/*

Open Asset Import Library (assimp)

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  following disclaimer.

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*/

/** @file  BlenderDNA.cpp

 *  @brief Implementation of the Blender `DNA`, that is its own

 *    serialized set of data structures.

 */

#ifndef ASSIMP_BUILD_NO_BLEND_IMPORTER

#include "BlenderDNA.h"

#include <assimp/StreamReader.h>

#include <assimp/TinyFormatter.h>

#include <assimp/fast_atof.h>

using namespace Assimp;

using namespace Assimp::Blender;

using namespace Assimp::Formatter;

static bool match4(StreamReaderAny &stream, const char *string) {

    ai_assert(nullptr != string);

    char tmp[4];

    tmp[0] = (stream).GetI1();

    tmp[1] = (stream).GetI1();

    tmp[2] = (stream).GetI1();

    tmp[3] = (stream).GetI1();

    return (tmp[0] == string[0] && tmp[1] == string[1] && tmp[2] == string[2] && tmp[3] == string[3]);

}

struct Type {

    size_t size;

    std::string name;

};

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

void DNAParser::Parse() {

    StreamReaderAny &stream = *db.reader;

    DNA &dna = db.dna;

    if (!match4(stream, "SDNA")) {

        throw DeadlyImportError("BlenderDNA: Expected SDNA chunk");

    }

    // name dictionary

    if (!match4(stream, "NAME")) {

        throw DeadlyImportError("BlenderDNA: Expected NAME field");

    }

    std::vector<std::string> names(stream.GetI4());

    for (std::string &s : names) {

        while (char c = stream.GetI1()) {

            s += c;

        }

    }

    // type dictionary

    for (; stream.GetCurrentPos() & 0x3; stream.GetI1())

        ;

    if (!match4(stream, "TYPE")) {

        throw DeadlyImportError("BlenderDNA: Expected TYPE field");

    }

    std::vector<Type> types(stream.GetI4());

    for (Type &s : types) {

        while (char c = stream.GetI1()) {

            s.name += c;

        }

    }

    // type length dictionary

    for (; stream.GetCurrentPos() & 0x3; stream.GetI1())

        ;

    if (!match4(stream, "TLEN")) {

        throw DeadlyImportError("BlenderDNA: Expected TLEN field");

    }

    for (Type &s : types) {

        s.size = stream.GetI2();

    }

    // structures dictionary

    for (; stream.GetCurrentPos() & 0x3; stream.GetI1())

        ;

    if (!match4(stream, "STRC")) {

        throw DeadlyImportError("BlenderDNA: Expected STRC field");

    }

    size_t end = stream.GetI4(), fields = 0;

    dna.structures.reserve(end);

    for (size_t i = 0; i != end; ++i) {

        uint16_t n = stream.GetI2();

        if (n >= types.size()) {

            throw DeadlyImportError("BlenderDNA: Invalid type index in structure name", n, " (there are only ", types.size(), " entries)");

        }

        // maintain separate indexes

        dna.indices[types[n].name] = dna.structures.size();

        dna.structures.push_back(Structure());

        Structure &s = dna.structures.back();

        s.name = types[n].name;

        n = stream.GetI2();

        s.fields.reserve(n);

        size_t offset = 0;

        for (size_t m = 0; m < n; ++m, ++fields) {

            uint16_t j = stream.GetI2();

            if (j >= types.size()) {

                throw DeadlyImportError("BlenderDNA: Invalid type index in structure field ", j, " (there are only ", types.size(), " entries)");

            }

            s.fields.push_back(Field());

            Field &f = s.fields.back();

            f.offset = offset;

            f.type = types[j].name;

            f.size = types[j].size;

            j = stream.GetI2();

            if (j >= names.size()) {

                throw DeadlyImportError("BlenderDNA: Invalid name index in structure field ", j, " (there are only ", names.size(), " entries)");

            }

            f.name = names[j];

            f.flags = 0u;

            // pointers always specify the size of the pointee instead of their own.

            // The pointer asterisk remains a property of the lookup name.

            if (f.name[0] == '*') {

                f.size = db.i64bit ? 8 : 4;

                f.flags |= FieldFlag_Pointer;

            }

            // arrays, however, specify the size of a single element so we

            // need to parse the (possibly multi-dimensional) array declaration

            // in order to obtain the actual size of the array in the file.

