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

Copyright (c) 2006-2020, assimp team



All rights reserved.

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* 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
  following disclaimer in the documentation and/or other
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  derived from this software without specific prior
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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*/

/** @file  BaseImporter.cpp
 *  @brief Implementation of BaseImporter
 */

#include <assimp/BaseImporter.h>
#include <assimp/ParsingUtils.h>
#include "FileSystemFilter.h"
#include "Importer.h"
#include <assimp/ByteSwapper.h>
#include <assimp/scene.h>
#include <assimp/Importer.hpp>
#include <assimp/postprocess.h>
#include <assimp/importerdesc.h>

#include <ios>
#include <list>
#include <memory>
#include <sstream>
#include <cctype>

using namespace Assimp;

// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
BaseImporter::BaseImporter() AI_NO_EXCEPT
: m_progress() {
    /**
    * Assimp Importer
    * unit conversions available
    * if you need another measurment unit add it below.
    * it's currently defined in assimp that we prefer meters.
    *
    * NOTE: Initialised here rather than in the header file
    * to workaround a VS2013 bug with brace initialisers
    * */
    importerUnits[ImporterUnits::M] = 1.0;
    importerUnits[ImporterUnits::CM] = 0.01;
    importerUnits[ImporterUnits::MM] = 0.001;
    importerUnits[ImporterUnits::INCHES] = 0.0254;
    importerUnits[ImporterUnits::FEET] = 0.3048;
}

// ------------------------------------------------------------------------------------------------
// Destructor, private as well
BaseImporter::~BaseImporter() {
    // nothing to do here
}

void BaseImporter::UpdateImporterScale( Importer* pImp )
{
    ai_assert(pImp != nullptr);
    ai_assert(importerScale != 0.0);
    ai_assert(fileScale != 0.0);

    double activeScale = importerScale * fileScale;

    // Set active scaling
    pImp->SetPropertyFloat( AI_CONFIG_APP_SCALE_KEY, static_cast<float>( activeScale) );

    ASSIMP_LOG_DEBUG_F("UpdateImporterScale scale set: %f", activeScale );
}

// ------------------------------------------------------------------------------------------------
// Imports the given file and returns the imported data.
aiScene* BaseImporter::ReadFile(Importer* pImp, const std::string& pFile, IOSystem* pIOHandler) {


    m_progress = pImp->GetProgressHandler();
    if (nullptr == m_progress) {
        return nullptr;
    }

    ai_assert(m_progress);

    // Gather configuration properties for this run
    SetupProperties( pImp );

    // Construct a file system filter to improve our success ratio at reading external files
    FileSystemFilter filter(pFile,pIOHandler);

    // create a scene object to hold the data
    std::unique_ptr<aiScene> sc(new aiScene());

    // dispatch importing
    try
    {
        InternReadFile( pFile, sc.get(), &filter);

        // Calculate import scale hook - required because pImp not available anywhere else
        // passes scale into ScaleProcess
        UpdateImporterScale(pImp);


    } catch( const std::exception& err )    {
        // extract error description
        m_ErrorText = err.what();
        ASSIMP_LOG_ERROR(m_ErrorText);
        return nullptr;
    }

    // return what we gathered from the import.
    return sc.release();
}

// ------------------------------------------------------------------------------------------------
void BaseImporter::SetupProperties(const Importer* )
{
    // the default implementation does nothing
}

// ------------------------------------------------------------------------------------------------
void BaseImporter::GetExtensionList(std::set<std::string>& extensions) {
    const aiImporterDesc* desc = GetInfo();
    ai_assert(desc != nullptr);

    const char* ext = desc->mFileExtensions;
    ai_assert(ext != nullptr );

    const char* last = ext;
    do {
        if (!*ext || *ext == ' ') {
            extensions.insert(std::string(last,ext-last));
            ai_assert(ext-last > 0);
            last = ext;
            while(*last == ' ') {
                ++last;
            }
        }
    }
    while(*ext++);
}

// ------------------------------------------------------------------------------------------------
/*static*/ bool BaseImporter::SearchFileHeaderForToken( IOSystem* pIOHandler,
    const std::string&  pFile,
    const char**        tokens,
    unsigned int        numTokens,
    unsigned int        searchBytes /* = 200 */,
    bool                tokensSol /* false */,
    bool                noAlphaBeforeTokens /* false */)
{
    ai_assert( nullptr != tokens );
    ai_assert( 0 != numTokens );
    ai_assert( 0 != searchBytes);

    if ( nullptr == pIOHandler ) {
        return false;
    }

    std::unique_ptr<IOStream> pStream (pIOHandler->Open(pFile));
    if (pStream) {
        // read 200 characters from the file
        std::unique_ptr<char[]> _buffer (new char[searchBytes+1 /* for the '\0' */]);
        char *buffer( _buffer.get() );
        const size_t read( pStream->Read(buffer,1,searchBytes) );
        if( 0 == read ) {
            return false;
        }

        for( size_t i = 0; i < read; ++i ) {
            buffer[ i ] = static_cast<char>( ::tolower( buffer[ i ] ) );
        }

