Show if blocked in /api/stats

This is experimental and is not listed in /api/stats:features yet.

src/lib/structures/RequestHistory.js

@@ -0,0 +1,37 @@
+class RequestHistory {
+	/**
+	 * @param {string[]} tracked list of things that can be tracked
+	 */
+	constructor(tracked) {
+		this.tracked = new Set(tracked)
+		/** @type {Map<string, {lastRequestAt: number | null, lastRequestSuccessful: boolean | null}>} */
+		this.store = new Map()
+		for (const key of tracked) {
+			this.store.set(key, {
+				lastRequestAt: null,
+				lastRequestSuccessful: null
+			})
+		}
+	}
+
+	/**
+	 * @param {string} key
+	 * @param {boolean} success
+	 */
+	report(key, success) {
+		if (!this.tracked.has(key)) throw new Error(`Trying to report key ${key}, but is not tracked`)
+		const entry = this.store.get(key)
+		entry.lastRequestAt = Date.now()
+		entry.lastRequestSuccessful = success
+	}
+
+	export() {
+		const result = {}
+		for (const key of this.store.keys()) {
+			result[key] = this.store.get(key)
+		}
+		return result
+	}
+}
+
+module.exports = RequestHistory