/*
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
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  following disclaimer in the documentation and/or other
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*/



#if !defined(ASSIMP_BUILD_NO_EXPORT) && !defined(ASSIMP_BUILD_NO_PLY_EXPORTER)

#include "PlyExporter.h"
#include <memory>
#include <cmath>
#include <assimp/Exceptional.h>
#include <assimp/scene.h>
#include <assimp/version.h>
#include <assimp/IOSystem.hpp>
#include <assimp/Exporter.hpp>
#include <assimp/qnan.h>


//using namespace Assimp;
namespace Assimp    {

// make sure type_of returns consistent output across different platforms
// also consider using: typeid(VAR).name()
template <typename T> const char* type_of(T&) { return "unknown"; }
template<> const char* type_of(float&) { return "float"; }
template<> const char* type_of(double&) { return "double"; }

// ------------------------------------------------------------------------------------------------
// Worker function for exporting a scene to PLY. Prototyped and registered in Exporter.cpp
void ExportScenePly(const char* pFile,IOSystem* pIOSystem, const aiScene* pScene, const ExportProperties* /*pProperties*/)
{
    // invoke the exporter
    PlyExporter exporter(pFile, pScene);

    if (exporter.mOutput.fail()) {
        throw DeadlyExportError("output data creation failed. Most likely the file became too large: " + std::string(pFile));
    }

    // we're still here - export successfully completed. Write the file.
    std::unique_ptr<IOStream> outfile (pIOSystem->Open(pFile,"wt"));
    if (outfile == nullptr) {
        throw DeadlyExportError("could not open output .ply file: " + std::string(pFile));
    }

    outfile->Write( exporter.mOutput.str().c_str(), static_cast<size_t>(exporter.mOutput.tellp()),1);
}

void ExportScenePlyBinary(const char* pFile, IOSystem* pIOSystem, const aiScene* pScene, const ExportProperties* /*pProperties*/)
{
    // invoke the exporter
    PlyExporter exporter(pFile, pScene, true);

    // we're still here - export successfully completed. Write the file.
    std::unique_ptr<IOStream> outfile(pIOSystem->Open(pFile, "wb"));
    if (outfile == nullptr) {
        throw DeadlyExportError("could not open output .ply file: " + std::string(pFile));
    }

    outfile->Write(exporter.mOutput.str().c_str(), static_cast<size_t>(exporter.mOutput.tellp()), 1);
}

#define PLY_EXPORT_HAS_NORMALS 0x1
#define PLY_EXPORT_HAS_TANGENTS_BITANGENTS 0x2
#define PLY_EXPORT_HAS_TEXCOORDS 0x4
#define PLY_EXPORT_HAS_COLORS (PLY_EXPORT_HAS_TEXCOORDS << AI_MAX_NUMBER_OF_TEXTURECOORDS)

// ------------------------------------------------------------------------------------------------
PlyExporter::PlyExporter(const char* _filename, const aiScene* pScene, bool binary)
: filename(_filename)
, endl("\n")
{
    // make sure that all formatting happens using the standard, C locale and not the user's current locale
    const std::locale& l = std::locale("C");
    mOutput.imbue(l);
    mOutput.precision(ASSIMP_AI_REAL_TEXT_PRECISION);

    unsigned int faces = 0u, vertices = 0u, components = 0u;
    for (unsigned int i = 0; i < pScene->mNumMeshes; ++i) {
        const aiMesh& m = *pScene->mMeshes[i];
        faces += m.mNumFaces;
        vertices += m.mNumVertices;

        if (m.HasNormals()) {
            components |= PLY_EXPORT_HAS_NORMALS;
        }
        if (m.HasTangentsAndBitangents()) {
            components |= PLY_EXPORT_HAS_TANGENTS_BITANGENTS;
        }
        for (unsigned int t = 0; m.HasTextureCoords(t); ++t) {
            components |= PLY_EXPORT_HAS_TEXCOORDS << t;
        }
        for (unsigned int t = 0; m.HasVertexColors(t); ++t) {
            components |= PLY_EXPORT_HAS_COLORS << t;
        }
    }

