module Vapid
  class Template
    # A wrapper around Nokogiri's node, so we can manipulate using our own methods
    class Node
      attr_reader :directives, :clone_index

      def initialize(node, clone_index = 0)
        @node = node
        @directives = parse_directives
        @clone_index = node["vp-clone"].present? ? node["vp-clone"].to_i : clone_index
      end

      def group_expr
        @directives["group"]
      end

      def group?
        group_expr.present?
      end

      def clone(num_clones = 1)
        num_clones.times do |n|
          cloned = @node.dup
          cloned["vp-clone"] = num_clones - n
          @node.after cloned
        end
      end

      def clone?
        clone_index > 0
      end

      def cloneable?
        group? && !clone?
      end

      def directives?
        @directives.any?
      end

      def first_child
        wrap @node.first_element_child
      end

      def next_sibling
        wrap @node.next_element
      end

      # TODO: Abstract this, so that directives only need to pass in
      #       html, text, etc, and don't have to know about Nokogiri methods/concepts
      def modify(obj)
        return unless obj
        
        obj.each do |prop, value|
          if value.is_a?(String)
            @node.send "#{prop}=", value
          elsif prop == :attributes
            modify_attributes(value)
          elsif value.is_a?(Hash)
            modify_properties(prop, value)
          elsif prop == :placeholder
            @node["vp-placeholder"] = true
          end
        end
      end

      private

        def wrap(node)
          node && self.class.new(node, clone_index)
        end

        def parse_directives
          @node.attribute_nodes.each_with_object({}) do |attribute, memo|
            vp_type = attribute.name[/^(?:data-)?vp-(.+)$/, 1]
            memo[vp_type] = attribute.value if Directives[vp_type]
          end
        end

        def modify_attributes(attributes)
          attributes.each { |k, v| @node[k.to_s] = v }
        end

        def modify_properties(prop, values)
          property = @node.send(prop)
          values.each { |k, v| property[k.to_s] = v }
          @node.send "#{prop}=", property
        end
    end
  end
end