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Open Asset Import Library (assimp)
----------------------------------------------------------------------

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  copyright notice, this list of conditions and the
  following disclaimer.

* Redistributions in binary form must reproduce the above
  copyright notice, this list of conditions and the
  following disclaimer in the documentation and/or other
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* Neither the name of the assimp team, nor the names of its
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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*/

/** @file  C4DImporter.cpp
 *  @brief Implementation of the Cinema4D importer class.
 */
#ifndef ASSIMP_BUILD_NO_C4D_IMPORTER

// no #ifdefing here, Cinema4D support is carried out in a branch of assimp
// where it is turned on in the CMake settings.

#ifndef _MSC_VER
#   error C4D support is currently MSVC only
#endif

#include "C4DImporter.h"
#include <memory>
#include <assimp/IOSystem.hpp>
#include <assimp/scene.h>
#include <assimp/ai_assert.h>

#if defined(_M_X64) || defined(__amd64__)
#   define __C4D_64BIT
#endif

#define __PC
#include "c4d_file.h"
#include "default_alien_overloads.h"

namespace {

aiString aiStringFrom(cineware::String const & cinestring) {
    aiString result;
    cinestring.GetCString(result.data, MAXLEN-1);
    result.length = static_cast<ai_uint32>(cinestring.GetLength());
    return result;
}

}

using namespace Assimp;
using namespace cineware;

// overload this function and fill in your own unique data
void GetWriterInfo(int &id, String &appname) {
    id = 2424226;
    appname = "Open Asset Import Library";
}

namespace Assimp {
    template<> const char* LogFunctions<C4DImporter>::Prefix() {
        return "C4D: ";
    }
}

static const aiImporterDesc desc = {
    "Cinema4D Importer",
    "",
    "",
    "",
    aiImporterFlags_SupportBinaryFlavour,
    0,
    0,
    0,
    0,
    "c4d"
};


// ------------------------------------------------------------------------------------------------
C4DImporter::C4DImporter() = default;

// ------------------------------------------------------------------------------------------------
C4DImporter::~C4DImporter() = default;

// ------------------------------------------------------------------------------------------------
bool C4DImporter::CanRead( const std::string& pFile, IOSystem* /*pIOHandler*/, bool /*checkSig*/) const {
    const std::string& extension = GetExtension(pFile);
    if (extension == "c4d") {
        return true;
    } else if ((!extension.length() || checkSig) && pIOHandler)   {
        // TODO
    }

    return false;
}

// ------------------------------------------------------------------------------------------------
const aiImporterDesc* C4DImporter::GetInfo () const {
    return &desc;
}


// ------------------------------------------------------------------------------------------------
// Imports the given file into the given scene structure.
void C4DImporter::InternReadFile( const std::string& pFile, aiScene* pScene, IOSystem* pIOHandler) {
    std::unique_ptr<IOStream> file( pIOHandler->Open( pFile));

    if( file.get() == nullptr ) {
        ThrowException("failed to open file " + pFile);
    }

    const size_t file_size = file->FileSize();

    std::vector<uint8_t> mBuffer(file_size);
    file->Read(&mBuffer[0], 1, file_size);

    Filename f;
    f.SetMemoryReadMode(&mBuffer[0], file_size);

    // open document first
    BaseDocument* doc = LoadDocument(f, SCENEFILTER_OBJECTS | SCENEFILTER_MATERIALS);
    if(doc == nullptr ) {
        ThrowException("failed to read document " + pFile);
    }

    // Generate the root-node
    pScene->mRootNode = new aiNode("<C4DRoot>");

    // convert left-handed to right-handed
    pScene->mRootNode->mTransformation.a1 = 0.01f;
    pScene->mRootNode->mTransformation.b2 = 0.01f;
    pScene->mRootNode->mTransformation.c3 = -0.01f;

    // first convert all materials
    ReadMaterials(doc->GetFirstMaterial());

