From c25e7cdcc2983bd4fbf155f6b37060d1b10aa33c Mon Sep 17 00:00:00 2001
From: Dmitri <dtroshchenkov@gmail.com>
Date: Wed, 25 Mar 2026 13:18:03 +0400
Subject: [PATCH] fixed transition smoothing issue for presentations

---
 .../src/components/RuntimePresentation.tsx    | 142 ++++++++----------
 1 file changed, 60 insertions(+), 82 deletions(-)

diff --git a/frontend/src/components/RuntimePresentation.tsx b/frontend/src/components/RuntimePresentation.tsx
index d1ae29f..5331e4c 100644
--- a/frontend/src/components/RuntimePresentation.tsx
+++ b/frontend/src/components/RuntimePresentation.tsx
@@ -24,7 +24,7 @@ import LayoutGuest from '../layouts/Guest';
 import { getPageTitle } from '../config';
 import { PRELOAD_CONFIG } from '../config/preload.config';
 import { usePreloadOrchestrator } from '../hooks/usePreloadOrchestrator';
-import { useReversePlayback } from '../hooks/useReversePlayback';
+import { useTransitionPlayback } from '../hooks/useTransitionPlayback';
 import { logger } from '../lib/logger';
 import { resolveAssetPlaybackUrl } from '../lib/assetUrl';
 import { buildElementStyle } from '../lib/elementStyles';
@@ -32,7 +32,6 @@ import type {
   RuntimeProject,
   RuntimePage,
   RuntimePageLink,
-  TransitionOverlayState,
 } from '../types/runtime';
 
 interface RuntimePresentationProps {
@@ -133,13 +132,16 @@ export default function RuntimePresentation({
   const [pageLinks, setPageLinks] = useState<RuntimePageLink[]>([]);
   const [selectedPageId, setSelectedPageId] = useState<string | null>(null);
   const [pageHistory, setPageHistory] = useState<string[]>([]);
-  const [overlayTransition, setOverlayTransition] =
-    useState<TransitionOverlayState | null>(null);
+  const [transitionPreview, setTransitionPreview] = useState<{
+    targetPageId: string;
+    videoUrl: string;
+    isReverse: boolean;
+  } | null>(null);
   const [error, setError] = useState('');
   const [isLoading, setIsLoading] = useState(true);
   const [isFullscreen, setIsFullscreen] = useState(false);
 
-  const overlayVideoRef = useRef<HTMLVideoElement | null>(null);
+  const transitionVideoRef = useRef<HTMLVideoElement>(null);
 
   // API request config with custom headers for project/environment
   const apiConfig = useMemo(
@@ -212,6 +214,50 @@ export default function RuntimePresentation({
     enabled: !isLoading && !error,
   });
 
+  // Integrate useTransitionPlayback hook for smooth transitions (matches Constructor pattern)
+  const { isBuffering } = useTransitionPlayback({
+    videoRef: transitionVideoRef,
+    transition: transitionPreview
+      ? {
+          videoUrl: transitionPreview.videoUrl,
+          reverseMode: transitionPreview.isReverse ? 'reverse' : 'none',
+          targetPageId: transitionPreview.targetPageId,
+          displayName: 'Transition',
+        }
+      : null,
+    onComplete: (targetPageId) => {
+      if (targetPageId) {
+        const targetPage = pages.find((p) => p.id === targetPageId);
+        waitForPageImages(targetPage || null).then(() => {
+          setSelectedPageId(targetPageId);
+          setPageHistory((prev) => [...prev, targetPageId]);
+          requestAnimationFrame(() => {
+            requestAnimationFrame(() => {
+              setTransitionPreview(null);
+            });
+          });
+        });
+      }
+    },
+    features: {
+      useBlobUrl: true,
+      preDecodeImages: true,
+      getTargetPageImages: () => {
+        if (!transitionPreview?.targetPageId) return [];
+        const targetPage = pages.find(
+          (p) => p.id === transitionPreview.targetPageId,
+        );
+        if (!targetPage?.background_image_url) return [];
+        const url = resolveAssetPlaybackUrl(targetPage.background_image_url);
+        return url ? [url] : [];
+      },
+    },
+    preload: {
+      preloadedUrls: preloadOrchestrator?.preloadedUrls || new Set(),
+      getCachedBlobUrl: preloadOrchestrator?.getCachedBlobUrl,
+    },
+  });
+
   const toggleFullscreen = useCallback(async () => {
     try {
       if (!document.fullscreenElement) {
@@ -361,10 +407,9 @@ export default function RuntimePresentation({
       if (!targetPage) return;
 
