/*
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/** @file  XFileImporter.cpp
 *  @brief Implementation of the XFile importer class
 */

#ifndef ASSIMP_BUILD_NO_X_IMPORTER

#include "AssetLib/X/XFileImporter.h"
#include "AssetLib/X/XFileParser.h"
#include "PostProcessing/ConvertToLHProcess.h"

#include <assimp/TinyFormatter.h>
#include <assimp/IOSystem.hpp>
#include <assimp/scene.h>
#include <assimp/DefaultLogger.hpp>
#include <assimp/importerdesc.h>

#include <cctype>
#include <memory>

namespace Assimp {

using namespace Assimp::Formatter;

static constexpr aiImporterDesc desc = {
    "Direct3D XFile Importer",
    "",
    "",
    "",
    aiImporterFlags_SupportTextFlavour | aiImporterFlags_SupportBinaryFlavour | aiImporterFlags_SupportCompressedFlavour,
    1,
    3,
    1,
    5,
    "x"
};

// ------------------------------------------------------------------------------------------------
// Returns whether the class can handle the format of the given file.
bool XFileImporter::CanRead(const std::string &pFile, IOSystem *pIOHandler, bool /*checkSig*/) const {
    static const uint32_t token[] = { AI_MAKE_MAGIC("xof ") };
    return CheckMagicToken(pIOHandler, pFile, token, AI_COUNT_OF(token));
}

// ------------------------------------------------------------------------------------------------
// Get file extension list
const aiImporterDesc *XFileImporter::GetInfo() const {
    return &desc;
}

// ------------------------------------------------------------------------------------------------
// Imports the given file into the given scene structure.
void XFileImporter::InternReadFile(const std::string &pFile, aiScene *pScene, IOSystem *pIOHandler) {
    // read file into memory
    std::unique_ptr<IOStream> file(pIOHandler->Open(pFile));
    if (file == nullptr) {
        throw DeadlyImportError("Failed to open file ", pFile, ".");
    }

    static const size_t MinSize = 16;
    size_t fileSize = file->FileSize();
    if (fileSize < MinSize) {
        throw DeadlyImportError("XFile is too small.");
    }

    // in the hope that binary files will never start with a BOM ...
    mBuffer.resize(fileSize + 1);
    file->Read(&mBuffer.front(), 1, fileSize);
    ConvertToUTF8(mBuffer);

    // parse the file into a temporary representation
    XFileParser parser(mBuffer);

    // and create the proper return structures out of it
    CreateDataRepresentationFromImport(pScene, parser.GetImportedData());

    // if nothing came from it, report it as error
    if (!pScene->mRootNode) {
        throw DeadlyImportError("XFile is ill-formatted - no content imported.");
    }
}

// ------------------------------------------------------------------------------------------------
// Constructs the return data structure out of the imported data.
void XFileImporter::CreateDataRepresentationFromImport(aiScene *pScene, XFile::Scene *pData) {
    // Read the global materials first so that meshes referring to them can find them later
    ConvertMaterials(pScene, pData->mGlobalMaterials);

    // copy nodes, extracting meshes and materials on the way
    pScene->mRootNode = CreateNodes(pScene, nullptr, pData->mRootNode);

    // extract animations
    CreateAnimations(pScene, pData);

    // read the global meshes that were stored outside of any node
    if (!pData->mGlobalMeshes.empty()) {
        // create a root node to hold them if there isn't any, yet
        if (pScene->mRootNode == nullptr) {
            pScene->mRootNode = new aiNode;
            pScene->mRootNode->mName.Set("$dummy_node");
        }

        // convert all global meshes and store them in the root node.
        // If there was one before, the global meshes now suddenly have its transformation matrix...
        // Don't know what to do there, I don't want to insert another node under the present root node
        // just to avoid this.
        CreateMeshes(pScene, pScene->mRootNode, pData->mGlobalMeshes);
    }

    if (!pScene->mRootNode) {
        throw DeadlyImportError("No root node");
    }

    // Convert everything to OpenGL space... it's the same operation as the conversion back, so we can reuse the step directly
    MakeLeftHandedProcess convertProcess;
    convertProcess.Execute(pScene);

