malice

import assert from 'node:assert/strict';

import { test } from 'node:test';

import { createAvatarLoader, type AvatarCache } from '../src/lib/avatar-cache.ts';

function memoryCache(): AvatarCache & { entries: Map<string, Response> } {

  const entries = new Map<string, Response>();

  return {

    entries,

    async match(key) {

      return entries.get(key)?.clone();

    },

    async put(key, response) {

      entries.set(key, response.clone());

    }

  };

}

function image(body = 'avatar', status = 200): Response {

  return new Response(body, { status, headers: { 'Content-Type': 'image/png' } });

}

test('avatar cache coalesces simultaneous misses and persists results', async () => {

  const store = memoryCache();

  let loads = 0;

  let release: ((response: Response) => void) | undefined;

  let signalLoadStarted: (() => void) | undefined;

  const loadStarted = new Promise<void>((resolve) => (signalLoadStarted = resolve));

  const loader = createAvatarLoader(async () => store, async () => {

    loads += 1;

    signalLoadStarted?.();

    return new Promise((resolve) => (release = resolve));

  });

  const first = loader('/api/media?mxc=avatar', 'avatar');

  const second = loader('/api/media?mxc=avatar', 'avatar');

  await loadStarted;

  assert.equal(loads, 1);

  release?.(image());

  assert.equal(await (await first).text(), 'avatar');

  assert.equal(await (await second).text(), 'avatar');

  const nextWorker = createAvatarLoader(async () => store, async () => {

    loads += 1;

    return image('unexpected');

  });

  assert.equal(await (await nextWorker('/api/media?mxc=avatar', 'avatar')).text(), 'avatar');

  assert.equal(loads, 1);

});

test('avatar cache retries unsuccessful responses', async () => {

  const store = memoryCache();

  let loads = 0;

  const loader = createAvatarLoader(async () => store, async () => ++loads === 1 ? image('missing', 404) : image());

  assert.equal((await loader('/avatar', 'avatar')).status, 404);

  assert.equal(await (await loader('/avatar', 'avatar')).text(), 'avatar');

  assert.equal(loads, 2);

});

test('avatar cache read failures still return the image', async () => {

  let loads = 0;

  const cache: AvatarCache = {

    async match() {

      throw new Error('read failed');

    },

    async put() {}

  };

  const loader = createAvatarLoader(async () => cache, async () => {

    loads += 1;

    return image();

  });

  assert.equal(await (await loader('/avatar', 'avatar')).text(), 'avatar');

  assert.equal(loads, 1);

});

test('avatar cache write failures still return the image', async () => {

  let loads = 0;

  const cache: AvatarCache = {

    async match() {

      return undefined;

    },

    async put() {

      throw new Error('write failed');

    }

  };

  const loader = createAvatarLoader(async () => cache, async () => {

    loads += 1;

    return image();

  });

  assert.equal(await (await loader('/avatar', 'avatar')).text(), 'avatar');

  assert.equal(loads, 1);

});