full update

src/lib/videoPreload.ts

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+import { Post } from "@/types/types";
+import { buildStorageUrl } from "@/components/main/BaseUrl";
+import { resolvePostMediaType } from "@/lib/reelsMediaType";
+
+const MAX_WARM_VIDEOS = 8;
+const warmVideos = new Map<string, HTMLVideoElement>();
+const prefetchedLinks = new Set<string>();
+
+export function getPostVideoSrc(post: Pick<Post, "files" | "type">): string | undefined {
+  const videoFile =
+    post.files?.find((file) => file.type === "video") ??
+    (resolvePostMediaType(post) === "video" ? post.files?.[0] : undefined);
+
+  if (!videoFile?.path) return undefined;
+  return buildStorageUrl(videoFile.path);
+}
+
+function evictOldestWarmVideo() {
+  const firstKey = warmVideos.keys().next().value as string | undefined;
+  if (!firstKey) return;
+  warmVideos.get(firstKey)?.remove();
+  warmVideos.delete(firstKey);
+}
+
+function warmVideoElement(url: string) {
+  if (typeof window === "undefined" || !url || warmVideos.has(url)) return;
+
+  const video = document.createElement("video");
+  video.preload = "auto";
+  video.muted = true;
+  video.playsInline = true;
+  video.setAttribute("playsinline", "");
+  video.setAttribute("webkit-playsinline", "");
+  video.src = url;
+  video.style.cssText =
+    "position:fixed;width:0;height:0;opacity:0;pointer-events:none;z-index:-1";
+
+  document.body.appendChild(video);
+  video.load();
+
+  if (warmVideos.size >= MAX_WARM_VIDEOS) evictOldestWarmVideo();
+  warmVideos.set(url, video);
+}
+
+function linkPrefetchVideo(url: string) {
+  if (typeof window === "undefined" || !url || prefetchedLinks.has(url)) return;
+  prefetchedLinks.add(url);
+
+  const link = document.createElement("link");
+  link.rel = "prefetch";
+  link.as = "video";
+  link.href = url;
+  document.head.appendChild(link);
+}
+
+export type VideoPrefetchPriority = "high" | "low";
+
+/** پیش‌بارگذاری ویدئو در HTTP cache + buffer مخفی */
+export function prefetchVideoUrl(
+  url: string | undefined,
+  priority: VideoPrefetchPriority = "high"
+) {
+  if (!url) return;
+  linkPrefetchVideo(url);
+  if (priority === "high") warmVideoElement(url);
+}
+
+export function prefetchPostVideo(
+  post: Pick<Post, "files" | "type" | "_id"> | null | undefined,
+  priority: VideoPrefetchPriority = "high"
+) {
+  prefetchVideoUrl(getPostVideoSrc(post ?? undefined), priority);
+}
+
+export function prefetchPostVideos(
+  posts: Array<Pick<Post, "files" | "type" | "_id">>,
+  priority: VideoPrefetchPriority = "low"
+) {
+  posts.forEach((post) => prefetchPostVideo(post, priority));
+}
+
+export function isVideoWarming(url: string | undefined): boolean {
+  return !!url && warmVideos.has(url);
+}