArray( unitToDisable ) ||
                    ( $.isPlainObject( unitToDisable ) && unitToDisable.from && unitToDisable.to )
                ) {
                    disabledItems.push( unitToDisable )
                }
            }
        })
    }

    // Return the updated collection.
    return disabledItems
} //DatePicker.prototype.deactivate


/**
 * Mark a collection of dates as “enabled”.
 */
DatePicker.prototype.activate = function( type, datesToEnable ) {

    var calendar = this,
        disabledItems = calendar.item.disable,
        disabledItemsCount = disabledItems.length

    // If we’re flipping, that’s all we need to do.
    if ( datesToEnable == 'flip' ) {
        calendar.flipEnable()
    }

    else if ( datesToEnable === true ) {
        calendar.flipEnable(1)
        disabledItems = []
    }

    else if ( datesToEnable === false ) {
        calendar.flipEnable(-1)
        disabledItems = []
    }

    // Otherwise go through the disabled dates.
    else {

        datesToEnable.map(function( unitToEnable ) {

            var matchFound,
                disabledUnit,
                index,
                isExactRange

            // Go through the disabled items and try to find a match.
            for ( index = 0; index < disabledItemsCount; index += 1 ) {

                disabledUnit = disabledItems[index]

                // When an exact match is found, remove it from the collection.
                if ( calendar.isDateExact( disabledUnit, unitToEnable ) ) {
                    matchFound = disabledItems[index] = null
                    isExactRange = true
                    break
                }

                // When an overlapped match is found, add the “inverted” state to it.
                else if ( calendar.isDateOverlap( disabledUnit, unitToEnable ) ) {
                    if ( $.isPlainObject( unitToEnable ) ) {
                        unitToEnable.inverted = true
                        matchFound = unitToEnable
                    }
                    else if ( $.isArray( unitToEnable ) ) {
                        matchFound = unitToEnable
                        if ( !matchFound[3] ) matchFound.push( 'inverted' )
                    }
                    else if ( _.isDate( unitToEnable ) ) {
                        matchFound = [ unitToEnable.getFullYear(), unitToEnable.getMonth(), unitToEnable.getDate(), 'inverted' ]
                    }
                    break
                }
            }

            // If a match was found, remove a previous duplicate entry.
            if ( matchFound ) for ( index = 0; index < disabledItemsCount; index += 1 ) {
                if ( calendar.isDateExact( disabledItems[index], unitToEnable ) ) {
                    disabledItems[index] = null
                    break
                }
            }

            // In the event that we’re dealing with an exact range of dates,
            // make sure there are no “inverted” dates because of it.
            if ( isExactRange ) for ( index = 0; index < disabledItemsCount; index += 1 ) {
                if ( calendar.isDateOverlap( disabledItems[index], unitToEnable ) ) {
                    disabledItems[index] = null
                    break
                }
            }

            // If something is still matched, add it into the collection.
            if ( matchFound ) {
                disabledItems.push( matchFound )
            }
        })
    }

    // Return the updated collection.
    return disabledItems.filter(function( val ) { return val != null })
} //DatePicker.prototype.activate


/**
 * Create a string for the nodes in the picker.
 */
DatePicker.prototype.nodes = function( isOpen ) {

    var
        calendar = this,
        settings = calendar.settings,
        calendarItem = calendar.item,
        nowObject = calendarItem.now,
        selectedObject = calendarItem.select,
        highlightedObject = calendarItem.highlight,
        viewsetObject = calendarItem.view,
        disabledCollection = calendarItem.disable,
        minLimitObject = calendarItem.min,
        maxLimitObject = calendarItem.max,


        // Create the calendar table head using a copy of weekday labels collection.
        // * We do a copy so we don't mutate the original array.
        tableHead = (function( collection, fullCollection ) {

            // If the first day should be Monday, move Sunday to the end.
            if ( settings.firstDay ) {
                collection.push( collection.shift() )
                fullCollection.push( fullCollection.shift() )
            }

            // Create and return the table head group.
            return _.node(
                'thead',
                _.node(
                    'tr',
                    _.group({
                        min: 0,
                        max: DAYS_IN_WEEK - 1,
                        i: 1,
                        node: 'th',
                        item: function( counter ) {
                            return [
                                collection[ counter ],
                                settings.klass.weekdays,
                                'scope=col title="' + fullCollection[ counter ] + '"'
                            ]
                        }
                    })
                )
            ) //endreturn
        })( ( settings.showWeekdaysFull ? settings.weekdaysFull : settings.weekdaysShort ).slice( 0 ), settings.weekdaysFull.slice( 0 ) ), //tableHead


        // Create the nav for next/prev month.
        createMonthNav = function( next ) {

            // Otherwise, return the created month tag.
            return _.node(
                'div',
                ' ',
                settings.klass[ 'nav' + ( next ? 'Next' : 'Prev' ) ] + (

