#ifndef TCG_EDGE_H
#define TCG_EDGE_H

// STD includes
#include "assert.h"

namespace tcg
{

template <typename E>
struct edge_traits {
	typedef typename E::vertices_const_iterator vertices_const_iterator;
	typedef typename E::vertices_iterator vertices_iterator;

	typedef typename E::faces_const_iterator faces_const_iterator;
	typedef typename E::faces_iterator faces_iterator;
};

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

class Edge
{
public:
	typedef const int *vertices_const_iterator;
	typedef int *vertices_iterator;

	typedef const int *faces_const_iterator;
	typedef int *faces_iterator;

protected:
	int m_v[2];
	int m_f[2];
	int m_index;

public:
	Edge() : m_index(-1)
	{
		m_v[0] = -1, m_v[1] = -1;
		m_f[0] = -1, m_f[1] = -1;
	}
	Edge(int v1, int v2) : m_index(-1)
	{
		m_v[0] = v1, m_v[1] = v2;
		m_f[0] = -1, m_f[1] = -1;
	}
	~Edge() {}

	void setIndex(int idx) { m_index = idx; }
	int getIndex() const { return m_index; }

	int vertex(int i) const { return m_v[i]; }
	int verticesCount() const { return m_v[0] < 0 ? 0 : m_v[1] < 0 ? 1 : 2; }
	int otherVertex(int v) const { return m_v[0] == v ? m_v[1] : m_v[0]; }

	void addVertex(int v)
	{
		assert(verticesCount() < 2);
		m_v[verticesCount()] = v;
	}
	void setVertex(int i, int v) { assert(i < verticesCount()), m_v[i] = v; }
	vertices_iterator eraseVertex(vertices_iterator it)
	{
		*std::copy(it + 1, verticesEnd(), it) = -1;
		return it;
	}

	vertices_const_iterator verticesBegin() const { return m_v; }
	vertices_const_iterator verticesEnd() const { return m_v + verticesCount(); }
	vertices_iterator verticesBegin() { return m_v; }
	vertices_iterator verticesEnd() { return m_v + verticesCount(); }

	int face(int i) const { return m_f[i]; }
	int facesCount() const { return m_f[0] < 0 ? 0 : m_f[1] < 0 ? 1 : 2; }
	int otherFace(int f) const { return m_f[0] == f ? m_f[1] : m_f[0]; }

	void addFace(int f)
	{
		assert(facesCount() < 2);
		m_f[facesCount()] = f;
	}
	void setFace(int i, int f) { assert(i < facesCount()), m_f[i] = f; }
	faces_iterator eraseFace(faces_iterator it)
	{
		*std::copy(it + 1, facesEnd(), it) = -1;
		return it;
	}

	faces_const_iterator facesBegin() const { return m_f; }
	faces_const_iterator facesEnd() const { return m_f + facesCount(); }
	faces_iterator facesBegin() { return m_f; }
	faces_iterator facesEnd() { return m_f + facesCount(); }
};

} // namespace tcg

#endif // TCG_EDGE_H