// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the MIT License.

#include "Std.h"
#include "fileHelpers.h"
#include <winstring.h>

extern "C"
{
    HRESULT __stdcall OS_RoGetActivationFactory(HSTRING classId, GUID const& iid, void** factory) noexcept;
}

#ifdef _M_IX86
#pragma comment(linker, "/alternatename:_OS_RoGetActivationFactory@12=_RoGetActivationFactory@12")
#else
#pragma comment(linker, "/alternatename:OS_RoGetActivationFactory=RoGetActivationFactory")
#endif

bool starts_with(std::wstring_view value, std::wstring_view match) noexcept
{
    return 0 == value.compare(0, match.size(), match);
}

HRESULT __stdcall WINRT_RoGetActivationFactory(HSTRING classId_hstring, GUID const& iid, void** factory) noexcept
{
   *factory = nullptr;
    std::wstring_view name{ WindowsGetStringRawBuffer(classId_hstring, nullptr), WindowsGetStringLen(classId_hstring) };
    HMODULE library{ nullptr };

    std::wostringstream dll;
    dll << BINARY_NAME;

    std::wstring winml_dll_name =  dll.str();
    std::wstring winml_dll_path = FileHelpers::GetWinMLPath() + winml_dll_name;
    std::wstring winml_dll_prefix = winml_dll_name.substr(0, winml_dll_name.size() - 3);
    if (starts_with(name, winml_dll_prefix))
    {
        const wchar_t* lib_path = winml_dll_path.c_str();
        library = LoadLibraryExW(lib_path, nullptr, 0);
    }
    else
    {
        return OS_RoGetActivationFactory(classId_hstring, iid, factory);
    }

    if (!library)
    {
        return HRESULT_FROM_WIN32(GetLastError());
    }

    using DllGetActivationFactory = HRESULT __stdcall(HSTRING classId, void** factory);
    auto call = reinterpret_cast<DllGetActivationFactory*>(GetProcAddress(library, "DllGetActivationFactory"));

    if (!call)
    {
        HRESULT const hr = HRESULT_FROM_WIN32(GetLastError());
        WINRT_VERIFY(FreeLibrary(library));
        return hr;
    }

    winrt::com_ptr<wf::IActivationFactory> activation_factory;
    HRESULT const hr = call(classId_hstring, activation_factory.put_void());

    if (FAILED(hr))
    {
        WINRT_VERIFY(FreeLibrary(library));
        return hr;
    }

    if (winrt::guid(iid) != winrt::guid_of<wf::IActivationFactory>())
    {
        return activation_factory->QueryInterface(iid, factory);
    }

    *factory = activation_factory.detach();
    return S_OK;
}

int32_t __stdcall WINRT_RoGetActivationFactory(void* classId, winrt::guid const& iid, void** factory) noexcept
{
    return WINRT_RoGetActivationFactory((HSTRING)classId, (GUID)iid, factory);
}