# ==============================================================================
# Script Name: Update-8x8Work-DualSession.ps1
# Description: Downloads 8x8, launches a zero-console interactive JCT600 GUI 
#              in the active user's session via VBScript wrapper (BOM fixed), 
#              waits for completion/override (1-hour countdown), silently installs, 
#              launches 8x8 as standard user, and cleans up tasks.
# ==============================================================================

# Ensure script is running elevated
if (-not ([Security.Principal.WindowsPrincipal][Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole([Security.Principal.WindowsBuiltInRole]::Administrator)) {
    Write-Error "This script must be executed with Administrator privileges."
    exit 1
}

# Use C:\ProgramData\ so standard users have full read/execute access
$workDir   = "C:\ProgramData\JCT600_8x8Update"
$flagFile  = Join-Path $workDir "8x8_Update_Proceed.flag"
$guiScript = Join-Path $workDir "Show-8x8UserGui.ps1"
$vbsScript = Join-Path $workDir "LaunchGuiHidden.vbs"
$taskName  = "JCT600_8x8_Update_Notification"

if (-not (Test-Path $workDir)) {
    New-Item -Path $workDir -ItemType Directory -Force | Out-Null
}

# Clean stale flag file
if (Test-Path $flagFile) { Remove-Item $flagFile -Force }

try {
    # --------------------------------------------------------------------------
    # Step 1: Download 8x8 Setup Installer
    # --------------------------------------------------------------------------
    $installerUrl  = "https://work-desktop-assets.8x8.com/prod-publish/ga/work-64-msi-v8.35.2-6.msi"
    $installerPath = Join-Path $workDir "8x8_Work_Installer.msi"

    Write-Host "[1/5] Downloading 8x8 Work installer..." -ForegroundColor Cyan
    try {
        Invoke-WebRequest -Uri $installerUrl -OutFile $installerPath -UseBasicParsing
        Write-Host "Download complete: $installerPath" -ForegroundColor Green
    } catch {
        Write-Error "Failed to download installer from $installerUrl. Error: $_"
        exit 1
    }

    # --------------------------------------------------------------------------
    # Step 2: Write User GUI & Zero-Console VBS Launcher
    # --------------------------------------------------------------------------
    Write-Host "[2/5] Generating user-session GUI and hidden launcher..." -ForegroundColor Cyan

    $guiContent = @'
Add-Type -AssemblyName System.Windows.Forms
Add-Type -AssemblyName System.Drawing

$signature = @"
[DllImport("user32.dll", SetLastError = true)]
public static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int X, int Y, int cx, int cy, uint uFlags);
"@
$Win32SetWindowPos = Add-Type -memberDefinition $signature -Name "Win32SetWindowPos" -namespace Win32Functions -passThru

$flagPath = "C:\ProgramData\JCT600_8x8Update\8x8_Update_Proceed.flag"

$form = New-Object System.Windows.Forms.Form
$form.Text = "JCT600 IT Support — 8x8 Work Update"
$form.Size = New-Object System.Drawing.Size(440, 250)
$form.StartPosition = 'CenterScreen'
$form.FormBorderStyle = 'FixedDialog'
$form.MaximizeBox = $false
$form.MinimizeBox = $false
$form.ControlBox = $false
$form.TopMost = $true

$script:allowClose = $false
$form.Add_FormClosing({
    param($sender, $e)
    if (-not $script:allowClose) { $e.Cancel = $true }
})

$labelHeader = New-Object System.Windows.Forms.Label
$labelHeader.Text = "JCT600 — IT SUPPORT"
$labelHeader.Location = New-Object System.Drawing.Point(20, 15)
$labelHeader.Size = New-Object System.Drawing.Size(380, 25)
$labelHeader.Font = New-Object System.Drawing.Font("Segoe UI", 11, [System.Drawing.FontStyle]::Bold)
$labelHeader.ForeColor = [System.Drawing.Color]::Navy
$labelHeader.TextAlign = 'TopCenter'
$form.Controls.Add($labelHeader)

