module SortableTable
  module App
    module Helpers
      module ApplicationHelper
      
        def self.included(base)
          base.class_eval do
            include InstanceMethods
          end
        end
        
        module InstanceMethods
          def sortable_table_header(*args)
            opts = args.extract_options!

            inner_html = args
            if inner_html.blank?
              raise ArgumentError("Must specify inner_html as first argument")
            end

            # if args.first.is_a?(String)
            #   inner_html = args.shift
            # elsif opts.first.is_a?(Hash)
            #   if opts.has_key?(:inner_html)
            #     inner_html = opts[:inner_html]
            #   else
            #     # raise ArgumentError unless opts.has_key?(:sort)
            #     inner_html = opts[:sort].humanize
            #   end
            # else
            #   raise ArgumentError, 
            #     "calling signature must be String, Hash or Hash"
            # end

            # anchor = opts[:anchor].blank? ? "" : "##{opts[:anchor]}"
            # sortable_url(opts) + anchor

            content_tag :th, 
              link_to(inner_html, 
                sortable_url(opts), 
                :title => opts[:title]),
              :class => class_name_for_sortable_table_header_tag(opts)
          end

          def class_name_for_sortable_table_header_tag(opts)
            if default_sort_to_most_recent? opts
              class_name = 'descending'
            elsif re_sort? opts
              class_name = params[:order]
            else
              class_name = ""
            end
            class_name << " #{opts[:class_name]}"
          end

          def sortable_url(opts)
            url_for(params.merge(:sort => opts[:sort], :order => link_sort_order(opts), :page => 1))
          end

          def link_sort_order(opts)
            if default_sort_to_most_recent? opts
              'ascending'
            elsif re_sort? opts
              reverse_order params[:order]
            else
              'ascending'
            end
          end

          def default_sort_to_most_recent?(opts)
            params[:sort].nil? && opts[:sort] == @sorted_column
          end

          def re_sort?(opts)
            params[:sort] == opts[:sort]
          end

          def reverse_order(order)
            order == 'ascending' ? 'descending' : 'ascending'
          end  
        end
        
      end
    end
  end
end