// slang-platform.cpp

#define _CRT_SECURE_NO_WARNINGS

#include "slang-platform.h"

#include "slang-common.h"
#include "slang-io.h"

#ifdef _WIN32
	#include <windows.h>
#else
	#include "slang-string.h"
	#include <dlfcn.h>
#endif

namespace Slang
{
	// SharedLibrary

/* static */SlangResult SharedLibrary::load(const char* path, SharedLibrary::Handle& handleOut)
{
    StringBuilder builder;
    calcPlatformPath(UnownedStringSlice(path), builder);
    return loadWithPlatformPath(builder.begin(), handleOut);
}

/* static */void SharedLibrary::calcPlatformPath(const UnownedStringSlice& path, StringBuilder& outPath)
{
    // Work out the shared library name
    String parent = Path::getParentDirectory(path);
    String filename = Path::getFileName(path);

    if (parent.getLength() > 0)
    {
        // Work out the filename platform name (as in add .dll say on windows)
        StringBuilder platformFileNameBuilder;
        SharedLibrary::appendPlatformFileName(filename.getUnownedSlice(), platformFileNameBuilder);

        Path::combineIntoBuilder(parent.getUnownedSlice(), platformFileNameBuilder.getUnownedSlice(), outPath);
    }
    else if (filename.getLength() > 0)
    {     
        appendPlatformFileName(filename.getUnownedSlice(), outPath);
    }
}

/* static */String SharedLibrary::calcPlatformPath(const UnownedStringSlice& path)
{
    StringBuilder builder;
    calcPlatformPath(path, builder);
    return builder.toString();
}

#ifdef _WIN32

// Make sure SlangResult match for common standard window HRESULT
SLANG_COMPILE_TIME_ASSERT(E_FAIL == SLANG_FAIL);
SLANG_COMPILE_TIME_ASSERT(E_NOINTERFACE == SLANG_E_NO_INTERFACE);
SLANG_COMPILE_TIME_ASSERT(E_HANDLE == SLANG_E_INVALID_HANDLE);
SLANG_COMPILE_TIME_ASSERT(E_NOTIMPL == SLANG_E_NOT_IMPLEMENTED);
SLANG_COMPILE_TIME_ASSERT(E_INVALIDARG == SLANG_E_INVALID_ARG);
SLANG_COMPILE_TIME_ASSERT(E_OUTOFMEMORY == SLANG_E_OUT_OF_MEMORY);

/* static */SlangResult PlatformUtil::getInstancePath(StringBuilder& out)
{
    wchar_t path[_MAX_PATH];
    ::GetModuleFileName(::GetModuleHandle(NULL), path, SLANG_COUNT_OF(path));
    String pathString = String::fromWString(path);

    // We don't want the instance name, just the path to it
    out.clear();
    out.append(Path::getParentDirectory(pathString));

    return out.getLength() > 0 ? SLANG_OK : SLANG_FAIL;
}

/* static */SlangResult PlatformUtil::appendResult(SlangResult res, StringBuilder& builderOut)
{
    if (SLANG_FAILED(res) && res != SLANG_FAIL)
    {
        LPWSTR buffer = nullptr;
        FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_ALLOCATE_BUFFER,
            nullptr,
            res,
            MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
            (LPWSTR)&buffer,
            0,
            nullptr);

        if (buffer)
        {
            builderOut << " ";
            // Convert to string
            builderOut.append(String::fromWString(buffer));
            LocalFree(buffer);
            return SLANG_OK;
        }
    }
    return SLANG_FAIL;
}

/* static */SlangResult SharedLibrary::loadWithPlatformPath(char const* platformFileName, SharedLibrary::Handle& handleOut)
{
    handleOut = nullptr;
    if (!platformFileName || strlen(platformFileName) == 0)
    {
        if (!GetModuleHandleExA(0, nullptr, (HMODULE*)&handleOut))
            return SLANG_FAIL;
        return SLANG_OK;
    }

    // https://docs.microsoft.com/en-us/windows/desktop/api/libloaderapi/nf-libloaderapi-loadlibrarya
    const HMODULE h = LoadLibraryA(platformFileName);
    if (!h)
    {
        const DWORD lastError = GetLastError();
        switch (lastError)
        {
            case ERROR_MOD_NOT_FOUND:
            case ERROR_PATH_NOT_FOUND:
            case ERROR_FILE_NOT_FOUND:  
            {
                return SLANG_E_NOT_FOUND;
            }
            case ERROR_INVALID_ACCESS:
            case ERROR_ACCESS_DENIED: 
            case ERROR_INVALID_DATA:
            {
                return SLANG_E_CANNOT_OPEN;
            }
            default: break;
        }
        // Turn to Result, if not one of the well known errors
        return HRESULT_FROM_WIN32(lastError);
    }
    handleOut = (Handle)h;
    return SLANG_OK;
}

/* static */void SharedLibrary::unload(Handle handle)
{
    SLANG_ASSERT(handle);
    ::FreeLibrary((HMODULE)handle);
}

/* static */ void* SharedLibrary::findSymbolAddressByName(Handle handle, char const* name)
{
    SLANG_ASSERT(handle);
    return GetProcAddress((HMODULE)handle, name);
}

/* static */void SharedLibrary::appendPlatformFileName(const UnownedStringSlice& name, StringBuilder& dst)
{
    dst.append(name);
    dst.append(".dll");
}