        // It is not a proper handling of unicode files here ...
        // ehm ... but it works in most cases.
        char* cur = buffer,*cur2 = buffer,*end = &buffer[read];
        while (cur != end)  {
            if( *cur ) {
                *cur2++ = *cur;
            }
            ++cur;
        }
        *cur2 = '\0';

        std::string token;
        for (unsigned int i = 0; i < numTokens; ++i ) {
            ai_assert( nullptr != tokens[i] );
            const size_t len( strlen( tokens[ i ] ) );
            token.clear();
            const char *ptr( tokens[ i ] );
            for ( size_t tokIdx = 0; tokIdx < len; ++tokIdx ) {
                token.push_back( static_cast<char>( tolower( *ptr ) ) );
                ++ptr;
            }
            const char* r = strstr( buffer, token.c_str() );
            if( !r ) {
                continue;
            }
            // We need to make sure that we didn't accidentially identify the end of another token as our token,
            // e.g. in a previous version the "gltf " present in some gltf files was detected as "f "
            if (noAlphaBeforeTokens && (r != buffer && isalpha(r[-1]))) {
                continue;
            }
            // We got a match, either we don't care where it is, or it happens to
            // be in the beginning of the file / line
            if (!tokensSol || r == buffer || r[-1] == '\r' || r[-1] == '\n') {
                ASSIMP_LOG_DEBUG_F( "Found positive match for header keyword: ", tokens[i] );
                return true;
            }
        }
    }

    return false;
}

// ------------------------------------------------------------------------------------------------
// Simple check for file extension
/*static*/ bool BaseImporter::SimpleExtensionCheck (const std::string& pFile,
    const char* ext0,
    const char* ext1,
    const char* ext2)
{
    std::string::size_type pos = pFile.find_last_of('.');

    // no file extension - can't read
    if( pos == std::string::npos)
        return false;

    const char* ext_real = & pFile[ pos+1 ];
    if( !ASSIMP_stricmp(ext_real,ext0) )
        return true;

    // check for other, optional, file extensions
    if (ext1 && !ASSIMP_stricmp(ext_real,ext1))
        return true;

    if (ext2 && !ASSIMP_stricmp(ext_real,ext2))
        return true;

    return false;
}

// ------------------------------------------------------------------------------------------------
// Get file extension from path
std::string BaseImporter::GetExtension( const std::string& file ) {
    std::string::size_type pos = file.find_last_of('.');

    // no file extension at all
    if (pos == std::string::npos) {
        return "";
    }

    // thanks to Andy Maloney for the hint
    std::string ret = file.substr( pos + 1 );
    std::transform( ret.begin(), ret.end(), ret.begin(), ToLower<char>);

    return ret;
}

// ------------------------------------------------------------------------------------------------
// Check for magic bytes at the beginning of the file.
/* static */ bool BaseImporter::CheckMagicToken(IOSystem* pIOHandler, const std::string& pFile,
    const void* _magic, unsigned int num, unsigned int offset, unsigned int size)
{
    ai_assert( size <= 16 );
    ai_assert( _magic );

    if (!pIOHandler) {
        return false;
    }
    union {
        const char* magic;
        const uint16_t* magic_u16;
        const uint32_t* magic_u32;
    };
    magic = reinterpret_cast<const char*>(_magic);
    std::unique_ptr<IOStream> pStream (pIOHandler->Open(pFile));
    if (pStream) {

        // skip to offset
        pStream->Seek(offset,aiOrigin_SET);

        // read 'size' characters from the file
        union {
            char data[16];
            uint16_t data_u16[8];
            uint32_t data_u32[4];
        };
        if(size != pStream->Read(data,1,size)) {
            return false;
        }

        for (unsigned int i = 0; i < num; ++i) {
            // also check against big endian versions of tokens with size 2,4
            // that's just for convenience, the chance that we cause conflicts
            // is quite low and it can save some lines and prevent nasty bugs
            if (2 == size) {
                uint16_t rev = *magic_u16;
                ByteSwap::Swap(&rev);
                if (data_u16[0] == *magic_u16 || data_u16[0] == rev) {
                    return true;
                }
            }
            else if (4 == size) {
                uint32_t rev = *magic_u32;
                ByteSwap::Swap(&rev);
                if (data_u32[0] == *magic_u32 || data_u32[0] == rev) {
                    return true;
                }
            }
            else {
                // any length ... just compare
                if(!memcmp(magic,data,size)) {
                    return true;
                }
            }
            magic += size;
        }
    }
    return false;
}

