begin addition of a simple ratelimit

src/proxy/skins/SimpleRatelimit.ts

@@ -0,0 +1,65 @@
+export default class SimpleRatelimit<T> {
+    readonly requestCount: number
+    readonly resetInterval: number
+    private entries: Map<T, Ratelimit>
+
+    constructor(requestCount: number, resetInterval: number) {
+        this.requestCount = requestCount
+        this.resetInterval = resetInterval
+        this.entries = new Map()
+    }
+
+    public get(key: T): Ratelimit {
+        return this.entries.get(key) ?? {
+            remainingRequests: this.requestCount,
+            resetTime: new Date(0)
+        }
+    }
+
+    public consume(key: T, count?: number): Ratelimit | never {
+        if (this.entries.has(key)) {
+            const ratelimit = this.entries.get(key)
+            if (ratelimit.remainingRequests - (count ?? 1) < 0) {
+                if (this.requestCount - (count ?? 1) < 0) {
+                    throw new RatelimitExceededError(`Consume request count is higher than default available request count!`)
+                } else {
+                    throw new RatelimitExceededError(`Ratelimit exceeded, try again in ${ratelimit.resetTime.getDate() - Date.now()} ms!`)
+                }
+            }
+            ratelimit.remainingRequests -= count ?? 1
+            return ratelimit
+        } else {
+            if (this.requestCount - (count ?? 1) < 0) {
+                throw new RatelimitExceededError(`Consume request count is higher than default available request count!`)
+            }
+            const ratelimit: Ratelimit = {
+                remainingRequests: this.requestCount - (count ?? 1),
+                resetTime: new Date(Date.now() + this.resetInterval),
+                timer: null
+            }
+            this.entries.set(key, ratelimit)
+            ratelimit.timer = this._onAdd(ratelimit)
+            return ratelimit
+        }
+    }
+
+    private _onAdd(ratelimit: Ratelimit): NodeJS.Timer {
+        return setInterval(() => {
+            // TODO: work on
+        }, this.resetInterval)
+    }
+}
+
+export type Ratelimit = {
+    remainingRequests: number,
+    resetTime: Date,
+    timer?: NodeJS.Timer
+}
+
+export class RatelimitExceededError extends Error {
+    constructor(message: { toString: () => string }) {
+        super(message.toString())
+        this.name = "RatelimitExceededError"
+        Object.setPrototypeOf(this, RatelimitExceededError.prototype)
+    }
+}