element-call/src/lotus/lotusAudioInject.test.ts

/*
Copyright 2026 Lotus Guild

SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
Please see LICENSE in the repository root for full details.
*/

import { EventEmitter } from "events";
import { afterEach, beforeEach, expect, test, vi } from "vitest";
import { of } from "rxjs";

import { type CallViewModel } from "../state/CallViewModel/CallViewModel";
import { startLotusAudioInject } from "./lotusAudioInject";
import { LotusWidgetActions } from "./lotusActions";

const lazyActions = new EventEmitter();
const reply = vi.fn();

vi.mock("../widget", () => ({
  widget: {
    api: { transport: { reply: (...args: unknown[]) => reply(...args) } },
    // Getter: `vi.mock` factories run at import time, before the const above.
    get lazyActions(): EventEmitter {
      return lazyActions;
    },
  },
}));

function send(data: unknown): void {
  lazyActions.emit(LotusWidgetActions.InjectAudio, { detail: { data } });
}

/** Flush the microtask queue enough times to drain the async awaits in
 * `playInjectedClip` (fetch -> arrayBuffer -> resume -> decodeAudioData ->
 * publishTrack...), none of which use real timers in this test. */
async function flush(times = 30): Promise<void> {
  for (let i = 0; i < times; i++) await Promise.resolve();
}

function makeTrack(): MediaStreamTrack {
  return {
    clone: vi.fn(() => makeTrack()),
    stop: vi.fn(),
  } as unknown as MediaStreamTrack;
}

function makeRoom(isMicrophoneEnabled: boolean): {
  localParticipant: {
    isMicrophoneEnabled: boolean;
    publishTrack: ReturnType<typeof vi.fn>;
    unpublishTrack: ReturnType<typeof vi.fn>;
  };
} {
  return {
    localParticipant: {
      isMicrophoneEnabled,
      publishTrack: vi.fn(async (clone: unknown) => {
        await Promise.resolve();
        return { track: clone };
      }),
      unpublishTrack: vi.fn().mockResolvedValue(undefined),
    },
  };
}

function mockVm(rooms: unknown[]): CallViewModel {
  return {
    allConnections$: of({
      getConnections: () => rooms.map((livekitRoom) => ({ livekitRoom })),
    }),
  } as unknown as CallViewModel;
}

/** Fake AudioContext/nodes good enough to drive playInjectedClip end to end,
 * tracking how many contexts and destinations get constructed (#14). */
let contextInstances: FakeAudioContext[];
class FakeAudioContext {
  public state = "running";
  public resume = vi.fn().mockResolvedValue(undefined);
  public close = vi.fn().mockResolvedValue(undefined);
  public decodeAudioData = vi
    .fn()
    .mockResolvedValue({ duration: 0.01 } as AudioBuffer);
  public createMediaStreamDestination = vi.fn(() => ({
    stream: { getAudioTracks: (): MediaStreamTrack[] => [makeTrack()] },
  }));
  public createGain = vi.fn(() => ({
    gain: { value: 0 },
    connect: vi.fn((n: unknown) => n),
    disconnect: vi.fn(),
  }));
  public createBufferSource = vi.fn(() => ({
    buffer: undefined as AudioBuffer | undefined,
    connect: vi.fn((n: unknown) => n),
    disconnect: vi.fn(),
    start: vi.fn(),
    stop: vi.fn(),
    onended: null as (() => void) | null,
    addEventListener: vi.fn(),
  }));
  public constructor() {
    contextInstances.push(this);
  }
}

beforeEach(() => {
  contextInstances = [];
  reply.mockClear();
  // The module sets a real `setTimeout` guard per clip (MAX_CLIP_MS safety
  // net); use fake timers so a test ending before that guard fires doesn't
  // leave a real timer pending.
  vi.useFakeTimers();
  vi.stubGlobal("AudioContext", FakeAudioContext);
  vi.stubGlobal(
    "fetch",
    vi.fn().mockResolvedValue({
      ok: true,
      arrayBuffer: async () => {
        await Promise.resolve();
        return new ArrayBuffer(8);
      },
    }),
  );
  // `lotusParam`/`lotusFlag` re-parse `window.location` on every call, so
  // just set the flag before each test.
  window.location.hash = "#/room?lotusAudioInject=1";
});

afterEach(() => {
  lazyActions.removeAllListeners();
  vi.unstubAllGlobals();
  vi.useRealTimers();
});

test("#13: a muted local mic blocks the clip and replies with a machine-readable reason", async () => {
  const room = makeRoom(false);
  const vm = mockVm([room]);
  const stop = startLotusAudioInject(vm);

  send({ url: "https://example.com/clip.mp3" });
  await flush();

  expect(reply).toHaveBeenCalledWith(expect.anything(), {
    played: false,
    reason: "muted",
  });
  expect(room.localParticipant.publishTrack).not.toHaveBeenCalled();
  // No context should even be created for a clip that never plays.
  expect(contextInstances).toHaveLength(0);

  stop();
});

test("#13: an unmuted local mic plays the clip normally", async () => {
  const room = makeRoom(true);
  const vm = mockVm([room]);
  const stop = startLotusAudioInject(vm);

  send({ url: "https://example.com/clip.mp3" });
  await flush();

  expect(reply).toHaveBeenCalledWith(expect.anything(), {});
  expect(room.localParticipant.publishTrack).toHaveBeenCalledTimes(1);

  stop();
});

test("#14: one shared AudioContext/destination is reused across clips, and closed only on the last teardown", async () => {
  const room = makeRoom(true);
  const vm = mockVm([room]);
  const stop = startLotusAudioInject(vm);

  send({ url: "https://example.com/a.mp3" });
  await flush();
  expect(contextInstances).toHaveLength(1);
  const ctx = contextInstances[0];
  expect(ctx.createMediaStreamDestination).toHaveBeenCalledTimes(1);

  // Finish the first clip (as if it played to completion) before starting a
  // second one, matching the module's own "one clip at a time" contract.
  const firstSource = ctx.createBufferSource.mock.results[0]!.value as {
    onended: (() => void) | null;
  };
  firstSource.onended?.();
  await flush();
  expect(room.localParticipant.unpublishTrack).toHaveBeenCalledTimes(1);

  // A second clip must reuse the SAME context/destination rather than
  // creating a new one.
  send({ url: "https://example.com/b.mp3" });
  await flush();
  expect(contextInstances).toHaveLength(1);
  expect(ctx.createMediaStreamDestination).toHaveBeenCalledTimes(1);
  expect(ctx.close).not.toHaveBeenCalled();

  const secondSource = ctx.createBufferSource.mock.results[1]!.value as {
    onended: (() => void) | null;
  };
  secondSource.onended?.();
  await flush();

  // Tearing down the (only) active instance closes the shared context.
  stop();
  expect(ctx.close).toHaveBeenCalledTimes(1);
});

test("#14: the shared context stays open while another instance is still active", async () => {
  const roomA = makeRoom(true);
  const roomB = makeRoom(true);
  const stopA = startLotusAudioInject(mockVm([roomA]));
  const stopB = startLotusAudioInject(mockVm([roomB]));

  send({ url: "https://example.com/a.mp3" });
  await flush();
  expect(contextInstances).toHaveLength(1);
  const ctx = contextInstances[0];

  // Tearing down the first (of two) active instances must not close the
  // context out from under the other one.
  stopA();
  expect(ctx.close).not.toHaveBeenCalled();

  stopB();
  expect(ctx.close).toHaveBeenCalledTimes(1);
});