// This file is part of the SimMedTK project.
// Copyright (c) Center for Modeling, Simulation, and Imaging in Medicine,
//                        Rensselaer Polytechnic Institute
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
//---------------------------------------------------------------------------
//
// Authors:
//
// Contact:
//---------------------------------------------------------------------------

#ifndef SMMESH_H
#define SMMESH_H

// STL includes
#include <vector>

// SimMedTK includes
#include "Core/Config.h"
#include "Core/BaseMesh.h"
#include "Core/CoreClass.h"
#include "Core/ErrorLog.h"
#include "Core/Vector.h"
#include "Core/Matrix.h"
#include "Core/CollisionConfig.h"
#include "Core/Geometry.h"

#define SIMMEDTK_MESH_AABBSKINFACTOR 0.1  ///Bounding box skin value
#define SIMMEDTK_MESH_RESERVEDMAXEDGES 6000  ///this value is initially allocated buffer size for thge edges

// VegaFEM class
class ObjMesh;

struct TexCoord;
struct Triangle;
struct Tetrahedra;
struct Edge;

/// \brief: this is a generic Mesh class from which surface and volume meshes are inherited
/// Note: this class cannot exist on its own
class Mesh: public Core::BaseMesh
{
public:
    /// \brief constructor
    Mesh();

    /// \brief destructor
    virtual ~Mesh();

    /// \brief compute the neighbors of the vertex
    void getVertexNeighbors();

    /// \brief compute the neighbors of the triangle
    void getTriangleNeighbors();

    /// \brief initialize vertex arrays
    bool initVertexArrays(int nbr);

    /// \brief initialize triangle arrays
    bool initTriangleArrays(int nbr);

    /// \brief initialize the neighbors of the vertex
    void initVertexNeighbors();

    /// \brief !!
    void allocateAABBTris();

    /// \brief compute the normal of a triangle
    core::Vec3d calculateTriangleNormal(int triNbr);

    /// \brief update the normals of triangles after they moved
    void updateTriangleNormals();

    /// \brief update the normals of vertices after they moved
    void updateVertexNormals();

    /// \brief update Eigen::AlignedBox3d after the mesh moved
    void upadateAABB();

    /// \brief update Eigen::AlignedBox3d of each triangle after mesh moved
    void updateTriangleAABB();

    /// \brief compute triangle tangents
    void calcTriangleTangents();

    /// \brief compute the tangent give the three vertices
    core::Vec3d calculateTangent(const core::Vec3d& p1,
                                 const core::Vec3d& p2,
                                 const core::Vec3d& p3,
                                 const core::Vec2f& t1,
                                 const core::Vec2f& t2,
                                 const core::Vec2f& t3);

    /// \brief !!
    core::Vec3d calculateTangent_test(const core::Vec3d& p1,
                                      const core::Vec3d& p2,
                                      const core::Vec3d& p3,
                                      const core::Vec2f& t1,
                                      const core::Vec2f& t2,
                                      const core::Vec2f& t3);

    /// \brief find the neighbors of all vertices of mesh
    void calcNeighborsVertices();

    /// \brief find all the edges of the mesh
    void calcEdges();

    /// \brief rotate the mesh
    void rotate(const Quaterniond &rotation);

    /// \brief check if there is a consistent orientation of triangle vertices
    /// across the entire surface mesh
    void checkCorrectWinding();

    /// \brief get the type fo mesh
    MeshType getMeshType()
    {
        return meshType;
    };

    /// \brief load the mesh
    virtual bool loadMesh(const std::string& fileName, const MeshFileType &fileType) = 0;

    /// \brief load the mesh
    bool importSurfaceMeshFromVegaFormat(std::shared_ptr<ObjMesh> vegaSurfaceMesh, const bool perProcessingStage);

    /// \brief update the surface mesh data after the deformation
    void updateSurfaceMeshFromVegaFormat(std::shared_ptr<ObjMesh> vegaSurfaceMesh);

    /// \brief get number of triangles
    int getNumTriangles()  const
    {
        return this->nbrTriangles;
    }

    /// \brief get number of edges
    size_t getNumEdges() const
    {
        return this->edges.size();
    }

public:
    int  nbrTriangles; ///< number of triangles
    std::vector<Triangle> triangles; ///< list of triangles
    TexCoord *texCoordForTrianglesOBJ; ///< !! tansel for OBJ
    int nbrTexCoordForTrainglesOBJ; ///< !! tansel for OBJ
    core::Vec3d *triNormals; ///< triangle normals
    core::Vec3d *vertNormals; ///< vertex normals
    core::Vec3d *triTangents; ///< triangle tangents
    core::Vec3d *vertTangents; ///< vertex tangents
    bool tangentChannel; ///< !!
    std::vector< std::vector<int> > vertTriNeighbors; ///< list of neighbors for a triangle
    std::vector< std::vector<int> > vertVertNeighbors; ///< list of neighbors for a vertex
    std::vector<Edge> edges; ///< list of edges

    ///AABBB of the mesh.
    ///This value is allocated and computed by only collision detection module
    ///Therefore it is initially nullptr
    std::vector<Eigen::AlignedBox3d> triAABBs;

    MeshType meshType; ///< type of mesh (rigid, deformable etc.)
    MeshFileType meshFileType; ///< type of input mesh
};

/// \brief holds the texture co-ordinates
struct TexCoord
{
    float u, v;
};

/// \brief holds the vertex indices of triangle
struct Triangle
{
    std::array<unsigned int,3> vert;
};

/// \brief holds the vertex indices of tetrahedron
struct Tetrahedra
{
    std::array<unsigned int,4> vert;
};

/// \brief holds the vertex indices of edge
struct Edge
{
    std::array<unsigned int,2> vert;
};

#endif