PFP caching

src/seqta/utils/cloudPfpCache.ts

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+import localforage from "localforage";
+import { cloudAuth } from "@/seqta/utils/CloudAuth";
+
+const ACCOUNTS_BASE = "https://accounts.betterseqta.org";
+
+const store = localforage.createInstance({
+  name: "cloud-pfp-store",
+  storeName: "cloudPfp",
+});
+
+function hashKey(userId: string) {
+  return `hash:${userId}`;
+}
+
+function blobKey(userId: string) {
+  return `blob:${userId}`;
+}
+
+export function isAccountsHostedPfpUrl(url: string): boolean {
+  if (!url.includes("/api/user/pfp/")) return false;
+  if (url.includes("/hist/")) return false;
+  return /\/api\/user\/pfp\/[^/?#]+/.test(url.split("?")[0]!);
+}
+
+export function pfpUrlWithHash(url: string, hash: string | null | undefined): string {
+  if (!url || !hash || !isAccountsHostedPfpUrl(url)) return url;
+  const base = url.split("?")[0]!;
+  return `${base}?v=${hash}`;
+}
+
+async function fetchServerHash(userId: string): Promise<string | null> {
+  const res = await fetch(`${ACCOUNTS_BASE}/api/user/pfp/${userId}/meta`);
+  if (!res.ok) return null;
+  const data = (await res.json()) as { pfpHash?: string | null };
+  return data.pfpHash ?? null;
+}
+
+async function clearLocal(userId: string): Promise<void> {
+  await store.removeItem(hashKey(userId));
+  await store.removeItem(blobKey(userId));
+}
+
+export async function clearCloudPfpCache(userId?: string): Promise<void> {
+  const id = userId ?? cloudAuth.state.user?.id;
+  if (!id) return;
+  await clearLocal(id);
+}
+
+export type ResolveCloudPfpResult = {
+  src: string;
+  fromCache: boolean;
+};
+
+/**
+ * Returns an object URL or direct URL for the cloud profile picture.
+ * Order: session hash match → local blob; else meta → download → store blob then hash.
+ */
+export async function resolveCloudPfp(
+  userId: string,
+  pfpUrl: string,
+): Promise<ResolveCloudPfpResult | null> {
+  if (!isAccountsHostedPfpUrl(pfpUrl)) {
+    return { src: pfpUrl, fromCache: false };
+  }
+
+  const sessionHash = cloudAuth.state.user?.pfpHash ?? null;
+  const localHash = await store.getItem<string>(hashKey(userId));
+  const localBlob = await store.getItem<Blob>(blobKey(userId));
+
+  let serverHash = sessionHash;
+
+  const localMatches =
+    !!serverHash && serverHash === localHash && localBlob instanceof Blob;
+  if (localMatches) {
+    return { src: URL.createObjectURL(localBlob), fromCache: true };
+  }
+
+  if (!serverHash || serverHash !== localHash) {
+    serverHash = await fetchServerHash(userId);
+  }
+
+  if (!serverHash) {
+    await clearLocal(userId);
+    return null;
+  }
+
+  if (serverHash === localHash && localBlob instanceof Blob) {
+    return { src: URL.createObjectURL(localBlob), fromCache: true };
+  }
+
+  await clearLocal(userId);
+
+  const imageUrl = pfpUrlWithHash(pfpUrl, serverHash);
+  const headers: HeadersInit = {};
+  if (localHash) {
+    headers["If-None-Match"] = `"${localHash}"`;
+  }
+
+  const res = await fetch(imageUrl, { headers });
+  if (res.status === 304 && localBlob instanceof Blob) {
+    await store.setItem(hashKey(userId), serverHash);
+    return { src: URL.createObjectURL(localBlob), fromCache: true };
+  }
+
+  if (!res.ok) return null;
+
+  const blob = await res.blob();
+  await store.setItem(blobKey(userId), blob);
+  await store.setItem(hashKey(userId), serverHash);
+
+  return { src: URL.createObjectURL(blob), fromCache: false };
+}