/*

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*/

/** @file A helper class that processes texture transformations */

#include "TextureTransform.h"

#include <assimp/Importer.hpp>

#include <assimp/postprocess.h>

#include <assimp/DefaultLogger.hpp>

#include <assimp/scene.h>

#include <assimp/StringUtils.h>

namespace Assimp {

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

// Returns whether the processing step is present in the given flag field.

bool TextureTransformStep::IsActive( unsigned int pFlags) const {

    return  (pFlags & aiProcess_TransformUVCoords) != 0;

}

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

// Setup properties

void TextureTransformStep::SetupProperties(const Importer* pImp) {

    configFlags = pImp->GetPropertyInteger(AI_CONFIG_PP_TUV_EVALUATE,AI_UVTRAFO_ALL);

}

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

void TextureTransformStep::PreProcessUVTransform(STransformVecInfo& info) {

    /*  This function tries to simplify the input UV transformation.

     *  That's very important as it allows us to reduce the number

     *  of output UV channels. The order in which the transformations

     *  are applied is - as always - scaling, rotation, translation.

     */

  int rounded;

  char szTemp[512] = {};

    /* Optimize the rotation angle. That's slightly difficult as

     * we have an inprecise floating-point number (when comparing

     * UV transformations we'll take that into account by using

     * an epsilon of 5 degrees). If there is a rotation value, we can't

     * perform any further optimizations.

     */

    if (info.mRotation) {

        float out = info.mRotation;

        rounded = static_cast<int>((info.mRotation / static_cast<float>(AI_MATH_TWO_PI)));

        if (rounded) {

            out -= rounded * static_cast<float>(AI_MATH_PI);

            ASSIMP_LOG_INFO("Texture coordinate rotation ", info.mRotation, " can be simplified to ", out);

        }

        // Next step - convert negative rotation angles to positives

        if (out < 0.f)

            out = (float)AI_MATH_TWO_PI * 2 + out;

        info.mRotation = out;

        return;

    }

    /* Optimize UV translation in the U direction. To determine whether

     * or not we can optimize we need to look at the requested mapping

     * type (e.g. if mirroring is active there IS a difference between

     * offset 2 and 3)

     */

    rounded = (int)info.mTranslation.x;

    if (rounded) {

        float out = 0.0f;

        szTemp[0] = 0;

        if (aiTextureMapMode_Wrap == info.mapU) {

            // Wrap - simple take the fraction of the field

            out = info.mTranslation.x-(float)rounded;

      ai_snprintf(szTemp, 512, "[w] UV U offset %f can be simplified to %f", info.mTranslation.x, out);

        }

        else if (aiTextureMapMode_Mirror == info.mapU && 1 != rounded)  {

            // Mirror

            if (rounded % 2)

                rounded--;

            out = info.mTranslation.x-(float)rounded;

            ai_snprintf(szTemp,512,"[m/d] UV U offset %f can be simplified to %f",info.mTranslation.x,out);

        }

        else if (aiTextureMapMode_Clamp == info.mapU || aiTextureMapMode_Decal == info.mapU)    {

            // Clamp - translations beyond 1,1 are senseless

            ai_snprintf(szTemp,512,"[c] UV U offset %f can be clamped to 1.0f",info.mTranslation.x);

            out = 1.f;

        }

        if (szTemp[0])      {

            ASSIMP_LOG_INFO(szTemp);

            info.mTranslation.x = out;

        }

    }

    /* Optimize UV translation in the V direction. To determine whether

     * or not we can optimize we need to look at the requested mapping

     * type (e.g. if mirroring is active there IS a difference between

     * offset 2 and 3)

     */

    rounded = (int)info.mTranslation.y;

    if (rounded) {

        float out = 0.0f;

        szTemp[0] = 0;

        if (aiTextureMapMode_Wrap == info.mapV) {

            // Wrap - simple take the fraction of the field

            out = info.mTranslation.y-(float)rounded;

            ::ai_snprintf(szTemp,512,"[w] UV V offset %f can be simplified to %f",info.mTranslation.y,out);

        }

        else if (aiTextureMapMode_Mirror == info.mapV  && 1 != rounded) {

            // Mirror

            if (rounded % 2)

                rounded--;

            out = info.mTranslation.x-(float)rounded;

            ::ai_snprintf(szTemp,512,"[m/d] UV V offset %f can be simplified to %f",info.mTranslation.y,out);

        }

        else if (aiTextureMapMode_Clamp == info.mapV || aiTextureMapMode_Decal == info.mapV)    {

            // Clamp - translations beyond 1,1 are senseless

            ::ai_snprintf(szTemp,512,"[c] UV V offset %f can be clamped to 1.0f",info.mTranslation.y);

            out = 1.f;