            // Also we need to alter the lookup name to include no array

            // brackets anymore or size fixup won't work (if our size does

            // not match the size read from the DNA).

            if (*f.name.rbegin() == ']') {

                const std::string::size_type rb = f.name.find('[');

                if (rb == std::string::npos) {

                    throw DeadlyImportError("BlenderDNA: Encountered invalid array declaration ", f.name);

                }

                f.flags |= FieldFlag_Array;

                DNA::ExtractArraySize(f.name, f.array_sizes);

                f.name = f.name.substr(0, rb);

                f.size *= f.array_sizes[0] * f.array_sizes[1];

            }

            // maintain separate indexes

            s.indices[f.name] = s.fields.size() - 1;

            offset += f.size;

        }

        s.size = offset;

    }

    ASSIMP_LOG_DEBUG("BlenderDNA: Got ", dna.structures.size(), " structures with totally ", fields, " fields");

#if ASSIMP_BUILD_BLENDER_DEBUG_DNA

    dna.DumpToFile();

#endif

    dna.AddPrimitiveStructures();

    dna.RegisterConverters();

}

#if ASSIMP_BUILD_BLENDER_DEBUG_DNA

#include <fstream>

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

void DNA ::DumpToFile() {

    // we don't bother using the VFS here for this is only for debugging.

    // (and all your bases are belong to us).

    std::ofstream f("dna.txt");

    if (f.fail()) {

        ASSIMP_LOG_ERROR("Could not dump dna to dna.txt");

        return;

    }

    f << "Field format: type name offset size"

      << "\n";

    f << "Structure format: name size"

      << "\n";

    for (const Structure &s : structures) {

        f << s.name << " " << s.size << "\n\n";

        for (const Field &ff : s.fields) {

            f << "\t" << ff.type << " " << ff.name << " " << ff.offset << " " << ff.size << "\n";

        }

        f << "\n";

    }

    f << std::flush;

    ASSIMP_LOG_INFO("BlenderDNA: Dumped dna to dna.txt");

}

#endif // ASSIMP_BUILD_BLENDER_DEBUG_DNA

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

/*static*/ void DNA ::ExtractArraySize(

        const std::string &out,

        size_t array_sizes[2]) {

    array_sizes[0] = array_sizes[1] = 1;

    std::string::size_type pos = out.find('[');

    if (pos++ == std::string::npos) {

        return;

    }

    array_sizes[0] = strtoul10(&out[pos]);

    pos = out.find('[', pos);

    if (pos++ == std::string::npos) {

        return;

    }

    array_sizes[1] = strtoul10(&out[pos]);

}

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

std::shared_ptr<ElemBase> DNA ::ConvertBlobToStructure(

        const Structure &structure,

        const FileDatabase &db) const {

    std::map<std::string, FactoryPair>::const_iterator it = converters.find(structure.name);

    if (it == converters.end()) {

        return std::shared_ptr<ElemBase>();

    }

    std::shared_ptr<ElemBase> ret = (structure.*((*it).second.first))();

    (structure.*((*it).second.second))(ret, db);

    return ret;

}

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

DNA::FactoryPair DNA ::GetBlobToStructureConverter(

        const Structure &structure,

        const FileDatabase & /*db*/

) const {

    std::map<std::string, FactoryPair>::const_iterator it = converters.find(structure.name);

    return it == converters.end() ? FactoryPair() : (*it).second;

}

// basing on http://www.blender.org/development/architecture/notes-on-sdna/

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

void DNA ::AddPrimitiveStructures() {

    // NOTE: these are just dummies. Their presence enforces

    // Structure::Convert<target_type> to be called on these

    // empty structures. These converters are special

    // overloads which scan the name of the structure and

    // perform the required data type conversion if one

    // of these special names is found in the structure

    // in question.

    indices["int"] = structures.size();

    structures.push_back(Structure());

    structures.back().name = "int";

    structures.back().size = 4;

    indices["short"] = structures.size();

    structures.push_back(Structure());

    structures.back().name = "short";

    structures.back().size = 2;

    indices["char"] = structures.size();

    structures.push_back(Structure());

    structures.back().name = "char";

    structures.back().size = 1;

    indices["float"] = structures.size();

    structures.push_back(Structure());

    structures.back().name = "float";

    structures.back().size = 4;

    indices["double"] = structures.size();

    structures.push_back(Structure());

    structures.back().name = "double";

    structures.back().size = 8;

    // no long, seemingly.

}

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

void SectionParser ::Next() {

    stream.SetCurrentPos(current.start + current.size);

    const char tmp[] = {

        (char)stream.GetI1(),

        (char)stream.GetI1(),

        (char)stream.GetI1(),

        (char)stream.GetI1()

    };

    current.id = std::string(tmp, tmp[3] ? 4 : tmp[2] ? 3 : tmp[1] ? 2 : 1);

    current.size = stream.GetI4();

    current.address.val = ptr64 ? stream.GetU8() : stream.GetU4();

    current.dna_index = stream.GetI4();

    current.num = stream.GetI4();

    current.start = stream.GetCurrentPos();

    if (stream.GetRemainingSizeToLimit() < current.size) {

        throw DeadlyImportError("BLEND: invalid size of file block");

    }

#ifdef ASSIMP_BUILD_BLENDER_DEBUG

    ASSIMP_LOG_VERBOSE_DEBUG(current.id);

#endif

}

#endif