# GOTT Remote Agent - Windows PowerShell Client
# Verbindet sich per WebSocket zum GOTT-Server und fuehrt Befehle aus.
#
# Verwendung:
#   irm https://gott.example.com/remote.ps1 | iex
#   oder:
#   .\remote.ps1 -Url "wss://gott.example.com/api/remote"

param(
    [string]$Url = "{{WS_URL}}"
)

$ErrorActionPreference = "Stop"

Write-Host ""
Write-Host "  ============================" -ForegroundColor Cyan
Write-Host "   GOTT Remote Agent" -ForegroundColor Cyan
Write-Host "  ============================" -ForegroundColor Cyan
Write-Host ""
Write-Host "  Verbinde zu: $Url" -ForegroundColor Gray
Write-Host ""

try {
    $ws = New-Object System.Net.WebSockets.ClientWebSocket
    $ct = New-Object System.Threading.CancellationToken

    # Verbindung aufbauen
    $ws.ConnectAsync([Uri]$Url, $ct).GetAwaiter().GetResult()
    Write-Host "  [OK] Verbunden!" -ForegroundColor Green

    # Hello-Message senden
    $hostname = $env:COMPUTERNAME
    $username = $env:USERNAME
    $osVersion = [System.Environment]::OSVersion.VersionString
    $hello = @{
        type = "hello"
        hostname = $hostname
        username = $username
        os = $osVersion
    } | ConvertTo-Json -Compress

    $helloBytes = [System.Text.Encoding]::UTF8.GetBytes($hello)
    $segment = New-Object System.ArraySegment[byte] -ArgumentList @(,$helloBytes)
    $ws.SendAsync($segment, [System.Net.WebSockets.WebSocketMessageType]::Text, $true, $ct).GetAwaiter().GetResult()

    Write-Host "  Host: $username@$hostname ($osVersion)" -ForegroundColor Gray
    Write-Host ""
    Write-Host "  Warte auf Befehle... (Strg+C zum Beenden)" -ForegroundColor Yellow
    Write-Host ""

    # Empfangs-Loop
    $buffer = New-Object byte[] 65536
    $messageBuffer = New-Object System.IO.MemoryStream

    # Heartbeat-Timer (alle 30 Sekunden)
    $lastPing = [DateTime]::UtcNow

    while ($ws.State -eq [System.Net.WebSockets.WebSocketState]::Open) {
        # Heartbeat senden
        if (([DateTime]::UtcNow - $lastPing).TotalSeconds -gt 30) {
            $pingBytes = [System.Text.Encoding]::UTF8.GetBytes('{"type":"ping"}')
            $pingSegment = New-Object System.ArraySegment[byte] -ArgumentList @(,$pingBytes)
            try {
                $ws.SendAsync($pingSegment, [System.Net.WebSockets.WebSocketMessageType]::Text, $true, $ct).GetAwaiter().GetResult()
            } catch {
                break
            }
            $lastPing = [DateTime]::UtcNow
        }

        # Auf Nachricht warten (mit Timeout fuer Heartbeat)
        $receiveTask = $ws.ReceiveAsync((New-Object System.ArraySegment[byte] -ArgumentList @(,$buffer)), $ct)
        if (-not $receiveTask.Wait(5000)) {
            continue
        }

        $result = $receiveTask.Result

        if ($result.MessageType -eq [System.Net.WebSockets.WebSocketMessageType]::Close) {
            Write-Host "  Server hat Verbindung geschlossen." -ForegroundColor Yellow
            break
        }

        $messageBuffer.SetLength(0)
        $messageBuffer.Write($buffer, 0, $result.Count)

        # Mehrteilige Nachrichten zusammenbauen
        while (-not $result.EndOfMessage) {
            $result = $ws.ReceiveAsync((New-Object System.ArraySegment[byte] -ArgumentList @(,$buffer)), $ct).GetAwaiter().GetResult()
            $messageBuffer.Write($buffer, 0, $result.Count)
        }

        $json = [System.Text.Encoding]::UTF8.GetString($messageBuffer.ToArray())
        $msg = $json | ConvertFrom-Json

        switch ($msg.type) {
            "execute" {
                $command = $msg.command
                $timestamp = Get-Date -Format "HH:mm:ss"
                Write-Host "  [$timestamp] Ausfuehren: " -NoNewline -ForegroundColor Cyan
                Write-Host $command -ForegroundColor White

                $exitCode = 0
                $stdout = ""
                $stderr = ""

                try {
                    # PowerShell-Befehl ausfuehren
                    $output = & powershell.exe -NoProfile -NonInteractive -Command $command 2>&1
                    $stdout = ($output | Where-Object { $_ -isnot [System.Management.Automation.ErrorRecord] }) -join "`n"
                    $stderrLines = ($output | Where-Object { $_ -is [System.Management.Automation.ErrorRecord] }) | ForEach-Object { $_.ToString() }
                    $stderr = $stderrLines -join "`n"
                    $exitCode = $LASTEXITCODE
                    if ($null -eq $exitCode) { $exitCode = 0 }
                } catch {
                    $stderr = $_.Exception.Message
                    $exitCode = 1
                }

                # Ergebnis senden
                $response = @{
                    type = "result"
                    exitCode = $exitCode
                    output = if ($stdout) { $stdout } else { "" }
                    error = if ($stderr) { $stderr } else { "" }
                } | ConvertTo-Json -Compress

                $responseBytes = [System.Text.Encoding]::UTF8.GetBytes($response)
                $responseSegment = New-Object System.ArraySegment[byte] -ArgumentList @(,$responseBytes)
                $ws.SendAsync($responseSegment, [System.Net.WebSockets.WebSocketMessageType]::Text, $true, $ct).GetAwaiter().GetResult()

                # Kurzausgabe
                if ($stdout) {
                    $preview = if ($stdout.Length -gt 200) { $stdout.Substring(0, 200) + "..." } else { $stdout }
                    Write-Host "  -> $preview" -ForegroundColor Gray
                }
                if ($stderr) {
                    Write-Host "  [stderr] $stderr" -ForegroundColor Red
                }
                Write-Host "  [Exit: $exitCode]" -ForegroundColor $(if ($exitCode -eq 0) { "Green" } else { "Red" })
                Write-Host ""
            }
            "pong" {
                # Heartbeat-Antwort – ignorieren
            }
            default {
                Write-Host "  Unbekannte Nachricht: $($msg.type)" -ForegroundColor Yellow
            }
        }
    }
} catch [System.Net.WebSockets.WebSocketException] {
    Write-Host "  Verbindung verloren." -ForegroundColor Red
} catch {
    Write-Host "  Fehler: $_" -ForegroundColor Red
} finally {
    if ($ws -and $ws.State -eq [System.Net.WebSockets.WebSocketState]::Open) {
        try {
            $ws.CloseAsync([System.Net.WebSockets.WebSocketCloseStatus]::NormalClosure, "bye", $ct).GetAwaiter().GetResult()
        } catch { }
    }
    if ($ws) { $ws.Dispose() }
    Write-Host ""
    Write-Host "  Verbindung beendet." -ForegroundColor Yellow
}