/*
Open Asset Import Library (assimp)
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  following disclaimer.

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*/

/** @file  ZipArchiveIOSystem.cpp
 *  @brief Zip File I/O implementation for #Importer
 */

#include <assimp/BaseImporter.h>
#include <assimp/ZipArchiveIOSystem.h>

#include <assimp/ai_assert.h>

#include <map>
#include <memory>

#ifdef ASSIMP_USE_HUNTER
#    include <minizip/unzip.h>
#else
#    include <unzip.h>
#endif

namespace Assimp {

// ----------------------------------------------------------------
// A read-only file inside a ZIP

class ZipFile : public IOStream {
    friend class ZipFileInfo;
    explicit ZipFile(std::string &filename, size_t size);

public:
    std::string m_Filename;
    virtual ~ZipFile() override;

    // IOStream interface
    size_t Read(void *pvBuffer, size_t pSize, size_t pCount) override;
    size_t Write(const void * /*pvBuffer*/, size_t /*pSize*/, size_t /*pCount*/) override { return 0; }
    size_t FileSize() const override;
    aiReturn Seek(size_t pOffset, aiOrigin pOrigin) override;
    size_t Tell() const override;
    void Flush() override {}

private:
    size_t m_Size = 0;
    size_t m_SeekPtr = 0;
    std::unique_ptr<uint8_t[]> m_Buffer;
};


// ----------------------------------------------------------------
// Wraps an existing Assimp::IOSystem for unzip
class IOSystem2Unzip {
public:
    static voidpf open(voidpf opaque, const char *filename, int mode);
    static voidpf opendisk(voidpf opaque, voidpf stream, uint32_t number_disk, int mode);
    static uLong read(voidpf opaque, voidpf stream, void *buf, uLong size);
    static uLong write(voidpf opaque, voidpf stream, const void *buf, uLong size);
    static long tell(voidpf opaque, voidpf stream);
    static long seek(voidpf opaque, voidpf stream, uLong offset, int origin);
    static int close(voidpf opaque, voidpf stream);
    static int testerror(voidpf opaque, voidpf stream);
    static zlib_filefunc_def get(IOSystem *pIOHandler);
};

voidpf IOSystem2Unzip::open(voidpf opaque, const char *filename, int mode) {
    IOSystem *io_system = reinterpret_cast<IOSystem *>(opaque);

    const char *mode_fopen = nullptr;
    if ((mode & ZLIB_FILEFUNC_MODE_READWRITEFILTER) == ZLIB_FILEFUNC_MODE_READ) {
        mode_fopen = "rb";
    } else {
        if (mode & ZLIB_FILEFUNC_MODE_EXISTING) {
            mode_fopen = "r+b";
        } else {
            if (mode & ZLIB_FILEFUNC_MODE_CREATE) {
                mode_fopen = "wb";
            }
        }
    }

    return (voidpf)io_system->Open(filename, mode_fopen);
}

voidpf IOSystem2Unzip::opendisk(voidpf opaque, voidpf stream, uint32_t number_disk, int mode) {
    ZipFile *io_stream = (ZipFile *)stream;
    voidpf ret = nullptr;
    int i;

    char *disk_filename = (char*)malloc(io_stream->m_Filename.length() + 1);
    strncpy(disk_filename, io_stream->m_Filename.c_str(), io_stream->m_Filename.length() + 1);
    for (i = (int)io_stream->m_Filename.length() - 1; i >= 0; i -= 1)
    {
        if (disk_filename[i] != '.')
            continue;
        snprintf(&disk_filename[i], io_stream->m_Filename.length() - size_t(i), ".z%02u", number_disk + 1);
        break;
    }

    if (i >= 0)
        ret = open(opaque, disk_filename, mode);

    free(disk_filename);
    return ret;
}

uLong IOSystem2Unzip::read(voidpf /*opaque*/, voidpf stream, void *buf, uLong size) {
    IOStream *io_stream = (IOStream *)stream;

    return static_cast<uLong>(io_stream->Read(buf, 1, size));
}

uLong IOSystem2Unzip::write(voidpf /*opaque*/, voidpf stream, const void *buf, uLong size) {
    IOStream *io_stream = (IOStream *)stream;

    return static_cast<uLong>(io_stream->Write(buf, 1, size));
}

long IOSystem2Unzip::tell(voidpf /*opaque*/, voidpf stream) {
    IOStream *io_stream = (IOStream *)stream;

    return static_cast<long>(io_stream->Tell());
}

long IOSystem2Unzip::seek(voidpf /*opaque*/, voidpf stream, uLong offset, int origin) {
    IOStream *io_stream = (IOStream *)stream;

