module RDoc; end

module RDoc::DOT

  TAB = '  '
  TAB2 = TAB * 2

  # options for node declaration
  NODE_OPTS = [
    'bgcolor',
    'color',
    'fontcolor',
    'fontname',
    'fontsize',
    'height',
    'width',
    'label',
    'layer',
    'rank',
    'shape',
    'shapefile',
    'style',
    'URL',
  ]

  # options for edge declaration
  EDGE_OPTS = [
    'color',
    'decorate',
    'dir',
    'fontcolor',
    'fontname',
    'fontsize',
    'id',
    'label',
    'layer',
    'lhead',
    'ltail',
    'minlen',
    'style',
    'weight'
  ]

  # options for graph declaration
  GRAPH_OPTS = [
    'bgcolor',
    'center',
    'clusterrank',
    'color',
    'compound',
    'concentrate',
    'fillcolor',
    'fontcolor',
    'fontname',
    'fontsize',
    'label',
    'layerseq',
    'margin',
    'mclimit',
    'nodesep',
    'nslimit',
    'ordering',
    'orientation',
    'page',
    'rank',
    'rankdir',
    'ranksep',
    'ratio',
    'size',
    'style',
    'URL'
  ]

  # a root class for any element in dot notation
  class SimpleElement
    attr_accessor :name

    def initialize( params = {} )
      @label = params['name'] ? params['name'] : ''
    end

    def to_s
      @name
    end
  end

  # an element that has options ( node, edge or graph )
  class Element < SimpleElement
    #attr_reader :parent
    attr_accessor :name, :options

    def initialize( params = {}, option_list = [] )
      super( params )
      @name = params['name'] ? params['name'] : nil
      @parent = params['parent'] ? params['parent'] : nil
      @options = {}
      option_list.each{ |i|
        @options[i] = params[i] if params[i]
      }
      @options['label'] ||= @name if @name != 'node'
    end

    def each_option
      @options.each{ |i| yield i }
    end

    def each_option_pair
      @options.each_pair{ |key, val| yield key, val }
    end

    #def parent=( thing )
    #    @parent.delete( self ) if defined?( @parent ) and @parent
    #    @parent = thing
    #end
  end


  # this is used when we build nodes that have shape=record
  # ports don't have options :)
  class Port < SimpleElement
    attr_accessor :label

    def initialize( params = {} )
      super( params )
      @name = params['label'] ? params['label'] : ''
    end
    def to_s
      ( @name && @name != "" ? "<#{@name}>" : "" ) + "#{@label}"
    end
  end

  # node element
  class Node < Element

    def initialize( params = {}, option_list = NODE_OPTS )
      super( params, option_list )
      @ports = params['ports'] ? params['ports'] : []
    end

    def each_port
      @ports.each{ |i| yield i }
    end

    def << ( thing )
      @ports << thing
    end

    def push ( thing )
      @ports.push( thing )
    end

    def pop
      @ports.pop
    end

    def to_s( t = '' )

      label = @options['shape'] != 'record' && @ports.length == 0 ?
        @options['label'] ?
        t + TAB + "label = \"#{@options['label']}\"\n" :
                    '' :
                    t + TAB + 'label = "' + " \\\n" +
                    t + TAB2 + "#{@options['label']}| \\\n" +
                    @ports.collect{ |i|
        t + TAB2 + i.to_s
      }.join( "| \\\n" ) + " \\\n" +
        t + TAB + '"' + "\n"

        t + "#{@name} [\n" +
        @options.to_a.collect{ |i|
        i[1] && i[0] != 'label' ?
          t + TAB + "#{i[0]} = #{i[1]}" : nil
      }.compact.join( ",\n" ) + ( label != '' ? ",\n" : "\n" ) +
        label +
        t + "]\n"
    end
  end

  # subgraph element is the same to graph, but has another header in dot
  # notation
  class Subgraph < Element

    def initialize( params = {}, option_list = GRAPH_OPTS )
      super( params, option_list )
      @nodes = params['nodes'] ? params['nodes'] : []
      @dot_string = 'subgraph'
    end

    def each_node
      @nodes.each{ |i| yield i }
    end

    def << ( thing )
      @nodes << thing
    end

    def push( thing )
      @nodes.push( thing )
    end

    def pop
      @nodes.pop
    end

    def to_s( t = '' )
      hdr = t + "#{@dot_string} #{@name} {\n"

      options = @options.to_a.collect{ |name, val|
        val && name != 'label' ?
          t + TAB + "#{name} = #{val}" :
        name ? t + TAB + "#{name} = \"#{val}\"" : nil
      }.compact.join( "\n" ) + "\n"

      nodes = @nodes.collect{ |i|
        i.to_s( t + TAB )
      }.join( "\n" ) + "\n"
      hdr + options + nodes + t + "}\n"
    end
  end

  # this is graph
  class Digraph < Subgraph
    def initialize( params = {}, option_list = GRAPH_OPTS )
      super( params, option_list )
      @dot_string = 'digraph'
    end
  end

  # this is edge
  class Edge < Element
    attr_accessor :from, :to
    def initialize( params = {}, option_list = EDGE_OPTS )
      super( params, option_list )
      @from = params['from'] ? params['from'] : nil
      @to = params['to'] ? params['to'] : nil
    end

    def to_s( t = '' )
      t + "#{@from} -> #{to} [\n" +
        @options.to_a.collect{ |i|
        i[1] && i[0] != 'label' ?
          t + TAB + "#{i[0]} = #{i[1]}" :
        i[1] ? t + TAB + "#{i[0]} = \"#{i[1]}\"" : nil
      }.compact.join( "\n" ) + "\n" + t + "]\n"
    end
  end

end