/*
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Open Asset Import Library (assimp)
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*/

/** @file  NDOLoader.cpp
 *  Implementation of the NDO importer class.
 */

#ifndef ASSIMP_BUILD_NO_NDO_IMPORTER

#include "NDOLoader.h"
#include <assimp/DefaultLogger.hpp>
#include <assimp/IOSystem.hpp>
#include <assimp/scene.h>
#include <assimp/importerdesc.h>
#include <assimp/StreamReader.h>
#include <map>
#include <limits>

using namespace Assimp;

static constexpr aiImporterDesc desc = {
    "Nendo Mesh Importer",
    "",
    "",
    "http://www.izware.com/nendo/index.htm",
    aiImporterFlags_SupportBinaryFlavour,
    0,
    0,
    0,
    0,
    "ndo"
};

// ------------------------------------------------------------------------------------------------
// Returns whether the class can handle the format of the given file.
bool NDOImporter::CanRead( const std::string& pFile, IOSystem* pIOHandler, bool /*checkSig*/) const
{
    static const char* tokens[] = {"nendo"};
    return SearchFileHeaderForToken(pIOHandler,pFile,tokens,AI_COUNT_OF(tokens),5);
}

// ------------------------------------------------------------------------------------------------
// Build a string of all file extensions supported
const aiImporterDesc* NDOImporter::GetInfo () const
{
    return &desc;
}

// ------------------------------------------------------------------------------------------------
// Setup configuration properties for the loader
void NDOImporter::SetupProperties(const Importer* /*pImp*/)
{
    // nothing to be done for the moment
}

// ------------------------------------------------------------------------------------------------
// Helper function to process edges and vertices for a face
void ProcessFaceEdgesAndVertices(const NDOImporter::Object& obj,
    unsigned int start_edge, unsigned int key,
    std::vector<aiVector3D>& vertices, std::vector<unsigned int>& indices)
{
    unsigned int cur_edge = start_edge;
    do {
        unsigned int next_edge, next_vert;
        if (key == obj.edges[cur_edge].edge[3]) {
            next_edge = obj.edges[cur_edge].edge[5];
            next_vert = obj.edges[cur_edge].edge[1];
        }
        else {
            next_edge = obj.edges[cur_edge].edge[4];
            next_vert = obj.edges[cur_edge].edge[0];
        }
        indices.push_back( static_cast<unsigned int>(vertices.size()) );
        if (next_vert < obj.vertices.size()) {
            vertices.push_back(obj.vertices[ next_vert ].val);
        }
        else {
            ASSIMP_LOG_WARN("NDOImporter: next_vert is out of bounds, skipping invalid access.");
            break;
        }

        cur_edge = next_edge;
    } while (cur_edge != start_edge);
}

// ------------------------------------------------------------------------------------------------
// Imports the given file into the given scene structure.
void NDOImporter::InternReadFile( const std::string& pFile,
    aiScene* pScene, IOSystem* pIOHandler)
{

    auto file = pIOHandler->Open( pFile, "rb");
    if (!file) {
        throw DeadlyImportError("Nendo: Could not open ", pFile);
    }

    StreamReaderBE reader(file);

    // first 9 bytes are nendo file format ("nendo 1.n")
    const char* head = (const char*)reader.GetPtr();
    reader.IncPtr(9);

    if (strncmp("nendo ",head,6)) {
        throw DeadlyImportError("Not a Nendo file; magic signature missing");
    }
    // check if this is a supported version. if not, continue, too -- users,
    // please don't complain if it doesn't work then ...
    unsigned int file_format = 12;
    if (!strncmp("1.0",head+6,3)) {
        file_format = 10;
        ASSIMP_LOG_INFO("NDO file format is 1.0");
    }
    else if (!strncmp("1.1",head+6,3)) {
        file_format = 11;
        ASSIMP_LOG_INFO("NDO file format is 1.1");
    }
    else if (!strncmp("1.2",head+6,3)) {
        file_format = 12;
        ASSIMP_LOG_INFO("NDO file format is 1.2");
    }
    else {
        char buff[4] = {0};
        memcpy(buff, head+6, 3);
        ASSIMP_LOG_WARN( "Unrecognized nendo file format version, continuing happily ... :", buff);
    }

    reader.IncPtr(2); /* skip flags */
    if (file_format >= 12) {
        reader.IncPtr(2);
    }
    unsigned int temp = reader.GetU1();

    std::vector<Object> objects(temp); /* buffer to store all the loaded objects in */

