[CmdletBinding()]
param(
    [string]$OutputName = 'VoxelForgeCoreStandalone.exe',
    [ValidateSet('All','Core')][string]$Target = 'All'
)

$ErrorActionPreference = 'Stop'
$BuildHostProcess = Get-Process -Id $PID
$BuildHostProcess.PriorityClass = 'BelowNormal'
$BuildHostProcess.ProcessorAffinity = [IntPtr]0xFF00
$Root = [IO.Path]::GetFullPath($PSScriptRoot)
$BuildDir = Join-Path $Root 'Build\VoxelForgeCore'
$BinDir = Join-Path $Root 'bin'
[IO.Directory]::CreateDirectory($BuildDir) | Out-Null
[IO.Directory]::CreateDirectory($BinDir) | Out-Null

if ($Target -eq 'All' -and ([IO.Path]::GetFileName($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
$CoreLibrary = Join-Path $BuildDir 'VoxelForgeCore.lib'
$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" }

$SourceManifest = Join-Path $Root 'Core\core_sources.txt'
if (-not (Test-Path -LiteralPath $SourceManifest -PathType Leaf)) { throw "Core source manifest not found: $SourceManifest" }
$CoreSourceNames = @(Get-Content -LiteralPath $SourceManifest | ForEach-Object { $_.Trim() } |
    Where-Object { $_ -and -not $_.StartsWith('#') })
if ($CoreSourceNames.Count -eq 0) { throw "Core source manifest is empty: $SourceManifest" }
$CoreSources = @($CoreSourceNames | ForEach-Object {
    $SourcePath = [IO.Path]::GetFullPath((Join-Path $Root $_))
    if (-not $SourcePath.StartsWith($Root,[StringComparison]::OrdinalIgnoreCase)) {
        throw "Core source path escapes Standalone: $_"
    }
    $SourcePath
})
foreach ($Source in $CoreSources) {
    if (-not (Test-Path -LiteralPath $Source -PathType Leaf)) { throw "Required core source is missing: $Source" }
}

$IncludeArgs = @(
    ('/I"{0}"' -f (Join-Path $Root 'Core\include')),
    ('/I"{0}"' -f (Join-Path $Root 'Core\src')),
    ('/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'))
)
$CommonFlags = @('/nologo','/std:c++20','/O2','/arch:AVX2','/fp:precise','/EHsc','/MP8','/D_CRT_SECURE_NO_WARNINGS') + $IncludeArgs
$CoreRsp = Join-Path $BuildDir 'core-compile.rsp'
$CoreRspLines = $CommonFlags + @('/c') + @($CoreSources | ForEach-Object { '"{0}"' -f $_ })
[IO.File]::WriteAllLines($CoreRsp,$CoreRspLines,[Text.UTF8Encoding]::new($false))

$Objects = @($CoreSources | ForEach-Object { '"{0}.obj"' -f [IO.Path]::GetFileNameWithoutExtension($_) })
$LibRsp = Join-Path $BuildDir 'core-library.rsp'
[IO.File]::WriteAllLines($LibRsp,@('/nologo',('/OUT:"{0}"' -f $CoreLibrary)) + $Objects,[Text.UTF8Encoding]::new($false))

$ViewerRsp = Join-Path $BuildDir 'viewer-link.rsp'
$ViewerRspLines = $CommonFlags + @(
    ('/Fe"{0}"' -f $OutputPath),
    ('"{0}"' -f (Join-Path $Root 'Source\StandaloneViewer.cpp')),
    ('"{0}"' -f $CoreLibrary),
    '/link','d3d11.lib','dxgi.lib','d3dcompiler.lib','user32.lib','gdi32.lib'
)
[IO.File]::WriteAllLines($ViewerRsp,$ViewerRspLines,[Text.UTF8Encoding]::new($false))

Push-Location $BuildDir
try {
    # One cl process with /MP8 bounds compiler work to eight processes; MSVC, lib.exe, and the
    # viewer link inherit BelowNormal priority and the 0xFF00 process affinity from this host.
    $CommandLine = 'call "{0}" >nul && cl.exe @"{1}" && lib.exe @"{2}"' -f $VcVars,$CoreRsp,$LibRsp
    if ($Target -eq 'All') { $CommandLine += ' && cl.exe @"{0}"' -f $ViewerRsp }
    & $env:ComSpec /d /s /c $CommandLine
    if ($LASTEXITCODE -eq -1073741502) { throw 'A build process exited with 0xC0000142; stopping as required.' }
    if ($LASTEXITCODE -ne 0) { throw "VoxelForgeCore build failed with exit code $LASTEXITCODE" }
    if (-not (Test-Path -LiteralPath $CoreLibrary -PathType Leaf)) { throw "Core library was not produced: $CoreLibrary" }
    if ($Target -eq 'All' -and -not (Test-Path -LiteralPath $OutputPath -PathType Leaf)) { throw "Viewer was not produced: $OutputPath" }
} finally {
    Pop-Location
}
Write-Host "Built $CoreLibrary"
if ($Target -eq 'All') { Write-Host "Built $OutputPath" }