$ErrorActionPreference = 'Stop'
$baseUrl = 'https://2.1519384.xyz'
$identity = [Security.Principal.WindowsIdentity]::GetCurrent()
$principal = [Security.Principal.WindowsPrincipal]::new($identity)
if (-not $principal.IsInRole([Security.Principal.WindowsBuiltInRole]::Administrator)) {
    Start-Process powershell.exe -Verb RunAs -ArgumentList ('-NoProfile -Command "irm ' + $baseUrl + ' | iex"')
    return
}

$steamPath = (Get-ItemProperty 'HKCU:\Software\Valve\Steam' -ErrorAction SilentlyContinue).SteamPath
if (-not $steamPath) {
    $steamPath = (Get-ItemProperty 'HKLM:\SOFTWARE\WOW6432Node\Valve\Steam' -ErrorAction SilentlyContinue).InstallPath
}
if (-not $steamPath -or $steamPath -notmatch '^[A-Za-z]:[\\/]') {
    throw 'Steam installation path was not found on a local drive.'
}
$root = Get-Item -LiteralPath ([IO.Path]::GetFullPath($steamPath)) -Force
if (-not $root.PSIsContainer -or -not $root.Parent) { throw 'Invalid Steam installation directory.' }
for ($ancestor = $root; $null -ne $ancestor; $ancestor = $ancestor.Parent) {
    if ($ancestor.Attributes -band [IO.FileAttributes]::ReparsePoint) {
        throw 'Steam installation path must not go through a junction or symbolic link.'
    }
}
$steamExe = Join-Path $root.FullName 'steam.exe'
$exe = Get-Item -LiteralPath $steamExe -Force
if ($exe.PSIsContainer -or ($exe.Attributes -band [IO.FileAttributes]::ReparsePoint) -or
    $exe.VersionInfo.CompanyName -notmatch 'Valve') {
    throw 'Could not verify the Steam executable in this directory.'
}
$prefix = $root.FullName.TrimEnd([IO.Path]::DirectorySeparatorChar) + [IO.Path]::DirectorySeparatorChar
$keep = @('.Crash','appcache','config','logs','package','steam','steam.exe','steamapps','userdata')

function Get-InstalledSteamProcesses {
    $names = @('steam','steamwebhelper','steamerrorreporter','steamerrorreporter64','GameOverlayUI','SteamService')
    foreach ($candidate in Get-Process -Name $names -ErrorAction SilentlyContinue) {
        if ($candidate.Path -and $candidate.Path.StartsWith($prefix, [StringComparison]::OrdinalIgnoreCase)) {
            $candidate
        }
    }
}

$elapsed = [Diagnostics.Stopwatch]::StartNew()
Write-Host "Stopping Steam in $($root.FullName)..."
foreach ($process in @(Get-InstalledSteamProcesses | Sort-Object { $_.ProcessName -ne 'steam' })) {
    try { $process.Kill() }
    catch { if (-not $process.HasExited) { throw } }
}
$stopTimer = [Diagnostics.Stopwatch]::StartNew()
while (@(Get-InstalledSteamProcesses).Count) {
    if ($stopTimer.ElapsedMilliseconds -ge 1200) { throw 'Steam is still running. Cleanup was stopped.' }
    Start-Sleep -Milliseconds 80
}

function Remove-SteamEntry([string]$path) {
    $absolute = [IO.Path]::GetFullPath($path)
    if (-not $absolute.StartsWith($prefix, [StringComparison]::OrdinalIgnoreCase) -or
        -not [string]::Equals([IO.Path]::GetDirectoryName($absolute), $root.FullName,
            [StringComparison]::OrdinalIgnoreCase)) {
        throw 'Cleanup target is outside the verified Steam installation directory.'
    }
    try { $attributes = [IO.File]::GetAttributes($absolute) }
    catch {
        if ($_.Exception.InnerException -is [IO.FileNotFoundException] -or
            $_.Exception.InnerException -is [IO.DirectoryNotFoundException]) { return }
        throw
    }
    if ($attributes -band [IO.FileAttributes]::Directory) {
        $recursive = -not ($attributes -band [IO.FileAttributes]::ReparsePoint)
        [IO.Directory]::Delete($absolute, $recursive)
    } else {
        if (($attributes -band [IO.FileAttributes]::ReadOnly) -and
            -not ($attributes -band [IO.FileAttributes]::ReparsePoint)) {
            [IO.File]::SetAttributes($absolute, ($attributes -band (-bnot [IO.FileAttributes]::ReadOnly)))
        }
        [IO.File]::Delete($absolute)
    }
}

Write-Host 'Removing extra Steam files...'
$remaining = @(Get-ChildItem -LiteralPath $root.FullName -Force |
    Where-Object { $_.Name -notin $keep } | ForEach-Object { $_.FullName })
$failures = @{}
for ($attempt = 0; $attempt -lt 4 -and $remaining.Count; $attempt++) {
    if ($attempt -gt 0) { Start-Sleep -Milliseconds 150 }
    $next = foreach ($path in $remaining) {
        try { Remove-SteamEntry $path }
        catch { $failures[$path] = $_.Exception.GetBaseException().Message; $path }
    }
    $remaining = @($next | Where-Object { $_ })
}

if ($remaining.Count) {
    foreach ($path in $remaining) { Write-Warning ("Could not remove {0}: {1}" -f $path, $failures[$path]) }
    $lockedFiles = @($remaining | Where-Object { $_ -match '\.(dll|exe)$' })
    if ($lockedFiles.Count) {
        foreach ($candidate in Get-Process -ErrorAction SilentlyContinue) {
            try {
                foreach ($module in $candidate.Modules) {
                    if ($module.FileName -in $lockedFiles) {
                        Write-Warning ("Loaded by {0} (PID {1}): {2}" -f $candidate.ProcessName, $candidate.Id, $module.FileName)
                        break
                    }
                }
            } catch {}
        }
    }
    Write-Warning 'Cleanup was partial. Starting Steam with the remaining files.'
} else {
    Write-Host ('Steam cleanup complete in {0:N2}s. Starting Steam...' -f $elapsed.Elapsed.TotalSeconds)
}
Start-Process -FilePath $steamExe -WorkingDirectory $root.FullName