import { describe, expect, it } from "vitest";

import { createFixedWindowRateLimiter } from "./fixed-window-rate-limit.js";

function expectConsumeResult(

result: { allowed: boolean; remaining: number; retryAfterMs: number },

expected: { allowed: boolean; remaining: number; retryAfterMs: number },

): void {

expect(result.allowed).toBe(expected.allowed);

expect(result.remaining).toBe(expected.remaining);

expect(result.retryAfterMs).toBe(expected.retryAfterMs);

}

describe("fixed-window rate limiter", () => {

it("blocks after max requests until window reset", () => {

let nowMs = 1_000;

now: () => nowMs,

});

expect(limiter.consume()).toMatchObject({ allowed: true, remaining: 1 });

expect(limiter.consume()).toMatchObject({ allowed: true, remaining: 0 });

expect(limiter.consume()).toMatchObject({ allowed: false, retryAfterMs: 1_000 });

expectConsumeResult(limiter.consume(), { allowed: true, remaining: 1, retryAfterMs: 0 });

expectConsumeResult(limiter.consume(), { allowed: true, remaining: 0, retryAfterMs: 0 });

expectConsumeResult(limiter.consume(), { allowed: false, remaining: 0, retryAfterMs: 1_000 });

nowMs += 1_000;

expect(limiter.consume()).toMatchObject({ allowed: true, remaining: 1 });

expectConsumeResult(limiter.consume(), { allowed: true, remaining: 1, retryAfterMs: 0 });

});

it("clamps maxRequests and windowMs to at least one", () => {

now: () => nowMs,

});

expect(limiter.consume()).toMatchObject({ allowed: true, remaining: 0, retryAfterMs: 0 });

expect(limiter.consume()).toMatchObject({ allowed: false, remaining: 0, retryAfterMs: 1 });

expectConsumeResult(limiter.consume(), { allowed: true, remaining: 0, retryAfterMs: 0 });

expectConsumeResult(limiter.consume(), { allowed: false, remaining: 0, retryAfterMs: 1 });

nowMs += 1;

expect(limiter.consume()).toMatchObject({ allowed: true, remaining: 0 });

expectConsumeResult(limiter.consume(), { allowed: true, remaining: 0, retryAfterMs: 0 });

});

it("reports the remaining retry window after later blocked attempts", () => {

now: () => nowMs,

});

expect(limiter.consume()).toMatchObject({ allowed: true, remaining: 0 });

expectConsumeResult(limiter.consume(), { allowed: true, remaining: 0, retryAfterMs: 0 });

nowMs += 250;

expect(limiter.consume()).toMatchObject({ allowed: false, retryAfterMs: 750 });

expectConsumeResult(limiter.consume(), { allowed: false, remaining: 0, retryAfterMs: 750 });

});

it("supports explicit reset", () => {