# setup-msvc.ps1
# Runs vcvarsall.bat and exports only the new/changed environment
# variables to GitHub Actions, avoiding clobbering existing ones.

param(
    [string]$Arch = "x64"
)

# Find VS installation
$vsWhere = "C:\Program Files (x86)\Microsoft Visual Studio\Installer\vswhere.exe"
$vsPath  = & $vsWhere -latest -property installationPath
$vcvars  = Join-Path $vsPath "VC\Auxiliary\Build\vcvarsall.bat"

if (-not (Test-Path $vcvars)) {
    Write-Error "vcvarsall.bat not found at: $vcvars"
    exit 1
}

# Snapshot environment before
$before = @{}
Get-ChildItem env: | ForEach-Object { $before[$_.Name] = $_.Value }

# Run vcvarsall.bat and import its environment into this process
cmd /c "`"$vcvars`" $Arch && set" | ForEach-Object {
    if ($_ -match '^([^=]+)=(.*)$') {
        [System.Environment]::SetEnvironmentVariable($Matches[1], $Matches[2])
    }
}

# Export only changed/new variables to GitHub Actions
$count = 0
Get-ChildItem env: | ForEach-Object {
    if ($before[$_.Name] -ne $_.Value) {
        "$($_.Name)=$($_.Value)" | Out-File -Append -Encoding utf8 $env:GITHUB_ENV
        $count++
    }
}

Write-Host "Exported $count environment variables to GITHUB_ENV"