        }

        if (szTemp[0])  {

            ASSIMP_LOG_INFO(szTemp);

            info.mTranslation.y = out;

        }

    }

}

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

void UpdateUVIndex(const std::list<TTUpdateInfo>& l, unsigned int n) {

    // Don't set if == 0 && wasn't set before

    for (std::list<TTUpdateInfo>::const_iterator it = l.begin();it != l.end(); ++it) {

        const TTUpdateInfo& info = *it;

        if (info.directShortcut)

            *info.directShortcut = n;

        else if (!n)

        {

            info.mat->AddProperty<int>((int*)&n,1,AI_MATKEY_UVWSRC(info.semantic,info.index));

        }

    }

}

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

inline static const char* MappingModeToChar(aiTextureMapMode map) {

    if (aiTextureMapMode_Wrap == map)

        return "-w";

    if (aiTextureMapMode_Mirror == map)

        return "-m";

    return "-c";

}

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

void TextureTransformStep::Execute( aiScene* pScene) {

    ASSIMP_LOG_DEBUG("TransformUVCoordsProcess begin");

    /*  We build a per-mesh list of texture transformations we'll need

     *  to apply. To achieve this, we iterate through all materials,

     *  find all textures and get their transformations and UV indices.

     *  Then we search for all meshes using this material.

     */

    typedef std::list<STransformVecInfo> MeshTrafoList;

    std::vector<MeshTrafoList> meshLists(pScene->mNumMeshes);

    for (unsigned int i = 0; i < pScene->mNumMaterials;++i) {

        aiMaterial* mat = pScene->mMaterials[i];

        for (unsigned int a = 0; a < mat->mNumProperties;++a)   {

            aiMaterialProperty* prop = mat->mProperties[a];

            if (!::strcmp( prop->mKey.data, "$tex.file"))   {

                STransformVecInfo info;

                // Setup a shortcut structure to allow for a fast updating

                // of the UV index later

                TTUpdateInfo update;

                update.mat = (aiMaterial*) mat;

                update.semantic = prop->mSemantic;

                update.index = prop->mIndex;

                // Get textured properties and transform

                for (unsigned int a2 = 0; a2 < mat->mNumProperties;++a2)  {

                    aiMaterialProperty* prop2 = mat->mProperties[a2];

                    if (prop2->mSemantic != prop->mSemantic || prop2->mIndex != prop->mIndex) {

                        continue;

                    }

                    if ( !::strcmp( prop2->mKey.data, "$tex.uvwsrc")) {

                        info.uvIndex = *((int*)prop2->mData);

                        // Store a direct pointer for later use

                        update.directShortcut = (unsigned int*) prop2->mData;

                    }

                    else if ( !::strcmp( prop2->mKey.data, "$tex.mapmodeu")) {

                        info.mapU = *((aiTextureMapMode*)prop2->mData);

                    }

                    else if ( !::strcmp( prop2->mKey.data, "$tex.mapmodev")) {

                        info.mapV = *((aiTextureMapMode*)prop2->mData);

                    }

                    else if ( !::strcmp( prop2->mKey.data, "$tex.uvtrafo"))  {

                        // ValidateDS should check this

                        ai_assert(prop2->mDataLength >= 20);

                        ::memcpy(&info.mTranslation.x,prop2->mData,sizeof(float)*5);

                        // Directly remove this property from the list

                        mat->mNumProperties--;

                        for (unsigned int a3 = a2; a3 < mat->mNumProperties;++a3) {

                            mat->mProperties[a3] = mat->mProperties[a3+1];

                        }

                        delete prop2;

                        // Warn: could be an underflow, but this does not invoke undefined behaviour

                        --a2;

                    }

                }

                // Find out which transformations are to be evaluated

                if (!(configFlags & AI_UVTRAFO_ROTATION)) {

                    info.mRotation = 0.f;

                }

                if (!(configFlags & AI_UVTRAFO_SCALING)) {

                    info.mScaling = aiVector2D(1.f,1.f);

                }

                if (!(configFlags & AI_UVTRAFO_TRANSLATION)) {

                    info.mTranslation = aiVector2D(0.f,0.f);

                }

                // Do some preprocessing

                PreProcessUVTransform(info);

                info.uvIndex = std::min(info.uvIndex,AI_MAX_NUMBER_OF_TEXTURECOORDS -1u);

                // Find out whether this material is used by more than

                // one mesh. This will make our task much, much more difficult!

                unsigned int cnt = 0;

                for (unsigned int n = 0; n < pScene->mNumMeshes;++n)    {

                    if (pScene->mMeshes[n]->mMaterialIndex == i)

                        ++cnt;

                }

                if (!cnt)

                    continue;

                else if (1 != cnt)  {

                    // This material is referenced by more than one mesh!

