# ==============================================================================
# Script Name: 8x8_Work_Updater.ps1
# Description: Downloads 8x8 with a progress bar, triggers a native service 
#              notification modal dialog on the user screen (bypasses non-interactive 
#              Session 0 blocks), silently installs, and relaunches 8x8.
# ==============================================================================

# 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
}

# Load required assemblies
Add-Type -AssemblyName System.Windows.Forms
Add-Type -AssemblyName System.Net.Http

$workDir       = "C:\ProgramData\JCT600_8x8Update"
$installerPath = Join-Path $workDir "8x8_Work_Installer.msi"

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

try {
    # --------------------------------------------------------------------------
    # Step 1: Download 8x8 Installer with Stream Progress Bar
    # --------------------------------------------------------------------------
    $installerUrl = "https://work-desktop-assets.8x8.com/prod-publish/ga/work-64-msi-v8.35.2-6.msi"
    Write-Host "[1/4] Downloading 8x8 Work installer..." -ForegroundColor Cyan

    try {
        $httpClient = New-Object System.Net.Http.HttpClient
        $response = $httpClient.GetAsync($installerUrl, [System.Net.Http.HttpCompletionOption]::ResponseHeadersRead).Result
        if (-not $response.IsSuccessStatusCode) { throw "HTTP Error $($response.StatusCode)" }

        $totalBytes = $response.Content.Headers.ContentLength
        $inputStream = $response.Content.ReadAsStreamAsync().Result
        $outputStream = [System.IO.File]::Create($installerPath)
        $buffer = New-Object byte[] 8192
        $totalBytesRead = 0; $bytesRead = 0

        while (($bytesRead = $inputStream.Read($buffer, 0, $buffer.Length)) -gt 0) {
            $outputStream.Write($buffer, 0, $bytesRead)
            $totalBytesRead += $bytesRead

            if ($totalBytes -gt 0) {
                $percent = [math]::Round(($totalBytesRead / $totalBytes) * 100)
                $downloadedMB = [math]::Round($totalBytesRead / 1MB, 2)
                $totalMB = [math]::Round($totalBytes / 1MB, 2)
                $barLength = 30
                $filledLength = [math]::Round(($percent / 100) * $barLength)
                $bar = ("#" * $filledLength) + ("-" * ($barLength - $filledLength))

                Write-Host "`rDownloading: [$bar] $percent% ($downloadedMB MB / $totalMB MB)" -NoNewline -ForegroundColor Yellow
            }
        }
        $outputStream.Close(); $inputStream.Close(); $httpClient.Dispose()
        Write-Host "`nDownload complete: $installerPath" -ForegroundColor Green
    } catch {
        Write-Error "`nFailed to download installer. Error: $_"
        exit 1
    }

    # --------------------------------------------------------------------------
    # Step 2: Show ServiceNotification Dialog (Crosses Session 0 Isolation)
    # --------------------------------------------------------------------------
    Write-Host "[2/4] Displaying interactive notification on user desktop..." -ForegroundColor Cyan

    $title   = "JCT600 IT Support — 8x8 Work Update"
    $message = "An automatic update for 8x8 Work has been scheduled by IT Support.`n`nPlease save active work and wrap up ongoing calls.`n`nClick OK to proceed with the update."

    # Use ServiceNotification flag to display onto the interactive desktop
    [System.Windows.Forms.MessageBox]::Show(
        $message,
        $title,
        [System.Windows.Forms.MessageBoxButtons]::OK,
        [System.Windows.Forms.MessageBoxIcon]::Information,
        [System.Windows.Forms.MessageBoxDefaultButton]::Button1,
        [System.Windows.Forms.MessageBoxOptions]::ServiceNotification
    ) | Out-Null

    # --------------------------------------------------------------------------
    # Step 3: Close Running 8x8 Processes & Install Silently
    # --------------------------------------------------------------------------
    Write-Host "[3/4] 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 4: Launch 8x8 Work
    # --------------------------------------------------------------------------
    Write-Host "[4/4] Launching 8x8 Work..." -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 ($exePath) {
        # Using explorer.exe to launch the executable forces standard user graphics execution
        Start-Process "explorer.exe" -ArgumentList "`"$exePath`""
        Write-Host "8x8 Work launched successfully." -ForegroundColor Green
    } else {
        Write-Warning "Could not locate 8x8 Work executable."
    }

} finally {
    Write-Host "Cleaning up temporary files..." -ForegroundColor Gray
    if (Test-Path $workDir) {
        Remove-Item $workDir -Recurse -Force -ErrorAction SilentlyContinue
    }
}