#include "sweepstore/utils/file_handle.h"

// Constructor
SweepstoreFileHandle::SweepstoreFileHandle(const std::string& p, std::ios::openmode mode)
    : path(p)
#ifdef WITH_UNREAL
{
    IPlatformFile& platformFile = FPlatformFileManager::Get().GetPlatformFile();

    // Map std::ios flags to Unreal flags
    bool read = (mode & std::ios::in) != 0;
    bool write = (mode & std::ios::out) != 0;

    if (read && write) {
        unrealHandle = platformFile.OpenReadWrite(*FString(path.c_str()), true);
    } else if (write) {
        unrealHandle = platformFile.OpenWrite(*FString(path.c_str()), false, false);
    } else {
        unrealHandle = platformFile.OpenRead(*FString(path.c_str()), false);
    }

    if (!unrealHandle) {
        throw std::runtime_error("Failed to open file: " + path);
    }
}
#else
    , stream(std::make_unique<std::fstream>(p, mode))
{
    if (!stream->is_open()) {
        throw std::runtime_error("Failed to open file: " + path);
    }
}
#endif

// isOpen
bool SweepstoreFileHandle::isOpen() const {
#ifdef WITH_UNREAL
    return unrealHandle != nullptr;
#else
    return stream && stream->is_open();
#endif
}

// close
void SweepstoreFileHandle::close() {
#ifdef WITH_UNREAL
    if (unrealHandle) {
        delete unrealHandle;
        unrealHandle = nullptr;
    }
#else
    if (stream) {
        stream->close();
    }
#endif
}

// readSeek
void SweepstoreFileHandle::readSeek(std::streampos pos, std::ios::seekdir dir) {
#ifdef WITH_UNREAL
    // Unreal doesn't have separate read/write pointers, so just seek
    int64 unrealPos = static_cast<int64>(pos);
    if (dir == std::ios::beg) {
        unrealHandle->Seek(unrealPos);
    } else if (dir == std::ios::cur) {
        unrealHandle->Seek(unrealHandle->Tell() + unrealPos);
    } else if (dir == std::ios::end) {
        unrealHandle->SeekFromEnd(unrealPos);
    }
#else
    #ifdef _WIN32
        // On Windows, flush and sync to disk, then invalidate buffers
        stream->flush();
        stream->sync();
        stream->clear();
        // Sync both pointers to same position
        stream->seekp(pos, dir);
        stream->seekg(pos, dir);
    #else
        stream->seekg(pos, dir);
    #endif
#endif
}

// writeSeek
void SweepstoreFileHandle::writeSeek(std::streampos pos, std::ios::seekdir dir) {
#ifdef WITH_UNREAL
    // Same as readSeek for Unreal
    readSeek(pos, dir);
#else
    #ifdef _WIN32
        stream->flush();
        stream->sync();
    #endif
    stream->seekp(pos, dir);
#endif
}

// readBytes
void SweepstoreFileHandle::readBytes(char* buffer, std::streamsize size) {
#ifdef WITH_UNREAL
    unrealHandle->Read(reinterpret_cast<uint8*>(buffer), size);
#else
    stream->read(buffer, size);
    #ifdef _WIN32
        // Check for read errors on Windows
        if (stream->fail() && !stream->eof()) {
            stream->clear();
        }
    #endif
#endif
}

// writeBytes
void SweepstoreFileHandle::writeBytes(const char* buffer, std::streamsize size) {
#ifdef WITH_UNREAL
    unrealHandle->Write(reinterpret_cast<const uint8*>(buffer), size);
    unrealHandle->Flush();  // Unreal requires explicit flush
#else
    stream->write(buffer, size);
    #ifdef _WIN32
        // Check for write errors on Windows
        if (stream->fail()) {
            stream->clear();
        }
    #endif
#endif
}