#ifdef ASSIMP_USE_HUNTER
#  include <utf8/utf8.h>
#else
#  include "../contrib/utf8cpp/source/utf8.h"
#endif

// ------------------------------------------------------------------------------------------------
// Convert to UTF8 data
void BaseImporter::ConvertToUTF8(std::vector<char>& data)
{
    //ConversionResult result;
    if(data.size() < 8) {
        throw DeadlyImportError("File is too small");
    }

    // UTF 8 with BOM
    if((uint8_t)data[0] == 0xEF && (uint8_t)data[1] == 0xBB && (uint8_t)data[2] == 0xBF) {
        ASSIMP_LOG_DEBUG("Found UTF-8 BOM ...");

        std::copy(data.begin()+3,data.end(),data.begin());
        data.resize(data.size()-3);
        return;
    }
    
    
    // UTF 32 BE with BOM
    if(*((uint32_t*)&data.front()) == 0xFFFE0000) {

        // swap the endianness ..
        for(uint32_t* p = (uint32_t*)&data.front(), *end = (uint32_t*)&data.back(); p <= end; ++p) {
            AI_SWAP4P(p);
        }
    }

    // UTF 32 LE with BOM
    if(*((uint32_t*)&data.front()) == 0x0000FFFE) {
        ASSIMP_LOG_DEBUG("Found UTF-32 BOM ...");

        std::vector<char> output;
        int *ptr = (int*)&data[ 0 ];
        int *end = ptr + ( data.size() / sizeof(int) ) +1;
        utf8::utf32to8( ptr, end, back_inserter(output));
        return;
    }

    // UTF 16 BE with BOM
    if(*((uint16_t*)&data.front()) == 0xFFFE) {

        // swap the endianness ..
        for(uint16_t* p = (uint16_t*)&data.front(), *end = (uint16_t*)&data.back(); p <= end; ++p) {
            ByteSwap::Swap2(p);
        }
    }

    // UTF 16 LE with BOM
    if(*((uint16_t*)&data.front()) == 0xFEFF) {
        ASSIMP_LOG_DEBUG("Found UTF-16 BOM ...");

        std::vector<unsigned char> output;
        utf8::utf16to8(data.begin(), data.end(), back_inserter(output));
        return;
    }
}

// ------------------------------------------------------------------------------------------------
// Convert to UTF8 data to ISO-8859-1
void BaseImporter::ConvertUTF8toISO8859_1(std::string& data)
{
    size_t size = data.size();
    size_t i = 0, j = 0;

    while(i < size) {
        if ((unsigned char) data[i] < (size_t) 0x80) {
            data[j] = data[i];
        } else if(i < size - 1) {
            if((unsigned char) data[i] == 0xC2) {
                data[j] = data[++i];
            } else if((unsigned char) data[i] == 0xC3) {
                data[j] = ((unsigned char) data[++i] + 0x40);
            } else {
                std::stringstream stream;
                stream << "UTF8 code " << std::hex << data[i] << data[i + 1] << " can not be converted into ISA-8859-1.";
                ASSIMP_LOG_ERROR( stream.str() );

                data[j++] = data[i++];
                data[j] = data[i];
            }
        } else {
            ASSIMP_LOG_ERROR("UTF8 code but only one character remaining");

            data[j] = data[i];
        }

        i++; j++;
    }

    data.resize(j);
}

// ------------------------------------------------------------------------------------------------
void BaseImporter::TextFileToBuffer(IOStream* stream,
    std::vector<char>& data,
    TextFileMode mode)
{
    ai_assert(nullptr != stream);

    const size_t fileSize = stream->FileSize();
    if (mode == FORBID_EMPTY) {
        if(!fileSize) {
            throw DeadlyImportError("File is empty");
        }
    }

    data.reserve(fileSize+1);
    data.resize(fileSize);
    if(fileSize > 0) {
        if(fileSize != stream->Read( &data[0], 1, fileSize)) {
            throw DeadlyImportError("File read error");
        }

        ConvertToUTF8(data);
    }

    // append a binary zero to simplify string parsing
    data.push_back(0);
}

// ------------------------------------------------------------------------------------------------
namespace Assimp {
    // Represents an import request
    struct LoadRequest {
        LoadRequest(const std::string& _file, unsigned int _flags,const BatchLoader::PropertyMap* _map, unsigned int _id)
        : file(_file)
        , flags(_flags)
        , refCnt(1)
        , scene(NULL)
        , loaded(false)
        , id(_id) {
            if ( _map ) {
                map = *_map;
            }
        }

        bool operator== ( const std::string& f ) const {
            return file == f;
        }

        const std::string        file;
        unsigned int             flags;
        unsigned int             refCnt;
        aiScene                 *scene;
        bool                     loaded;
        BatchLoader::PropertyMap map;
        unsigned int             id;
    };
}

