software-mansion__argent/packages/tool-server/test/screen-recording.test.ts

import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
import { EventEmitter } from "events";
import { promises as fs } from "fs";
import os from "os";
import path from "path";
import { getFailureSignal, FAILURE_CODES, type DeviceInfo } from "@argent/registry";
import type { ChildProcess } from "child_process";

vi.mock("child_process", async (importOriginal) => {
  const actual = await importOriginal<typeof import("child_process")>();
  return { ...actual, spawn: vi.fn() };
});
vi.mock("../src/tools/screen-recording/mjpeg-stream", async (importOriginal) => {
  const actual =
    await importOriginal<typeof import("../src/tools/screen-recording/mjpeg-stream")>();
  // readJpegDimensions stays real (it is exercised directly further down).
  return { ...actual, openMjpegStream: vi.fn() };
});
vi.mock("../src/tools/screen-recording/watermark", async (importOriginal) => {
  const actual = await importOriginal<typeof import("../src/tools/screen-recording/watermark")>();
  return {
    ...actual,
    resolveFfmpeg: vi.fn(async () => "/fake/ffmpeg"),
    writeLogoTemp: vi.fn(async () => "/tmp/fake-logo.png"),
  };
});

import { spawn } from "child_process";
import {
  screenRecordingSessionBlueprint,
  type ScreenRecordingSessionApi,
} from "../src/blueprints/screen-recording-session";
import {
  startCapture,
  stopCapture,
  framesDue,
  ffmpegArgs,
  type PointerControl,
} from "../src/tools/screen-recording/capture";
import { setPointerTrail, setPointerVisible } from "../src/utils/simulator-client";
import { makePointerControl } from "../src/tools/screen-recording/screen-recording-start";
import type { SimulatorServerApi } from "../src/blueprints/simulator-server";
import { openMjpegStream, readJpegDimensions } from "../src/tools/screen-recording/mjpeg-stream";
import { resolveFfmpeg, writeLogoTemp } from "../src/tools/screen-recording/watermark";
import {
  __resetActiveScreenRecordingsForTesting,
  getActiveScreenRecordings,
} from "../src/utils/screen-recording-reminder";
import { __resetReapedSessionsForTesting } from "../src/utils/reaped-sessions";

const mockSpawn = vi.mocked(spawn);
const mockOpenStream = vi.mocked(openMjpegStream);
const mockResolveFfmpeg = vi.mocked(resolveFfmpeg);

const IOS_UDID = "6DBF83B4-0000-0000-0000-000000000000";
const ANDROID_SERIAL = "emulator-5554";
const STREAM_URL = "http://127.0.0.1:54321/stream.mjpeg";
/** Grace the start holds after spawning ffmpeg before declaring it live. */
const READY_GRACE_MS = 800;

/** Minimal JPEG: SOI + SOF0 declaring the frame size + EOI. */
function fakeJpeg(width = 1320, height = 2868): Buffer {
  const sof = Buffer.alloc(19);
  sof.writeUInt16BE(0xffd8, 0); // SOI
  sof.writeUInt16BE(0xffc0, 2); // SOF0
  sof.writeUInt16BE(17, 4); // segment length
  sof.writeUInt8(8, 6); // precision
  sof.writeUInt16BE(height, 7);
  sof.writeUInt16BE(width, 9);
  sof.writeUInt16BE(0xffd9, 17); // EOI
  return sof;
}

class FakeStdin extends EventEmitter {
  writable = true;
  writableLength = 0;
  ended = false;
  writes: Buffer[] = [];
  write = vi.fn((chunk: Buffer) => {
    this.writes.push(chunk);
    return true;
  });
  end = vi.fn(() => {
    this.ended = true;
    this.writable = false;
  });
}

class FakeChild extends EventEmitter {
  stdout = new EventEmitter();
  stderr = new EventEmitter();
  stdin = new FakeStdin();
  exitCode: number | null = null;
  signalCode: NodeJS.Signals | null = null;
  kill = vi.fn((_signal?: NodeJS.Signals) => true);

  /** Simulate the process ending: stamps exitCode/signalCode, emits 'exit'. */
  exit(code: number | null, signal: NodeJS.Signals | null = null): void {
    this.exitCode = code;
    this.signalCode = signal;
    this.emit("exit", code, signal);
  }