       if (transitionVideoUrl) {
-        // Play transition (forward or reverse)
-        setOverlayTransition({
+        // Play transition using useTransitionPlayback hook
+        setTransitionPreview({
           targetPageId,
-          transitionName: 'Transition',
           videoUrl: resolveAssetPlaybackUrl(transitionVideoUrl),
           isReverse: isBack,
         });
@@ -391,67 +436,6 @@ export default function RuntimePresentation({
     [navigateToPage],
   );
 
-  const finishOverlayTransition = useCallback(async () => {
-    if (!overlayTransition) return;
-
-    const targetPage = pages.find(
-      (p) => p.id === overlayTransition.targetPageId,
-    );
-
-    // Wait for images while showing last frame
-    await waitForPageImages(targetPage || null);
-
-    // Switch page
-    setSelectedPageId(overlayTransition.targetPageId);
-    setPageHistory((prev) => [...prev, overlayTransition.targetPageId]);
-
-    // Hide transition after React renders
-    requestAnimationFrame(() => {
-      requestAnimationFrame(() => {
-        setOverlayTransition(null);
-      });
-    });
-  }, [overlayTransition, pages]);
-
-  // Use the reverse playback hook (same as constructor.tsx)
-  const { startReverse, stopReverse } = useReversePlayback({
-    videoRef: overlayVideoRef,
-    onComplete: finishOverlayTransition,
-    preloadedUrls: preloadOrchestrator.preloadedUrls,
-    videoUrl: overlayTransition?.videoUrl,
-    getCachedBlobUrl: preloadOrchestrator.getCachedBlobUrl,
-  });
-
-  // Handle reverse playback when transition starts in reverse mode
-  useEffect(() => {
-    if (!overlayTransition?.isReverse) return;
-
-    const video = overlayVideoRef.current;
-    if (!video) return;
-
-    // Start reverse when video data is ready (preloaded assets load instantly)
-    const handleLoadedData = () => {
-      startReverse();
-    };
-
-    if (video.readyState >= 2) {
-      handleLoadedData();
-    } else {
-      video.addEventListener('loadeddata', handleLoadedData, { once: true });
-    }
-
-    return () => {
-      stopReverse();
-      video.removeEventListener('loadeddata', handleLoadedData);
-    };
-  }, [
-    overlayTransition?.isReverse,
-    overlayTransition?.videoUrl,
-    overlayTransition?.durationSec,
-    startReverse,
-    stopReverse,
-  ]);
-
   // Render element content based on type
   const renderElementContent = (element: any) => {
     // Navigation buttons
@@ -769,23 +753,17 @@ export default function RuntimePresentation({
           </span>
         </div>
 
-        {/* Transition overlay */}
-        {overlayTransition && (
-          <div className='absolute inset-0 z-40 bg-black'>
+        {/* Transition overlay - uses useTransitionPlayback hook for smooth transitions */}
+        {transitionPreview && (
+          <div className='fixed inset-0 z-50 overflow-hidden pointer-events-none'>
             <video
-              ref={overlayVideoRef}
-              className='w-full h-full object-cover'
-              src={overlayTransition.videoUrl}
-              autoPlay={!overlayTransition.isReverse}
+              ref={transitionVideoRef}
+              className='absolute inset-0 h-full w-full object-cover transition-opacity duration-300 ease-linear'
+              style={{ opacity: isBuffering ? 0 : 1 }}
               muted
               playsInline
               preload='auto'
-              onEnded={
-                overlayTransition.isReverse
-                  ? undefined
-                  : finishOverlayTransition
-              }
-              onError={finishOverlayTransition}
+              disablePictureInPicture
             />
           </div>
         )}