struct NodeDesc {
  std::string label;
  std::string shape;
  std::string color;
  std::string fillcolor;
};

struct EdgeDesc {
  std::string label;
  std::string color;
  bool constraint;
};

template <class DownAttr_tpl>
class TopDown : public AstTopDownProcessing<DownAttr<DownAttr_tpl> > {
  public:
    TopDown();
    void toDot(std::ostream & out) const;
    void clear();

    NodeDesc & addNode(SgNode * node);
    EdgeDesc & addEdge(SgNode * node, SgNode * parent);

  protected:
    virtual bool skipNode(SgNode * node, const DownAttr_tpl & attr_in);
    virtual void computeAttr(SgNode * node, const DownAttr_tpl & attr_in, DownAttr_tpl & attr_out);

    virtual bool stopAtNode(SgNode * node, const DownAttr_tpl & attr_in, const DownAttr_tpl & attr_out);

    virtual void editNodeDesc(SgNode * node, const DownAttr_tpl & attr_in, const DownAttr_tpl & attr_out, NodeDesc & node_desc) = 0;
    virtual void editEdgeDesc(SgNode * node, const DownAttr_tpl & attr_in, const DownAttr_tpl & attr_out, SgNode * parent, EdgeDesc & edge_desc) = 0;

    DownAttr<DownAttr_tpl> evaluateInheritedAttribute(SgNode * node, DownAttr<DownAttr_tpl> attr_in);
};

struct EmptyDownAttr {};

class Basic : public AST2GraphViz::TopDown<EmptyDownAttr> {
  public:
    typedef AST2GraphViz::DownAttr<EmptyDownAttr> DownAttr;
    typedef AST2GraphViz::NodeDesc NodeDesc;
    typedef AST2GraphViz::EdgeDesc EdgeDesc;

  protected:
    void editNodeDesc(SgNode * node, const EmptyDownAttr & attr_in, const EmptyDownAttr & attr_out, NodeDesc & node_desc) {
      node_desc.label = node->class_name().getString();
      node_desc.shape = "box";
      node_desc.color = "black";
      node_desc.fillcolor = "white";
    }

    void editEdgeDesc(SgNode * node, const EmptyDownAttr & attr_in, const EmptyDownAttr & attr_out, SgNode * parent, EdgeDesc & edge_desc) {
      edge_desc.label = "";
      edge_desc.color = "black";
      edge_desc.constraint = true;
    }
};