    // read all objects
    for (unsigned int o = 0; o < objects.size(); ++o) {

//      if (file_format < 12) {
            if (!reader.GetI1()) {
                continue; /* skip over empty object */
            }
        //  reader.GetI2();
//      }
        Object& obj = objects[o];

        temp = file_format >= 12 ? reader.GetU4() : reader.GetU2();
        head = (const char*)reader.GetPtr();
        if (std::numeric_limits<unsigned int>::max() - 76 < temp) {
            throw DeadlyImportError("Invalid name length");
        }
        reader.IncPtr(temp + 76); /* skip unknown stuff */

        obj.name = std::string(head, temp);

        // read edge table
        temp = file_format >= 12 ? reader.GetU4() : reader.GetU2();
        obj.edges.reserve(temp);
        for (unsigned int e = 0; e < temp; ++e) {

            obj.edges.emplace_back();
            Edge& edge = obj.edges.back();

            for (unsigned int i = 0; i< 8; ++i) {
                edge.edge[i] = file_format >= 12 ? reader.GetU4() : reader.GetU2();
            }
            edge.hard =  file_format >= 11 ? reader.GetU1() : 0;
            for (unsigned int i = 0; i< 8; ++i) {
                edge.color[i] = reader.GetU1();
            }
        }

        // read face table
        temp = file_format >= 12 ? reader.GetU4() : reader.GetU2();
        obj.faces.reserve(temp);
        for (unsigned int e = 0; e < temp; ++e) {

            obj.faces.emplace_back();
            Face& face = obj.faces.back();

            face.elem = file_format >= 12 ? reader.GetU4() : reader.GetU2();
        }

        // read vertex table
        temp = file_format >= 12 ? reader.GetU4() : reader.GetU2();
        obj.vertices.reserve(temp);
        for (unsigned int e = 0; e < temp; ++e) {

            obj.vertices.emplace_back();
            Vertex& v = obj.vertices.back();

            v.num = file_format >= 12 ? reader.GetU4() : reader.GetU2();
            v.val.x = reader.GetF4();
            v.val.y = reader.GetF4();
            v.val.z = reader.GetF4();
        }

        // read UVs
        temp = file_format >= 12 ? reader.GetU4() : reader.GetU2();
        for (unsigned int e = 0; e < temp; ++e) {
             file_format >= 12 ? reader.GetU4() : reader.GetU2();
        }

        temp = file_format >= 12 ? reader.GetU4() : reader.GetU2();
        for (unsigned int e = 0; e < temp; ++e) {
             file_format >= 12 ? reader.GetU4() : reader.GetU2();
        }

        if (reader.GetU1()) {
            const unsigned int x = reader.GetU2(), y = reader.GetU2();
            temp = 0;
            while (temp < x*y)  {
                unsigned int repeat = reader.GetU1();
                reader.GetU1();
                reader.GetU1();
                reader.GetU1();
                temp += repeat;
            }
        }
    }

    // construct a dummy node graph and add all named objects as child nodes
    aiNode* root = pScene->mRootNode = new aiNode("$NDODummyRoot");
    aiNode** cc = root->mChildren = new aiNode* [ root->mNumChildren = static_cast<unsigned int>( objects.size()) ] ();
    pScene->mMeshes = new aiMesh* [ root->mNumChildren] ();

    std::vector<aiVector3D> vertices;
    std::vector<unsigned int> indices;

    for(const Object& obj : objects) {
        aiNode* nd = *cc++ = new aiNode(obj.name);
        nd->mParent = root;

        // translated from a python dict() - a vector might be sufficient as well
        typedef std::map<unsigned int, unsigned int>  FaceTable;
        FaceTable face_table;

        unsigned int n = 0;
        for(const Edge& edge : obj.edges) {

            face_table[edge.edge[2]] = n;
            face_table[edge.edge[3]] = n;

            ++n;
        }

        aiMesh* mesh = new aiMesh();
        mesh->mNumFaces=static_cast<unsigned int>(face_table.size());
        aiFace* faces = mesh->mFaces = new aiFace[mesh->mNumFaces];

        vertices.clear();
        vertices.reserve(4 * face_table.size()); // arbitrarily chosen
        for(FaceTable::value_type& v : face_table) {
            indices.clear();

            aiFace& f = *faces++;

            ProcessFaceEdgesAndVertices(obj, v.second, v.first, vertices, indices);

            f.mIndices = new unsigned int[f.mNumIndices = static_cast<unsigned int>(indices.size())];
            std::copy(indices.begin(),indices.end(),f.mIndices);
        }

        mesh->mVertices = new aiVector3D[mesh->mNumVertices = static_cast<unsigned int>(vertices.size())];
        std::copy(vertices.begin(),vertices.end(),mesh->mVertices);

        if (mesh->mNumVertices) {
            pScene->mMeshes[pScene->mNumMeshes] = mesh;

            (nd->mMeshes = new unsigned int[nd->mNumMeshes=1])[0]=pScene->mNumMeshes++;
        }else
            delete mesh;
    }
}

#endif