    // process C4D scene-graph recursively
    try {
        RecurseHierarchy(doc->GetFirstObject(), pScene->mRootNode);
    } catch(...) {
        for(aiMesh* mesh : meshes) {
            delete mesh;
        }
        BaseDocument::Free(doc);
        throw;
    }
    BaseDocument::Free(doc);

    // copy meshes over
    pScene->mNumMeshes = static_cast<unsigned int>(meshes.size());
    pScene->mMeshes = new aiMesh*[pScene->mNumMeshes]();
    std::copy(meshes.begin(), meshes.end(), pScene->mMeshes);

    // copy materials over, adding a default material if necessary
    unsigned int mat_count = static_cast<unsigned int>(materials.size());
    for(aiMesh* mesh : meshes) {
        ai_assert(mesh->mMaterialIndex <= mat_count);
        if(mesh->mMaterialIndex >= mat_count) {
            ++mat_count;

            std::unique_ptr<aiMaterial> def_material(new aiMaterial());
            const aiString name(AI_DEFAULT_MATERIAL_NAME);
            def_material->AddProperty(&name, AI_MATKEY_NAME);

            materials.push_back(def_material.release());
            break;
        }
    }

    pScene->mNumMaterials = static_cast<unsigned int>(materials.size());
    pScene->mMaterials = new aiMaterial*[pScene->mNumMaterials]();
    std::copy(materials.begin(), materials.end(), pScene->mMaterials);
}


// ------------------------------------------------------------------------------------------------
bool C4DImporter::ReadShader(aiMaterial* out, BaseShader* shader) {
    // based on Cineware sample code (C4DImportExport.cpp)
    while(shader) {
        if(shader->GetType() == Xlayer) {
            BaseContainer* container = shader->GetDataInstance();
            GeData blend = container->GetData(SLA_LAYER_BLEND);
            iBlendDataType* blend_list = reinterpret_cast<iBlendDataType*>(blend.GetCustomDataType(CUSTOMDATA_BLEND_LIST));
            if (!blend_list)
            {
                LogWarn("ignoring XLayer shader: no blend list given");
                continue;
            }

            LayerShaderLayer *lsl = dynamic_cast<LayerShaderLayer*>(blend_list->m_BlendLayers.GetObject(0));

            // Ignore the actual layer blending - models for real-time rendering should not
            // use them in a non-trivial way. Just try to find textures that we can apply
            // to the model.
            while (lsl) {
                if (lsl->GetType() == TypeFolder) {
                    BlendFolder* const folder = dynamic_cast<BlendFolder*>(lsl);
                    LayerShaderLayer *subLsl = dynamic_cast<LayerShaderLayer*>(folder->m_Children.GetObject(0));

                    while (subLsl) {
                        if (subLsl->GetType() == TypeShader) {
                            BlendShader* const shader = dynamic_cast<BlendShader*>(subLsl);
                            if(ReadShader(out, static_cast<BaseShader*>(shader->m_pLink->GetLink()))) {
                                return true;
                            }
                        }

                        subLsl = subLsl->GetNext();
                    }
                } else if (lsl->GetType() == TypeShader) {
                    BlendShader* const shader = dynamic_cast<BlendShader*>(lsl);
                    if(ReadShader(out, static_cast<BaseShader*>(shader->m_pLink->GetLink()))) {
                        return true;
                    }
                }

                lsl = lsl->GetNext();
            }
        } else if ( shader->GetType() == Xbitmap ) {
            auto const path = aiStringFrom(shader->GetFileName().GetString());
            out->AddProperty(&path, AI_MATKEY_TEXTURE_DIFFUSE(0));
            return true;
        } else {
            LogWarn("ignoring shader type: ", GetObjectTypeName(shader->GetType()));
        }
        shader = shader->GetNext();
    }

    return false;
}

// ------------------------------------------------------------------------------------------------
void C4DImporter::ReadMaterials(BaseMaterial* mat) {
    // based on Cineware sample code
    while (mat) {
        if (mat->GetType() == Mmaterial) {
            aiMaterial* out = new aiMaterial();
            material_mapping[mat] = static_cast<unsigned int>(materials.size());
            materials.push_back(out);

            auto const ai_name = aiStringFrom(mat->GetName());
            out->AddProperty(&ai_name, AI_MATKEY_NAME);