    aiOrigin assimp_origin;
    switch (origin) {
        default:
        case ZLIB_FILEFUNC_SEEK_CUR:
            assimp_origin = aiOrigin_CUR;
            break;
        case ZLIB_FILEFUNC_SEEK_END:
            assimp_origin = aiOrigin_END;
            break;
        case ZLIB_FILEFUNC_SEEK_SET:
            assimp_origin = aiOrigin_SET;
            break;
    }

    return (io_stream->Seek(offset, assimp_origin) == aiReturn_SUCCESS ? 0 : -1);
}

int IOSystem2Unzip::close(voidpf opaque, voidpf stream) {
    IOSystem *io_system = (IOSystem *)opaque;
    IOStream *io_stream = (IOStream *)stream;

    io_system->Close(io_stream);

    return 0;
}

int IOSystem2Unzip::testerror(voidpf /*opaque*/, voidpf /*stream*/) {
    return 0;
}

zlib_filefunc_def IOSystem2Unzip::get(IOSystem *pIOHandler) {
    zlib_filefunc_def mapping;

    mapping.zopen_file = (open_file_func)open;
#ifdef _UNZ_H
    mapping.zopendisk_file = (opendisk_file_func)opendisk;
#endif
    mapping.zread_file = (read_file_func)read;
    mapping.zwrite_file = (write_file_func)write;
    mapping.ztell_file = (tell_file_func)tell;
    mapping.zseek_file = (seek_file_func)seek;
    mapping.zclose_file = (close_file_func)close;
    mapping.zerror_file = testerror;

    mapping.opaque = reinterpret_cast<voidpf>(pIOHandler);

    return mapping;
}

// ----------------------------------------------------------------
// Info about a read-only file inside a ZIP
class ZipFileInfo {
public:
    explicit ZipFileInfo(unzFile zip_handle, size_t size);

    // Allocate and Extract data from the ZIP
    ZipFile *Extract(std::string &filename, unzFile zip_handle) const;

private:
    size_t m_Size = 0;
    unz_file_pos_s m_ZipFilePos;
};

ZipFileInfo::ZipFileInfo(unzFile zip_handle, size_t size) :
        m_Size(size) {
    ai_assert(m_Size != 0);
    // Workaround for MSVC 2013 - C2797
    m_ZipFilePos.num_of_file = 0;
    m_ZipFilePos.pos_in_zip_directory = 0;
    unzGetFilePos(zip_handle, &(m_ZipFilePos));
}

ZipFile *ZipFileInfo::Extract(std::string &filename, unzFile zip_handle) const {
    // Find in the ZIP. This cannot fail
    unz_file_pos_s *filepos = const_cast<unz_file_pos_s *>(&(m_ZipFilePos));
    if (unzGoToFilePos(zip_handle, filepos) != UNZ_OK)
        return nullptr;

    if (unzOpenCurrentFile(zip_handle) != UNZ_OK)
        return nullptr;

    ZipFile *zip_file = new ZipFile(filename, m_Size);

    // Unzip has a limit of UINT16_MAX bytes buffer
    uint16_t unzipBufferSize = zip_file->m_Size <= UINT16_MAX ? static_cast<uint16_t>(zip_file->m_Size) : UINT16_MAX;
    std::unique_ptr<uint8_t[]> unzipBuffer = std::unique_ptr<uint8_t[]>(new uint8_t[unzipBufferSize]);
    size_t readCount = 0;
    while (readCount < zip_file->m_Size)
    {
        size_t bufferSize = zip_file->m_Size - readCount;
        if (bufferSize > UINT16_MAX) {
            bufferSize = UINT16_MAX;
        }

        int ret = unzReadCurrentFile(zip_handle, unzipBuffer.get(), static_cast<unsigned int>(bufferSize));
        if (ret != static_cast<int>(bufferSize))
        {
            // Failed, release the memory
            delete zip_file;
            zip_file = nullptr;
            break;
        }

        std::memcpy(zip_file->m_Buffer.get() + readCount, unzipBuffer.get(), ret);
        readCount += ret;
    }

    ai_assert(unzCloseCurrentFile(zip_handle) == UNZ_OK);
    return zip_file;
}

ZipFile::ZipFile(std::string &filename, size_t size) :
        m_Filename(filename), m_Size(size) {
    ai_assert(m_Size != 0);
    m_Buffer = std::unique_ptr<uint8_t[]>(new uint8_t[m_Size]);
}

