fix(live-log): Fehlermeldung wenn keine Systemkamera vorhanden ist

Prüft videoinput-Geräte beim Öffnen des Foto-Modals und zeigt eine
klare Meldung statt leerem Kamera-UI; getUserMedia-Fehler differenziert.

Co-authored-by: Cursor <cursoragent@cursor.com>

client/src/components/LiveCameraCapture.tsx

@@ -1,6 +1,10 @@
 import { useCallback, useEffect, useRef, useState } from 'react'
 import { useTranslation } from 'react-i18next'
 import { Camera, X } from 'lucide-react'
+import {
+  cameraErrorKeyFromDomException,
+  probeCameraAvailability
+} from '../utils/cameraAvailability.js'
 import {
   captureVideoFrame,
   preferNativeCameraPicker
@@ -15,7 +19,7 @@ interface LiveCameraCaptureProps {
   onCapture: (blob: Blob) => void
 }
 
-type Phase = 'live' | 'preview' | 'native'
+type Phase = 'checking' | 'live' | 'preview' | 'native'
 
 export default function LiveCameraCapture({
   open,
@@ -34,7 +38,7 @@ export default function LiveCameraCapture({
   const [cameraError, setCameraError] = useState<string | null>(null)
   const [ready, setReady] = useState(false)
   const [capturing, setCapturing] = useState(false)
-  const [phase, setPhase] = useState<Phase>(() => (preferNativeCameraPicker() ? 'native' : 'live'))
+  const [phase, setPhase] = useState<Phase>('checking')
   const [previewUrl, setPreviewUrl] = useState<string | null>(null)
   const [previewBlob, setPreviewBlob] = useState<Blob | null>(null)
   const [streamGeneration, setStreamGeneration] = useState(0)
@@ -87,12 +91,37 @@ export default function LiveCameraCapture({
       clearPreview()
       setCameraError(null)
       setCapturing(false)
-      setPhase(preferNativeCameraPicker() ? 'native' : 'live')
+      setPhase('checking')
       return
     }
-    setPhase(preferNativeCameraPicker() ? 'native' : 'live')
+
+    let cancelled = false
     clearPreview()
-  }, [open, stopStream, clearPreview])
+    setCameraError(null)
+    setCapturing(false)
+    setPhase('checking')
+
+    const probe = async () => {
+      const availability = await probeCameraAvailability()
+      if (cancelled) return
+
+      if (availability === 'unsupported') {
+        setCameraError(t('logs.live_photo_camera_unavailable'))
+        return
+      }
+      if (availability === 'none') {
+        setCameraError(t('logs.live_photo_no_camera'))
+        return
+      }
+
+      setPhase(preferNativeCameraPicker() ? 'native' : 'live')
+    }
+
+    void probe()
+    return () => {
+      cancelled = true
+    }
+  }, [open, clearPreview, stopStream, t])
 
   useEffect(() => {
     if (!open || phase !== 'live') {
@@ -105,11 +134,6 @@ export default function LiveCameraCapture({
     const start = async () => {
       setCameraError(null)
       setReady(false)
-      if (!navigator.mediaDevices?.getUserMedia) {
-        setCameraError(t('logs.live_photo_camera_unavailable'))
-        return
-      }
-
       try {
         const stream = await navigator.mediaDevices.getUserMedia({
           video: {
@@ -141,7 +165,7 @@ export default function LiveCameraCapture({
       } catch (err) {
         console.error('Camera access failed:', err)
         if (!cancelled) {
-          setCameraError(t('logs.live_photo_camera_denied'))
+          setCameraError(t(cameraErrorKeyFromDomException(err)))
         }
       }
     }
@@ -243,7 +267,9 @@ export default function LiveCameraCapture({
               className="live-camera-preview live-camera-preview-still"
             />
           </div>
-        ) : phase === 'native' ? (
+        ) : phase === 'checking' && !cameraError ? (
+          <p className="live-camera-loading">{t('logs.live_photo_camera_starting')}</p>
+        ) : phase === 'native' && !cameraError ? (
           <div className="live-camera-native-prompt">
             <p className="live-log-modal-hint">{t('logs.live_photo_native_hint')}</p>
             <button
@@ -256,7 +282,7 @@ export default function LiveCameraCapture({
               {t('logs.live_photo_open_camera_btn')}
             </button>
           </div>
-        ) : cameraError && !ready ? null : (
+        ) : phase === 'live' && !cameraError ? (
           <div className="live-camera-preview-wrap">
             <video
               ref={videoRef}
@@ -269,7 +295,7 @@ export default function LiveCameraCapture({
               <p className="live-camera-loading">{t('logs.live_photo_camera_starting')}</p>
             )}
           </div>
-        )}
+        ) : null}
 
