#ifndef TCG_MESH_BGL_H

#define TCG_MESH_BGL_H

// TCG includes

#include "mesh.h"

// Boost includes

#include <boost/graph/graph_traits.hpp>

/*

  \file     tcg_mesh_bgl.h

  \brief    This file contains TCG adapters to Boost's Graph Library (BGL).

*/

//************************************************************************************

//    boost::graph_traits to tcg::Mesh concept type

//************************************************************************************

namespace boost

{

template <typename V, typename E, typename F>

struct graph_traits<typename tcg::Mesh<V, E, F>> {

	// Preliminar typedefs

	typedef typename tcg::Mesh<V, E, F> mesh_type;

	typedef typename mesh_type::vertex_type vertex_type;

	typedef typename mesh_type::edge_type edge_type;

	typedef typename vertex_type::edges_const_iterator edge_const_iterator;

	// V/E descriptors

	typedef int vertex_descriptor;

	struct edge_descriptor // NOTE: Can't use std::pair due to std conflicts

	{

		int m_e, m_src;

		edge_descriptor() : m_e(-1), m_src(-1) {}

		edge_descriptor(int e, int src) : m_e(e), m_src(src) {}

		bool operator==(const edge_descriptor &e_d) { return m_e == e_d.m_e; } // Undirected

		bool operator!=(const edge_descriptor &e_d) { return !operator==(e_d); }

	};

	// Iterators

	struct out_edge_iterator : public edge_const_iterator {

		int m_src;

		out_edge_iterator() : edge_const_iterator(), m_src(-1) {}

		out_edge_iterator(const edge_const_iterator &it, int src)

			: edge_const_iterator(it), m_src(src) {}

		edge_descriptor operator*() const

		{

			return edge_descriptor(edge_const_iterator::operator*(), m_src);

		}

	};

	typedef typename tcg::list<vertex_type>::const_iterator vertex_iterator;

	typedef typename tcg::list<edge_type>::const_iterator edge_iterator;

	// Categories

	typedef undirected_tag directed_category;

	typedef allow_parallel_edge_tag edge_parallel_category;

	typedef struct our_category : public bidirectional_graph_tag, public vertex_list_graph_tag, public edge_list_graph_tag {

	} traversal_category;

	// Sizes

	typedef int vertices_size_type;

	typedef int edges_size_type;

	typedef int degree_size_type;

	// Functions

	static inline vertex_descriptor null_vertex() { return -1; }

};

template <typename V, typename E, typename F>

struct graph_traits<typename tcg::TriMesh<V, E, F>>

	: public graph_traits<typename tcg::Mesh<V, E, F>> {

};

} // namespace boost

//************************************************************************************

//    tcg::bgl  helpers to edge data

//************************************************************************************

namespace tcg

{

namespace bgl

{

template <typename Mesh>

inline int source(const typename boost::graph_traits<Mesh>::edge_descriptor &edge_descr, const Mesh &mesh)

{

	return edge_descr.m_src;

}

//---------------------------------------------------------------------------------------

template <typename Mesh>

inline int target(const typename boost::graph_traits<Mesh>::edge_descriptor &edge_descr, const Mesh &mesh)

{

	const typename Mesh::edge_type &ed = mesh.edge(edge_descr.m_e);

	return (ed.vertex(0) == edge_descr.m_src) ? ed.vertex(1) : ed.vertex(0);

}

//---------------------------------------------------------------------------------------

template <typename Mesh>

inline std::pair<typename boost::graph_traits<Mesh>::out_edge_iterator,

				 typename boost::graph_traits<Mesh>::out_edge_iterator>

out_edges(int v, const Mesh &mesh)

{

	typedef typename boost::graph_traits<Mesh>::out_edge_iterator out_edge_iterator;

	return make_pair(

		out_edge_iterator(mesh.vertex(v).edgesBegin(), v),

		out_edge_iterator(mesh.vertex(v).edgesEnd(), v));

}

//---------------------------------------------------------------------------------------

template <typename Mesh>

inline int out_degree(int v, const Mesh &mesh)

{

	return mesh.vertex(v).edgesCount();

}

}

} // namespace tcg::bgl

#endif // TCG_MESH_BGL_H