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

Copyright (c) 2006-2019, assimp team

All rights reserved.

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with or without modification, are permitted provided that the following
conditions are met:

* Redistributions of source code must retain the above
  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
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  derived from this software without specific prior
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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*/

/** @file  B3DImporter.cpp
 *  @brief Implementation of the b3d importer class
 */


#ifndef ASSIMP_BUILD_NO_B3D_IMPORTER

// internal headers
#include "B3D/B3DImporter.h"
#include "PostProcessing/TextureTransform.h"
#include "PostProcessing/ConvertToLHProcess.h"

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

#include <memory>

using namespace Assimp;
using namespace std;

static const aiImporterDesc desc = {
    "BlitzBasic 3D Importer",
    "",
    "",
    "http://www.blitzbasic.com/",
    aiImporterFlags_SupportBinaryFlavour,
    0,
    0,
    0,
    0,
    "b3d"
};

#ifdef _MSC_VER
#	pragma warning (disable: 4018)
#endif

//#define DEBUG_B3D

template<typename T>
void DeleteAllBarePointers(std::vector<T>& x) {
    for(auto p : x) {
        delete p;
    }
}

B3DImporter::~B3DImporter()
{
}

// ------------------------------------------------------------------------------------------------
bool B3DImporter::CanRead( const std::string& pFile, IOSystem* /*pIOHandler*/, bool /*checkSig*/) const{

    size_t pos=pFile.find_last_of( '.' );
    if( pos==string::npos ) {
        return false;
    }

    string ext=pFile.substr( pos+1 );
    if( ext.size()!=3 ) {
        return false;
    }

    return (ext[0]=='b' || ext[0]=='B') && (ext[1]=='3') && (ext[2]=='d' || ext[2]=='D');
}

// ------------------------------------------------------------------------------------------------
// Loader meta information
const aiImporterDesc* B3DImporter::GetInfo () const
{
    return &desc;
}

// ------------------------------------------------------------------------------------------------
void B3DImporter::InternReadFile( const std::string& pFile, aiScene* pScene, IOSystem* pIOHandler){
    std::unique_ptr<IOStream> file( pIOHandler->Open( pFile));

    // Check whether we can read from the file
    if( file.get() == nullptr) {
        throw DeadlyImportError( "Failed to open B3D file " + pFile + ".");
    }

    // check whether the .b3d file is large enough to contain
    // at least one chunk.
    size_t fileSize = file->FileSize();
    if( fileSize<8 ) {
        throw DeadlyImportError( "B3D File is too small.");
    }

    _pos=0;
    _buf.resize( fileSize );
    file->Read( &_buf[0],1,fileSize );
    _stack.clear();

    ReadBB3D( pScene );
}

// ------------------------------------------------------------------------------------------------
AI_WONT_RETURN void B3DImporter::Oops(){
    throw DeadlyImportError( "B3D Importer - INTERNAL ERROR" );
}

// ------------------------------------------------------------------------------------------------
AI_WONT_RETURN void B3DImporter::Fail( string str ){
#ifdef DEBUG_B3D
    ASSIMP_LOG_ERROR_F("Error in B3D file data: ", str);
#endif
    throw DeadlyImportError( "B3D Importer - error in B3D file data: "+str );
}

// ------------------------------------------------------------------------------------------------
int B3DImporter::ReadByte(){
    if( _pos<_buf.size() ) {
        return _buf[_pos++];
    }
    
    Fail( "EOF" );
    return 0;
}

// ------------------------------------------------------------------------------------------------
int B3DImporter::ReadInt(){
    if( _pos+4<=_buf.size() ){
        int n;
        memcpy(&n, &_buf[_pos], 4);
        _pos+=4;
        return n;
    }
    Fail( "EOF" );
    return 0;
}

// ------------------------------------------------------------------------------------------------
float B3DImporter::ReadFloat(){
    if( _pos+4<=_buf.size() ){
        float n;
        memcpy(&n, &_buf[_pos], 4);
        _pos+=4;
        return n;
    }
    Fail( "EOF" );
    return 0.0f;
}

// ------------------------------------------------------------------------------------------------
aiVector2D B3DImporter::ReadVec2(){
    float x=ReadFloat();
    float y=ReadFloat();
    return aiVector2D( x,y );
}