    FlipWindingOrderProcess flipper;
    flipper.Execute(pScene);

    // finally: create a dummy material if not material was imported
    if (pScene->mNumMaterials == 0) {
        pScene->mNumMaterials = 1;
        // create the Material
        aiMaterial *mat = new aiMaterial;
        int shadeMode = (int)aiShadingMode_Gouraud;
        mat->AddProperty<int>(&shadeMode, 1, AI_MATKEY_SHADING_MODEL);
        // material colours
        int specExp = 1;

        aiColor3D clr = aiColor3D(0, 0, 0);
        mat->AddProperty(&clr, 1, AI_MATKEY_COLOR_EMISSIVE);
        mat->AddProperty(&clr, 1, AI_MATKEY_COLOR_SPECULAR);

        clr = aiColor3D(0.5f, 0.5f, 0.5f);
        mat->AddProperty(&clr, 1, AI_MATKEY_COLOR_DIFFUSE);
        mat->AddProperty(&specExp, 1, AI_MATKEY_SHININESS);

        pScene->mMaterials = new aiMaterial *[1];
        pScene->mMaterials[0] = mat;
    }
}

// ------------------------------------------------------------------------------------------------
// Recursively creates scene nodes from the imported hierarchy.
aiNode *XFileImporter::CreateNodes(aiScene *pScene, aiNode *pParent, const XFile::Node *pNode) {
    if (!pNode) {
        return nullptr;
    }

    // create node
    aiNode *node = new aiNode;
    node->mName.length = (ai_uint32)pNode->mName.length();
    node->mParent = pParent;
    memcpy(node->mName.data, pNode->mName.c_str(), pNode->mName.length());
    node->mName.data[node->mName.length] = 0;
    node->mTransformation = pNode->mTrafoMatrix;

    // convert meshes from the source node
    CreateMeshes(pScene, node, pNode->mMeshes);

    // handle children
    if (!pNode->mChildren.empty()) {
        node->mNumChildren = (unsigned int)pNode->mChildren.size();
        node->mChildren = new aiNode *[node->mNumChildren];

        for (unsigned int a = 0; a < pNode->mChildren.size(); ++a) {
            node->mChildren[a] = CreateNodes(pScene, node, pNode->mChildren[a]);
        }
    }

    return node;
}

// ------------------------------------------------------------------------------------------------
// Creates the meshes for the given node.
void XFileImporter::CreateMeshes(aiScene *pScene, aiNode *pNode, const std::vector<XFile::Mesh *> &pMeshes) {
    if (pMeshes.empty()) {
        return;
    }

    // create a mesh for each mesh-material combination in the source node
    std::vector<aiMesh *> meshes;
    for (unsigned int a = 0; a < pMeshes.size(); ++a) {
        XFile::Mesh *sourceMesh = pMeshes[a];
        if (nullptr == sourceMesh) {
            continue;
        }

        // first convert its materials so that we can find them with their index afterwards
        ConvertMaterials(pScene, sourceMesh->mMaterials);

        unsigned int numMaterials = std::max((unsigned int)sourceMesh->mMaterials.size(), 1u);
        for (unsigned int b = 0; b < numMaterials; ++b) {
            // collect the faces belonging to this material
            std::vector<unsigned int> faces;
            unsigned int numVertices = 0;
            if (!sourceMesh->mFaceMaterials.empty()) {
                // if there is a per-face material defined, select the faces with the corresponding material
                for (unsigned int c = 0; c < sourceMesh->mFaceMaterials.size(); ++c) {
                    if (sourceMesh->mFaceMaterials[c] == b) {
                        faces.push_back(c);
                        numVertices += (unsigned int)sourceMesh->mPosFaces[c].mIndices.size();
                    }
                }
            } else {
                // if there is no per-face material, place everything into one mesh
                for (unsigned int c = 0; c < sourceMesh->mPosFaces.size(); ++c) {
                    faces.push_back(c);
                    numVertices += (unsigned int)sourceMesh->mPosFaces[c].mIndices.size();
                }
            }

