# Photograph the framebuffer console after driving it with escape sequences.
#
# The serial line and the framebuffer are two different consumers of console
# output, and they behave differently on purpose: escapes are passed through
# to the serial line verbatim (a real terminal emulator is on the other end
# and understands them better than we do) and *interpreted* for the
# framebuffer. So the serial transcript can never tell you whether the escape
# parser works -- it contains the raw bytes either way. Only a picture can.
#
#   tools/ttyshot.ps1

param(
    [int]$BootSeconds = 22,
    [string]$Out = "build/ttyshot.ppm",
    [string]$Qemu
)

# QEMU, on whichever host this is.
#
# PowerShell 7 runs on Linux, macOS and the BSDs as well as Windows, so these
# scripts are usable from all of them -- but the old default was a hardcoded
# scoop path under $env:USERPROFILE, which exists on exactly one of those. PATH
# first, because a package-managed qemu is on it everywhere; the scoop location
# is only a fallback for the Windows install that does not add itself to PATH.
function Find-Qemu {
    $exe = if ($IsWindows -or $env:OS -eq 'Windows_NT') { 'qemu-system-x86_64.exe' }
           else { 'qemu-system-x86_64' }
    $onPath = Get-Command $exe -ErrorAction SilentlyContinue
    if ($onPath) { return $onPath.Source }
    if ($env:USERPROFILE) {
        $scoop = Join-Path (Join-Path $env:USERPROFILE 'scoop/apps/qemu/current') $exe
        if (Test-Path $scoop) { return $scoop }
    }
    foreach ($p in @('/usr/bin', '/usr/local/bin', '/opt/homebrew/bin')) {
        $c = Join-Path $p $exe
        if (Test-Path $c) { return $c }
    }
    throw "qemu-system-x86_64 not found on PATH. Install QEMU, or pass -Qemu <path>."
}

if (-not $Qemu) { $Qemu = Find-Qemu }

$ErrorActionPreference = 'Stop'
# Repo root is two levels up: this script lives in tools/windows/.
$root = Split-Path (Split-Path $PSScriptRoot -Parent) -Parent
$hda  = Join-Path $root 'schos.img'
# The root filesystem. SchFS is the only root there is: the kernel mounts
# device 1 in forkret() and panics if it is not a SchFS volume, so this is
# not a choice and there is no -SchFS switch any more. It used to default to
# build/fs.img, which stopped being bootable the moment SchFS became root.
$hdb  = Join-Path $root 'build/schfs.img'
$log  = Join-Path $root 'build/ttyshot.log'
$ppm  = Join-Path $root $Out
$monPort = 55571

# Each line exercises one thing the console could not do before: colour,
# bright colour, background colour, cursor addressing, erase-to-end-of-line,
# and non-ASCII text.
$commands = @(
    'clear'
    'printf ''\033[31mRED \033[32mGREEN \033[34mBLUE \033[35mMAGENTA \033[36mCYAN \033[0mdefault\n'''
    'printf ''\033[1;31mbold red \033[1;32mbold green \033[1;34mbold blue\033[0m\n'''
    'printf ''\033[37;44m white on blue \033[0m normal\n'''
    'printf ''caf\303\251 \303\251t\303\251 na\303\257ve \303\274ber sch\303\266n a\303\261o\n'''
    'printf ''ERASED-THIS\033[13G\033[Kkept this\n'''
    'printf ''\033[12;40Hcursor addressed to row 12 col 40\n'''
    # Tab used to be drawn as glyph 9, which in CP437 is a hollow circle --
    # so pressing Tab printed a circle instead of moving the cursor. Every
    # other control character had the same problem waiting behind it.
    'printf ''A\tB\tC\tD -- tabs, not circles\n'''
)

$psi = New-Object System.Diagnostics.ProcessStartInfo
$psi.FileName = $Qemu
$psi.Arguments = @(
    "-drive file=`"$hda`",format=raw,index=0,media=disk"
    "-drive file=`"$hdb`",format=raw,index=1,media=disk"
    '-m 1G -smp 1 -cpu qemu64,+rdtscp -machine pc-i440fx-9.2'
    '-display none'
    "-chardev stdio,id=c0,logfile=`"$log`""
    '-serial chardev:c0'
    "-monitor tcp:127.0.0.1:$monPort,server,nowait"
) -join ' '
$psi.RedirectStandardInput = $true
$psi.UseShellExecute       = $false

Write-Host '==> booting' -ForegroundColor Cyan
$p = [System.Diagnostics.Process]::Start($psi)

try {
    Start-Sleep -Seconds $BootSeconds
    foreach ($cmd in $commands) {
        Write-Host "  > $cmd" -ForegroundColor DarkGray
        foreach ($ch in ($cmd + "`n").ToCharArray()) {
            $p.StandardInput.Write($ch)
            $p.StandardInput.Flush()
            Start-Sleep -Milliseconds 20   # serial has no flow control
        }
        Start-Sleep -Seconds 2
    }

    Write-Host '==> capturing the framebuffer' -ForegroundColor Cyan
    $client = New-Object System.Net.Sockets.TcpClient('127.0.0.1', $monPort)
    $writer = New-Object System.IO.StreamWriter($client.GetStream())
    $writer.AutoFlush = $true
    Start-Sleep -Milliseconds 500
    $writer.WriteLine("screendump $ppm")
    Start-Sleep -Seconds 2
    $writer.WriteLine('quit')
    Start-Sleep -Milliseconds 500
    $client.Close()
} finally {
    if (-not $p.HasExited) { $p.Kill() }
    Start-Sleep -Milliseconds 800
}

if (Test-Path $ppm) {
    Write-Host "==> $ppm ($((Get-Item $ppm).Length) bytes)" -ForegroundColor Green
} else {
    Write-Host 'FAIL: no screendump was produced' -ForegroundColor Red
    exit 1
}