# E07-S02: autostart the editor on a disposable disk copy (D151: the C128 Vim
# in x128 80-column mode by default; -Emulator x64sc selects the C64 build).
#
# The session is strictly sequential: this launcher refuses to start while a
# compiler session owns the same image, waits for the emulator to exit and for
# the image to flush, and never writes the source disk it copies from.
[CmdletBinding()]
param(
    [string]$EditorPrg = "",
    [string]$SourceImage = "",
    [string]$DiskImage = "",
    [ValidateSet("x128", "x64sc")][string]$Emulator = "x128",
    [int]$LimitCycles = 0,
    [string]$Screenshot = "",
    [switch]$Warp
)

$ErrorActionPreference = "Stop"
$project = Split-Path $PSScriptRoot -Parent
$repository = Split-Path $project -Parent
$build = Join-Path $project "build"
Import-Module (Join-Path $PSScriptRoot "lib\Nova128Launcher.psm1") -Force

if ($EditorPrg -eq "") {
    if ($Emulator -eq "x128") {
        $EditorPrg = Join-Path $repository "vim\vim128.prg"
    } else {
        throw "the C64 editor lives on ../vim/vim-improved.d81; extract 'vim' and pass -EditorPrg"
    }
}
if ($SourceImage -eq "") { $SourceImage = Join-Path $repository "vim\vim-improved.d81" }
if ($DiskImage -eq "") { $DiskImage = Join-Path $build "newlang-edit.d81" }
$EditorPrg = [IO.Path]::GetFullPath($EditorPrg)
$DiskImage = [IO.Path]::GetFullPath($DiskImage)
if ($SourceImage) { $SourceImage = [IO.Path]::GetFullPath($SourceImage) }

if (-not (Test-Path -LiteralPath $EditorPrg -PathType Leaf)) {
    throw "editor program not found: $EditorPrg (build Vim or pass -EditorPrg)"
}
$null = Get-Nova128ViceTool $Emulator

$sourceHash = $null
New-Item -ItemType Directory -Force -Path (Split-Path $DiskImage -Parent) | Out-Null
if ($SourceImage) {
    if (-not (Test-Path -LiteralPath $SourceImage -PathType Leaf)) {
        throw "source disk image not found: $SourceImage"
    }
    if ([string]::Equals($SourceImage, $DiskImage, [StringComparison]::OrdinalIgnoreCase)) {
        throw "the editor must never start on the source disk image"
    }
    $sourceHash = (Get-FileHash -LiteralPath $SourceImage -Algorithm SHA256).Hash
    if (Test-Path -LiteralPath $DiskImage) { Remove-Item -LiteralPath $DiskImage -Force }
    Copy-Item -LiteralPath $SourceImage -Destination $DiskImage
    Write-Host "fresh editor disk: $DiskImage"
}

# The session's own disk carries the editor, so the machine can reload it and
# the source image stays untouched.
if ($Emulator -eq "x128") {
    if (-not (Test-Path -LiteralPath $DiskImage)) {
        throw "the C128 editor needs a writable disk image: $DiskImage"
    }
    Add-Nova128DiskFile -Image $DiskImage -HostPath $EditorPrg -DiskName "vim128" -Type prg
    Write-Host "injected vim128 into $DiskImage"
    # The editor is then started from the disk copy, not from the host path:
    # a host-loaded program has no device number, and vim128's saves would
    # report success without reaching the image.
    $EditorPrg = "vim128"
}

$session = $null
try {
    $session = Enter-Nova128ImageSession -Image $DiskImage -Kind "editor"
    $session = $session
    $null = Invoke-Nova128Emulator -Emulator $Emulator -Program $EditorPrg `
        -DiskImage $DiskImage -Screenshot $Screenshot -LimitCycles $LimitCycles `
        -Warp:$Warp -EightyColumn:($Emulator -eq "x128") `
        -ProgramOnDisk:($Emulator -eq "x128")
} finally {
    if ($session) { Exit-Nova128ImageSession -Session $session }
}

if ($sourceHash) {
    $after = (Get-FileHash -LiteralPath $SourceImage -Algorithm SHA256).Hash
    if ($after -ne $sourceHash) { throw "the source disk image changed during the editor session" }
    Write-Host "source disk unchanged: $after"
}
Write-Host "editor session closed and the image is flushed"
Write-Host "next: run scripts\launch-compiler.ps1; never attach two writable sessions"