            // no faces/vertices using this material? strange...
            if (numVertices == 0) {
                continue;
            }

            // create a submesh using this material
            aiMesh *mesh = new aiMesh;
            meshes.push_back(mesh);

            // find the material in the scene's material list. Either own material
            // or referenced material, it should already have a valid index
            if (!sourceMesh->mFaceMaterials.empty()) {
                mesh->mMaterialIndex = static_cast<unsigned int>(sourceMesh->mMaterials[b].sceneIndex);
            } else {
                mesh->mMaterialIndex = 0;
            }

            // Create properly sized data arrays in the mesh. We store unique vertices per face,
            // as specified
            mesh->mNumVertices = numVertices;
            mesh->mVertices = new aiVector3D[numVertices];
            mesh->mNumFaces = (unsigned int)faces.size();
            mesh->mFaces = new aiFace[mesh->mNumFaces];

            // name
            mesh->mName.Set(sourceMesh->mName);

            // normals?
            if (sourceMesh->mNormals.size() > 0) {
                mesh->mNormals = new aiVector3D[numVertices];
            }
            // texture coords
            for (unsigned int c = 0; c < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++c) {
                if (!sourceMesh->mTexCoords[c].empty()) {
                    mesh->mTextureCoords[c] = new aiVector3D[numVertices];
                }
            }
            // vertex colors
            for (unsigned int c = 0; c < AI_MAX_NUMBER_OF_COLOR_SETS; ++c) {
                if (!sourceMesh->mColors[c].empty()) {
                    mesh->mColors[c] = new aiColor4D[numVertices];
                }
            }

            // now collect the vertex data of all data streams present in the imported mesh
            unsigned int newIndex(0);
            std::vector<unsigned int> orgPoints; // from which original point each new vertex stems
            orgPoints.resize(numVertices, 0);

            for (unsigned int c = 0; c < faces.size(); ++c) {
                unsigned int f = faces[c]; // index of the source face
                const XFile::Face &pf = sourceMesh->mPosFaces[f]; // position source face

                // create face. either triangle or triangle fan depending on the index count
                aiFace &df = mesh->mFaces[c]; // destination face
                df.mNumIndices = (unsigned int)pf.mIndices.size();
                df.mIndices = new unsigned int[df.mNumIndices];

                // collect vertex data for indices of this face
                for (unsigned int d = 0; d < df.mNumIndices; ++d) {
                    df.mIndices[d] = newIndex;
                    const unsigned int newIdx = pf.mIndices[d];
                    if (newIdx >= sourceMesh->mPositions.size()) {
                        continue;
                    }

                    orgPoints[newIndex] = pf.mIndices[d];

                    // Position
                    mesh->mVertices[newIndex] = sourceMesh->mPositions[pf.mIndices[d]];
                    // Normal, if present
                    if (mesh->HasNormals()) {
                        if (sourceMesh->mNormFaces[f].mIndices.size() > d) {
                            const size_t idx(sourceMesh->mNormFaces[f].mIndices[d]);
                            if (idx < sourceMesh->mNormals.size()) {
                                mesh->mNormals[newIndex] = sourceMesh->mNormals[idx];
                            }
                        }
                    }

                    // texture coord sets
                    for (unsigned int e = 0; e < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++e) {
                        if (mesh->HasTextureCoords(e)) {
                            aiVector2D tex = sourceMesh->mTexCoords[e][pf.mIndices[d]];
                            mesh->mTextureCoords[e][newIndex] = aiVector3D(tex.x, 1.0f - tex.y, 0.0f);
                        }
                    }
                    // vertex color sets
                    for (unsigned int e = 0; e < AI_MAX_NUMBER_OF_COLOR_SETS; ++e) {
                        if (mesh->HasVertexColors(e)) {
                            mesh->mColors[e][newIndex] = sourceMesh->mColors[e][pf.mIndices[d]];
                        }
                    }

                    newIndex++;
                }
            }

            // there should be as much new vertices as we calculated before
            ai_assert(newIndex == numVertices);

