//========= Copyright Valve Corporation ============//
#include <vrcore/sharedlibtools_public.h>
#include <string.h>

#if defined(_WIN32)
#include <windows.h>
#endif

#if defined(POSIX)
#include <dlfcn.h>
#endif

SharedLibHandle SharedLib_Load( const char *pchPath, std::string *pErrStr )
{
	SharedLibHandle pHandle = nullptr;
#if defined( _WIN32)
	// Convert char* to wchar_t* for Unicode Windows API
	int wchars_num = MultiByteToWideChar(CP_UTF8, 0, pchPath, -1, NULL, 0);
	wchar_t* wstr = new wchar_t[wchars_num];
	MultiByteToWideChar(CP_UTF8, 0, pchPath, -1, wstr, wchars_num);
	pHandle = (SharedLibHandle)LoadLibraryExW(wstr, NULL, LOAD_WITH_ALTERED_SEARCH_PATH);
	delete[] wstr;
#elif defined(LINUXARM64)	
	pHandle = (SharedLibHandle) dlopen( pchPath, RTLD_LOCAL|RTLD_DEEPBIND|RTLD_NOW );
#elif defined(POSIX)
	pHandle = (SharedLibHandle) dlopen( pchPath, RTLD_LOCAL|RTLD_NOW );
#endif

	if ( pHandle == nullptr && pErrStr )
	{
#if defined( _WIN32)
		// TODO: Consider using FormatMessage to get an error string for this error code
		*pErrStr =  std::to_string( GetLastError() );
#elif defined(POSIX)
		char * pErr = dlerror();
		if ( pErr )
		{
			*pErrStr = std::string ( pErr );
		}
#endif
	}

	return pHandle;
}

void *SharedLib_GetFunction( SharedLibHandle lib, const char *pchFunctionName)
{
#if defined( _WIN32)
	return (void*)GetProcAddress( (HMODULE)lib, pchFunctionName );
#elif defined(POSIX)
	return dlsym( lib, pchFunctionName );
#endif
}


void SharedLib_Unload( SharedLibHandle lib )
{
	if ( !lib )
		return;
#if defined( _WIN32)
	FreeLibrary( (HMODULE)lib );
#elif defined(POSIX)
	dlclose( lib );
#endif
}