                    // If the focused month is outside the range, disabled the button.
                    ( next && viewsetObject.year >= maxLimitObject.year && viewsetObject.month >= maxLimitObject.month ) ||
                    ( !next && viewsetObject.year <= minLimitObject.year && viewsetObject.month <= minLimitObject.month ) ?
                    ' ' + settings.klass.navDisabled : ''
                ),
                'data-nav=' + ( next || -1 ) + ' ' +
                _.ariaAttr({
                    role: 'button',
                    controls: calendar.$node[0].id + '_table'
                }) + ' ' +
                'title="' + (next ? settings.labelMonthNext : settings.labelMonthPrev ) + '"'
            ) //endreturn
        }, //createMonthNav


        // Create the month label.
        createMonthLabel = function() {

            var monthsCollection = settings.showMonthsShort ? settings.monthsShort : settings.monthsFull

            // If there are months to select, add a dropdown menu.
            if ( settings.selectMonths ) {

                return _.node( 'select',
                    _.group({
                        min: 0,
                        max: 11,
                        i: 1,
                        node: 'option',
                        item: function( loopedMonth ) {

                            return [

                                // The looped month and no classes.
                                monthsCollection[ loopedMonth ], 0,

                                // Set the value and selected index.
                                'value=' + loopedMonth +
                                ( viewsetObject.month == loopedMonth ? ' selected' : '' ) +
                                (
                                    (
                                        ( viewsetObject.year == minLimitObject.year && loopedMonth < minLimitObject.month ) ||
                                        ( viewsetObject.year == maxLimitObject.year && loopedMonth > maxLimitObject.month )
                                    ) ?
                                    ' disabled' : ''
                                )
                            ]
                        }
                    }),
                    settings.klass.selectMonth,
                    ( isOpen ? '' : 'disabled' ) + ' ' +
                    _.ariaAttr({ controls: calendar.$node[0].id + '_table' }) + ' ' +
                    'title="' + settings.labelMonthSelect + '"'
                )
            }

            // If there's a need for a month selector
            return _.node( 'div', monthsCollection[ viewsetObject.month ], settings.klass.month )
        }, //createMonthLabel


        // Create the year label.
        createYearLabel = function() {

            var focusedYear = viewsetObject.year,

            // If years selector is set to a literal "true", set it to 5. Otherwise
            // divide in half to get half before and half after focused year.
            numberYears = settings.selectYears === true ? 5 : ~~( settings.selectYears / 2 )

            // If there are years to select, add a dropdown menu.
            if ( numberYears ) {

                var
                    minYear = minLimitObject.year,
                    maxYear = maxLimitObject.year,
                    lowestYear = focusedYear - numberYears,
                    highestYear = focusedYear + numberYears

                // If the min year is greater than the lowest year, increase the highest year
                // by the difference and set the lowest year to the min year.
                if ( minYear > lowestYear ) {
                    highestYear += minYear - lowestYear
                    lowestYear = minYear
                }

                // If the max year is less than the highest year, decrease the lowest year
                // by the lower of the two: available and needed years. Then set the
                // highest year to the max year.
                if ( maxYear < highestYear ) {

                    var availableYears = lowestYear - minYear,
                        neededYears = highestYear - maxYear

                    lowestYear -= availableYears > neededYears ? neededYears : availableYears
                    highestYear = maxYear
                }

                return _.node( 'select',
                    _.group({
                        min: lowestYear,
                        max: highestYear,
                        i: 1,
                        node: 'option',
                        item: function( loopedYear ) {
                            return [

                                // The looped year and no classes.
                                loopedYear, 0,

                                // Set the value and selected index.
                                'value=' + loopedYear + ( focusedYear == loopedYear ? ' selected' : '' )
                            ]
                        }
                    }),
                    settings.klass.selectYear,
                    ( isOpen ? '' : 'disabled' ) + ' ' + _.ariaAttr({ controls: calendar.$node[0].id + '_table' }) + ' ' +
                    'title="' + settings.labelYearSelect + '"'
                )
            }

            // Otherwise just return the year focused
            return _.node( 'div', focusedYear, settings.klass.year )
        } //createYearLabel


    // Create and return the entire calendar.
    return _.node(
        'div',
        ( settings.selectYears ? createYearLabel() + createMonthLabel() : createMonthLabel() + createYearLabel() ) +
        createMonthNav() + createMonthNav( 1 ),
        settings.klass.header
    ) + _.node(
        'table',
        tableHead +
        _.node(
            'tbody',
            _.group({
                min: 0,
                max: WEEKS_IN_CALENDAR - 1,
                i: 1,
                node: 'tr',
                item: function( rowCounter ) {

                    // If Monday is the first day and the month starts on Sunday, shift the date back a week.
                    var shiftDateBy = settings.firstDay && calendar.create([ viewsetObject.year, viewsetObject.month, 1 ]).day === 0 ? -7 : 0

                    return [
                        _.group({
                            min: DAYS_IN_WEEK * rowCounter - viewsetObject.day + shiftDateBy + 1, // Add 1 for weekday 0index
                            max: function() {
                                return this.min + DAYS_IN_WEEK - 1
                            },
                            i: 1,
                            node: 'td',
                            item: function( targetDate ) {