            // convert all bones of the source mesh which influence vertices in this newly created mesh
            const std::vector<XFile::Bone> &bones = sourceMesh->mBones;
            std::vector<aiBone *> newBones;
            for (unsigned int c = 0; c < bones.size(); ++c) {
                const XFile::Bone &obone = bones[c];
                // set up a vertex-linear array of the weights for quick searching if a bone influences a vertex
                std::vector<ai_real> oldWeights(sourceMesh->mPositions.size(), 0.0);
                for (unsigned int d = 0; d < obone.mWeights.size(); ++d) {
                    // TODO  The conditional against boneIdx which was added in commit f844c33
                    // TODO      (https://github.com/assimp/assimp/commit/f844c3397d7726477ab0fdca8efd3df56c18366b)
                    // TODO  causes massive breakage as detailed in:
                    // TODO      https://github.com/assimp/assimp/issues/5332
                    // TODO  In cases like this unit tests are less useful, since the model still has
                    // TODO  meshes, textures, animations etc. and asserts against these values may pass;
                    // TODO  when touching importer code, it is crucial that developers also run manual, visual
                    // TODO  checks to ensure there's no obvious breakage _before_ commiting to main branch 
                    //const unsigned int boneIdx = obone.mWeights[d].mVertex;
                    //if (boneIdx < obone.mWeights.size()) {
                        oldWeights[obone.mWeights[d].mVertex] = obone.mWeights[d].mWeight;
                    //}
                }

                // collect all vertex weights that influence a vertex in the new mesh
                std::vector<aiVertexWeight> newWeights;
                newWeights.reserve(numVertices);
                for (unsigned int d = 0; d < orgPoints.size(); ++d) {
                    // does the new vertex stem from an old vertex which was influenced by this bone?
                    ai_real w = oldWeights[orgPoints[d]];
                    if (w > 0.0) {
                        newWeights.emplace_back(d, w);
                    }
                }

                // if the bone has no weights in the newly created mesh, ignore it
                if (newWeights.empty()) {
                    continue;
                }

                // create
                aiBone *nbone = new aiBone;
                newBones.push_back(nbone);
                // copy name and matrix
                nbone->mName.Set(obone.mName);
                nbone->mOffsetMatrix = obone.mOffsetMatrix;
                nbone->mNumWeights = (unsigned int)newWeights.size();
                nbone->mWeights = new aiVertexWeight[nbone->mNumWeights];
                for (unsigned int d = 0; d < newWeights.size(); ++d) {
                    nbone->mWeights[d] = newWeights[d];
                }
            }

            // store the bones in the mesh
            mesh->mNumBones = (unsigned int)newBones.size();
            if (!newBones.empty()) {
                mesh->mBones = new aiBone *[mesh->mNumBones];
                std::copy(newBones.begin(), newBones.end(), mesh->mBones);
            }
        }
    }

    // reallocate scene mesh array to be large enough
    aiMesh **prevArray = pScene->mMeshes;
    pScene->mMeshes = new aiMesh *[pScene->mNumMeshes + meshes.size()];
    if (prevArray) {
        memcpy(pScene->mMeshes, prevArray, pScene->mNumMeshes * sizeof(aiMesh *));
        delete[] prevArray;
    }

    // allocate mesh index array in the node
    pNode->mNumMeshes = (unsigned int)meshes.size();
    pNode->mMeshes = new unsigned int[pNode->mNumMeshes];

    // store all meshes in the mesh library of the scene and store their indices in the node
    for (unsigned int a = 0; a < meshes.size(); a++) {
        pScene->mMeshes[pScene->mNumMeshes] = meshes[a];
        pNode->mMeshes[a] = pScene->mNumMeshes;
        pScene->mNumMeshes++;
    }
}

// ------------------------------------------------------------------------------------------------
// Converts the animations from the given imported data and creates them in the scene.
void XFileImporter::CreateAnimations(aiScene *pScene, const XFile::Scene *pData) {
    std::vector<aiAnimation *> newAnims;

    for (unsigned int a = 0; a < pData->mAnims.size(); ++a) {
        const XFile::Animation *anim = pData->mAnims[a];
        // some exporters mock me with empty animation tags.
        if (anim->mAnims.empty()) {
            continue;
        }