                    // So we need to make sure the UV index for the texture

                    // is identical for each of it ...

                    info.lockedPos = AI_TT_UV_IDX_LOCK_TBD;

                }

                // Get all corresponding meshes

                for (unsigned int n = 0; n < pScene->mNumMeshes;++n)    {

                    aiMesh* mesh = pScene->mMeshes[n];

                    if (mesh->mMaterialIndex != i || !mesh->mTextureCoords[0])

                        continue;

                    unsigned int uv = info.uvIndex;

                    if (!mesh->mTextureCoords[uv])  {

                        // If the requested UV index is not available, take the first one instead.

                        uv = 0;

                    }

                    if (mesh->mNumUVComponents[info.uvIndex] >= 3){

                        ASSIMP_LOG_WARN("UV transformations on 3D mapping channels are not supported");

                        continue;

                    }

                    MeshTrafoList::iterator it;

                    // Check whether we have this transform setup already

                    for (it = meshLists[n].begin();it != meshLists[n].end(); ++it)  {

                        if ((*it) == info && (*it).uvIndex == uv)   {

                            (*it).updateList.push_back(update);

                            break;

                        }

                    }

                    if (it == meshLists[n].end())   {

                        meshLists[n].push_back(info);

                        meshLists[n].back().uvIndex = uv;

                        meshLists[n].back().updateList.push_back(update);

                    }

                }

            }

        }

    }

    char buffer[1024]; // should be sufficiently large

    unsigned int outChannels = 0, inChannels = 0, transformedChannels = 0;

    // Now process all meshes. Important: we don't remove unreferenced UV channels.

    // This is a job for the RemoveUnreferencedData-Step.

    for (unsigned int q = 0; q < pScene->mNumMeshes;++q)    {

        aiMesh* mesh = pScene->mMeshes[q];

        MeshTrafoList& trafo =  meshLists[q];

        inChannels += mesh->GetNumUVChannels();

        if (!mesh->mTextureCoords[0] || trafo.empty() ||  (trafo.size() == 1 && trafo.begin()->IsUntransformed())) {

            outChannels += mesh->GetNumUVChannels();

            continue;

        }

        // Move untransformed UV channels to the first position in the list ....

        // except if we need a new locked index which should be as small as possible

        bool veto = false, need = false;

        unsigned int cnt = 0;

        unsigned int untransformed = 0;

        MeshTrafoList::iterator it,it2;

        for (it = trafo.begin();it != trafo.end(); ++it,++cnt)  {

            if (!(*it).IsUntransformed()) {

                need = true;

            }

            if ((*it).lockedPos == AI_TT_UV_IDX_LOCK_TBD)   {

                // Lock this index and make sure it won't be changed

                (*it).lockedPos = cnt;

                veto = true;

                continue;

            }

            if (!veto && it != trafo.begin() && (*it).IsUntransformed())    {

                for (it2 = trafo.begin();it2 != it; ++it2) {

                    if (!(*it2).IsUntransformed())

                        break;

                }

                trafo.insert(it2,*it);

                trafo.erase(it);

                break;

            }

        }

        if (!need)

            continue;

        // Find all that are not at their 'locked' position and move them to it.

        // Conflicts are possible but quite unlikely.

        cnt = 0;

        for (it = trafo.begin();it != trafo.end(); ++it,++cnt) {

            if ((*it).lockedPos != AI_TT_UV_IDX_LOCK_NONE && (*it).lockedPos != cnt) {

                it2 = trafo.begin();

                while ((*it2).lockedPos != (*it).lockedPos)

                    ++it2;

                if ((*it2).lockedPos != AI_TT_UV_IDX_LOCK_NONE) {

                    ASSIMP_LOG_ERROR("Channel mismatch, can't compute all transformations properly [design bug]");

                    continue;

                }

                std::swap(*it2,*it);

                if ((*it).lockedPos == untransformed)

                    untransformed = cnt;

            }

        }

        // ... and add dummies for all unreferenced channels

        // at the end of the list

        bool ref[AI_MAX_NUMBER_OF_TEXTURECOORDS];

        for (unsigned int n = 0; n < AI_MAX_NUMBER_OF_TEXTURECOORDS;++n)

            ref[n] = !mesh->mTextureCoords[n];

        for (it = trafo.begin();it != trafo.end(); ++it)

            ref[(*it).uvIndex] = true;

        for (unsigned int n = 0; n < AI_MAX_NUMBER_OF_TEXTURECOORDS;++n) {

            if (ref[n])

                continue;

            trafo.emplace_back();

            trafo.back().uvIndex = n;

        }

        // Then check whether this list breaks the channel limit.