         {onCaptionChange && (
           <div className="input-group live-camera-caption">

client/src/i18n/locales/da.json

@@ -266,6 +266,7 @@
       "live_photo_camera_starting": "Starter kamera…",
       "live_photo_camera_denied": "Kameraadgang nægtet eller utilgængelig.",
       "live_photo_camera_unavailable": "Kamera understøttes ikke i denne browser.",
+      "live_photo_no_camera": "Der er intet kamera tilgængeligt på denne enhed.",
       "live_photo_error": "Foto kunne ikke gemmes.",
       "live_photo_entry": "Foto: {{caption}}",
       "live_photo_entry_plain": "Foto taget",

client/src/i18n/locales/de.json

@@ -266,6 +266,7 @@
       "live_photo_camera_starting": "Kamera wird gestartet…",
       "live_photo_camera_denied": "Kamerazugriff verweigert oder nicht verfügbar.",
       "live_photo_camera_unavailable": "Kamera wird von diesem Browser nicht unterstützt.",
+      "live_photo_no_camera": "Auf diesem Gerät ist keine Kamera verfügbar.",
       "live_photo_error": "Foto konnte nicht gespeichert werden.",
       "live_photo_entry": "Foto: {{caption}}",
       "live_photo_entry_plain": "Foto aufgenommen",

client/src/i18n/locales/en.json

@@ -266,6 +266,7 @@
       "live_photo_camera_starting": "Starting camera…",
       "live_photo_camera_denied": "Camera access denied or unavailable.",
       "live_photo_camera_unavailable": "Camera is not supported in this browser.",
+      "live_photo_no_camera": "No camera is available on this device.",
       "live_photo_error": "Could not save photo.",
       "live_photo_entry": "Photo: {{caption}}",
       "live_photo_entry_plain": "Photo captured",

client/src/i18n/locales/nb.json

@@ -266,6 +266,7 @@
       "live_photo_camera_starting": "Starter kamera…",
       "live_photo_camera_denied": "Kameratilgang nektet eller utilgjengelig.",
       "live_photo_camera_unavailable": "Kamera støttes ikke i denne nettleseren.",
+      "live_photo_no_camera": "Ingen kamera er tilgjengelig på denne enheten.",
       "live_photo_error": "Kunne ikke lagre foto.",
       "live_photo_entry": "Foto: {{caption}}",
       "live_photo_entry_plain": "Foto tatt",

client/src/i18n/locales/sv.json

@@ -266,6 +266,7 @@
       "live_photo_camera_starting": "Startar kamera…",
       "live_photo_camera_denied": "Kameraåtkomst nekad eller ej tillgänglig.",
       "live_photo_camera_unavailable": "Kameran stöds inte i den här webbläsaren.",
+      "live_photo_no_camera": "Ingen kamera finns på den här enheten.",
       "live_photo_error": "Foto kunde inte sparas.",
       "live_photo_entry": "Foto: {{caption}}",
       "live_photo_entry_plain": "Foto taget",

client/src/utils/cameraAvailability.test.ts

@@ -0,0 +1,47 @@
+import { describe, expect, it, vi } from 'vitest'
+import {
+  cameraErrorKeyFromDomException,
+  isCameraApiSupported,
+  probeCameraAvailability
+} from './cameraAvailability.js'
+
+describe('cameraAvailability', () => {
+  it('detects missing camera API', () => {
+    const nav = { mediaDevices: undefined }
+    vi.stubGlobal('navigator', nav)
+    expect(isCameraApiSupported()).toBe(false)
+    vi.unstubAllGlobals()
+  })
+
+  it('returns none when no videoinput devices', async () => {
+    vi.stubGlobal('navigator', {
+      mediaDevices: {
+        getUserMedia: vi.fn(),
+        enumerateDevices: vi.fn().mockResolvedValue([
+          { kind: 'audioinput', deviceId: 'a1', label: '', groupId: '' }
+        ])
+      }
+    })
+    await expect(probeCameraAvailability()).resolves.toBe('none')
+    vi.unstubAllGlobals()
+  })
+
+  it('returns available when a videoinput exists', async () => {
+    vi.stubGlobal('navigator', {
+      mediaDevices: {
+        getUserMedia: vi.fn(),
+        enumerateDevices: vi.fn().mockResolvedValue([
+          { kind: 'videoinput', deviceId: 'v1', label: '', groupId: '' }
+        ])
+      }
+    })
+    await expect(probeCameraAvailability()).resolves.toBe('available')
+    vi.unstubAllGlobals()
+  })
+
+  it('maps NotFoundError to no-camera i18n key', () => {
+    expect(cameraErrorKeyFromDomException(new DOMException('', 'NotFoundError'))).toBe(
+      'logs.live_photo_no_camera'
+    )
+  })
+})

client/src/utils/cameraAvailability.ts

@@ -0,0 +1,33 @@
+export type CameraAvailability = 'available' | 'none' | 'unsupported'
+
+/** Whether the browser exposes camera APIs at all. */
+export function isCameraApiSupported(): boolean {
+  return typeof navigator !== 'undefined' && !!navigator.mediaDevices?.getUserMedia
+}
+
+/** Best-effort probe for at least one video input device (no permission prompt). */
+export async function probeCameraAvailability(): Promise<CameraAvailability> {
+  if (!isCameraApiSupported()) return 'unsupported'
+  if (!navigator.mediaDevices?.enumerateDevices) {
+    // Cannot list devices; defer to getUserMedia attempt in the capture UI.
+    return 'available'
+  }
+  try {
+    const devices = await navigator.mediaDevices.enumerateDevices()
+    if (devices.some((d) => d.kind === 'videoinput')) return 'available'
+    return 'none'
+  } catch {
+    return 'none'
+  }
+}
+
+export function cameraErrorKeyFromDomException(err: unknown): string {
+  const name = err instanceof DOMException ? err.name : ''
+  if (name === 'NotFoundError' || name === 'OverconstrainedError') {
+    return 'logs.live_photo_no_camera'
+  }
+  if (name === 'NotAllowedError' || name === 'NotReadableError' || name === 'SecurityError') {
+    return 'logs.live_photo_camera_denied'
+  }
+  return 'logs.live_photo_camera_unavailable'
+}