// ------------------------------------------------------------------------------------------------
aiVector3D B3DImporter::ReadVec3(){
    float x=ReadFloat();
    float y=ReadFloat();
    float z=ReadFloat();
    return aiVector3D( x,y,z );
}

// ------------------------------------------------------------------------------------------------
aiQuaternion B3DImporter::ReadQuat(){
    // (aramis_acg) Fix to adapt the loader to changed quat orientation
    float w=-ReadFloat();
    float x=ReadFloat();
    float y=ReadFloat();
    float z=ReadFloat();
    return aiQuaternion( w,x,y,z );
}

// ------------------------------------------------------------------------------------------------
string B3DImporter::ReadString(){
    string str;
    while( _pos<_buf.size() ){
        char c=(char)ReadByte();
        if( !c ) {
            return str;
        }
        str+=c;
    }
    Fail( "EOF" );
    return string();
}

// ------------------------------------------------------------------------------------------------
string B3DImporter::ReadChunk(){
    string tag;
    for( int i=0;i<4;++i ){
        tag+=char( ReadByte() );
    }
#ifdef DEBUG_B3D
    ASSIMP_LOG_DEBUG_F("ReadChunk: ", tag);
#endif
    unsigned sz=(unsigned)ReadInt();
    _stack.push_back( _pos+sz );
    return tag;
}

// ------------------------------------------------------------------------------------------------
void B3DImporter::ExitChunk(){
    _pos=_stack.back();
    _stack.pop_back();
}

// ------------------------------------------------------------------------------------------------
unsigned B3DImporter::ChunkSize(){
    return _stack.back()-_pos;
}
// ------------------------------------------------------------------------------------------------

template<class T>
T *B3DImporter::to_array( const vector<T> &v ){
    if( v.empty() ) {
        return 0;
    }
    T *p=new T[ v.size() ];
    for( size_t i=0;i<v.size();++i ){
        p[i]=v[i];
    }
    return p;
}

// ------------------------------------------------------------------------------------------------
template<class T>
T **unique_to_array( vector<std::unique_ptr<T> > &v ){
    if( v.empty() ) {
        return 0;
    }
    T **p = new T*[ v.size() ];
    for( size_t i = 0; i < v.size(); ++i ){
        p[i] = v[i].release();
    }
    return p;
}

// ------------------------------------------------------------------------------------------------
void B3DImporter::ReadTEXS(){
    while( ChunkSize() ){
        string name=ReadString();
        /*int flags=*/ReadInt();
        /*int blend=*/ReadInt();
        /*aiVector2D pos=*/ReadVec2();
        /*aiVector2D scale=*/ReadVec2();
        /*float rot=*/ReadFloat();

        _textures.push_back( name );
    }
}

// ------------------------------------------------------------------------------------------------
void B3DImporter::ReadBRUS(){
    int n_texs=ReadInt();
    if( n_texs<0 || n_texs>8 ){
        Fail( "Bad texture count" );
    }
    while( ChunkSize() ){
        string name=ReadString();
        aiVector3D color=ReadVec3();
        float alpha=ReadFloat();
        float shiny=ReadFloat();
        /*int blend=**/ReadInt();
        int fx=ReadInt();

        std::unique_ptr<aiMaterial> mat(new aiMaterial);

        // Name
        aiString ainame( name );
        mat->AddProperty( &ainame,AI_MATKEY_NAME );

        // Diffuse color
        mat->AddProperty( &color,1,AI_MATKEY_COLOR_DIFFUSE );

        // Opacity
        mat->AddProperty( &alpha,1,AI_MATKEY_OPACITY );

        // Specular color
        aiColor3D speccolor( shiny,shiny,shiny );
        mat->AddProperty( &speccolor,1,AI_MATKEY_COLOR_SPECULAR );

        // Specular power
        float specpow=shiny*128;
        mat->AddProperty( &specpow,1,AI_MATKEY_SHININESS );

        // Double sided
        if( fx & 0x10 ){
            int i=1;
            mat->AddProperty( &i,1,AI_MATKEY_TWOSIDED );
        }