        // create a new animation to hold the data
        aiAnimation *nanim = new aiAnimation;
        newAnims.push_back(nanim);
        nanim->mName.Set(anim->mName);
        // duration will be determined by the maximum length
        nanim->mDuration = 0;
        nanim->mTicksPerSecond = pData->mAnimTicksPerSecond;
        nanim->mNumChannels = (unsigned int)anim->mAnims.size();
        nanim->mChannels = new aiNodeAnim *[nanim->mNumChannels];

        for (unsigned int b = 0; b < anim->mAnims.size(); ++b) {
            const XFile::AnimBone *bone = anim->mAnims[b];
            aiNodeAnim *nbone = new aiNodeAnim;
            nbone->mNodeName.Set(bone->mBoneName);
            nanim->mChannels[b] = nbone;

            // key-frames are given as combined transformation matrix keys
            if (!bone->mTrafoKeys.empty()) {
                nbone->mNumPositionKeys = (unsigned int)bone->mTrafoKeys.size();
                nbone->mPositionKeys = new aiVectorKey[nbone->mNumPositionKeys];
                nbone->mNumRotationKeys = (unsigned int)bone->mTrafoKeys.size();
                nbone->mRotationKeys = new aiQuatKey[nbone->mNumRotationKeys];
                nbone->mNumScalingKeys = (unsigned int)bone->mTrafoKeys.size();
                nbone->mScalingKeys = new aiVectorKey[nbone->mNumScalingKeys];

                for (unsigned int c = 0; c < bone->mTrafoKeys.size(); ++c) {
                    // deconstruct each matrix into separate position, rotation and scaling
                    double time = bone->mTrafoKeys[c].mTime;
                    aiMatrix4x4 trafo = bone->mTrafoKeys[c].mMatrix;

                    // extract position
                    aiVector3D pos(trafo.a4, trafo.b4, trafo.c4);

                    nbone->mPositionKeys[c].mTime = time;
                    nbone->mPositionKeys[c].mValue = pos;

                    // extract scaling
                    aiVector3D scale;
                    scale.x = aiVector3D(trafo.a1, trafo.b1, trafo.c1).Length();
                    scale.y = aiVector3D(trafo.a2, trafo.b2, trafo.c2).Length();
                    scale.z = aiVector3D(trafo.a3, trafo.b3, trafo.c3).Length();
                    nbone->mScalingKeys[c].mTime = time;
                    nbone->mScalingKeys[c].mValue = scale;

                    // reconstruct rotation matrix without scaling
                    aiMatrix3x3 rotmat(
                            trafo.a1 / scale.x, trafo.a2 / scale.y, trafo.a3 / scale.z,
                            trafo.b1 / scale.x, trafo.b2 / scale.y, trafo.b3 / scale.z,
                            trafo.c1 / scale.x, trafo.c2 / scale.y, trafo.c3 / scale.z);

                    // and convert it into a quaternion
                    nbone->mRotationKeys[c].mTime = time;
                    nbone->mRotationKeys[c].mValue = aiQuaternion(rotmat);
                }

                // longest lasting key sequence determines duration
                nanim->mDuration = std::max(nanim->mDuration, bone->mTrafoKeys.back().mTime);
            } else {
                // separate key sequences for position, rotation, scaling
                nbone->mNumPositionKeys = (unsigned int)bone->mPosKeys.size();
                if (nbone->mNumPositionKeys != 0) {
                    nbone->mPositionKeys = new aiVectorKey[nbone->mNumPositionKeys];
                    for (unsigned int c = 0; c < nbone->mNumPositionKeys; ++c) {
                        aiVector3D pos = bone->mPosKeys[c].mValue;

                        nbone->mPositionKeys[c].mTime = bone->mPosKeys[c].mTime;
                        nbone->mPositionKeys[c].mValue = pos;
                    }
                }