ZipFile::~ZipFile() = default;

size_t ZipFile::Read(void *pvBuffer, size_t pSize, size_t pCount) {
    // Should be impossible
    ai_assert(m_Buffer != nullptr);
    ai_assert(nullptr != pvBuffer);
    ai_assert(0 != pSize);
    ai_assert(0 != pCount);

    // Clip down to file size
    size_t byteSize = pSize * pCount;
    if ((byteSize + m_SeekPtr) > m_Size) {
        pCount = (m_Size - m_SeekPtr) / pSize;
        byteSize = pSize * pCount;
        if (byteSize == 0) {
            return 0;
        }
    }

    std::memcpy(pvBuffer, m_Buffer.get() + m_SeekPtr, byteSize);

    m_SeekPtr += byteSize;

    return pCount;
}

size_t ZipFile::FileSize() const {
    return m_Size;
}

aiReturn ZipFile::Seek(size_t pOffset, aiOrigin pOrigin) {
    switch (pOrigin) {
        case aiOrigin_SET: {
            if (pOffset > m_Size) return aiReturn_FAILURE;
            m_SeekPtr = pOffset;
            return aiReturn_SUCCESS;
        }

        case aiOrigin_CUR: {
            if ((pOffset + m_SeekPtr) > m_Size) return aiReturn_FAILURE;
            m_SeekPtr += pOffset;
            return aiReturn_SUCCESS;
        }

        case aiOrigin_END: {
            if (pOffset > m_Size) return aiReturn_FAILURE;
            m_SeekPtr = m_Size - pOffset;
            return aiReturn_SUCCESS;
        }
        default:;
    }

    return aiReturn_FAILURE;
}

size_t ZipFile::Tell() const {
    return m_SeekPtr;
}

// ----------------------------------------------------------------
// pImpl of the Zip Archive IO
class ZipArchiveIOSystem::Implement {
public:
    static const unsigned int FileNameSize = 256;

    Implement(IOSystem *pIOHandler, const char *pFilename, const char *pMode);
    ~Implement();

    bool isOpen() const;
    void getFileList(std::vector<std::string> &rFileList);
    void getFileListExtension(std::vector<std::string> &rFileList, const std::string &extension);
    bool Exists(std::string &filename);
    IOStream *OpenFile(std::string &filename);

    static void SimplifyFilename(std::string &filename);

private:
    void MapArchive();

private:
    typedef std::map<std::string, ZipFileInfo> ZipFileInfoMap;

    unzFile m_ZipFileHandle = nullptr;
    ZipFileInfoMap m_ArchiveMap;
};

ZipArchiveIOSystem::Implement::Implement(IOSystem *pIOHandler, const char *pFilename, const char *pMode) {
    ai_assert(strcmp(pMode, "r") == 0);
    ai_assert(pFilename != nullptr);
    if (pFilename[0] == 0 || nullptr == pMode) {
        return;
    }

    zlib_filefunc_def mapping = IOSystem2Unzip::get(pIOHandler);
    m_ZipFileHandle = unzOpen2(pFilename, &mapping);
}

ZipArchiveIOSystem::Implement::~Implement() {
    if (m_ZipFileHandle != nullptr) {
        unzClose(m_ZipFileHandle);
    }
}

void ZipArchiveIOSystem::Implement::MapArchive() {
    if (m_ZipFileHandle == nullptr)
        return;

    if (!m_ArchiveMap.empty())
        return;

    //  At first ensure file is already open
    if (unzGoToFirstFile(m_ZipFileHandle) != UNZ_OK)
        return;

    // Loop over all files
    do {
        char filename[FileNameSize];
        unz_file_info fileInfo;

        if (unzGetCurrentFileInfo(m_ZipFileHandle, &fileInfo, filename, FileNameSize, nullptr, 0, nullptr, 0) == UNZ_OK) {
            if (fileInfo.uncompressed_size != 0 && fileInfo.size_filename <= FileNameSize) {
                std::string filename_string(filename, fileInfo.size_filename);
                SimplifyFilename(filename_string);
                m_ArchiveMap.emplace(filename_string, ZipFileInfo(m_ZipFileHandle, fileInfo.uncompressed_size));
            }
        }
    } while (unzGoToNextFile(m_ZipFileHandle) != UNZ_END_OF_LIST_OF_FILE);
}

bool ZipArchiveIOSystem::Implement::isOpen() const {
    return (m_ZipFileHandle != nullptr);
}

void ZipArchiveIOSystem::Implement::getFileList(std::vector<std::string> &rFileList) {
    MapArchive();
    rFileList.clear();

    for (const auto &file : m_ArchiveMap) {
        rFileList.push_back(file.first);
    }
}

void ZipArchiveIOSystem::Implement::getFileListExtension(std::vector<std::string> &rFileList, const std::string &extension) {
    MapArchive();
    rFileList.clear();

    for (const auto &file : m_ArchiveMap) {
        if (extension == BaseImporter::GetExtension(file.first))
            rFileList.push_back(file.first);
    }
}

bool ZipArchiveIOSystem::Implement::Exists(std::string &filename) {
    MapArchive();

