#ifndef GRAPHTOGRAPHVIZ_H_
#define GRAPHTOGRAPHVIZ_H_

#include <lemon/list_graph.h>
#include <unordered_map>

using namespace lemon;
using namespace std;

/* USAGE:
 * ListDigraph::NodeMap<unordered_map<string, string>> nodeAttribs(g);
 * ListDigraph::ArcMap<unordered_map<string, string>> arcAttribs(g);
 * nodeAttribs[node]["label"] = "node_label";
 * string dot = graphToGraphviz(g, &nodeAttribs, &arcAttribs, "hello");
 */

template<class Map>
string getAttribs(Map &map){
    string attribs = "";
    for (const auto &el : map){
        if (el.second != "")
            attribs += "\"" + el.first + "\"=\"" + el.second + "\",";
    }
    if (attribs != "")
        attribs = " [" + attribs + "]";
    return attribs;
}


template<class Graph,
         class NodeAttribs = ListDigraph::NodeMap<std::unordered_map<string, string>>,
         class ArcAttribs = ListDigraph::ArcMap<std::unordered_map<string, string>>
         >
string graphToGraphviz(Graph       &graph,
                       NodeAttribs *nattribs = NULL,
                       ArcAttribs  *aattribs = NULL,
                       string      name      = "")
{

    typedef typename Graph::template NodeMap<string> NodeMap;
    typedef typename Graph::NodeIt NodeIterator;
    typedef typename Graph::ArcIt  ArcIterator;

    NodeMap labels(graph);
    ostringstream layout;
    layout << "strict digraph \""+name+"\" {\n";

    // prepare labels
    for (NodeIterator node(graph); node != INVALID; ++node){
        string label = "";
        if (nattribs != NULL)
            label = (*nattribs)[node]["label"];
        if (label == "") label = static_cast<ostringstream*>( &(ostringstream() << graph.id(node)) )->str();
        label = "\"" + label + "\"";
        labels[node] = label;
    }

    // initialize nodes
    for (NodeIterator node(graph); node != INVALID; ++node){
        layout << labels[node];
        if (nattribs != NULL)
            layout << getAttribs((*nattribs)[node]);
        layout << ";" << std::endl;
    }

    // initialize arcs
    for (ArcIterator arc(graph); arc != INVALID; ++arc){
        layout << labels[graph.source(arc)] << "->" << labels[graph.target(arc)];
        if (aattribs != NULL)
            layout << getAttribs((*aattribs)[arc]);
        layout << ";" << std::endl;
    }
    layout << "}";
    return layout.str();
}


#endif /* GRAPHTOGRAPHVIZ_H_ */

int main ()
{
    lemon::ListDigraph g;
    graphToGraphviz(g);
}