mobile: recover from mid-playback decode/seek errors (doply NAL)

Bug f6c86847/b1b5e1a2: doply/playmogo plays fine but seeking throws
"source error, invalid NAL length" in ExoPlayer. Investigation (cross-IP,
2026-06-01) showed the stream is well-formed — faststart MP4 (moov before
mdat) on cloudatacdn.com which fully supports HTTP range (206, correct
content-range, repeatable token, no redirect). So it is an ExoPlayer-internal
seek failure, not an HTTP/container problem, and expo-video exposes no
extractor/MIME hint to influence it.

Mitigation: when the native player errors *after* it had already loaded
(i.e. a mid-playback/seek failure, not an initial-load failure) and the error
is not a 404/410, recreate the source via player.replace() and resume at the
last known position — this opens a fresh connection and re-parses moov, which
typically clears the transient decode error. Hard-capped at 2 attempts per
mount to avoid any auto-reload loop; if it still fails it falls through to the
existing proxy/WebView fallback and error UI. Initial-load errors are
untouched, so the resolver and the ~59k working doply sources are unaffected.

Also thread playbackId/entityKind through the resolved-hoster and proxy/WebView
nav.replace calls so those paths get the 404 "Mark broken" affordance too, and
complete the local RouteParams type with headers/fallbackProxyUrl.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

mobile/src/screens/PlayerScreen.tsx

@@ -39,6 +39,8 @@ interface RouteParams {
   refererHost?: string;
   title?: string;
   mode?: 'video' | 'webview';
+  headers?: Record<string, string>;
+  fallbackProxyUrl?: string;
   fallbackEmbedUrl?: string;
 }
 
@@ -179,14 +181,53 @@ function NativeVideoPlayer({ params }: { params: RouteParams }) {
   // Każdy step ma osobną ref żeby nie loopować.
   const didFallbackProxyRef = React.useRef(false);
   const didFallbackWebViewRef = React.useRef(false);
+  // Seek/decode recovery (bug f6c86847: doply/playmogo „invalid NAL length” przy
+  // przewijaniu). Stream jest poprawny — faststart MP4, CDN wspiera Range 206
+  // (zweryfikowane 2026-06-01 cross-IP) — więc to wewnętrzny błąd seeka ExoPlayera,
+  // nie HTTP. `replace(source)` otwiera świeże połączenie + re-parsuje moov; resume
+  // na ostatniej dobrej pozycji ratuje playback. Twardy limit 2 prób / mount żeby
+  // NIE wpaść w auto-loop. Tylko gdy player JUŻ grał (post-load, czyli seek-error,
+  // nie initial-load) i błąd nie jest 404/410.
+  const loadedOnceRef = React.useRef(false);
+  const lastGoodPositionRef = React.useRef(0);
+  const seekRecoveryRef = React.useRef(0);
+  React.useEffect(() => {
+    if (status === 'readyToPlay') loadedOnceRef.current = true;
+  }, [status]);
   React.useEffect(() => {
     if (status !== 'error') return;
+    // Step 0: post-load decode/seek error → recover in-place (przed proxy/WebView,
+    // które są dla INITIAL-load errorów IP-bound CDN).
+    if (
+      loadedOnceRef.current &&
+      seekRecoveryRef.current < 2 &&
+      !isGoneError(playerError?.message)
+    ) {
+      seekRecoveryRef.current += 1;
+      const resumeAt = lastGoodPositionRef.current;
+      try {
+        player.replace(source);
+        setTimeout(() => {
+          try {
+            if (resumeAt > 0) player.currentTime = resumeAt;
+            player.play();
+          } catch {
+            // disposed/za wcześnie — następny error tick spróbuje znów (do limitu)
+          }
+        }, 700);
+      } catch {
+        // replace failed — przepuść do fallback chain niżej
+      }
+      return;
+    }
     // Step 1 → 2: direct fail (403/410/etc), spróbuj proxy URL.
     if (fallbackProxyUrl && !didFallbackProxyRef.current && url !== fallbackProxyUrl) {
       didFallbackProxyRef.current = true;
       nav.replace('Player', {
         url: fallbackProxyUrl,
         sceneId,
+        playbackId: params.playbackId,
+        entityKind,
         durationSec,
         refererHost,
         title,
@@ -203,13 +244,15 @@ function NativeVideoPlayer({ params }: { params: RouteParams }) {
       nav.replace('Player', {
         url: fallbackEmbedUrl,
         sceneId,
+        playbackId: params.playbackId,
+        entityKind,
         durationSec,
         refererHost,
         title,
         mode: 'webview',
       });
     }
-  }, [status, fallbackProxyUrl, fallbackEmbedUrl, url, nav, sceneId, durationSec, refererHost, title]);
+  }, [status, fallbackProxyUrl, fallbackEmbedUrl, url, nav, sceneId, durationSec, refererHost, title, player, source, playerError]);
 
   const lastReportedRef = React.useRef(0);
   // Lokalny tick co 500ms — driver dla custom scrubber + time labels. expo-video
@@ -221,6 +264,8 @@ function NativeVideoPlayer({ params }: { params: RouteParams }) {
       try {
         const pos = player.currentTime || 0;
         setPosition(pos);
+        // Ostatnia „dobra” pozycja dla seek-recovery (tylko gdy faktycznie gra).
+        if (player.playing && pos > 0) lastGoodPositionRef.current = pos;
         const dur = player.duration || 0;
         if (dur > 0 && Math.abs(dur - knownDuration) > 0.5) setKnownDuration(dur);
         const posInt = Math.floor(pos);
@@ -1124,6 +1169,8 @@ function EmbedWebViewPlayer({ params }: { params: RouteParams }) {
         nav.replace('Player', {
           url: result.url,
           sceneId,
+          playbackId: params.playbackId,
+          entityKind,
           durationSec,
           refererHost,
           headers: result.headers,