module ActiveAdmin::Inputs::Filters::Base

def collection_from_options
  if options[:collection].is_a?(Proc)
    template.instance_exec(&options[:collection])
  else
    super
  end
end

def input_wrapping(&block)
  template.content_tag :div, template.capture(&block), wrapper_html_options
end

def label_from_options
  res = super
  res = res.call if res.is_a? Proc
  res
end

def required?
  false
end

def wrapper_html_options
  opts = super
  (opts[:class] ||= "") << " filter_form_field filter_#{as}"
  opts
end