                // rotation
                nbone->mNumRotationKeys = (unsigned int)bone->mRotKeys.size();
                if (nbone->mNumRotationKeys != 0) {
                    nbone->mRotationKeys = new aiQuatKey[nbone->mNumRotationKeys];
                    for (unsigned int c = 0; c < nbone->mNumRotationKeys; ++c) {
                        aiMatrix3x3 rotmat = bone->mRotKeys[c].mValue.GetMatrix();

                        nbone->mRotationKeys[c].mTime = bone->mRotKeys[c].mTime;
                        nbone->mRotationKeys[c].mValue = aiQuaternion(rotmat);
                        nbone->mRotationKeys[c].mValue.w *= -1.0f; // needs quat inversion
                    }
                }

                // scaling
                nbone->mNumScalingKeys = (unsigned int)bone->mScaleKeys.size();
                if (nbone->mNumScalingKeys != 0) {
                    nbone->mScalingKeys = new aiVectorKey[nbone->mNumScalingKeys];
                    for (unsigned int c = 0; c < nbone->mNumScalingKeys; c++)
                        nbone->mScalingKeys[c] = bone->mScaleKeys[c];
                }

                // longest lasting key sequence determines duration
                if (bone->mPosKeys.size() > 0)
                    nanim->mDuration = std::max(nanim->mDuration, bone->mPosKeys.back().mTime);
                if (bone->mRotKeys.size() > 0)
                    nanim->mDuration = std::max(nanim->mDuration, bone->mRotKeys.back().mTime);
                if (bone->mScaleKeys.size() > 0)
                    nanim->mDuration = std::max(nanim->mDuration, bone->mScaleKeys.back().mTime);
            }
        }
    }

    // store all converted animations in the scene
    if (newAnims.size() > 0) {
        pScene->mNumAnimations = (unsigned int)newAnims.size();
        pScene->mAnimations = new aiAnimation *[pScene->mNumAnimations];
        for (unsigned int a = 0; a < newAnims.size(); a++)
            pScene->mAnimations[a] = newAnims[a];
    }
}

// ------------------------------------------------------------------------------------------------
// Converts all materials in the given array and stores them in the scene's material list.
void XFileImporter::ConvertMaterials(aiScene *pScene, std::vector<XFile::Material> &pMaterials) {
    // count the non-referrer materials in the array
    unsigned int numNewMaterials(0);
    for (unsigned int a = 0; a < pMaterials.size(); ++a) {
        if (!pMaterials[a].mIsReference) {
            ++numNewMaterials;
        }
    }

    // resize the scene's material list to offer enough space for the new materials
    if (numNewMaterials > 0) {
        aiMaterial **prevMats = pScene->mMaterials;
        pScene->mMaterials = new aiMaterial *[pScene->mNumMaterials + numNewMaterials];
        if (nullptr != prevMats) {
            ::memcpy(pScene->mMaterials, prevMats, pScene->mNumMaterials * sizeof(aiMaterial *));
            delete[] prevMats;
        }
    }

    // convert all the materials given in the array
    for (unsigned int a = 0; a < pMaterials.size(); ++a) {
        XFile::Material &oldMat = pMaterials[a];
        if (oldMat.mIsReference) {
            // find the material it refers to by name, and store its index
            for (size_t b = 0; b < pScene->mNumMaterials; ++b) {
                aiString name;
                pScene->mMaterials[b]->Get(AI_MATKEY_NAME, name);
                if (strcmp(name.C_Str(), oldMat.mName.data()) == 0) {
                    oldMat.sceneIndex = b;
                    break;
                }
            }

            if (oldMat.sceneIndex == SIZE_MAX) {
                ASSIMP_LOG_WARN("Could not resolve global material reference \"", oldMat.mName, "\"");
                oldMat.sceneIndex = 0;
            }

            continue;
        }

        aiMaterial *mat = new aiMaterial;
        aiString name;
        name.Set(oldMat.mName);
        mat->AddProperty(&name, AI_MATKEY_NAME);