    ZipFileInfoMap::const_iterator it = m_ArchiveMap.find(filename);
    return (it != m_ArchiveMap.end());
}

IOStream *ZipArchiveIOSystem::Implement::OpenFile(std::string &filename) {
    MapArchive();

    SimplifyFilename(filename);

    // Find in the map
    ZipFileInfoMap::const_iterator zip_it = m_ArchiveMap.find(filename);
    if (zip_it == m_ArchiveMap.cend())
        return nullptr;

    const ZipFileInfo &zip_file = (*zip_it).second;
    return zip_file.Extract(filename, m_ZipFileHandle);
}

inline void ReplaceAll(std::string &data, const std::string &before, const std::string &after) {
    size_t pos = data.find(before);
    while (pos != std::string::npos) {
        data.replace(pos, before.size(), after);
        pos = data.find(before, pos + after.size());
    }
}

inline void ReplaceAllChar(std::string &data, const char before, const char after) {
    size_t pos = data.find(before);
    while (pos != std::string::npos) {
        data[pos] = after;
        pos = data.find(before, pos + 1);
    }
}

void ZipArchiveIOSystem::Implement::SimplifyFilename(std::string &filename) {
    ReplaceAllChar(filename, '\\', '/');

    // Remove all . and / from the beginning of the path
    size_t pos = filename.find_first_not_of("./");
    if (pos != 0)
        filename.erase(0, pos);

    // Simplify "my/folder/../file.png" constructions, if any
    static const std::string relative("/../");
    const size_t relsize = relative.size() - 1;
    pos = filename.find(relative);
    while (pos != std::string::npos) {
        // Previous slash
        size_t prevpos = filename.rfind('/', pos - 1);
        if (prevpos == pos)
            filename.erase(0, pos + relative.size());
        else
            filename.erase(prevpos, pos + relsize - prevpos);

        pos = filename.find(relative);
    }
}

ZipArchiveIOSystem::ZipArchiveIOSystem(IOSystem *pIOHandler, const char *pFilename, const char *pMode) :
        pImpl(new Implement(pIOHandler, pFilename, pMode)) {
}

// ----------------------------------------------------------------
// The ZipArchiveIO
ZipArchiveIOSystem::ZipArchiveIOSystem(IOSystem *pIOHandler, const std::string &rFilename, const char *pMode) :
        pImpl(new Implement(pIOHandler, rFilename.c_str(), pMode)) {
}

ZipArchiveIOSystem::~ZipArchiveIOSystem() {
    delete pImpl;
}

bool ZipArchiveIOSystem::Exists(const char *pFilename) const {
    ai_assert(pFilename != nullptr);

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

    std::string filename(pFilename);
    return pImpl->Exists(filename);
}

// This is always '/' in a ZIP
char ZipArchiveIOSystem::getOsSeparator() const {
    return '/';
}

// Only supports Reading
IOStream *ZipArchiveIOSystem::Open(const char *pFilename, const char *pMode) {
    ai_assert(pFilename != nullptr);

    for (size_t i = 0; pMode[i] != 0; ++i) {
        ai_assert(pMode[i] != 'w');
        if (pMode[i] == 'w')
            return nullptr;
    }

    std::string filename(pFilename);
    return pImpl->OpenFile(filename);
}

void ZipArchiveIOSystem::Close(IOStream *pFile) {
    delete pFile;
}

bool ZipArchiveIOSystem::isOpen() const {
    return (pImpl->isOpen());
}

void ZipArchiveIOSystem::getFileList(std::vector<std::string> &rFileList) const {
    return pImpl->getFileList(rFileList);
}

void ZipArchiveIOSystem::getFileListExtension(std::vector<std::string> &rFileList, const std::string &extension) const {
    return pImpl->getFileListExtension(rFileList, extension);
}

bool ZipArchiveIOSystem::isZipArchive(IOSystem *pIOHandler, const char *pFilename) {
    Implement tmp(pIOHandler, pFilename, "r");
    return tmp.isOpen();
}

bool ZipArchiveIOSystem::isZipArchive(IOSystem *pIOHandler, const std::string &rFilename) {
    return isZipArchive(pIOHandler, rFilename.c_str());
}

} // namespace Assimp