            Material& m = dynamic_cast<Material&>(*mat);

            if (m.GetChannelState(CHANNEL_COLOR)) {
                GeData data;
                mat->GetParameter(MATERIAL_COLOR_COLOR, data);
                Vector color = data.GetVector();
                mat->GetParameter(MATERIAL_COLOR_BRIGHTNESS, data);
                const Float brightness = data.GetFloat();

                color *= brightness;

                aiVector3D v;
                v.x = color.x;
                v.y = color.y;
                v.z = color.z;
                out->AddProperty(&v, 1, AI_MATKEY_COLOR_DIFFUSE);
            }

            BaseShader* const shader = m.GetShader(MATERIAL_COLOR_SHADER);
            if(shader) {
                ReadShader(out, shader);
            }
        } else {
            LogWarn("ignoring plugin material: ", GetObjectTypeName(mat->GetType()));
        }
        mat = mat->GetNext();
    }
}

// ------------------------------------------------------------------------------------------------
void C4DImporter::RecurseHierarchy(BaseObject* object, aiNode* parent) {
    ai_assert(parent != nullptr );
    std::vector<aiNode*> nodes;

    // based on Cineware sample code
    while (object) {
        const LONG type = object->GetType();
        const Matrix& ml = object->GetMl();

        aiNode* const nd = new aiNode();

        nd->mParent = parent;
        nd->mName = aiStringFrom(object->GetName());

        nd->mTransformation.a1 = ml.v1.x;
        nd->mTransformation.b1 = ml.v1.y;
        nd->mTransformation.c1 = ml.v1.z;

        nd->mTransformation.a2 = ml.v2.x;
        nd->mTransformation.b2 = ml.v2.y;
        nd->mTransformation.c2 = ml.v2.z;

        nd->mTransformation.a3 = ml.v3.x;
        nd->mTransformation.b3 = ml.v3.y;
        nd->mTransformation.c3 = ml.v3.z;

        nd->mTransformation.a4 = ml.off.x;
        nd->mTransformation.b4 = ml.off.y;
        nd->mTransformation.c4 = ml.off.z;

        nodes.push_back(nd);

        GeData data;
        if (type == Ocamera) {
            object->GetParameter(CAMERAOBJECT_FOV, data);
            // TODO: read camera
        } else if (type == Olight) {
            // TODO: read light
        } else if (type == Opolygon) {
            aiMesh* const mesh = ReadMesh(object);
            if(mesh != nullptr) {
                nd->mNumMeshes = 1;
                nd->mMeshes = new unsigned int[1];
                nd->mMeshes[0] = static_cast<unsigned int>(meshes.size());
                meshes.push_back(mesh);
            }
        } else {
            LogWarn("ignoring object: ", GetObjectTypeName(type));
        }

        RecurseHierarchy(object->GetDown(), nd);
        object = object->GetNext();
    }

    // copy nodes over to parent
    parent->mNumChildren = static_cast<unsigned int>(nodes.size());
    parent->mChildren = new aiNode*[parent->mNumChildren]();
    std::copy(nodes.begin(), nodes.end(), parent->mChildren);
}

// ------------------------------------------------------------------------------------------------
aiMesh* C4DImporter::ReadMesh(BaseObject* object) {
    ai_assert(object != nullptr);
    ai_assert( object->GetType() == Opolygon );