        // Shading model: hard-coded to PHONG, there is no such information in an XFile
        // FIX (aramis): If the specular exponent is 0, use gouraud shading. This is a bugfix
        // for some models in the SDK (e.g. good old tiny.x)
        int shadeMode = (int)oldMat.mSpecularExponent == 0.0f ? aiShadingMode_Gouraud : aiShadingMode_Phong;

        mat->AddProperty<int>(&shadeMode, 1, AI_MATKEY_SHADING_MODEL);
        // material colours
        // Unclear: there's no ambient colour, but emissive. What to put for ambient?
        // Probably nothing at all, let the user select a suitable default.
        mat->AddProperty(&oldMat.mEmissive, 1, AI_MATKEY_COLOR_EMISSIVE);
        mat->AddProperty(&oldMat.mDiffuse, 1, AI_MATKEY_COLOR_DIFFUSE);
        mat->AddProperty(&oldMat.mSpecular, 1, AI_MATKEY_COLOR_SPECULAR);
        mat->AddProperty(&oldMat.mSpecularExponent, 1, AI_MATKEY_SHININESS);

        // texture, if there is one
        if (1 == oldMat.mTextures.size()) {
            const XFile::TexEntry &otex = oldMat.mTextures.back();
            if (otex.mName.length()) {
                // if there is only one texture assume it contains the diffuse color
                aiString tex(otex.mName);
                if (otex.mIsNormalMap) {
                    mat->AddProperty(&tex, AI_MATKEY_TEXTURE_NORMALS(0));
                } else {
                    mat->AddProperty(&tex, AI_MATKEY_TEXTURE_DIFFUSE(0));
                }
            }
        } else {
            // Otherwise ... try to search for typical strings in the
            // texture's file name like 'bump' or 'diffuse'
            unsigned int iHM = 0, iNM = 0, iDM = 0, iSM = 0, iAM = 0, iEM = 0;
            for (unsigned int b = 0; b < oldMat.mTextures.size(); ++b) {
                const XFile::TexEntry &otex = oldMat.mTextures[b];
                std::string sz = otex.mName;
                if (!sz.length()) {
                    continue;
                }

                // find the file name
                std::string::size_type s = sz.find_last_of("\\/");
                if (std::string::npos == s) {
                    s = 0;
                }

                // cut off the file extension
                std::string::size_type sExt = sz.find_last_of('.');
                if (std::string::npos != sExt) {
                    sz[sExt] = '\0';
                }

                // convert to lower case for easier comparison
                for (unsigned int c = 0; c < sz.length(); ++c) {
                    sz[c] = (char)tolower((unsigned char)sz[c]);
                }

                // Place texture filename property under the corresponding name
                aiString tex(oldMat.mTextures[b].mName);

                // bump map
                if (std::string::npos != sz.find("bump", s) || std::string::npos != sz.find("height", s)) {
                    mat->AddProperty(&tex, AI_MATKEY_TEXTURE_HEIGHT(iHM++));
                } else if (otex.mIsNormalMap || std::string::npos != sz.find("normal", s) || std::string::npos != sz.find("nm", s)) {
                    mat->AddProperty(&tex, AI_MATKEY_TEXTURE_NORMALS(iNM++));
                } else if (std::string::npos != sz.find("spec", s) || std::string::npos != sz.find("glanz", s)) {
                    mat->AddProperty(&tex, AI_MATKEY_TEXTURE_SPECULAR(iSM++));
                } else if (std::string::npos != sz.find("ambi", s) || std::string::npos != sz.find("env", s)) {
                    mat->AddProperty(&tex, AI_MATKEY_TEXTURE_AMBIENT(iAM++));
                } else if (std::string::npos != sz.find("emissive", s) || std::string::npos != sz.find("self", s)) {
                    mat->AddProperty(&tex, AI_MATKEY_TEXTURE_EMISSIVE(iEM++));
                } else {
                    // Assume it is a diffuse texture
                    mat->AddProperty(&tex, AI_MATKEY_TEXTURE_DIFFUSE(iDM++));
                }
            }
        }

        pScene->mMaterials[pScene->mNumMaterials] = mat;
        oldMat.sceneIndex = pScene->mNumMaterials;
        pScene->mNumMaterials++;
    }
}

} // namespace Assimp

#endif // !! ASSIMP_BUILD_NO_X_IMPORTER