                                // Convert the time date from a relative date to a target date.
                                targetDate = calendar.create([ viewsetObject.year, viewsetObject.month, targetDate + ( settings.firstDay ? 1 : 0 ) ])

                                var isSelected = selectedObject && selectedObject.pick == targetDate.pick,
                                    isHighlighted = highlightedObject && highlightedObject.pick == targetDate.pick,
                                    isDisabled = disabledCollection && calendar.disabled( targetDate ) || targetDate.pick < minLimitObject.pick || targetDate.pick > maxLimitObject.pick

                                return [
                                    _.node(
                                        'div',
                                        targetDate.date,
                                        (function( klasses ) {

                                            // Add the `infocus` or `outfocus` classes based on month in view.
                                            klasses.push( viewsetObject.month == targetDate.month ? settings.klass.infocus : settings.klass.outfocus )

                                            // Add the `today` class if needed.
                                            if ( nowObject.pick == targetDate.pick ) {
                                                klasses.push( settings.klass.now )
                                            }

                                            // Add the `selected` class if something's selected and the time matches.
                                            if ( isSelected ) {
                                                klasses.push( settings.klass.selected )
                                            }

                                            // Add the `highlighted` class if something's highlighted and the time matches.
                                            if ( isHighlighted ) {
                                                klasses.push( settings.klass.highlighted )
                                            }

                                            // Add the `disabled` class if something's disabled and the object matches.
                                            if ( isDisabled ) {
                                                klasses.push( settings.klass.disabled )
                                            }

                                            return klasses.join( ' ' )
                                        })([ settings.klass.day ]),
                                        'data-pick=' + targetDate.pick + ' ' + _.ariaAttr({
                                            role: 'gridcell',
                                            selected: isSelected && calendar.$node.val() === _.trigger(
                                                    calendar.formats.toString,
                                                    calendar,
                                                    [ settings.format, targetDate ]
                                                ) ? true : null,
                                            activedescendant: isHighlighted ? true : null,
                                            disabled: isDisabled ? true : null
                                        })
                                    ),
                                    '',
                                    _.ariaAttr({ role: 'presentation' })
                                ] //endreturn
                            }
                        })
                    ] //endreturn
                }
            })
        ),
        settings.klass.table,
        'id="' + calendar.$node[0].id + '_table' + '" ' + _.ariaAttr({
            role: 'grid',
            controls: calendar.$node[0].id,
            readonly: true
        })
    ) +

    // * For Firefox forms to submit, make sure to set the buttons’ `type` attributes as “button”.
    _.node(
        'div',
        _.node( 'button', settings.today, settings.klass.buttonToday,
            'type=button data-pick=' + nowObject.pick +
            ( isOpen ? '' : ' disabled' ) + ' ' +
            _.ariaAttr({ controls: calendar.$node[0].id }) ) +
        _.node( 'button', settings.clear, settings.klass.buttonClear,
            'type=button data-clear=1' +
            ( isOpen ? '' : ' disabled' ) + ' ' +
            _.ariaAttr({ controls: calendar.$node[0].id }) ),
        settings.klass.footer
    ) //endreturn
} //DatePicker.prototype.nodes




/**
 * The date picker defaults.
 */
DatePicker.defaults = (function( prefix ) {

    return {

        // The title label to use for the month nav buttons
        labelMonthNext: 'Next month',
        labelMonthPrev: 'Previous month',

        // The title label to use for the dropdown selectors
        labelMonthSelect: 'Select a month',
        labelYearSelect: 'Select a year',

        // Months and weekdays
        monthsFull: [ 'January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December' ],
        monthsShort: [ 'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec' ],
        weekdaysFull: [ 'Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday' ],
        weekdaysShort: [ 'Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat' ],

        // Today and clear
        today: 'Today',
        clear: 'Clear',

        // The format to show on the `input` element
        format: 'd mmmm, yyyy',

        // Classes
        klass: {

            table: prefix + 'table',

            header: prefix + 'header',

            navPrev: prefix + 'nav--prev',
            navNext: prefix + 'nav--next',
            navDisabled: prefix + 'nav--disabled',

            month: prefix + 'month',
            year: prefix + 'year',

            selectMonth: prefix + 'select--month',
            selectYear: prefix + 'select--year',

            weekdays: prefix + 'weekday',

            day: prefix + 'day',
            disabled: prefix + 'day--disabled',
            selected: prefix + 'day--selected',
            highlighted: prefix + 'day--highlighted',
            now: prefix + 'day--today',
            infocus: prefix + 'day--infocus',
            outfocus: prefix + 'day--outfocus',

            footer: prefix + 'footer',

            buttonClear: prefix + 'button--clear',
            buttonToday: prefix + 'button--today'
        }
    }
})( Picker.klasses().picker + '__' )





/**
 * Extend the picker to add the date picker.
 */
Picker.extend( 'pickadate', DatePicker )


}));