#include <foundation/platform.h>
#include <foundation/types.h>
#include <trace/detail/data.h>

//------------------------------------------------------------------------------
#ifdef _WIN32

DataSource::DataSource(const Path& path)
{
    HANDLE handle = CreateFileW(path.c_str(), GENERIC_READ, FILE_SHARE_READ,
        nullptr, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, nullptr);
    if (handle == INVALID_HANDLE_VALUE)
        throw std::runtime_error("Failed to open file");

    _handle = uintptr(handle);
}

DataSource::~DataSource()
{
    auto handle = HANDLE(_handle);
    CloseHandle(handle);
}

int32 DataSource::read(void* out, uint32 size)
{
    auto handle = HANDLE(_handle);

    DWORD bytes_read;
    if (!ReadFile(handle, out, size, &bytes_read, nullptr))
        throw std::runtime_error("Read error");

    return bytes_read;
}

int64 DataSource::get_size() const
{
    if (_size >= 0)
        return _size;

    auto handle = HANDLE(_handle);

    LARGE_INTEGER out;
    GetFileSizeEx(handle, &out);
    return _size = out.QuadPart;
}

#else // POSIX

DataSource::DataSource(const Path& path)
{
    int fd = ::open(path.string().c_str(), O_RDONLY);
    if (fd < 0)
        throw std::runtime_error("Failed to open file");

    _handle = uintptr(fd);
}

DataSource::~DataSource()
{
    ::close(int(_handle));
}

int32 DataSource::read(void* out, uint32 size)
{
    ssize_t bytes_read = ::read(int(_handle), out, size);
    if (bytes_read < 0)
        throw std::runtime_error("Read error");

    return int32(bytes_read);
}

int64 DataSource::get_size() const
{
    if (_size >= 0)
        return _size;

    struct stat st;
    if (fstat(int(_handle), &st) < 0)
        return _size = 0;

    return _size = st.st_size;
}

#endif



//------------------------------------------------------------------------------
DataStream::DataStream(DataSource& data_source, Allocator& allocator)
: _data_source(data_source)
, _allocator(allocator)
{
}

//------------------------------------------------------------------------------
uint64 DataStream::tell() const
{
    return _position;
}

//------------------------------------------------------------------------------
uint32 DataStream::get_available() const
{
    return _stream.get_remaining();
}

//------------------------------------------------------------------------------
Buffer DataStream::read(uint32 size)
{
    const uint8* ptr = _read(size);
    return _buffer.create_sub_buffer(ptr, size);
}

//------------------------------------------------------------------------------
const uint8* DataStream::_read(uint32 size)
{
    _position += size;

    if (_stream.get_remaining() >= size)
        return _stream.read(size);

    MutableBuffer buffer = _allocator.create_buffer(BUFFER_SIZE);
    uint8* cursor = buffer.get_pointer();
    uint32 buffer_size = buffer.get_size();

    if (uint32 remaining = _stream.get_remaining())
    {
        const void* src = _stream.read(remaining);
        std::memcpy(cursor, src, remaining);
        cursor += remaining;
        buffer_size -= remaining;
    }

    uint32 read_size = 0;
    while (true)
    {
        int32 i = _data_source.read(cursor + read_size, buffer_size - read_size);
        if (i <= 0)
            throw Eof();

        if ((read_size += i) >= size)
            break;
    }

    if (read_size < buffer_size)
    {
        buffer_size = BUFFER_SIZE - buffer_size + read_size;
        _buffer = buffer.create_sub_buffer(0u, buffer_size);
    }
    else
        _buffer = std::move(buffer);

    _stream = _buffer.create_stream();

    return _stream.read(size);
}

//------------------------------------------------------------------------------
template <>  int8  DataStream::read< int8 >() { return *( int8 *)_read(sizeof( int8 )); }
template <>  int16 DataStream::read< int16>() { return *( int16*)_read(sizeof( int16)); }
template <>  int32 DataStream::read< int32>() { return *( int32*)_read(sizeof( int32)); }
template <>  int64 DataStream::read< int64>() { return *( int64*)_read(sizeof( int64)); }
template <> uint8  DataStream::read<uint8 >() { return *(uint8 *)_read(sizeof(uint8 )); }
template <> uint16 DataStream::read<uint16>() { return *(uint16*)_read(sizeof(uint16)); }
template <> uint32 DataStream::read<uint32>() { return *(uint32*)_read(sizeof(uint32)); }
template <> uint64 DataStream::read<uint64>() { return *(uint64*)_read(sizeof(uint64)); }