    mOutput << "ply" << endl;
    if (binary) {
#if (defined AI_BUILD_BIG_ENDIAN)
        mOutput << "format binary_big_endian 1.0" << endl;
#else
        mOutput << "format binary_little_endian 1.0" << endl;
#endif
    }
    else {
        mOutput << "format ascii 1.0" << endl;
    }
    mOutput << "comment Created by Open Asset Import Library - http://assimp.sf.net (v"
        << aiGetVersionMajor() << '.' << aiGetVersionMinor() << '.'
        << aiGetVersionRevision() << ")" << endl;

    // Look through materials for a diffuse texture, and add it if found
    for ( unsigned int i = 0; i < pScene->mNumMaterials; ++i )
    {
        const aiMaterial* const mat = pScene->mMaterials[i];
        aiString s;
        if ( AI_SUCCESS == mat->Get( AI_MATKEY_TEXTURE_DIFFUSE( 0 ), s ) )
        {
            mOutput << "comment TextureFile " << s.data << endl;
        }
    }

    // TODO: probably want to check here rather than just assume something
    //       definitely not good to always write float even if we might have double precision

    ai_real tmp = 0.0;
    const char * typeName = type_of(tmp);

    mOutput << "element vertex " << vertices << endl;
    mOutput << "property " << typeName << " x" << endl;
    mOutput << "property " << typeName << " y" << endl;
    mOutput << "property " << typeName << " z" << endl;

    if(components & PLY_EXPORT_HAS_NORMALS) {
        mOutput << "property " << typeName << " nx" << endl;
        mOutput << "property " << typeName << " ny" << endl;
        mOutput << "property " << typeName << " nz" << endl;
    }

    // write texcoords first, just in case an importer does not support tangents
    // bitangents and just skips over the rest of the line upon encountering
    // unknown fields (Ply leaves pretty much every vertex component open,
    // but in reality most importers only know about vertex positions, normals
    // and texture coordinates).
    for (unsigned int n = PLY_EXPORT_HAS_TEXCOORDS, c = 0; (components & n) && c != AI_MAX_NUMBER_OF_TEXTURECOORDS; n <<= 1, ++c) {
        if (!c) {
            mOutput << "property " << typeName << " s" << endl;
            mOutput << "property " << typeName << " t" << endl;
        }
        else {
            mOutput << "property " << typeName << " s" << c << endl;
            mOutput << "property " << typeName << " t" << c << endl;
        }
    }

    for (unsigned int n = PLY_EXPORT_HAS_COLORS, c = 0; (components & n) && c != AI_MAX_NUMBER_OF_COLOR_SETS; n <<= 1, ++c) {
        if (!c) {
            mOutput << "property " << "uchar" << " red" << endl;
            mOutput << "property " << "uchar" << " green" << endl;
            mOutput << "property " << "uchar" << " blue" << endl;
            mOutput << "property " << "uchar" << " alpha" << endl;
        }
        else {
            mOutput << "property " << "uchar" << " red" << c << endl;
            mOutput << "property " << "uchar" << " green" << c << endl;
            mOutput << "property " << "uchar" << " blue" << c << endl;
            mOutput << "property " << "uchar" << " alpha" << c << endl;
        }
    }

    if(components & PLY_EXPORT_HAS_TANGENTS_BITANGENTS) {
        mOutput << "property " << typeName << " tx" << endl;
        mOutput << "property " << typeName << " ty" << endl;
        mOutput << "property " << typeName << " tz" << endl;
        mOutput << "property " << typeName << " bx" << endl;
        mOutput << "property " << typeName << " by" << endl;
        mOutput << "property " << typeName << " bz" << endl;
    }

    mOutput << "element face " << faces << endl;

