# SKYNET Windows 11 developer setup. Run from a normal PowerShell window.
# Packages come only from the Windows Package Manager and Microsoft Store.
[CmdletBinding()]
param()

$ErrorActionPreference = 'Stop'

if ($PSVersionTable.PSEdition -ne 'Desktop' -and $PSVersionTable.PSEdition -ne 'Core') {
    throw 'PowerShell is required.'
}
if ([Environment]::OSVersion.Platform -ne [PlatformID]::Win32NT -or
    [Environment]::OSVersion.Version.Build -lt 22000) {
    throw 'This installer requires Windows 11.'
}
if (-not (Get-Command winget.exe -ErrorAction SilentlyContinue)) {
    throw 'Windows Package Manager (winget) is unavailable. Install or update App Installer from Microsoft Store, then rerun.'
}

function Install-Package {
    param(
        [Parameter(Mandatory)] [string] $Id,
        [Parameter(Mandatory)] [ValidateSet('winget', 'msstore')] [string] $Source,
        [switch] $Force
    )
    Write-Host "Installing $Id from $Source..."
    if ($Force) {
        & winget.exe install --id $Id --exact --source $Source --accept-source-agreements --accept-package-agreements --force
    } else {
        & winget.exe install --id $Id --exact --source $Source --accept-source-agreements --accept-package-agreements
    }
    if ($LASTEXITCODE -ne 0) {
        throw "winget failed to install $Id (exit code $LASTEXITCODE)."
    }
}

# The current ChatGPT desktop app uses the OpenAI.Codex package identity.
function Get-ChatGPTPackage {
    Get-AppxPackage -Name 'OpenAI.Codex' -ErrorAction SilentlyContinue |
        Sort-Object { [version]$_.Version } -Descending |
        Select-Object -First 1
}

function Assert-ChatGPTInstalled {
    param([Parameter(Mandatory)] $Package)

    if ($Package.Status -ne 'Ok') {
        throw "ChatGPT is registered, but Windows reports package status '$($Package.Status)'."
    }
    $manifest = Get-AppxPackageManifest -Package $Package.PackageFullName
    $installedExecutable = @($manifest.Package.Applications.Application) |
        ForEach-Object { $_.Executable } |
        Where-Object { $_ -and (Test-Path (Join-Path $Package.InstallLocation $_)) } |
        Select-Object -First 1
    if (-not $installedExecutable) {
        throw 'ChatGPT package registration has no installed executable. Installation did not complete.'
    }
    Write-Host "ChatGPT desktop verified: $($Package.Name) $($Package.Version)"
}

# Install and verify the desktop app first so later optional tooling cannot mask a failure.
Write-Host 'Installing or repairing the current ChatGPT desktop app; Windows may request administrator approval.'
try {
    Install-Package -Id '9PLM9XGG6VKS' -Source 'msstore' -Force
} catch {
    throw "$($_.Exception.Message) Rerun PowerShell as Administrator and try again."
}
$chatGPTPackage = Get-ChatGPTPackage
if (-not $chatGPTPackage) {
    throw 'WinGet completed without registering ChatGPT for the current Windows user. Sign out and back in, then rerun this installer.'
}
Assert-ChatGPTInstalled -Package $chatGPTPackage

if (-not (Get-Command git.exe -ErrorAction SilentlyContinue)) {
    Install-Package -Id 'Git.Git' -Source 'winget'
}

# WinGet's Codex package downloads the OpenAI release and validates its manifest hash.
if (-not (Get-Command codex.exe -ErrorAction SilentlyContinue)) {
    Install-Package -Id 'OpenAI.Codex' -Source 'winget'
}

# Windows Terminal is included on most Windows 11 installations.
if (-not (Get-Command wt.exe -ErrorAction SilentlyContinue) -and
    -not (Get-AppxPackage -Name 'Microsoft.WindowsTerminal' -ErrorAction SilentlyContinue)) {
    Install-Package -Id 'Microsoft.WindowsTerminal' -Source 'winget'
}

$emacsChoice = Read-Host 'Install GNU Emacs? [y/N]'
if ($emacsChoice -match '^(?i:y|yes)$') {
    Install-Package -Id 'GNU.Emacs' -Source 'winget'
}

Write-Host 'Package setup complete. Open a new terminal and run codex --version to verify the CLI command.'
Write-Host 'If codex is not found there, check Windows Settings > Apps > Advanced app settings > App execution aliases, then rerun this installer.'
Write-Host 'Launch ChatGPT from Start and sign in to use the desktop app with Codex.'