module Loaf
  module Filters

    Crumb = Struct.new(:name, :url, :styles)

    module ClassMethods

      def add_breadcrumb(name, url, options = {})
        before_filter(options) do |instance|
          instance.send(:add_breadcrumb, _normalize_name(name), url)
        end
      end

      private

      def _normalize_name(name=nil)
        case name
        when NilClass
        when Proc
          name.call
        when Symbol
          name.to_s
        else
          name
        end
      end

      def _process_url(url)
      end
    end

    module InstanceMethods

      # Add collection of nested breadcrumbs.
      # * <tt>collection</tt> - required collection of object for iteration
      # * <tt>field</tt> - required object attribute name
      #
      def add_breadcrumbs(collection, field, options={})
        namespace = nil
        item_set = if _check_if_nested collection
           items = collection.pop
           namespace = collection
           items
        else
          collection
        end
        item_set.each do |item|
          add_breadcrumb item.send(field.to_sym), [ namespace, item ].flatten.compact
        end
      end

      def add_breadcrumb(name, url)
        _breadcrumbs << Crumb.new(name, url)
      end

      def _breadcrumbs
        @_breadcrumbs ||= []
      end

      def clear_crumbs
        _breadcrumbs.clear
      end

      private

      def _check_if_nested(collection)
        collection.last.is_a? Array
      end

    end # InstanceMethods

    def self.included(base)
      base.extend ClassMethods
      base.send :include, InstanceMethods
      base.send :helper_method, :_breadcrumbs
    end

  end # Filters
end # Loaf