install_cuda.bat

@echo off
setlocal EnableExtensions EnableDelayedExpansion

rem =========================================
rem default setting: CUDA 12.8
rem =========================================
set "TARGET_VER=12.8"
set "TARGET_VER_ALT=12.8.0"

rem =========================================
rem Check for admin rights and elevate if necessary
rem =========================================
>nul 2>&1 net session
if not %errorlevel%==0 (
  echo Administratorrechte sind erforderlich
  powershell -NoProfile -Command "Start-Process -Verb RunAs -FilePath '%~f0'"
  exit /b
)

rem =========================================
rem User selection of the desired CUDA version
rem (Default remains 12.8 if Enter is pressed or input is invalid)
rem =========================================
echo.
echo ===============================================
echo  Select CUDA-Version
echo    [1] CUDA 12.8  (Default)
echo    [2] CUDA 12.4
echo    [3] CUDA 12.1
echo ===============================================
echo.
set "USER_SEL="
set /p "USER_SEL=Please enter your selection (1/2/3) [Default: 1] and Enter: "

rem ---- Normalise input (remove spaces/quotation marks)
if not defined USER_SEL set "USER_SEL=1"
set "USER_SEL=%USER_SEL:"=%"
for /f "tokens=1 delims= " %%A in ("%USER_SEL%") do set "USER_SEL=%%A"

rem ---- Optional: map direct version entries to menu numbers
if /I "%USER_SEL%"=="12.8" set "USER_SEL=1"
if /I "%USER_SEL%"=="12.4" set "USER_SEL=2"
if /I "%USER_SEL%"=="12.1" set "USER_SEL=3"

rem ---- Branch selection (without using an else-if cascade)
if "%USER_SEL%"=="1" goto :sel_128
if "%USER_SEL%"=="2" goto :sel_124
if "%USER_SEL%"=="3" goto :sel_121

echo invalid selection "%USER_SEL%". The default (CUDA 12.8) will be used.
goto :sel_128

:sel_128
set "TARGET_VER=12.8"
set "TARGET_VER_ALT=12.8.0"
set "TARGET_LABEL=CUDA 12.8"
goto :after_choice

:sel_124
set "TARGET_VER=12.4"
set "TARGET_VER_ALT=12.4.1"
set "TARGET_LABEL=CUDA 12.4"
goto :after_choice

:sel_121
set "TARGET_VER=12.1"
set "TARGET_VER_ALT=12.1.0"
set "TARGET_LABEL=CUDA 12.1"
goto :after_choice

:after_choice
echo selected version: %TARGET_LABEL%
echo.

rem =========================================
rem Check Winget
rem =========================================
where winget >nul 2>&1
if errorlevel 1 (
  echo Winget was not found. Please install Microsoft App Installer.
  exit /b 1
)

rem Update Winget sources
winget source update >nul 2>&1

set "CUDA_VER="
call :detect_installed_version

if not defined CUDA_VER (
  echo No existing CUDA installation detected.
  goto :install
)

echo Detected CUDA version: !CUDA_VER!
call :compare_versions "!CUDA_VER!" "%TARGET_VER%"

if /I "!COMPARE_RESULT!"=="LT" (
  echo Older CUDA version found. Attempting uninstallation...
  winget uninstall --id NVIDIA.CUDA -e --silent --accept-package-agreements --accept-source-agreements >nul 2>&1
  timeout /t 2 >nul
  goto :install
) else (
  echo Version is equal to or newer than %TARGET_VER%. Nothing will be installed.
  goto :done
)

:install
echo Installation of CUDA %TARGET_VER% via winget is starting
winget install --id Nvidia.CUDA --version %TARGET_VER% -e --silent --accept-package-agreements --accept-source-agreements
if errorlevel 1 (
  echo First installation attempt failed. Fallback via %TARGET_VER_ALT%
  winget install --id Nvidia.CUDA --version %TARGET_VER_ALT% -e --silent --accept-package-agreements --accept-source-agreements
)

:done
echo Process completed.
exit /b 0

rem -------------------------------------------------------------
rem helper functions
rem -------------------------------------------------------------

:detect_installed_version
rem Determines the installed CUDA version EXCLUSIVELY via nvcc
rem If nvcc is not available: do not set a version → proceed with installation.
set "CUDA_VER="
set "REL_PART="
set "REL_CLEAN="

where nvcc >nul 2>&1
if errorlevel 1 (
  rem nvcc not found → no installed version detected
  exit /b 0
)


for /f "usebackq tokens=2 delims=," %%A in (`nvcc --version 2^>nul ^| findstr /i "release"`) do (
  set "REL_PART=%%~A"               rem " release 12.4"
)
if defined REL_PART (
  for /f "tokens=2" %%B in ("!REL_PART!") do (
    set "REL_CLEAN=%%~B"            rem "12.4"
  )
)

if defined REL_CLEAN (
  
  for /f "tokens=1,2 delims=." %%M in ("!REL_CLEAN!") do (
    if "%%N"=="" (
      set "CUDA_VER=%%M.0"
    ) else (
      set "CUDA_VER=%%M.%%N"
    )
  )
)
exit /b 0

:compare_versions
set "COMPARE_RESULT="
set "A=%~1"
set "B=%~2"
for /f "tokens=1,2 delims=." %%a in ("%A%") do (set "A1=%%a"& set "A2=%%b")
for /f "tokens=1,2 delims=." %%a in ("%B%") do (set "B1=%%a"& set "B2=%%b")
if not defined A2 set "A2=0"
if not defined B2 set "B2=0"
set /a MA=A1, MB=B1
if %MA% LSS %MB% (set "COMPARE_RESULT=LT"& exit /b 0)
if %MA% GTR %MB% (set "COMPARE_RESULT=GT"& exit /b 0)
set /a mi=A2, mj=B2
if %mi% LSS %mj% (set "COMPARE_RESULT=LT"& exit /b 0)
if %mi% GTR %mj% (set "COMPARE_RESULT=GT"& exit /b 0)
set "COMPARE_RESULT=EQ"
exit /b 0