@echo off

SET dotnet_releases_url=https://raw.githubusercontent.com/dotnet/core/master/release-notes/releases.json
SET script_path=%~dp0
SET tools_path=%script_path%tools

if [%1]==[help] goto help
if [%1]==[] goto help
if [%1]==[list] goto sdk_list
if [%1]==[latest] goto sdk_latest
if [%1]==[releases] goto sdk_releases
if [%1]==[get] goto sdk_download

for /f %%f in ('dir /b "%programfiles%\dotnet\sdk"') do (
    if %1==%%f goto switch
) 
echo The %1 version of .Net Core SDK was not found 
echo Please, run "dotnet sdk list" to make sure you have it installed in "%programfiles%\dotnet\sdk" 
goto end

:switch
echo Switching .NET Core SDK version to %1
(
echo {
echo   "sdk": {
echo     "version": "%1"
echo   }
echo }
) > global.json
goto end

:sdk_list
echo The installed .NET Core SDKs are:
dir /b "%programfiles%\dotnet\sdk" | find /i "."
goto end

:sdk_latest
if exist global.json del global.json
if exist ..\global.json (
    set /p choice= There's a global.json in your parent directory. Do you want to delete it? (N/y) 
    if /I "%choice%"=="y" (
        del ..\global.json
    ) else (
        SETLOCAL ENABLEDELAYEDEXPANSION
        set dotnetVersion=
        for /f "delims=" %%a in ('dotnet --version') do set dotnetVersion=%%a
        echo .NET Core SDK current version: !dotnetVersion!
        goto end
    )
) 
echo .NET Core SDK version switched to latest version.
dotnet --version

goto end

:help
echo .NET Core SDK Switcher
echo.
echo Usage: .net sdk [command]
echo Usage: .net sdk [version]
echo Usage: .net sdk get [version] [platform]
echo.
echo Commands:
echo   latest      Switches to the latest .NET Core SDK version
echo   list        Lists all installed .NET Core SDKs
echo   releases    Lists all available releases of .NET Core SDKs
echo   get         Downloads the provided release version. ('' or 'latest' for the latest release)
echo   help        Display help
echo.
echo version:
echo   An installed version number of a .NET Core SDK
echo.

goto end

:sdk_releases
echo Releases available for the .NET Core SDK are:
"%tools_path%\curl" %dotnet_releases_url% -H "Accept: application/json" -s | "%tools_path%\jq" "map({date: .date,sdk: .\"version-sdk\"}) | unique_by(.sdk) | .[] | \"\(.date)\t\(.sdk)\" " -r
echo.

goto end

:sdk_download
SETLOCAL
SET version=%2
if [%version%]==[] SET version=latest
if "%version%"=="latest" (
    "%tools_path%\curl" %dotnet_releases_url% -H "Accept: application/json" -s | "%tools_path%\jq" "map({sdk: .\"version-sdk\"}) | unique_by(.sdk) | .[-1] | .sdk " -r > version.dat
    set /p version=<version.dat
)

SET platform=win-x64
if NOT [%3]==[] SET platform=%3
SET platform_id=sdk-%platform%

"%tools_path%\curl" %dotnet_releases_url% -H "Accept: application/json" -s | "%tools_path%\jq" "map({sdk: .\"version-sdk\",url: (.\"blob-sdk\" + (.\"%platform_id%\" | rtrimstr(\".zip\")) + \".exe\"  )}) | unique_by(.sdk)  | .[] | select(.sdk==\"%version%\") | .url " -r > download.dat

SET /p url=<download.dat

echo Downloading .NET Core SDK version %version% for platform %platform%...

echo %url%

SET exe=.\installs\%version%.exe

powershell -Command "(New-Object Net.WebClient).DownloadFile('%url%', '%exe%')"
echo Download completed. If succeeded the installation will start shortly.
start %exe%

ENDLOCAL
goto end

:end