    // uchar seems to be the most common type for the number of indices per polygon and int seems to be most common for the vertex indices.
    // For instance, MeshLab fails to load meshes in which both types are uint. Houdini seems to have problems as well.
    // Obviously, using uchar will not work for meshes with polygons with more than 255 indices, but how realistic is this case?
    mOutput << "property list uchar int vertex_index" << endl;

    mOutput << "end_header" << endl;

    for (unsigned int i = 0; i < pScene->mNumMeshes; ++i) {
        if (binary) {
            WriteMeshVertsBinary(pScene->mMeshes[i], components);
        }
        else {
            WriteMeshVerts(pScene->mMeshes[i], components);
        }
    }
    for (unsigned int i = 0, ofs = 0; i < pScene->mNumMeshes; ++i) {
        if (binary) {
            WriteMeshIndicesBinary(pScene->mMeshes[i], ofs);
        }
        else {
            WriteMeshIndices(pScene->mMeshes[i], ofs);
        }
        ofs += pScene->mMeshes[i]->mNumVertices;
    }
}

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

// ------------------------------------------------------------------------------------------------
void PlyExporter::WriteMeshVerts(const aiMesh* m, unsigned int components)
{
    static const ai_real inf = std::numeric_limits<ai_real>::infinity();

    // If a component (for instance normal vectors) is present in at least one mesh in the scene,
    // then default values are written for meshes that do not contain this component.
    for (unsigned int i = 0; i < m->mNumVertices; ++i) {
        mOutput <<
            m->mVertices[i].x << " " <<
            m->mVertices[i].y << " " <<
            m->mVertices[i].z
        ;
        if(components & PLY_EXPORT_HAS_NORMALS) {
            if (m->HasNormals() && is_not_qnan(m->mNormals[i].x) && std::fabs(m->mNormals[i].x) != inf) {
                mOutput <<
                    " " << m->mNormals[i].x <<
                    " " << m->mNormals[i].y <<
                    " " << m->mNormals[i].z;
            }
            else {
                mOutput << " 0.0 0.0 0.0";
            }
        }

        for (unsigned int n = PLY_EXPORT_HAS_TEXCOORDS, c = 0; (components & n) && c != AI_MAX_NUMBER_OF_TEXTURECOORDS; n <<= 1, ++c) {
            if (m->HasTextureCoords(c)) {
                mOutput <<
                    " " << m->mTextureCoords[c][i].x <<
                    " " << m->mTextureCoords[c][i].y;
            }
            else {
                mOutput << " -1.0 -1.0";
            }
        }

        for (unsigned int n = PLY_EXPORT_HAS_COLORS, c = 0; (components & n) && c != AI_MAX_NUMBER_OF_COLOR_SETS; n <<= 1, ++c) {
            if (m->HasVertexColors(c)) {
                mOutput <<
                    " " << (int)(m->mColors[c][i].r * 255) <<
                    " " << (int)(m->mColors[c][i].g * 255) <<
                    " " << (int)(m->mColors[c][i].b * 255) <<
                    " " << (int)(m->mColors[c][i].a * 255);
            }
            else {
                mOutput << " 0 0 0";
            }
        }

        if(components & PLY_EXPORT_HAS_TANGENTS_BITANGENTS) {
            if (m->HasTangentsAndBitangents()) {
                mOutput <<
                " " << m->mTangents[i].x <<
                " " << m->mTangents[i].y <<
                " " << m->mTangents[i].z <<
                " " << m->mBitangents[i].x <<
                " " << m->mBitangents[i].y <<
                " " << m->mBitangents[i].z
                ;
            }
            else {
                mOutput << " 0.0 0.0 0.0 0.0 0.0 0.0";
            }
        }