        //Textures
        for( int i=0;i<n_texs;++i ){
            int texid=ReadInt();
            if( texid<-1 || (texid>=0 && texid>=static_cast<int>(_textures.size())) ){
                Fail( "Bad texture id" );
            }
            if( i==0 && texid>=0 ){
                aiString texname( _textures[texid] );
                mat->AddProperty( &texname,AI_MATKEY_TEXTURE_DIFFUSE(0) );
            }
        }
        _materials.emplace_back( std::move(mat) );
    }
}

// ------------------------------------------------------------------------------------------------
void B3DImporter::ReadVRTS(){
    _vflags=ReadInt();
    _tcsets=ReadInt();
    _tcsize=ReadInt();
    if( _tcsets<0 || _tcsets>4 || _tcsize<0 || _tcsize>4 ){
        Fail( "Bad texcoord data" );
    }

    int sz=12+(_vflags&1?12:0)+(_vflags&2?16:0)+(_tcsets*_tcsize*4);
    int n_verts=ChunkSize()/sz;

    int v0=static_cast<int>(_vertices.size());
    _vertices.resize( v0+n_verts );

    for( int i=0;i<n_verts;++i ){
        Vertex &v=_vertices[v0+i];

        memset( v.bones,0,sizeof(v.bones) );
        memset( v.weights,0,sizeof(v.weights) );

        v.vertex=ReadVec3();

        if( _vflags & 1 ) {
            v.normal=ReadVec3();
        }

        if( _vflags & 2 ) {
            ReadQuat();	//skip v 4bytes...
        }

        for( int i=0;i<_tcsets;++i ){
            float t[4]={0,0,0,0};
            for( int j=0;j<_tcsize;++j ){
                t[j]=ReadFloat();
            }
            t[1]=1-t[1];
            if( !i ) {
                v.texcoords=aiVector3D( t[0],t[1],t[2] );
            }
        }
    }
}

// ------------------------------------------------------------------------------------------------
void B3DImporter::ReadTRIS(int v0) {
	int matid = ReadInt();
	if (matid == -1) {
		matid = 0;
	} else if (matid < 0 || matid >= (int)_materials.size()) {
#ifdef DEBUG_B3D
		ASSIMP_LOG_ERROR_F("material id=", matid);
#endif
		Fail("Bad material id");
	}

	std::unique_ptr<aiMesh> mesh(new aiMesh);

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

	int n_tris = ChunkSize() / 12;
	aiFace *face = mesh->mFaces = new aiFace[n_tris];

	for (int i = 0; i < n_tris; ++i) {
		int i0 = ReadInt() + v0;
		int i1 = ReadInt() + v0;
		int i2 = ReadInt() + v0;
		if (i0 < 0 || i0 >= (int)_vertices.size() || i1 < 0 || i1 >= (int)_vertices.size() || i2 < 0 || i2 >= (int)_vertices.size()) {
#ifdef DEBUG_B3D
			ASSIMP_LOG_ERROR_F("Bad triangle index: i0=", i0, ", i1=", i1, ", i2=", i2);
#endif
			Fail("Bad triangle index");
			continue;
		}
		face->mNumIndices = 3;
		face->mIndices = new unsigned[3];
		face->mIndices[0] = i0;
		face->mIndices[1] = i1;
		face->mIndices[2] = i2;
		++mesh->mNumFaces;
		++face;
	}

	_meshes.emplace_back(std::move(mesh));
}

// ------------------------------------------------------------------------------------------------
void B3DImporter::ReadMESH(){
    /*int matid=*/ReadInt();

    int v0= static_cast<int>(_vertices.size());

    while( ChunkSize() ){
        string t=ReadChunk();
        if( t=="VRTS" ){
            ReadVRTS();
        }else if( t=="TRIS" ){
            ReadTRIS( v0 );
        }
        ExitChunk();
    }
}

// ------------------------------------------------------------------------------------------------
void B3DImporter::ReadBONE(int id) {
	while (ChunkSize()) {
		int vertex = ReadInt();
		float weight = ReadFloat();
		if (vertex < 0 || vertex >= (int)_vertices.size()) {
			Fail("Bad vertex index");
		}

		Vertex &v = _vertices[vertex];
		for (int i = 0; i < 4; ++i) {
			if (!v.weights[i]) {
				v.bones[i] = id;
				v.weights[i] = weight;
				break;
			}
		}
	}
}

