[CmdletBinding()]
param()

$ErrorActionPreference = 'Stop'
$WorkDir = [IO.Path]::GetFullPath($PSScriptRoot)
$Standalone = [IO.Path]::GetFullPath((Join-Path $WorkDir '..\..'))
$PluginRoot = [IO.Path]::GetFullPath((Join-Path $Standalone '..'))
$BuildDir = Join-Path $WorkDir 'build'
$OutDir = Join-Path $WorkDir 'bin'
[IO.Directory]::CreateDirectory($BuildDir) | Out-Null
[IO.Directory]::CreateDirectory($OutDir) | Out-Null

$Runner = Get-Process -Id $PID
$Runner.PriorityClass = 'BelowNormal'
$Runner.ProcessorAffinity = [IntPtr]0xFF00
$Affinity = [IntPtr]0xFF00
$VcVars = 'E:\Program Files\Microsoft Visual Studio\2022\Community\VC\Auxiliary\Build\vcvars64.bat'
if (-not (Test-Path -LiteralPath $VcVars -PathType Leaf)) { throw "MSVC environment script missing: $VcVars" }

# Import the exact MSVC environment without running the compiler through an unrestricted shell.
$EnvironmentLines = & $env:ComSpec /d /s /c "call `"$VcVars`" >nul 2>nul && set"
if ($LASTEXITCODE -ne 0) { throw "vcvars64 environment setup failed: $LASTEXITCODE" }
foreach ($Line in $EnvironmentLines) {
    $Equals = $Line.IndexOf('=')
    if ($Equals -le 0) { continue }
    $Name = $Line.Substring(0, $Equals)
    if ($Name.StartsWith('=')) { continue }
    [Environment]::SetEnvironmentVariable($Name, $Line.Substring($Equals + 1), 'Process')
}

$Compiler = Join-Path $env:VCToolsInstallDir 'bin\Hostx64\x64\cl.exe'
if (-not (Test-Path -LiteralPath $Compiler -PathType Leaf)) { throw "MSVC compiler missing: $Compiler" }
$Source = Join-Path $WorkDir 'SharpMesherSpike.cpp'
$CoreInclude = Join-Path $Standalone 'Core\include'
$CoreLibrary = Join-Path $Standalone 'Build\VoxelForgeCore\VoxelForgeCore.lib'
if (-not (Test-Path -LiteralPath $CoreLibrary -PathType Leaf)) { throw "Core library missing: $CoreLibrary" }
$Exe = Join-Path $OutDir 'SharpMesherSpike.exe'
$Obj = Join-Path $BuildDir 'SharpMesherSpike.obj'
$Stdout = Join-Path $WorkDir 'build.stdout.log'
$Stderr = Join-Path $WorkDir 'build.stderr.log'
$CompilerArguments = '/nologo /std:c++20 /O2 /fp:precise /EHsc /MP8 /D_CRT_SECURE_NO_WARNINGS ' +
    ('/I"{0}" /I"{1}" /I"{2}" /Fo"{3}" "{4}" /Fe:"{5}" /link "{6}"' -f `
        (Join-Path $Standalone 'Compat'), `
        (Join-Path $Standalone 'Source\VoxelForge\Public'), $CoreInclude, $Obj, $Source, $Exe, $CoreLibrary)

$Attempt = 0
do {
    $Attempt++
    Remove-Item -LiteralPath $Stdout, $Stderr -Force -ErrorAction SilentlyContinue
    $Info = [Diagnostics.ProcessStartInfo]::new()
    $Info.FileName = $Compiler
    $Info.Arguments = $CompilerArguments
    $Info.WorkingDirectory = $PluginRoot
    $Info.UseShellExecute = $false
    $Info.CreateNoWindow = $true
    $Info.RedirectStandardOutput = $true
    $Info.RedirectStandardError = $true
    $Process = [Diagnostics.Process]::new()
    $Process.StartInfo = $Info
    if (-not $Process.Start()) { throw 'Could not start cl.exe.' }
    $ProcessId = $Process.Id
    $Process.PriorityClass = [Diagnostics.ProcessPriorityClass]::BelowNormal
    $Process.ProcessorAffinity = $Affinity
    $OwnedPids = [Collections.Generic.HashSet[int]]::new()
    [void]$OwnedPids.Add($ProcessId)
    $StartAt = [DateTime]::UtcNow
    $OutputTask = $Process.StandardOutput.ReadToEndAsync()
    $ErrorTask = $Process.StandardError.ReadToEndAsync()
    $TimedOut = $false
    $MemoryStop = $false
    while (-not $Process.HasExited) {
        $Process.Refresh()
        $Processes = @(Get-CimInstance -ClassName Win32_Process -ErrorAction SilentlyContinue)
        $FoundChild = $true
        while ($FoundChild) {
            $FoundChild = $false
            foreach ($Candidate in $Processes) {
                if ($OwnedPids.Contains([int]$Candidate.ParentProcessId) -and
                    $OwnedPids.Add([int]$Candidate.ProcessId)) { $FoundChild = $true }
            }
        }
        foreach ($OwnedPid in $OwnedPids) {
            try {
                $Child = Get-Process -Id $OwnedPid -ErrorAction Stop
                $Child.PriorityClass = 'BelowNormal'
                $Child.ProcessorAffinity = $Affinity
                if ($Child.PrivateMemorySize64 -ge 8GB) { $MemoryStop = $true; Stop-Process -Id $OwnedPid -Force }
            } catch {}
        }
        if ($MemoryStop) { break }
        if (([DateTime]::UtcNow - $StartAt).TotalSeconds -ge 900) { $TimedOut = $true; break }
        Start-Sleep -Milliseconds 200
    }
    if ($TimedOut -or $MemoryStop) {
        foreach ($OwnedPid in $OwnedPids) { try { Stop-Process -Id $OwnedPid -Force -ErrorAction Stop } catch {} }
        try { $Process.Kill() } catch {}
    }
    $Process.WaitForExit()
    $CompilerStdout = $OutputTask.GetAwaiter().GetResult()
    $CompilerStderr = $ErrorTask.GetAwaiter().GetResult()
    [IO.File]::WriteAllText($Stdout, $CompilerStdout)
    [IO.File]::WriteAllText($Stderr, $CompilerStderr)
    if ($TimedOut) { throw 'Build exceeded 15 minutes and was stopped.' }
    if ($MemoryStop) { throw 'Build process reached the 8 GB private-memory cap and was stopped.' }
    if ($Process.ExitCode -eq -1073741502 -and $Attempt -eq 1) {
        Write-Output 'Build exited 0xC0000142; waiting 60 seconds before the one allowed retry.'
        Start-Sleep -Seconds 60
        continue
    }
    if ($Process.ExitCode -ne 0) {
        Write-Output "Build failed exit_code=$($Process.ExitCode) stdout=$Stdout stderr=$Stderr"
        if ($CompilerStdout) { Write-Output $CompilerStdout }
        if ($CompilerStderr) { Write-Output $CompilerStderr }
        throw 'Sharp mesher spike build failed.'
    }
} while ($Process.ExitCode -eq -1073741502 -and $Attempt -lt 2)

Write-Output "Build passed exe=$Exe elapsed_seconds=$([Math]::Round(([DateTime]::UtcNow - $StartAt).TotalSeconds,2)) priority=BelowNormal affinity=0xFF00"