<#
.SYNOPSIS
    Background Lua injection into Roblox Studio via UI Automation
.DESCRIPTION
    Injects Lua code into Roblox Studio's command bar using UIAutomation.
    Works when Studio is minimized, behind other windows, or in background.
    No window focus required.
.PARAMETER Code
    The Lua code to inject, or a path to a .lua file
.PARAMETER File
    Path to a .lua file to inject
.EXAMPLE
    .\bg_inject.ps1 -Code 'print("hello")'
    .\bg_inject.ps1 -File C:\scripts\build_map.lua
#>
param(
    [string]$Code = '',
    [string]$File = ''
)

Add-Type -AssemblyName UIAutomationClient
Add-Type -AssemblyName UIAutomationTypes

function Find-StudioCommandBar {
    $root = [System.Windows.Automation.AutomationElement]::RootElement

    # Find Studio window
    $windows = $root.FindAll(
        [System.Windows.Automation.TreeScope]::Children,
        [System.Windows.Automation.Condition]::TrueCondition
    )

    $studio = $null
    foreach ($w in $windows) {
        try {
            $n = $w.Current.Name
            if ($n -like "*Roblox Studio*") { $studio = $w; break }
        } catch {}
    }

    if (-not $studio) {
        $procs = Get-Process -Name "RobloxStudioBeta" -ErrorAction SilentlyContinue
        if (-not $procs) { return $null }
        $pidCond = New-Object System.Windows.Automation.PropertyCondition(
            [System.Windows.Automation.AutomationElement]::ProcessIdProperty,
            $procs[0].Id
        )
        $studio = $root.FindFirst([System.Windows.Automation.TreeScope]::Children, $pidCond)
    }

    if (-not $studio) { return $null }

    # Find command bar by AutomationId
    $autoIdCond = New-Object System.Windows.Automation.PropertyCondition(
        [System.Windows.Automation.AutomationElement]::AutomationIdProperty,
        "commandBarScriptEditor"
    )
    $cmdBar = $studio.FindFirst(
        [System.Windows.Automation.TreeScope]::Descendants,
        $autoIdCond
    )

    return $cmdBar
}

function Inject-LuaCode {
    param([string]$luaCode)

    $cmdBar = Find-StudioCommandBar
    if (-not $cmdBar) {
        Write-Error "ERROR: Roblox Studio command bar not found"
        return $false
    }

    try {
        $vp = $cmdBar.GetCurrentPattern([System.Windows.Automation.ValuePattern]::Pattern)
        $vp.SetValue($luaCode)

        # Send Enter via keyboard (requires brief focus)
        Add-Type -AssemblyName System.Windows.Forms
        $cmdBar.SetFocus()
        Start-Sleep -Milliseconds 100
        [System.Windows.Forms.SendKeys]::SendWait("{ENTER}")

        return $true
    } catch {
        Write-Error "Injection failed: $_"
        return $false
    }
}

# Main
if ($File -and (Test-Path $File)) {
    $Code = Get-Content $File -Raw
}
elseif ($Code -eq '') {
    # Read from stdin
    $Code = @($input) -join "`n"
}

if ($Code.Trim() -eq '') {
    Write-Error "No code provided. Use -Code or -File"
    exit 1
}

$result = Inject-LuaCode -luaCode $Code
if ($result) {
    Write-Output "OK: Code injected successfully"
} else {
    exit 1
}