require 'sass'
module Sass
  module Tree
    class Node
      private
      def tab(s, indent_level = 1)
        s.split("\n").join("\n" + "  " * indent_level)
      end
      def children_to_sass
        clean_children = children.inject([[],true]) do |m,c|
          if c.respond_to?(:doc) && !c.doc.nil?
            [m.first, c.doc]
          else
            if m.last
              [m.first + [c], true]
            else
              m
            end
          end
        end
        raise clean_children.first.inspect if clean_children.first.detect{|c| TrueClass === c}
        tab(clean_children.first.
          map{|c| c.to_sass}.join("\n"))
      end
    end
    class VariableNode < Node
      attr_accessor :name unless method_defined? :name
    end
    class IfNode < Node
      def to_sass
        sass_str = %Q{@if #{@expr.inspect unless @expr.nil?}
                     -  #{tab children_to_sass}
                     -}.gsub(/^\s+-/,'')
        if @else
          sass_str << %Q{@else
                       -  #{tab @else.to_sass}
                       -}.gsub(/^\s+-/,'')
        end
        sass_str
      end
    end
    class DebugNode < Node
      def to_sass
        ""
      end
    end
    class MixinNode < Node
      attr_accessor :name unless method_defined? :name
      attr_accessor :args unless method_defined? :args
      def to_sass
        sass_str = "+#{name}"
        if args.any?
          sass_str << "(#{args.map{|a| a.inspect}.join(", ")})"
        end
        sass_str
      end
    end
    class MixinDefNode < Node
      attr_accessor :name unless method_defined? :name
      attr_accessor :args unless method_defined? :args
      attr_accessor :comment unless method_defined? :comment
      
      def to_sass
        "#{sass_signature}\n  #{children_to_sass}\n"
      end

      def sass_signature(mode = :definition)
        prefix = case mode
        when :definition
          "="
        when :include
          "+"
        end
        "#{prefix}#{name}#{arglist_to_sass}"
      end

      private
      def arglist_to_sass
        if args.any?
          "(#{args.map{|a| arg_to_sass(a)}.join(", ")})"
        else
          ""
        end
      end
      def arg_to_sass(arg)
        name, default_value = arg
        sass_str = "#{name.inspect}"
        if default_value
          sass_str << " = "
          sass_str << default_value.inspect
        end
        sass_str
      end
    end
    class ImportNode < RootNode
      attr_accessor :imported_filename unless method_defined? :imported_filename
    end
    class CommentNode < Node
      def docstring
        ([value] + lines).join("\n")
      end
      def doc
        if value == "@doc off"
          false
        elsif value == "@doc on"
          true
        end
      end
    end
  end
end