// ------------------------------------------------------------------------------------------------
void B3DImporter::ReadKEYS( aiNodeAnim *nodeAnim ){
    vector<aiVectorKey> trans,scale;
    vector<aiQuatKey> rot;
    int flags=ReadInt();
    while( ChunkSize() ){
        int frame=ReadInt();
        if( flags & 1 ){
            trans.push_back( aiVectorKey( frame,ReadVec3() ) );
        }
        if( flags & 2 ){
            scale.push_back( aiVectorKey( frame,ReadVec3() ) );
        }
        if( flags & 4 ){
            rot.push_back( aiQuatKey( frame,ReadQuat() ) );
        }
    }

    if( flags & 1 ){
        nodeAnim->mNumPositionKeys=static_cast<unsigned int>(trans.size());
        nodeAnim->mPositionKeys=to_array( trans );
    }

    if( flags & 2 ){
        nodeAnim->mNumScalingKeys=static_cast<unsigned int>(scale.size());
        nodeAnim->mScalingKeys=to_array( scale );
    }

    if( flags & 4 ){
        nodeAnim->mNumRotationKeys=static_cast<unsigned int>(rot.size());
        nodeAnim->mRotationKeys=to_array( rot );
    }
}

// ------------------------------------------------------------------------------------------------
void B3DImporter::ReadANIM(){
    /*int flags=*/ReadInt();
    int frames=ReadInt();
    float fps=ReadFloat();

    std::unique_ptr<aiAnimation> anim(new aiAnimation);

    anim->mDuration=frames;
    anim->mTicksPerSecond=fps;
    _animations.emplace_back( std::move(anim) );
}

// ------------------------------------------------------------------------------------------------
aiNode *B3DImporter::ReadNODE( aiNode *parent ){

    string name=ReadString();
    aiVector3D t=ReadVec3();
    aiVector3D s=ReadVec3();
    aiQuaternion r=ReadQuat();

    aiMatrix4x4 trans,scale,rot;

    aiMatrix4x4::Translation( t,trans );
    aiMatrix4x4::Scaling( s,scale );
    rot=aiMatrix4x4( r.GetMatrix() );

    aiMatrix4x4 tform=trans * rot * scale;

    int nodeid=static_cast<int>(_nodes.size());

    aiNode *node=new aiNode( name );
    _nodes.push_back( node );

    node->mParent=parent;
    node->mTransformation=tform;

    std::unique_ptr<aiNodeAnim> nodeAnim;
    vector<unsigned> meshes;
    vector<aiNode*> children;

    while( ChunkSize() ){
        string t=ReadChunk();
        if( t=="MESH" ){
            unsigned int n= static_cast<unsigned int>(_meshes.size());
            ReadMESH();
            for( unsigned int i=n;i<static_cast<unsigned int>(_meshes.size());++i ){
                meshes.push_back( i );
            }
        }else if( t=="BONE" ){
            ReadBONE( nodeid );
        }else if( t=="ANIM" ){
            ReadANIM();
        }else if( t=="KEYS" ){
            if( !nodeAnim ){
                nodeAnim.reset(new aiNodeAnim);
                nodeAnim->mNodeName=node->mName;
            }
            ReadKEYS( nodeAnim.get() );
        }else if( t=="NODE" ){
            aiNode *child=ReadNODE( node );
            children.push_back( child );
        }
        ExitChunk();
    }

    if (nodeAnim) {
        _nodeAnims.emplace_back( std::move(nodeAnim) );
    }

    node->mNumMeshes= static_cast<unsigned int>(meshes.size());
    node->mMeshes=to_array( meshes );

    node->mNumChildren=static_cast<unsigned int>(children.size());
    node->mChildren=to_array( children );

    return node;
}

// ------------------------------------------------------------------------------------------------
void B3DImporter::ReadBB3D( aiScene *scene ){

    _textures.clear();

    _materials.clear();

    _vertices.clear();

    _meshes.clear();

    DeleteAllBarePointers(_nodes);
    _nodes.clear();

    _nodeAnims.clear();