$labelMsg = New-Object System.Windows.Forms.Label
$labelMsg.Text = "An automatic update for 8x8 Work has been scheduled by IT Support.`nPlease save active work or click 'Update Now' to begin."
$labelMsg.Location = New-Object System.Drawing.Point(20, 45)
$labelMsg.Size = New-Object System.Drawing.Size(380, 45)
$labelMsg.Font = New-Object System.Drawing.Font("Segoe UI", 9)
$labelMsg.TextAlign = 'TopCenter'
$form.Controls.Add($labelMsg)

$labelTimer = New-Object System.Windows.Forms.Label
$labelTimer.Location = New-Object System.Drawing.Point(20, 95)
$labelTimer.Size = New-Object System.Drawing.Size(380, 40)
$labelTimer.Font = New-Object System.Drawing.Font("Segoe UI", 20, [System.Drawing.FontStyle]::Bold)
$labelTimer.ForeColor = [System.Drawing.Color]::DarkRed
$labelTimer.TextAlign = 'MiddleCenter'
$form.Controls.Add($labelTimer)

$btnUpdateNow = New-Object System.Windows.Forms.Button
$btnUpdateNow.Text = "Update Now"
$btnUpdateNow.Font = New-Object System.Drawing.Font("Segoe UI", 9, [System.Drawing.FontStyle]::Bold)
$btnUpdateNow.Size = New-Object System.Drawing.Size(140, 35)
$btnUpdateNow.Location = New-Object System.Drawing.Point(140, 150)
$btnUpdateNow.UseVisualStyleBackColor = $true

$btnUpdateNow.Add_Click({
    $timer.Stop()
    $script:allowClose = $true
    New-Item -Path $flagPath -ItemType File -Force | Out-Null
    $form.Close()
})
$form.Controls.Add($btnUpdateNow)

$form.Add_Shown({
    [Win32Functions.Win32SetWindowPos]::SetWindowPos($form.Handle, [IntPtr] -1, 0, 0, 0, 0, 0x0003) | Out-Null
    $form.Activate()
})

$timer = New-Object System.Windows.Forms.Timer
$timer.Interval = 1000
$script:remaining = 3600 # 1 Hour

$timer.Add_Tick({
    if ($script:remaining -gt 0) {
        $timeSpan = [TimeSpan]::FromSeconds($script:remaining)
        $labelTimer.Text = $timeSpan.ToString("hh\:mm\:ss")
        $script:remaining--
        [Win32Functions.Win32SetWindowPos]::SetWindowPos($form.Handle, [IntPtr] -1, 0, 0, 0, 0, 0x0003) | Out-Null
    } else {
        $timer.Stop()
        $script:allowClose = $true
        New-Item -Path $flagPath -ItemType File -Force | Out-Null
        $form.Close()
    }
})

$initialSpan = [TimeSpan]::FromSeconds($script:remaining)
$labelTimer.Text = $initialSpan.ToString("hh\:mm\:ss")

$timer.Start()
$form.ShowDialog() | Out-Null
$timer.Dispose()
$form.Dispose()
'@

    # Write UTF8 without BOM
    $utf8NoBom = New-Object System.Text.UTF8Encoding($false)
    [System.IO.File]::WriteAllText($guiScript, $guiContent, $utf8NoBom)

    # VBScript Wrapper (ASCII)
    $vbsContent = @"
Set WshShell = CreateObject("WScript.Shell")
WshShell.Run "powershell.exe -ExecutionPolicy Bypass -WindowStyle Hidden -File ""$guiScript""", 0, False
"@
    [System.IO.File]::WriteAllText($vbsScript, $vbsContent, [System.Text.Encoding]::ASCII)

    # --------------------------------------------------------------------------
    # Step 3: Trigger Interactive GUI via VBS Wrapper in User's Session
    # --------------------------------------------------------------------------
    Write-Host "[3/5] Launching dialog in active user's desktop session..." -ForegroundColor Cyan

    $loggedUser = (Get-CimInstance -ClassName Win32_ComputerSystem).UserName
    if ([string]::IsNullOrEmpty($loggedUser)) {
        $explorerProc = Get-Process -Name explorer -ErrorAction SilentlyContinue | Select-Object -First 1
        if ($explorerProc) {
            $loggedUser = (Get-CimInstance -ClassName Win32_Process -Filter "ProcessId = $($explorerProc.Id)" | Invoke-CimMethod -MethodName GetOwner).User
        }
    }

    if ([string]::IsNullOrEmpty($loggedUser)) {
        Write-Warning "No active interactive user detected. Proceeding directly to silent update."
    } else {
        Write-Host "Detected active user: $loggedUser" -ForegroundColor Green

