Show Full-Video Labels on thumbnails

Co-authored-by: mini-bomba <mini-bomba@users.noreply.github.com>

src/utils/videoLabels.ts

@@ -0,0 +1,65 @@
+import { Category, VideoID } from "../types";
+import { getHash } from "@ajayyy/maze-utils/lib/hash";
+import Utils from "../utils";
+import { logWarn } from "./logger";
+
+const utils = new Utils();
+
+export interface LabelCacheEntry {
+    timestamp: number;
+    videos: Record<VideoID, Category>;
+}
+
+const labelCache: Record<string, LabelCacheEntry> = {};
+const cacheLimit = 1000;
+
+async function getLabelHashBlock(hashPrefix: string): Promise<LabelCacheEntry | null> {
+    // Check cache
+    const cachedEntry = labelCache[hashPrefix];
+    if (cachedEntry) {
+        return cachedEntry;
+    }
+
+    const response = await utils.asyncRequestToServer("GET", `/api/videoLabels/${hashPrefix}`);
+    if (response.status !== 200) {
+        // No video labels or server down
+        labelCache[hashPrefix] = {
+            timestamp: Date.now(),
+            videos: {},
+        };
+        return null;
+    }
+
+    try {
+        const data = JSON.parse(response.responseText);
+
+        const newEntry: LabelCacheEntry = {
+            timestamp: Date.now(),
+            videos: Object.fromEntries(data.map(video => [video.videoID, video.segments[0].category])),
+        };
+        labelCache[hashPrefix] = newEntry;
+
+        if (Object.keys(labelCache).length > cacheLimit) {
+            // Remove oldest entry
+            const oldestEntry = Object.entries(labelCache).reduce((a, b) => a[1].timestamp < b[1].timestamp ? a : b);
+            delete labelCache[oldestEntry[0]];
+        }
+
+        return newEntry;
+    } catch (e) {
+        logWarn(`Error parsing video labels: ${e}`);
+
+        return null;
+    }
+}
+
+export async function getVideoLabel(videoID: VideoID): Promise<Category | null> {
+    const prefix = (await getHash(videoID, 1)).slice(0, 3);
+    const result = await getLabelHashBlock(prefix);
+
+    if (result) {
+        return result.videos[videoID] ?? null;
+    }
+
+    return null;
+}