inital commit

Overlord-Server/src/thumbnails.ts

@@ -0,0 +1,49 @@
+const thumbnails = new Map<string, string>();
+const latestFrames = new Map<string, { bytes: Uint8Array; format: string }>();
+const thumbnailRequests = new Map<string, number>();
+
+export function setThumbnail(id: string, dataUrl: string) {
+  thumbnails.set(id, dataUrl);
+}
+
+export function getThumbnail(id: string) {
+  return thumbnails.get(id) ?? null;
+}
+
+export function clearThumbnail(id: string) {
+  thumbnails.delete(id);
+  latestFrames.delete(id);
+  thumbnailRequests.delete(id);
+}
+
+export function setLatestFrame(id: string, bytes: Uint8Array, format: string) {
+  latestFrames.set(id, { bytes, format });
+}
+
+export function generateThumbnail(id: string): boolean {
+  const frameData = latestFrames.get(id);
+  if (!frameData) {
+    return false;
+  }
+  
+  const { bytes, format } = frameData;
+  const b64 = Buffer.from(bytes).toString("base64");
+  const mime = format === "webp" ? "image/webp" : "image/jpeg";
+  thumbnails.set(id, `data:${mime};base64,${b64}`);
+  return true;
+}
+
+export function markThumbnailRequested(id: string) {
+  thumbnailRequests.set(id, Date.now());
+}
+
+export function consumeThumbnailRequest(id: string, windowMs = 5000): boolean {
+  const ts = thumbnailRequests.get(id);
+  if (!ts) return false;
+  if (Date.now() - ts > windowMs) {
+    thumbnailRequests.delete(id);
+    return false;
+  }
+  thumbnailRequests.delete(id);
+  return true;
+}