# Richtfunkplaner Local Handler PoC - PowerShell 5.1, keine Adminrechte erforderlich.
# Als Text veröffentlicht. Nur nach Freigabe durch die eigene Organisation in .ps1 umbenennen.
& {
    $ErrorActionPreference = 'Stop'
    $listener = New-Object System.Net.HttpListener
    $listener.Prefixes.Add('http://127.0.0.1:17777/')
    $allowedOrigin = 'https://richtfunkplaner.app'
    $tokenBytes = New-Object byte[] 24
    [Security.Cryptography.RandomNumberGenerator]::Create().GetBytes($tokenBytes)
    $token = [Convert]::ToBase64String($tokenBytes)
    $state = [hashtable]::Synchronized(@{ Stopping = $false })
    $cancelHandler = [ConsoleCancelEventHandler]{
        param($sender, $eventArgs)
        $eventArgs.Cancel = $true
        $state.Stopping = $true
    }

    function Send-Json($context, [int]$status, $body) {
        $json = $body | ConvertTo-Json -Compress -Depth 5
        $bytes = [Text.Encoding]::UTF8.GetBytes($json)
        $context.Response.StatusCode = $status
        $context.Response.ContentType = 'application/json; charset=utf-8'
        $context.Response.ContentLength64 = $bytes.Length
        $context.Response.OutputStream.Write($bytes, 0, $bytes.Length)
        $context.Response.Close()
    }

    try {
        [Console]::add_CancelKeyPress($cancelHandler)
        $listener.Start()
        Write-Host 'Richtfunkplaner Local Handler läuft auf http://127.0.0.1:17777/' -ForegroundColor Green
        Write-Host ('Einmal-Token für die PWA: ' + $token) -ForegroundColor Cyan
        Write-Host 'Beenden mit Strg+C.'

        while (-not $state.Stopping) {
            $pending = $listener.GetContextAsync()
            while (-not $pending.Wait(250)) { if ($state.Stopping) { break } }
            if ($state.Stopping) { break }
            $context = $pending.Result
            $origin = $context.Request.Headers['Origin']
            if ($origin -ne $allowedOrigin) { Send-Json $context 403 @{ error = 'Origin nicht erlaubt.' }; continue }
            $context.Response.Headers['Access-Control-Allow-Origin'] = $allowedOrigin
            $context.Response.Headers['Vary'] = 'Origin'
            if ($context.Request.HttpMethod -eq 'OPTIONS') {
                $context.Response.Headers['Access-Control-Allow-Methods'] = 'GET, OPTIONS'
                $context.Response.Headers['Access-Control-Allow-Headers'] = 'X-Richtfunkplaner-Token'
                $context.Response.Headers['Access-Control-Allow-Private-Network'] = 'true'
                $context.Response.StatusCode = 204
                $context.Response.Close()
                continue
            }
            if ($context.Request.Headers['X-Richtfunkplaner-Token'] -cne $token) {
                Send-Json $context 401 @{ error = 'Token ungültig.' }; continue
            }
            if ($context.Request.HttpMethod -ne 'GET') { Send-Json $context 405 @{ error = 'Methode nicht erlaubt.' }; continue }
            switch ($context.Request.Url.AbsolutePath) {
                '/health' { Send-Json $context 200 @{ status = 'ok'; version = '0.1-poc'; listener = '127.0.0.1'; utc = [DateTime]::UtcNow.ToString('o') } }
                '/lancom/status' { Send-Json $context 501 @{ status = 'prepared'; message = 'Read-only LANCOM-Zugriff ist noch nicht auf realer Hardware freigegeben.' } }
                '/sensor/status' { Send-Json $context 501 @{ status = 'prepared'; deviceClass = 'WT55-prefix'; message = 'UDP-Discovery ist vorbereitet, aber noch nicht aktiviert.' } }
                default { Send-Json $context 404 @{ error = 'Route nicht vorhanden.' } }
            }
        }
    }
    finally {
        if ($listener.IsListening) { $listener.Stop() }
        $listener.Close()
        [Console]::remove_CancelKeyPress($cancelHandler)
        Write-Host 'Richtfunkplaner Local Handler beendet.'
    }
}