#include "Exception.hpp"
#include "MeshBoolean.hpp"
#include "libslic3r/TriangleMesh.hpp"
#include "libslic3r/TryCatchSignal.hpp"
#undef PI

// Include igl first. It defines "L" macro which then clashes with our localization
#include <igl/copyleft/cgal/mesh_boolean.h>
#undef L

// CGAL headers
#include <CGAL/Polygon_mesh_processing/corefinement.h>
#include <CGAL/Exact_integer.h>
#include <CGAL/Surface_mesh.h>
#include <CGAL/Cartesian_converter.h>

namespace Slic3r {
namespace MeshBoolean {

using MapMatrixXfUnaligned = Eigen::Map<const Eigen::Matrix<float, Eigen::Dynamic, Eigen::Dynamic, Eigen::RowMajor | Eigen::DontAlign>>;
using MapMatrixXiUnaligned = Eigen::Map<const Eigen::Matrix<int,   Eigen::Dynamic, Eigen::Dynamic, Eigen::RowMajor | Eigen::DontAlign>>;

TriangleMesh eigen_to_triangle_mesh(const EigenMesh &emesh)
{
    auto &VC = emesh.first; auto &FC = emesh.second;
    
    indexed_triangle_set its;
    its.vertices.reserve(size_t(VC.rows()));
    its.indices.reserve(size_t(FC.rows()));
    
    for (Eigen::Index i = 0; i < VC.rows(); ++i)
        its.vertices.emplace_back(VC.row(i).cast<float>());
    
    for (Eigen::Index i = 0; i < FC.rows(); ++i)
        its.indices.emplace_back(FC.row(i));
    
    return TriangleMesh { std::move(its) };
}

EigenMesh triangle_mesh_to_eigen(const TriangleMesh &mesh)
{
    EigenMesh emesh;
    emesh.first = MapMatrixXfUnaligned(mesh.its.vertices.front().data(),
                                       Eigen::Index(mesh.its.vertices.size()),
                                       3).cast<double>();

    emesh.second = MapMatrixXiUnaligned(mesh.its.indices.front().data(),
                                        Eigen::Index(mesh.its.indices.size()),
                                        3);
    return emesh;
}

void minus(EigenMesh &A, const EigenMesh &B)
{
    auto &[VA, FA] = A;
    auto &[VB, FB] = B;
    
    Eigen::MatrixXd VC;
    Eigen::MatrixXi FC;
    igl::MeshBooleanType boolean_type(igl::MESH_BOOLEAN_TYPE_MINUS);
    igl::copyleft::cgal::mesh_boolean(VA, FA, VB, FB, boolean_type, VC, FC);
    
    VA = std::move(VC); FA = std::move(FC);
}

void minus(TriangleMesh& A, const TriangleMesh& B)
{
    EigenMesh eA = triangle_mesh_to_eigen(A);
    minus(eA, triangle_mesh_to_eigen(B));
    A = eigen_to_triangle_mesh(eA);
}

void self_union(EigenMesh &A)
{
    EigenMesh result;
    auto &[V, F] = A;
    auto &[VC, FC] = result;

    igl::MeshBooleanType boolean_type(igl::MESH_BOOLEAN_TYPE_UNION);
    igl::copyleft::cgal::mesh_boolean(V, F, Eigen::MatrixXd(), Eigen::MatrixXi(), boolean_type, VC, FC);
    
    A = std::move(result);
}

void self_union(TriangleMesh& mesh)
{
    auto eM = triangle_mesh_to_eigen(mesh);
    self_union(eM);
    mesh = eigen_to_triangle_mesh(eM);
}

namespace cgal {

namespace CGALProc    = CGAL::Polygon_mesh_processing;
namespace CGALParams  = CGAL::Polygon_mesh_processing::parameters;

using EpecKernel = CGAL::Exact_predicates_exact_constructions_kernel;
using EpicKernel = CGAL::Exact_predicates_inexact_constructions_kernel;
using _EpicMesh = CGAL::Surface_mesh<EpicKernel::Point_3>;
using _EpecMesh = CGAL::Surface_mesh<EpecKernel::Point_3>;

struct CGALMesh { _EpicMesh m; };