        mOutput << endl;
    }
}

// ------------------------------------------------------------------------------------------------
void PlyExporter::WriteMeshVertsBinary(const aiMesh* m, unsigned int components)
{
    // If a component (for instance normal vectors) is present in at least one mesh in the scene,
    // then default values are written for meshes that do not contain this component.
    aiVector3D defaultNormal(0, 0, 0);
    aiVector2D defaultUV(-1, -1);
    aiColor4D defaultColor(-1, -1, -1, -1);
    for (unsigned int i = 0; i < m->mNumVertices; ++i) {
        mOutput.write(reinterpret_cast<const char*>(&m->mVertices[i].x), 12);
        if (components & PLY_EXPORT_HAS_NORMALS) {
            if (m->HasNormals()) {
                mOutput.write(reinterpret_cast<const char*>(&m->mNormals[i].x), 12);
            }
            else {
                mOutput.write(reinterpret_cast<const char*>(&defaultNormal.x), 12);
            }
        }

        for (unsigned int n = PLY_EXPORT_HAS_TEXCOORDS, c = 0; (components & n) && c != AI_MAX_NUMBER_OF_TEXTURECOORDS; n <<= 1, ++c) {
            if (m->HasTextureCoords(c)) {
                mOutput.write(reinterpret_cast<const char*>(&m->mTextureCoords[c][i].x), 8);
            }
            else {
                mOutput.write(reinterpret_cast<const char*>(&defaultUV.x), 8);
            }
        }

        for (unsigned int n = PLY_EXPORT_HAS_COLORS, c = 0; (components & n) && c != AI_MAX_NUMBER_OF_COLOR_SETS; n <<= 1, ++c) {
            if (m->HasVertexColors(c)) {
                mOutput.write(reinterpret_cast<const char*>(&m->mColors[c][i].r), 16);
            }
            else {
                mOutput.write(reinterpret_cast<const char*>(&defaultColor.r), 16);
            }
        }

        if (components & PLY_EXPORT_HAS_TANGENTS_BITANGENTS) {
            if (m->HasTangentsAndBitangents()) {
                mOutput.write(reinterpret_cast<const char*>(&m->mTangents[i].x), 12);
                mOutput.write(reinterpret_cast<const char*>(&m->mBitangents[i].x), 12);
            }
            else {
                mOutput.write(reinterpret_cast<const char*>(&defaultNormal.x), 12);
                mOutput.write(reinterpret_cast<const char*>(&defaultNormal.x), 12);
            }
        }
    }
}

// ------------------------------------------------------------------------------------------------
void PlyExporter::WriteMeshIndices(const aiMesh* m, unsigned int offset)
{
    for (unsigned int i = 0; i < m->mNumFaces; ++i) {
        const aiFace& f = m->mFaces[i];
        mOutput << f.mNumIndices;
        for(unsigned int c = 0; c < f.mNumIndices; ++c) {
            mOutput << " " << (f.mIndices[c] + offset);
        }
        mOutput << endl;
    }
}

// Generic method in case we want to use different data types for the indices or make this configurable.
template<typename NumIndicesType, typename IndexType>
void WriteMeshIndicesBinary_Generic(const aiMesh* m, unsigned int offset, std::ostringstream& output)
{
    for (unsigned int i = 0; i < m->mNumFaces; ++i) {
        const aiFace& f = m->mFaces[i];
        NumIndicesType numIndices = static_cast<NumIndicesType>(f.mNumIndices);
        output.write(reinterpret_cast<const char*>(&numIndices), sizeof(NumIndicesType));
        for (unsigned int c = 0; c < f.mNumIndices; ++c) {
            IndexType index = f.mIndices[c] + offset;
            output.write(reinterpret_cast<const char*>(&index), sizeof(IndexType));
        }
    }
}

void PlyExporter::WriteMeshIndicesBinary(const aiMesh* m, unsigned int offset)
{
    WriteMeshIndicesBinary_Generic<unsigned char, int>(m, offset, mOutput);
}

} // end of namespace Assimp

#endif // !defined(ASSIMP_BUILD_NO_EXPORT) && !defined(ASSIMP_BUILD_NO_PLY_EXPORTER)