// ------------------------------------------------------------------------------------------------
// BatchLoader::pimpl data structure
struct Assimp::BatchData {
    BatchData( IOSystem* pIO, bool validate )
    : pIOSystem( pIO )
    , pImporter( nullptr )
    , next_id(0xffff)
    , validate( validate ) {
        ai_assert( nullptr != pIO );
        
        pImporter = new Importer();
        pImporter->SetIOHandler( pIO );
    }

    ~BatchData() {
        pImporter->SetIOHandler( nullptr ); /* get pointer back into our possession */
        delete pImporter;
    }

    // IO system to be used for all imports
    IOSystem* pIOSystem;

    // Importer used to load all meshes
    Importer* pImporter;

    // List of all imports
    std::list<LoadRequest> requests;

    // Base path
    std::string pathBase;

    // Id for next item
    unsigned int next_id;

    // Validation enabled state
    bool validate;
};

typedef std::list<LoadRequest>::iterator LoadReqIt;

// ------------------------------------------------------------------------------------------------
BatchLoader::BatchLoader(IOSystem* pIO, bool validate ) {
    ai_assert(nullptr != pIO);

    m_data = new BatchData( pIO, validate );
}

// ------------------------------------------------------------------------------------------------
BatchLoader::~BatchLoader()
{
    // delete all scenes what have not been polled by the user
    for ( LoadReqIt it = m_data->requests.begin();it != m_data->requests.end(); ++it) {
        delete (*it).scene;
    }
    delete m_data;
}

// ------------------------------------------------------------------------------------------------
void BatchLoader::setValidation( bool enabled ) {
    m_data->validate = enabled;
}

// ------------------------------------------------------------------------------------------------
bool BatchLoader::getValidation() const {
    return m_data->validate;
}

// ------------------------------------------------------------------------------------------------
unsigned int BatchLoader::AddLoadRequest(const std::string& file,
    unsigned int steps /*= 0*/, const PropertyMap* map /*= NULL*/)
{
    ai_assert(!file.empty());

    // check whether we have this loading request already
    for ( LoadReqIt it = m_data->requests.begin();it != m_data->requests.end(); ++it)  {
        // Call IOSystem's path comparison function here
        if ( m_data->pIOSystem->ComparePaths((*it).file,file)) {
            if (map) {
                if ( !( ( *it ).map == *map ) ) {
                    continue;
                }
            }
            else if ( !( *it ).map.empty() ) {
                continue;
            }

            (*it).refCnt++;
            return (*it).id;
        }
    }

    // no, we don't have it. So add it to the queue ...
    m_data->requests.emplace_back(file, steps, map, m_data->next_id);
    return m_data->next_id++;
}

// ------------------------------------------------------------------------------------------------
aiScene* BatchLoader::GetImport( unsigned int which )
{
    for ( LoadReqIt it = m_data->requests.begin();it != m_data->requests.end(); ++it) {
        if ((*it).id == which && (*it).loaded)  {
            aiScene* sc = (*it).scene;
            if (!(--(*it).refCnt))  {
                m_data->requests.erase(it);
            }
            return sc;
        }
    }
    return nullptr;
}



// ------------------------------------------------------------------------------------------------
void BatchLoader::LoadAll()
{
    // no threaded implementation for the moment
    for ( LoadReqIt it = m_data->requests.begin();it != m_data->requests.end(); ++it) {
        // force validation in debug builds
        unsigned int pp = (*it).flags;
        if ( m_data->validate ) {
            pp |= aiProcess_ValidateDataStructure;
        }

        // setup config properties if necessary
        ImporterPimpl* pimpl = m_data->pImporter->Pimpl();
        pimpl->mFloatProperties  = (*it).map.floats;
        pimpl->mIntProperties    = (*it).map.ints;
        pimpl->mStringProperties = (*it).map.strings;
        pimpl->mMatrixProperties = (*it).map.matrices;

        if (!DefaultLogger::isNullLogger())
        {
            ASSIMP_LOG_INFO("%%% BEGIN EXTERNAL FILE %%%");
            ASSIMP_LOG_INFO_F("File: ", (*it).file);
        }
        m_data->pImporter->ReadFile((*it).file,pp);
        (*it).scene = m_data->pImporter->GetOrphanedScene();
        (*it).loaded = true;

        ASSIMP_LOG_INFO("%%% END EXTERNAL FILE %%%");
    }
}