// /////////////////////////////////////////////////////////////////////////////
// Converions from and to CGAL mesh
// /////////////////////////////////////////////////////////////////////////////

template<class _Mesh>
void triangle_mesh_to_cgal(const std::vector<stl_vertex> &                 V,
                           const std::vector<stl_triangle_vertex_indices> &F,
                           _Mesh &out)
{
    if (F.empty()) return;

    size_t vertices_count = V.size();
    size_t edges_count    = (F.size()* 3) / 2;
    size_t faces_count    = F.size();
    out.reserve(vertices_count, edges_count, faces_count);

    for (auto &v : V)
        out.add_vertex(typename _Mesh::Point{v.x(), v.y(), v.z()});

    using VI = typename _Mesh::Vertex_index;
    for (auto &f : F)
        out.add_face(VI(f(0)), VI(f(1)), VI(f(2)));
}

inline Vec3f to_vec3f(const _EpicMesh::Point& v)
{
    return { float(v.x()), float(v.y()), float(v.z()) };
}

inline Vec3f to_vec3f(const _EpecMesh::Point& v)
{
    CGAL::Cartesian_converter<EpecKernel, EpicKernel> cvt;
    auto iv = cvt(v);
    return { float(iv.x()), float(iv.y()), float(iv.z()) };
}

template<class _Mesh>
indexed_triangle_set cgal_to_indexed_triangle_set(const _Mesh &cgalmesh)
{
    indexed_triangle_set its;
    its.vertices.reserve(cgalmesh.num_vertices());
    its.indices.reserve(cgalmesh.num_faces());
    
    const auto &faces = cgalmesh.faces();
    const auto &vertices = cgalmesh.vertices();
    int vsize = int(vertices.size());

    for (auto &vi : vertices) {
        auto &v = cgalmesh.point(vi); // Don't ask...
        its.vertices.emplace_back(to_vec3f(v));
    }

    for (auto &face : faces) {
        auto vtc = cgalmesh.vertices_around_face(cgalmesh.halfedge(face));

        int i = 0;
        Vec3i facet;
        for (auto v : vtc) {
            int iv = v;
            if (i > 2 || iv < 0 || iv >= vsize) { i = 0; break; }
            facet(i++) = iv;
        }

        if (i == 3)
            its.indices.emplace_back(facet);
    }
    
    return its;
}

std::unique_ptr<CGALMesh, CGALMeshDeleter>
triangle_mesh_to_cgal(const std::vector<stl_vertex> &V,
                      const std::vector<stl_triangle_vertex_indices> &F)
{
    std::unique_ptr<CGALMesh, CGALMeshDeleter> out(new CGALMesh{});
    triangle_mesh_to_cgal(V, F, out->m);
    return out;
}

TriangleMesh cgal_to_triangle_mesh(const CGALMesh &cgalmesh)
{
    return TriangleMesh{cgal_to_indexed_triangle_set(cgalmesh.m)};
}

indexed_triangle_set cgal_to_indexed_triangle_set(const CGALMesh &cgalmesh)
{
    return cgal_to_indexed_triangle_set(cgalmesh.m);
}

// /////////////////////////////////////////////////////////////////////////////
// Boolean operations for CGAL meshes
// /////////////////////////////////////////////////////////////////////////////

static bool _cgal_diff(CGALMesh &A, CGALMesh &B, CGALMesh &R)
{
    const auto &p = CGALParams::throw_on_self_intersection(true);
    return CGALProc::corefine_and_compute_difference(A.m, B.m, R.m, p, p);
}

static bool _cgal_union(CGALMesh &A, CGALMesh &B, CGALMesh &R)
{
    const auto &p = CGALParams::throw_on_self_intersection(true);
    return CGALProc::corefine_and_compute_union(A.m, B.m, R.m, p, p);
}

static bool _cgal_intersection(CGALMesh &A, CGALMesh &B, CGALMesh &R)
{
    const auto &p = CGALParams::throw_on_self_intersection(true);
    return CGALProc::corefine_and_compute_intersection(A.m, B.m, R.m, p, p);
}

