module ActiveAdmin
  module Filters

    # This form builder defines methods to build filter forms such
    # as the one found in the sidebar of the index page of a standard resource.
    class FormBuilder < ::ActiveAdmin::FormBuilder
      include ::ActiveAdmin::Filters::FormtasticAddons

      def initialize(*args)
        @use_form_buffer = true # force ActiveAdmin::FormBuilder to use the form buffer
        super
      end

      def filter(method, options = {})
        if method.present? && options[:as] ||= default_input_type(method)
          input(method, options)
        end
      end

      protected

      # Returns the default filter type for a given attribute
      def default_input_type(method, options = {})
        if method =~ /_(contains|starts_with|ends_with)\z/
          :string
        elsif reflection_for(method) || polymorphic_foreign_type?(method)
          :select
        elsif column = column_for(method)
          case column.type
          when :date, :datetime
            :date_range
          when :string, :text
            :string
          when :integer, :float, :decimal
            :numeric
          when :boolean
            :boolean
          end
        end
      end

      def custom_input_class_name(as)
        "Filter#{as.to_s.camelize}Input"
      end

      def active_admin_input_class_name(as)
        "ActiveAdmin::Inputs::Filter#{as.to_s.camelize}Input"
      end

    end


    # This module is included into the view
    module ViewHelper

      # Helper method to render a filter form
      def active_admin_filters_form_for(search, filters, options = {})
        defaults = { :builder => ActiveAdmin::Filters::FormBuilder,
                     :url     => collection_path,
                     :html    => {:class  => 'filter_form'} }
        required = { :html    => {:method => :get},
                     :as      => :q }
        options  = defaults.deep_merge(options).deep_merge(required)

        form_for search, options do |f|
          filters.group_by{ |o| o[:attribute] }.each do |attribute, array|
            opts     = array.last # grab last-defined `filter` call from DSL
            should   = opts.delete(:if)     || proc{ true }
            shouldnt = opts.delete(:unless) || proc{ false }

            if call_method_or_proc_on(self, should) && !call_method_or_proc_on(self, shouldnt)
              f.filter attribute, opts
            end
          end

          buttons = content_tag :div, :class => "buttons" do
            f.submit(I18n.t('active_admin.filters.buttons.filter')) +
              link_to(I18n.t('active_admin.filters.buttons.clear'), '#', :class => 'clear_filters_btn') +
              hidden_field_tags_for(params, :except => [:q, :page])
          end

          f.form_buffers.last + buttons
        end
      end

    end

  end
end