        $action = New-ScheduledTaskAction -Execute "wscript.exe" -Argument "`"$vbsScript`""
        $principal = New-ScheduledTaskPrincipal -UserId $loggedUser -LogonType Interactive -RunLevel Limited
        
        Register-ScheduledTask -TaskName $taskName -Action $action -Principal $principal -Force | Out-Null
        Start-ScheduledTask -TaskName $taskName

        Write-Host "Waiting for user dialog response or timer expiration (1 hour max)..." -ForegroundColor Yellow
        while (-not (Test-Path $flagFile)) {
            Start-Sleep -Seconds 2
        }
    }

    # --------------------------------------------------------------------------
    # Step 4: Close Running 8x8 Processes & Install Silently
    # --------------------------------------------------------------------------
    Write-Host "[4/5] Stopping 8x8 processes and installing silently..." -ForegroundColor Cyan

    $targetProcesses = Get-Process | Where-Object { 
        $_.ProcessName -like "*8x8*" -or $_.MainWindowTitle -like "*8x8*" 
    }

    if ($targetProcesses) {
        foreach ($proc in $targetProcesses) {
            Stop-Process -Id $proc.Id -Force -ErrorAction SilentlyContinue
        }
        Start-Sleep -Seconds 3
    }

    $msiArgs = "/i `"$installerPath`" /quiet /norestart"
    $installJob = Start-Process msiexec.exe -ArgumentList $msiArgs -Wait -PassThru

    if ($installJob.ExitCode -ne 0 -and $installJob.ExitCode -ne 3010) {
        Write-Error "Installation failed with exit code $($installJob.ExitCode)."
        exit $installJob.ExitCode
    }

    Write-Host "Installation completed successfully." -ForegroundColor Green

    # --------------------------------------------------------------------------
    # Step 5: Launch 8x8 Work under Active User Account
    # --------------------------------------------------------------------------
    Write-Host "[5/5] Launching 8x8 Work in user session..." -ForegroundColor Cyan

    $possiblePaths = @(
        "${env:ProgramFiles}\8x8 Inc\8x8 Work\8x8 Work.exe",
        "${env:ProgramFiles(x86)}\8x8 Inc\8x8 Work\8x8 Work.exe",
        "${env:ProgramFiles}\8x8 Work\8x8 Work.exe",
        "$env:LocalAppData\Programs\8x8 Work\8x8 Work.exe"
    )

    $exePath = $possiblePaths | Where-Object { Test-Path $_ } | Select-Object -First 1

    if ($exePath) {
        if (-not [string]::IsNullOrEmpty($loggedUser)) {
            # Launch 8x8 via standard user Scheduled Task to avoid Admin elevation GPU context crashes
            $launchTask = "JCT600_8x8_AppLaunch"
            $launchAction = New-ScheduledTaskAction -Execute "$exePath"
            $launchPrincipal = New-ScheduledTaskPrincipal -UserId $loggedUser -LogonType Interactive -RunLevel Limited
            
            Register-ScheduledTask -TaskName $launchTask -Action $launchAction -Principal $launchPrincipal -Force | Out-Null
            Start-ScheduledTask -TaskName $launchTask
            Start-Sleep -Seconds 3
            Unregister-ScheduledTask -TaskName $launchTask -Confirm:$false -ErrorAction SilentlyContinue
            Write-Host "8x8 Work launched successfully for $loggedUser." -ForegroundColor Green
        } else {
            Start-Process -FilePath $exePath
        }
    } else {
        Write-Warning "Could not locate 8x8 Work executable."
    }

} finally {
    # --------------------------------------------------------------------------
    # Mandatory Cleanup
    # --------------------------------------------------------------------------
    Write-Host "Cleaning up scheduled task and temporary files..." -ForegroundColor Gray
    Unregister-ScheduledTask -TaskName $taskName -Confirm:$false -ErrorAction SilentlyContinue
    
    if (Test-Path $workDir) {
        Remove-Item $workDir -Recurse -Force -ErrorAction SilentlyContinue
    }
}