(function ($) {
    var settings = {
        multiple: true,
        datePickerOptions: {
            format: 'm/d/yyyy',
            autoclose: true,
        }
    };

    var methods = {
        init: function (options) {
            settings = $.extend(true, settings, options);

            var pickers = this.each(function () {
                $(this).datepicker(settings.datePickerOptions);
            });
            return methods.setState.apply(this, [settings.multiple]);
        },
        setState: function (multiple) {
            settings.multiple = multiple;

            return methods.refresh.apply(this);
        },
        refresh: function () {
            return this.each(function () {
                var $this = $(this),
                    $inputs = $this.find('input.date').toArray(),
                    $startDate = $inputs.length > 0 ? $($inputs[0]) : null,
                    $startAddon = $startDate ? $startDate.next('span.input-group-addon') : null,
                    $endDate = $inputs.length > 1 ? $($inputs[1]) : null,
                    $endAddon = $endDate ? $endDate.next('span.input-group-addon') : null,
                    $rAddon = $this.find('div.input-group-addon');

                if (!$startDate || !$endDate) {
                    throw 'Container does not contain inputs for start/end dates'
                }

                // we should always hide calendar right after end date picker
                if ($endAddon)
                    $endAddon.hide();

                if (settings.multiple) {
                    if ($startAddon)
                        $startAddon.hide();

                    $endDate.show();
                    $rAddon.show();
                }
                else {
                    var picker = $endDate.datepicker('update', '');
                    if (picker.valid && typeof picker.valid === 'function')
                        picker.valid();

                    $endDate.hide();
                    $rAddon.hide();
                    if ($startAddon)
                        $startAddon.show();
                }
            });
        },
    };

    $.fn.datePickerRange = function (options) {
        if (typeof options === 'string' && typeof methods[options] === 'function') {
            return methods[options].apply(this, Array.prototype.slice.call(arguments, 1));
        } else if (typeof options === 'object' || !options) {
            return methods.init.apply(this, arguments);
        }
    };
}(jQuery));