#else // _WIN32

/* static */SlangResult PlatformUtil::getInstancePath([[maybe_unused]] StringBuilder& out)
{
    // On non Windows it's typically hard to get the instance path, so we'll say not implemented.
    // The meaning is also somewhat more ambiguous - is it the exe or the shared library path?
    return SLANG_E_NOT_IMPLEMENTED;
}

/* static */SlangResult PlatformUtil::appendResult([[maybe_unused]] SlangResult res, [[maybe_unused]] StringBuilder& builderOut)
{
    return SLANG_E_NOT_IMPLEMENTED;
}

/* static */SlangResult SharedLibrary::loadWithPlatformPath(char const* platformFileName, Handle& handleOut)
{
    handleOut = nullptr;
    // Work around
    // https://github.com/microsoft/DirectXShaderCompiler/issues/5119 and
    // https://github.com/doitsujin/dxvk/issues/3330
    // libdxcompiler.so invokes UB on dlclose, the dxvk libs break GDB when
    // closed
    const auto unclosableLibNames = {"libdxcompiler", "libdxvk_d3d11", "libdxvk_dxgi"};
    bool isUnclosable = false;
    for(auto n : unclosableLibNames)
    {
        if(strncmp(platformFileName, n, strlen(n)) == 0)
        {
            isUnclosable = true;
            break;
        }
    }
    if (strlen(platformFileName) == 0)
        platformFileName = nullptr;
    const auto mode = RTLD_NOW | RTLD_GLOBAL | (isUnclosable ? RTLD_NODELETE : 0);
    void *h = dlopen(platformFileName, mode);
    if (!h)
    {
#if 0
        // We can't output the error message here, because it will cause output when testing what code gen is available
		if(auto msg = dlerror())
		{
			fprintf(stderr, "error: %s\n", msg);
		}
#endif
        return SLANG_FAIL;
	}
    handleOut = (Handle)h;
    return SLANG_OK;
}

/* static */void SharedLibrary::unload(Handle handle)
{    
    SLANG_ASSERT(handle);
	dlclose(handle);
}

/* static */void* SharedLibrary::findSymbolAddressByName(Handle handle, char const* name)
{
	return dlsym((void*)handle, name);
}

/* static */void SharedLibrary::appendPlatformFileName(const UnownedStringSlice& name, StringBuilder& dst)
{
#if __CYGWIN__
    dst.append(name);
    dst.append(".dll");
#elif SLANG_APPLE_FAMILY
    dst.append("lib");
    dst.append(name);
    dst.append(".dylib");
#elif SLANG_LINUX_FAMILY
    if (!name.startsWith("lib"))
        dst.append("lib");
    dst.append(name);
    if (name.indexOf(UnownedStringSlice(".so.")) == -1)
        dst.append(".so");
#else
    // Just guess we can do with the name on it's own
    dst.append(name);
#endif
}

#endif // _WIN32


/* static */SlangResult PlatformUtil::getEnvironmentVariable(const UnownedStringSlice& name, StringBuilder& out)
{
    const char* value = getenv(String(name).getBuffer());
    if (value)
    {
        out.append(value);
        return SLANG_OK;
    }
    return SLANG_E_NOT_FOUND;
}

/* static */PlatformKind PlatformUtil::getPlatformKind()
{
#if SLANG_WINRT
    return PlatformKind::WinRT;
#elif SLANG_XBOXONE
    return PlatformKind::XBoxOne;
#elif SLANG_WIN64
    return PlatformKind::Win64;
#elif SLANG_X360
    return PlatformKind::X360;
#elif SLANG_WIN32
    return PlatformKind::Win32;
#elif SLANG_ANDROID
    return PlatformKind::Android;
#elif SLANG_LINUX
    return PlatformKind::Linux;
#elif SLANG_IOS
    return PlatformKind::IOS;
#elif SLANG_OSX
    return PlatformKind::OSX;
#elif SLANG_PS3
    return PlatformKind::PS3;
#elif SLANG_SLANG_PS4
    return PlatformKind::PS4;
#elif SLANG_PSP2
    return PlatformKind::PSP2;
#elif SLANG_WIIU
    return PlatformKind::WIIU;
#else
    return PlatformKind::Unknown;
#endif
}

static const PlatformFlags s_familyFlags[int(PlatformFamily::CountOf)] =
{
    0,                                                                                                                  // Unknown
    PlatformFlag::WinRT | PlatformFlag::Win32 | PlatformFlag::Win64,                                                    // Windows
    PlatformFlag::WinRT | PlatformFlag::Win32 | PlatformFlag::Win64 | PlatformFlag::X360 | PlatformFlag::XBoxOne,       // Microsoft
    PlatformFlag::Linux | PlatformFlag::Android,                                                                        // Linux
    PlatformFlag::IOS | PlatformFlag::OSX,                                                                              // Apple
    PlatformFlag::Linux | PlatformFlag::Android | PlatformFlag::IOS | PlatformFlag::OSX,                                // Unix
};

/* static */PlatformFlags PlatformUtil::getPlatformFlags(PlatformFamily family)
{
    return s_familyFlags[int(family)];
}

/* static */SlangResult PlatformUtil::outputDebugMessage([[maybe_unused]] const char* text)
{
#ifdef _WIN32
    OutputDebugStringA(text);
    return SLANG_OK;
#else
    return SLANG_E_NOT_AVAILABLE;
#endif
}

}