# Build a bootable SchOS ISO, ready for VMware or a real machine.
#
# Wraps `make iso`, which builds the ramdisk-root variant and wraps it in an
# El Torito image. The ramdisk root is the point: the ISO carries a complete
# userland inside the kernel, so it boots with no hard disk attached at all.
#
#   tools\makeiso.ps1              build it
#   tools\makeiso.ps1 -Run         build it, then boot it under QEMU to check
#   tools\makeiso.ps1 -Clean       force a full rebuild first
#
# Afterwards the ISO is schos.iso in the repository root; point a VM's optical
# drive at it and boot from CD.

param(
    [switch]$Run,
    [switch]$Clean,
    [string]$Qemu = "$env:USERPROFILE\scoop\apps\qemu\current\qemu-system-x86_64.exe"
)

$ErrorActionPreference = 'Stop'
$root = Split-Path $PSScriptRoot -Parent
Push-Location $root

function Fail($msg) {
    Write-Host "FAIL: $msg" -ForegroundColor Red
    Pop-Location
    exit 1
}

# Git Bash, found by full path and never as bare `bash`.
#
# From PowerShell, `bash` resolves to C:\...\WindowsApps\bash.exe -- the *WSL*
# launcher -- long before anything on PATH. On this machine WSL2 cannot start at
# all, because it needs the Hyper-V hypervisor underneath the whole system and
# that is deliberately off. So calling `bash` here does not run a different
# shell, it fails with a wall of virtualisation advice and an exit code that
# looks like the build broke.
$BashCandidates = @(
    "$env:ProgramFiles\Git\bin\bash.exe"
    "${env:ProgramFiles(x86)}\Git\bin\bash.exe"
    "$env:USERPROFILE\scoop\apps\git\current\bin\bash.exe"
    "$env:LOCALAPPDATA\Programs\Git\bin\bash.exe"
)
$Bash = $BashCandidates | Where-Object { Test-Path $_ } | Select-Object -First 1
if (-not $Bash) { Fail "Git Bash not found; looked in:`n  $($BashCandidates -join "`n  ")" }

function Invoke-Make([string]$cmd) {
    # -c, not -lc: a login shell sources the profile for no benefit here.
    # stderr folded in inside bash, because $ErrorActionPreference = 'Stop'
    # turns a native program's stderr into a terminating error, and mkisofs
    # writes a harmless warning there on every single run.
    & $Bash -c "cd '$($root -replace '\\','/')' && $cmd 2>&1"
}

# An ISO needs one of these to assemble the filesystem. There is no xorriso
# package for Windows in scoop; cdrtools provides mkisofs, and tools/mkiso.sh
# accepts either -- their El Torito arguments are compatible.
$haveIso = (Get-Command xorriso -ErrorAction SilentlyContinue) -or
           (Get-Command mkisofs -ErrorAction SilentlyContinue)
if (-not $haveIso) {
    Write-Host "Need xorriso or mkisofs on PATH." -ForegroundColor Yellow
    Write-Host "  Windows:       scoop install cdrtools"
    Write-Host "  Debian/Ubuntu: apt install xorriso"
    Fail "no ISO builder"
}

if ($Clean) {
    Write-Host "==> cleaning" -ForegroundColor Cyan
    # Not `make clean`: that would drop the ports too, and those take an
    # afternoon to rebuild on a host where they are not rebuilt at all.
    Invoke-Make "rm -rf build/kernel build/lib build/cmd" | Out-Null
}

Write-Host "==> building (this makes the ramdisk-root kernel, which is larger)" -ForegroundColor Cyan

# Output captured whole rather than piped through a filter. Piping a native
# command into ForEach-Object leaves $LASTEXITCODE reflecting the pipeline
# rather than the command, which reported a perfectly successful `make iso` as
# a failure. Redirect stderr inside bash too: with $ErrorActionPreference set to
# Stop, PowerShell turns a native program's stderr into terminating errors, and
# mkisofs writes a harmless warning there every single run.
$out = Invoke-Make "make iso"
$code = $LASTEXITCODE
$out | Where-Object { $_ -match '^==>|mkiso:|nmeta|rror' } |
    ForEach-Object { Write-Host "    $_" -ForegroundColor DarkGray }
if ($code -ne 0) {
    $out | Select-Object -Last 20 | ForEach-Object { Write-Host $_ }
    Fail "make iso returned $code"
}

$iso = Join-Path $root 'schos.iso'
if (-not (Test-Path $iso)) { Fail "schos.iso was not produced" }

# `make iso` leaves the tree holding objects compiled with -DRAMDISK_ROOT. A
# following plain `make` would then fail to link, on a missing ramdisk symbol,
# for reasons that look nothing like their cause. Put it back.
Write-Host "==> restoring the normal (disk-root) build" -ForegroundColor Cyan
Invoke-Make "rm -rf build/kernel build/lib build/cmd && make >/dev/null" | Out-Null

$mb = [Math]::Round((Get-Item $iso).Length / 1MB, 1)
Write-Host ""
Write-Host "==> $iso ($mb MB)" -ForegroundColor Green
Write-Host ""
Write-Host "VMware:" -ForegroundColor Cyan
Write-Host "  New VM -> I will install the OS later -> Other / Other 64-bit"
Write-Host "  CD/DVD -> Use ISO image file -> $iso, and tick Connect at power on"
Write-Host "  Boot order: CD-ROM first (F2 at power on for the firmware setup)"
Write-Host ""
Write-Host "  Set the VM to BIOS, not UEFI. SchOS's loader is 16-bit real"
Write-Host "  mode and there is no EFI stub yet, so a UEFI-only VM will not boot."
Write-Host ""
Write-Host "  Processors: as many as you like. SMP works as of 2026-08-08;"
Write-Host "  check with 'cat /proc/cpuinfo', which lists the online ones."
Write-Host ""
Write-Host "  RAM: 64 MB is plenty. The old 224 MB floor is gone."

if ($Run) {
    Write-Host ""
    Write-Host "==> booting the ISO under QEMU, no disk attached" -ForegroundColor Cyan
    $log = Join-Path $root 'build\isoboot.log'
    if (Test-Path $log) { Clear-Content $log }

    $psi = New-Object System.Diagnostics.ProcessStartInfo
    $psi.FileName = $Qemu
    $psi.Arguments = @(
        "-cdrom `"$iso`" -boot d"
        '-m 256M -smp 1 -cpu qemu64,+rdtscp -machine pc-i440fx-9.2'
        '-display none'
        "-chardev stdio,id=c0,logfile=`"$log`""
        '-serial chardev:c0'
        '-no-reboot'
    ) -join ' '
    $psi.RedirectStandardInput = $true
    $psi.UseShellExecute = $false

    $p = [System.Diagnostics.Process]::Start($psi)
    Start-Sleep -Seconds 25
    if (-not $p.HasExited) { $p.Kill() }
    Start-Sleep -Milliseconds 600

    $text = if (Test-Path $log) { Get-Content $log -Raw } else { "" }
    if ($text -match 'init: ready') {
        Write-Host "==> the ISO boots to a shell" -ForegroundColor Green
        ($text -split "`n" | Select-Object -First 12) | ForEach-Object { Write-Host "    $_" -ForegroundColor DarkGray }
    } else {
        Write-Host "==> the ISO did NOT reach a shell" -ForegroundColor Red
        Write-Host $text
        Pop-Location
        exit 1
    }
}

Pop-Location