module ActionView
  class Base

    # Creates a link that alternates between acending and descending. It basically
    # alternates between calling 2 named scopes: "ascend_by_*" and "descend_by_*"
    #
    # By default Searchlogic gives you these named scopes for all of your columns, but
    # if you wanted to create your own, it will work with those too.
    #
    # Examples:
    #
    #   order @search, :by => :username
    #   order @search, :by => :created_at, :as => "Created"
    #   order(@search, {:by => :last_login_at, :as => 'Login time', :arrow => true}, {:class => 'order'})
    #
    # This helper accepts the following options:
    #
    # * <tt>:by</tt> - the name of the named scope. This helper will prepend this value with "ascend_by_" and "descend_by_"
    # * <tt>:as</tt> - the text used in the link, defaults to whatever is passed to :by
    # * <tt>:ascend_scope</tt> - what scope to call for ascending the data, defaults to "ascend_by_:by"
    # * <tt>:descend_scope</tt> - what scope to call for descending the data, defaults to "descend_by_:by"
    # * <tt>:params</tt> - hash with additional params which will be added to generated url
    # * <tt>:params_scope</tt> - the name of the params key to scope the order condition by, defaults to :search
    # * <tt>:default_scope</tt> - either :asc or :desc, defaults to ascend_scope
    # * <tt>:arrow</tt> - set to true if you want an ascii arrow showing the ordering
    # * <tt>:css_classes</tt> - Array of what css classes you want to add, defaults to [:asc, :desc]. For old behaviour use [:ascending, :descending] here
    def order(search, options = {}, html_options = {})
      options[:params_scope]  ||= :search
      options[:as]            ||= options[:by].to_s.humanize
      options[:ascend_scope]  ||= "ascend_by_#{options[:by]}"
      options[:descend_scope] ||= "descend_by_#{options[:by]}"
      options[:css_classes]   ||= [:asc, :desc]
      selected = [options[:ascend_scope], options[:descend_scope]].include?(search.order.to_s)
      if selected
        ascending = search.order.to_s == options[:ascend_scope]
        new_scope = ascending ? options[:descend_scope] : options[:ascend_scope]
        css_classes = html_options[:class] ? html_options[:class].split(" ") : []
        if ascending
          options[:as] = "&#9650;&nbsp;#{options[:as]}" if options[:arrow]
          css_classes << options[:css_classes].first
        else
          options[:as] = "&#9660;&nbsp;#{options[:as]}" if options[:arrow]
          css_classes << options[:css_classes].last
        end
        html_options[:class] = css_classes.join(" ")
      else
        new_scope = (options[:default_scope] == :desc) ? options[:descend_scope] : options[:ascend_scope]
      end
      url_options = {
        options[:params_scope] => search.conditions.merge( { :order => new_scope } )
      }.deep_merge(options[:params] || {})
      link_to options[:as], url_for(url_options), html_options
    end

    # Automatically makes the form method :get if a Searchlogic::Search and sets
    # the params scope to :search
    def form_for_with_searchlogic(*args, &block)
      if search_obj = args.find { |arg| arg.is_a?(Searchlogic::Search) }
        options = args.extract_options!
        options[:html] ||= {}
        options[:html][:method] ||= :get
        options[:url] ||= url_for
        args.unshift(:search) if args.first == search_obj
        args << options
      end
      form_for_without_searchlogic(*args, &block)
    end
 
    # Automatically adds an "order" hidden field in your form to preserve how the data 
    # is being ordered.
    def fields_for_with_searchlogic(*args, &block)
      if search_obj = args.find { |arg| arg.is_a?(Searchlogic::Search) }
        args.unshift(:search) if args.first == search_obj
        concat(content_tag("div", hidden_field_tag("#{args.first}[order]", search_obj.order)) + "\n")
      end
      fields_for_without_searchlogic(*args, &block)
    end

  end
end