    // based on Cineware sample code
    PolygonObject* const polyObject = dynamic_cast<PolygonObject*>(object);
    ai_assert(polyObject != nullptr);

    const LONG pointCount = polyObject->GetPointCount();
    const LONG polyCount = polyObject->GetPolygonCount();
    if(!polyObject || !pointCount) {
        LogWarn("ignoring mesh with zero vertices or faces");
        return nullptr;
    }

    const Vector* points = polyObject->GetPointR();
    ai_assert(points != nullptr);

    const CPolygon* polys = polyObject->GetPolygonR();
    ai_assert(polys != nullptr);

    std::unique_ptr<aiMesh> mesh(new aiMesh());
    mesh->mNumFaces = static_cast<unsigned int>(polyCount);
    aiFace* face = mesh->mFaces = new aiFace[mesh->mNumFaces]();

    mesh->mPrimitiveTypes = aiPrimitiveType_TRIANGLE;
    mesh->mMaterialIndex = 0;

    unsigned int vcount = 0;

    // first count vertices
    for (LONG i = 0; i < polyCount; i++)
    {
        vcount += 3;

        // TODO: do we also need to handle lines or points with similar checks?
        if (polys[i].c != polys[i].d)
        {
            mesh->mPrimitiveTypes |= aiPrimitiveType_POLYGON;
            ++vcount;
        }
    }

    ai_assert(vcount > 0);

    mesh->mNumVertices = vcount;
    aiVector3D* verts = mesh->mVertices = new aiVector3D[mesh->mNumVertices];
    aiVector3D* normals, *uvs, *tangents, *bitangents;
    unsigned int n = 0;

    // check if there are normals, tangents or UVW coordinates
    BaseTag* tag = object->GetTag(Tnormal);
    NormalTag* normals_src = nullptr;
    if(tag) {
        normals_src = dynamic_cast<NormalTag*>(tag);
        normals = mesh->mNormals = new aiVector3D[mesh->mNumVertices]();
    }

    tag = object->GetTag(Ttangent);
    TangentTag* tangents_src = nullptr;
    if(tag) {
        tangents_src = dynamic_cast<TangentTag*>(tag);
        tangents = mesh->mTangents = new aiVector3D[mesh->mNumVertices]();
        bitangents = mesh->mBitangents = new aiVector3D[mesh->mNumVertices]();
    }

    tag = object->GetTag(Tuvw);
    UVWTag* uvs_src = nullptr;
    if(tag) {
        uvs_src = dynamic_cast<UVWTag*>(tag);
        uvs = mesh->mTextureCoords[0] = new aiVector3D[mesh->mNumVertices]();
    }

    // copy vertices and extra channels over and populate faces
    for (LONG i = 0; i < polyCount; ++i, ++face) {
        ai_assert(polys[i].a < pointCount && polys[i].a >= 0);
        const Vector& pointA = points[polys[i].a];
        verts->x = pointA.x;
        verts->y = pointA.y;
        verts->z = pointA.z;
        ++verts;

        ai_assert(polys[i].b < pointCount && polys[i].b >= 0);
        const Vector& pointB = points[polys[i].b];
        verts->x = pointB.x;
        verts->y = pointB.y;
        verts->z = pointB.z;
        ++verts;

        ai_assert(polys[i].c < pointCount && polys[i].c >= 0);
        const Vector& pointC = points[polys[i].c];
        verts->x = pointC.x;
        verts->y = pointC.y;
        verts->z = pointC.z;
        ++verts;

        // TODO: do we also need to handle lines or points with similar checks?
        if (polys[i].c != polys[i].d) {
            ai_assert(polys[i].d < pointCount && polys[i].d >= 0);

            face->mNumIndices = 4;
            mesh->mPrimitiveTypes |= aiPrimitiveType_POLYGON;
            const Vector& pointD = points[polys[i].d];
            verts->x = pointD.x;
            verts->y = pointD.y;
            verts->z = pointD.z;
            ++verts;
        } else {
            face->mNumIndices = 3;
        }
        face->mIndices = new unsigned int[face->mNumIndices];
        for(unsigned int j = 0; j < face->mNumIndices; ++j) {
            face->mIndices[j] = n++;
        }

