[CmdletBinding()]
param([string]$OutputName = 'VoxelForgeStandalone.exe')

$ErrorActionPreference = 'Stop'
$BuildHostProcess = Get-Process -Id $PID
$BuildHostProcess.PriorityClass = 'BelowNormal'
$BuildHostProcess.ProcessorAffinity = [IntPtr]0xFF00
$Root = [IO.Path]::GetFullPath($PSScriptRoot)
$BuildDir = Join-Path $Root 'Build'
$BinDir = Join-Path $Root 'bin'
if ([IO.Path]::GetFileName($OutputName) -ne $OutputName -or [IO.Path]::GetExtension($OutputName) -ne '.exe') {
    throw "OutputName must be an executable filename, not a path: $OutputName"
}
$OutputPath = Join-Path $BinDir $OutputName
[IO.Directory]::CreateDirectory($BuildDir) | Out-Null
[IO.Directory]::CreateDirectory($BinDir) | Out-Null
$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 not found: $VcVars" }

$Sources = @(
    (Join-Path $Root 'Source\StandaloneViewer.cpp'),
    (Join-Path $Root 'Compat\UnrealPerlin.cpp'),
    (Join-Path $Root 'Compat\StandaloneDataAssetGlue.cpp'),
    (Join-Path $Root 'Source\VoxelForge\Private\VoxelBiomeDefinition.cpp'),
    (Join-Path $Root 'Source\VoxelForge\Private\VoxelCaveMorphology.cpp'),
    (Join-Path $Root 'Source\VoxelForge\Private\VoxelDensityAblation.cpp'),
    (Join-Path $Root 'Source\VoxelForge\Private\VoxelDensityOpStack.cpp'),
    (Join-Path $Root 'Source\VoxelForge\Private\VoxelDensityProfile.cpp'),
    (Join-Path $Root 'Source\VoxelForge\Private\VoxelDiffLayer.cpp'),
    (Join-Path $Root 'Source\VoxelForge\Private\VoxelGenerator.cpp'),
    (Join-Path $Root 'Source\VoxelForge\Private\VoxelHeightOpStack.cpp'),
    (Join-Path $Root 'Source\VoxelForge\Private\VoxelMarchingCubesMesher.cpp'),
    (Join-Path $Root 'Source\VoxelForge\Private\VoxelSettings.cpp'),
    (Join-Path $Root 'Source\VoxelForge\Private\VoxelStrateComposer.cpp'),
    (Join-Path $Root 'Source\VoxelForge\Private\VoxelStrateManager.cpp'),
    (Join-Path $Root 'Source\VoxelForge\Private\VoxelStrateMeasure.cpp'),
    (Join-Path $Root 'Source\VoxelForge\Private\VoxelTerrainOpDefinition.cpp'),
    (Join-Path $Root 'Source\VoxelForge\Private\VoxelWormField.cpp')
)
foreach ($Source in $Sources) {
    if (-not (Test-Path -LiteralPath $Source -PathType Leaf)) { throw "Required source is missing: $Source" }
}

$ResponsePath = Join-Path $BuildDir 'standalone.rsp'
$RspLines = @(
    '/nologo', '/std:c++20', '/O2', '/arch:AVX2', '/fp:precise', '/EHsc',
    '/D_CRT_SECURE_NO_WARNINGS',
    ('/I"{0}"' -f (Join-Path $Root 'Compat')),
    ('/I"{0}"' -f (Join-Path $Root 'Source')),
    ('/I"{0}"' -f (Join-Path $Root 'Source\VoxelForge\Public')),
    ('/I"{0}"' -f (Join-Path $Root 'Source\VoxelForge\Private')),
    ('/Fe"{0}"' -f $OutputPath)
)
# This build stays serial (no /MP); the daytime ceiling is four compiler processes.
foreach ($Source in $Sources) { $RspLines += ('"{0}"' -f $Source) }
$RspLines += @('/link','d3d11.lib','dxgi.lib','d3dcompiler.lib','user32.lib','gdi32.lib')
[IO.File]::WriteAllLines($ResponsePath,$RspLines,[Text.UTF8Encoding]::new($false))

Push-Location $BuildDir
try {
    # This PowerShell process already runs BelowNormal with affinity 0xFF00;
    # compile directly so cmd returns cl.exe's real exit code.
    $CommandLine = 'call "{0}" >nul && cl.exe @"{1}"' -f $VcVars,$ResponsePath
    & $env:ComSpec /d /s /c $CommandLine
    if ($LASTEXITCODE -ne 0) { throw "Standalone MSVC build failed with exit code $LASTEXITCODE" }
    if (-not (Test-Path -LiteralPath $OutputPath -PathType Leaf)) {
        throw "Standalone MSVC build reported success but did not produce: $OutputPath"
    }
} finally {
    Pop-Location
}
Write-Host "Built $OutputPath"