        // The unimportant ones are at the end of the list, so

        // it shouldn't be too worse if we remove them.

        unsigned int size = (unsigned int)trafo.size();

        if (size > AI_MAX_NUMBER_OF_TEXTURECOORDS) {

            if (!DefaultLogger::isNullLogger()) {

                ASSIMP_LOG_ERROR(static_cast<unsigned int>(trafo.size()), " UV channels required but just ",

                    AI_MAX_NUMBER_OF_TEXTURECOORDS, " available");

            }

            size = AI_MAX_NUMBER_OF_TEXTURECOORDS;

        }

        aiVector3D* old[AI_MAX_NUMBER_OF_TEXTURECOORDS];

        for (unsigned int n = 0; n < AI_MAX_NUMBER_OF_TEXTURECOORDS;++n)

            old[n] = mesh->mTextureCoords[n];

        // Now continue and generate the output channels. Channels

        // that we're not going to need later can be overridden.

        it = trafo.begin();

        for (unsigned int n = 0; n < trafo.size();++n,++it) {

            if (n >= size)  {

                // Try to use an untransformed channel for all channels we threw over board

                UpdateUVIndex((*it).updateList,untransformed);

                continue;

            }

            ++outChannels;

            // Write to the log

            if (!DefaultLogger::isNullLogger()) {

                ::ai_snprintf(buffer,1024,"Mesh %u, channel %u: t(%.3f,%.3f), s(%.3f,%.3f), r(%.3f), %s%s",

                    q,n,

                    (*it).mTranslation.x,

                    (*it).mTranslation.y,

                    (*it).mScaling.x,

                    (*it).mScaling.y,

                    AI_RAD_TO_DEG( (*it).mRotation),

                    MappingModeToChar ((*it).mapU),

                    MappingModeToChar ((*it).mapV));

                ASSIMP_LOG_INFO(buffer);

            }

            // Check whether we need a new buffer here

            if (mesh->mTextureCoords[n])    {

                it2 = it;

    ++it2;

                for (unsigned int m = n+1; m < size;++m, ++it2) {

                    if ((*it2).uvIndex == n){

                        it2 = trafo.begin();

                        break;

                    }

                }

                if (it2 == trafo.begin()) {               

        {

                        std::unique_ptr<aiVector3D[]> oldTextureCoords(mesh->mTextureCoords[n]);

                    }

                    mesh->mTextureCoords[n] = new aiVector3D[mesh->mNumVertices];

                }

            }

            else mesh->mTextureCoords[n] = new aiVector3D[mesh->mNumVertices];

            aiVector3D* src = old[(*it).uvIndex];

            aiVector3D* dest, *end;

            dest = mesh->mTextureCoords[n];

            ai_assert(nullptr != src);

            // Copy the data to the destination array

            if (dest != src) {

                ::memcpy(dest,src,sizeof(aiVector3D)*mesh->mNumVertices);

            }

            end = dest + mesh->mNumVertices;

            // Build a transformation matrix and transform all UV coords with it

            if (!(*it).IsUntransformed()) {

                const aiVector2D& trl = (*it).mTranslation;

                const aiVector2D& scl = (*it).mScaling;

                // fixme: simplify ..

                ++transformedChannels;

                aiMatrix3x3 matrix;

                aiMatrix3x3 m2,m3,m4,m5;

                m4.a1 = scl.x;

                m4.b2 = scl.y;

                m2.a3 = m2.b3 = 0.5f;

                m3.a3 = m3.b3 = -0.5f;

                if ((*it).mRotation > AI_TT_ROTATION_EPSILON )

                    aiMatrix3x3::RotationZ((*it).mRotation,matrix);

                m5.a3 += trl.x; m5.b3 += trl.y;

                matrix = m2 * m4 * matrix * m3 * m5;

                for (src = dest; src != end; ++src) { /* manual homogeneous divide */

                    src->z = 1.f;

                    *src = matrix * *src;

                    src->x /= src->z;

                    src->y /= src->z;

                    src->z = 0.f;

                }

            }

            // Update all UV indices

            UpdateUVIndex((*it).updateList,n);

        }

    }

    // Print some detailed statistics into the log

    if (!DefaultLogger::isNullLogger()) {

        if (transformedChannels)    {

            ASSIMP_LOG_INFO("TransformUVCoordsProcess end: ", outChannels, " output channels (in: ", inChannels, ", modified: ", transformedChannels,")");

        } else {

            ASSIMP_LOG_INFO("TransformUVCoordsProcess finished");

        }

    }

}

} // namespace Assimp