        // copy normals
        if (normals_src) {
            if(i >= normals_src->GetDataCount()) {
                LogError("unexpected number of normals, ignoring");
            } else {
                ConstNormalHandle normal_handle = normals_src->GetDataAddressR();
                NormalStruct nor;
                NormalTag::Get(normal_handle, i, nor);
                normals->x = nor.a.x;
                normals->y = nor.a.y;
                normals->z = nor.a.z;
                ++normals;

                normals->x = nor.b.x;
                normals->y = nor.b.y;
                normals->z = nor.b.z;
                ++normals;

                normals->x = nor.c.x;
                normals->y = nor.c.y;
                normals->z = nor.c.z;
                ++normals;

                if(face->mNumIndices == 4) {
                    normals->x = nor.d.x;
                    normals->y = nor.d.y;
                    normals->z = nor.d.z;
                    ++normals;
                }
            }
        }

        // copy tangents and bitangents
        if (tangents_src) {

            for(unsigned int k = 0; k < face->mNumIndices; ++k) {
                LONG l;
                switch(k) {
                case 0:
                    l = polys[i].a;
                    break;
                case 1:
                    l = polys[i].b;
                    break;
                case 2:
                    l = polys[i].c;
                    break;
                case 3:
                    l = polys[i].d;
                    break;
                default:
                    ai_assert(false);
                }
                if(l >= tangents_src->GetDataCount()) {
                    LogError("unexpected number of tangents, ignoring");
                    break;
                }

                Tangent tan = tangents_src->GetDataR()[l];
                tangents->x = tan.vl.x;
                tangents->y = tan.vl.y;
                tangents->z = tan.vl.z;
                ++tangents;

                bitangents->x = tan.vr.x;
                bitangents->y = tan.vr.y;
                bitangents->z = tan.vr.z;
                ++bitangents;
            }
        }

        // copy UVs
        if (uvs_src) {
            if(i >= uvs_src->GetDataCount()) {
                LogError("unexpected number of UV coordinates, ignoring");
            }
            else {
                UVWStruct uvw;
                uvs_src->Get(uvs_src->GetDataAddressR(),i,uvw);

                uvs->x = uvw.a.x;
                uvs->y = 1.0f-uvw.a.y;
                uvs->z = uvw.a.z;
                ++uvs;

                uvs->x = uvw.b.x;
                uvs->y = 1.0f-uvw.b.y;
                uvs->z = uvw.b.z;
                ++uvs;

                uvs->x = uvw.c.x;
                uvs->y = 1.0f-uvw.c.y;
                uvs->z = uvw.c.z;
                ++uvs;

                if(face->mNumIndices == 4) {
                    uvs->x = uvw.d.x;
                    uvs->y = 1.0f-uvw.d.y;
                    uvs->z = uvw.d.z;
                    ++uvs;
                }
            }
        }
    }

    mesh->mMaterialIndex = ResolveMaterial(polyObject);

    return mesh.release();
}

// ------------------------------------------------------------------------------------------------
unsigned int C4DImporter::ResolveMaterial(PolygonObject* obj) {
    ai_assert(obj != nullptr);

    const unsigned int mat_count = static_cast<unsigned int>(materials.size());

    BaseTag* tag = obj->GetTag(Ttexture);
    if(tag == nullptr) {
        return mat_count;
    }

    TextureTag& ttag = dynamic_cast<TextureTag&>(*tag);

    BaseMaterial* const mat = ttag.GetMaterial();
    ai_assert(mat != nullptr);

    const MaterialMap::const_iterator it = material_mapping.find(mat);
    if(it == material_mapping.end()) {
        return mat_count;
    }

    ai_assert((*it).second < mat_count);

    return (*it).second;
}

#endif // ASSIMP_BUILD_NO_C4D_IMPORTER