template<class Op> void _cgal_do(Op &&op, CGALMesh &A, CGALMesh &B)
{
    bool success = false;
    bool hw_fail = false;
    try {
        CGALMesh result;
        try_catch_signal({SIGSEGV, SIGFPE}, [&success, &A, &B, &result, &op] {
            success = op(A, B, result);
        }, [&] { hw_fail = true; });
        A = std::move(result);      // In-place operation does not work
    } catch (...) {
        success = false;
    }

    if (hw_fail)
        throw Slic3r::HardCrash("CGAL mesh boolean operation crashed.");

    if (! success)
        throw Slic3r::RuntimeError("CGAL mesh boolean operation failed.");
}

void minus(CGALMesh &A, CGALMesh &B) { _cgal_do(_cgal_diff, A, B); }
void plus(CGALMesh &A, CGALMesh &B) { _cgal_do(_cgal_union, A, B); }
void intersect(CGALMesh &A, CGALMesh &B) { _cgal_do(_cgal_intersection, A, B); }
bool does_self_intersect(const CGALMesh &mesh) { return CGALProc::does_self_intersect(mesh.m); }

// /////////////////////////////////////////////////////////////////////////////
// Now the public functions for TriangleMesh input:
// /////////////////////////////////////////////////////////////////////////////

template<class Op> void _mesh_boolean_do(Op &&op, indexed_triangle_set &A, const indexed_triangle_set &B)
{
    CGALMesh meshA;
    CGALMesh meshB;
    triangle_mesh_to_cgal(A.vertices, A.indices, meshA.m);
    triangle_mesh_to_cgal(B.vertices, B.indices, meshB.m);
    
    _cgal_do(op, meshA, meshB);
    
    A = cgal_to_indexed_triangle_set(meshA.m);
}

template<class Op> void _mesh_boolean_do(Op &&op, TriangleMesh &A, const TriangleMesh &B)
{
    CGALMesh meshA;
    CGALMesh meshB;
    triangle_mesh_to_cgal(A.its.vertices, A.its.indices, meshA.m);
    triangle_mesh_to_cgal(B.its.vertices, B.its.indices, meshB.m);

    _cgal_do(op, meshA, meshB);

    A = cgal_to_triangle_mesh(meshA);
}

void minus(TriangleMesh &A, const TriangleMesh &B)
{
    _mesh_boolean_do(_cgal_diff, A, B);
}

void plus(TriangleMesh &A, const TriangleMesh &B)
{
    _mesh_boolean_do(_cgal_union, A, B);
}

void intersect(TriangleMesh &A, const TriangleMesh &B)
{
    _mesh_boolean_do(_cgal_intersection, A, B);
}

void minus(indexed_triangle_set &A, const indexed_triangle_set &B)
{
    _mesh_boolean_do(_cgal_diff, A, B);
}

void plus(indexed_triangle_set &A, const indexed_triangle_set &B)
{
    _mesh_boolean_do(_cgal_union, A, B);
}

void intersect(indexed_triangle_set &A, const indexed_triangle_set &B)
{
    _mesh_boolean_do(_cgal_intersection, A, B);
}

bool does_self_intersect(const TriangleMesh &mesh)
{
    CGALMesh cgalm;
    triangle_mesh_to_cgal(mesh.its.vertices, mesh.its.indices, cgalm.m);
    return CGALProc::does_self_intersect(cgalm.m);
}

void CGALMeshDeleter::operator()(CGALMesh *ptr) { delete ptr; }

bool does_bound_a_volume(const CGALMesh &mesh)
{
    return CGAL::is_closed(mesh.m) && CGALProc::does_bound_a_volume(mesh.m);
}

bool empty(const CGALMesh &mesh)
{
    return mesh.m.is_empty();
}

CGALMeshPtr clone(const CGALMesh &m)
{
    return CGALMeshPtr{new CGALMesh{m}};
}

} // namespace cgal

} // namespace MeshBoolean
} // namespace Slic3r