    _animations.clear();

    string t=ReadChunk();
    if( t=="BB3D" ){
        int version=ReadInt();

        if (!DefaultLogger::isNullLogger()) {
            char dmp[128];
            ai_snprintf(dmp, 128, "B3D file format version: %i",version);
            ASSIMP_LOG_INFO(dmp);
        }

        while( ChunkSize() ){
            string t=ReadChunk();
            if( t=="TEXS" ){
                ReadTEXS();
            }else if( t=="BRUS" ){
                ReadBRUS();
            }else if( t=="NODE" ){
                ReadNODE( 0 );
            }
            ExitChunk();
        }
    }
    ExitChunk();

    if( !_nodes.size() ) {
        Fail( "No nodes" );
    }

    if( !_meshes.size() ) {
        Fail( "No meshes" );
    }

    // Fix nodes/meshes/bones
    for(size_t i=0;i<_nodes.size();++i ){
        aiNode *node=_nodes[i];

        for( size_t j=0;j<node->mNumMeshes;++j ){
            aiMesh *mesh = _meshes[node->mMeshes[j]].get();

            int n_tris=mesh->mNumFaces;
            int n_verts=mesh->mNumVertices=n_tris * 3;

            aiVector3D *mv=mesh->mVertices=new aiVector3D[ n_verts ],*mn=0,*mc=0;
            if( _vflags & 1 ) {
                mn=mesh->mNormals=new aiVector3D[ n_verts ];
            }
            if( _tcsets ) {
                mc=mesh->mTextureCoords[0]=new aiVector3D[ n_verts ];
            }

            aiFace *face=mesh->mFaces;

            vector< vector<aiVertexWeight> > vweights( _nodes.size() );

            for( int i=0;i<n_verts;i+=3 ){
                for( int j=0;j<3;++j ){
                    Vertex &v=_vertices[face->mIndices[j]];

                    *mv++=v.vertex;
                    if( mn ) *mn++=v.normal;
                    if( mc ) *mc++=v.texcoords;

                    face->mIndices[j]=i+j;

                    for( int k=0;k<4;++k ){
                        if( !v.weights[k] ) break;

                        int bone=v.bones[k];
                        float weight=v.weights[k];

                        vweights[bone].push_back( aiVertexWeight(i+j,weight) );
                    }
                }
                ++face;
            }

            vector<aiBone*> bones;
            for(size_t i=0;i<vweights.size();++i ){
                vector<aiVertexWeight> &weights=vweights[i];
                if( !weights.size() ) continue;

                aiBone *bone=new aiBone;
                bones.push_back( bone );

                aiNode *bnode=_nodes[i];

                bone->mName=bnode->mName;
                bone->mNumWeights= static_cast<unsigned int>(weights.size());
                bone->mWeights=to_array( weights );

                aiMatrix4x4 mat=bnode->mTransformation;
                while( bnode->mParent ){
                    bnode=bnode->mParent;
                    mat=bnode->mTransformation * mat;
                }
                bone->mOffsetMatrix=mat.Inverse();
            }
            mesh->mNumBones= static_cast<unsigned int>(bones.size());
            mesh->mBones=to_array( bones );
        }
    }

    //nodes
    scene->mRootNode=_nodes[0];
    _nodes.clear();  // node ownership now belongs to scene

    //material
    if( !_materials.size() ){
        _materials.emplace_back( std::unique_ptr<aiMaterial>(new aiMaterial) );
    }
    scene->mNumMaterials= static_cast<unsigned int>(_materials.size());
    scene->mMaterials = unique_to_array( _materials );

    //meshes
    scene->mNumMeshes= static_cast<unsigned int>(_meshes.size());
    scene->mMeshes = unique_to_array( _meshes );

    //animations
    if( _animations.size()==1 && _nodeAnims.size() ){

        aiAnimation *anim = _animations.back().get();
        anim->mNumChannels=static_cast<unsigned int>(_nodeAnims.size());
        anim->mChannels = unique_to_array( _nodeAnims );

        scene->mNumAnimations=static_cast<unsigned int>(_animations.size());
        scene->mAnimations=unique_to_array( _animations );
    }

    // convert to RH
    MakeLeftHandedProcess makeleft;
    makeleft.Execute( scene );

    FlipWindingOrderProcess flip;
    flip.Execute( scene );
}

#endif // !! ASSIMP_BUILD_NO_B3D_IMPORTER