  /** ffmpeg's real behaviour: stdin EOF finalizes the file and it exits. */
  exitOnStdinEnd(code = 0): void {
    this.stdin.end.mockImplementation(() => {
      this.stdin.ended = true;
      this.stdin.writable = false;
      queueMicrotask(() => this.exit(code));
    });
  }
}

interface FakeStream {
  latest: Buffer | null;
  frameCount: number;
  error: Error | null;
  waitForFirstFrame: ReturnType<typeof vi.fn>;
  close: ReturnType<typeof vi.fn>;
}

function fakeStream(overrides: Partial<FakeStream> = {}): FakeStream {
  const frame = fakeJpeg();
  const stream: FakeStream = {
    latest: frame,
    frameCount: 1,
    error: null,
    waitForFirstFrame: vi.fn(async () => frame),
    close: vi.fn(),
    ...overrides,
  };
  mockOpenStream.mockResolvedValueOnce(stream as never);
  return stream;
}

function fakeChild(): FakeChild {
  const child = new FakeChild();
  mockSpawn.mockReturnValueOnce(child as unknown as ChildProcess);
  return child;
}

/** A PointerControl whose enable/disable calls are observable. */
function fakePointer(enableResult = true) {
  const enable = vi.fn(async () => enableResult);
  const disable = vi.fn(async () => {});
  return { enable, disable } satisfies PointerControl;
}

async function makeSession(device: DeviceInfo): Promise<ScreenRecordingSessionApi> {
  // The payload argument is unused by this factory; options carry the device.
  const instance = await screenRecordingSessionBlueprint.factory({}, device, {
    device,
  } as never);
  return instance.api;
}

/**
 * Drive a start through its fail-fast grace. With fake timers the grace timer
 * has to be advanced by hand; `flush` lets the promise chain settle first.
 */
async function startAndSettle(
  api: ScreenRecordingSessionApi,
  params: {
    timeLimitSeconds?: number;
    watermark?: boolean;
    trimStatic?: boolean;
    pointer?: PointerControl;
  } = {}
): Promise<Awaited<ReturnType<typeof startCapture>>> {
  const promise = startCapture(api, {
    streamUrl: STREAM_URL,
    timeLimitSeconds: params.timeLimitSeconds ?? 180,
    watermark: params.watermark ?? false,
    // Default off in the helper so pacing/duration tests exercise the plain
    // wall-clock path; trim-specific tests opt in explicitly.
    trimStatic: params.trimStatic ?? false,
    pointer: params.pointer,
  });
  // Mark it handled: a start that rejects while the timers below are being
  // advanced would otherwise surface as an unhandled rejection, even though
  // the caller awaits the same promise for its error.
  promise.catch(() => {});
  await vi.advanceTimersByTimeAsync(READY_GRACE_MS);
  return promise;
}

const iosDevice: DeviceInfo = { id: IOS_UDID, platform: "ios", kind: "simulator" } as DeviceInfo;
const androidDevice: DeviceInfo = {
  id: ANDROID_SERIAL,
  platform: "android",
  kind: "emulator",
} as DeviceInfo;

beforeEach(() => {
  __resetActiveScreenRecordingsForTesting();
  __resetReapedSessionsForTesting();
  mockSpawn.mockReset();
  mockOpenStream.mockReset();
  mockResolveFfmpeg.mockReset();
  mockResolveFfmpeg.mockResolvedValue("/fake/ffmpeg");
  vi.useFakeTimers();
});

afterEach(() => {
  vi.useRealTimers();
});

describe("screen-recording session blueprint", () => {
  it("rejects a factory call without a resolved device", async () => {
    try {
      await screenRecordingSessionBlueprint.factory({}, iosDevice, {} as never);
      expect.unreachable();
    } catch (err) {
      expect(getFailureSignal(err)?.error_code).toBe(
        FAILURE_CODES.SCREEN_RECORDING_FACTORY_OPTIONS_MISSING
      );
    }
  });

  it("dispose reaps a child whose start is still mid-readiness", async () => {
    const instance = await screenRecordingSessionBlueprint.factory({}, iosDevice, {
      device: iosDevice,
    } as never);
    const child = new FakeChild();
    instance.api.pendingChild = child as unknown as ChildProcess;

    await instance.dispose();

    expect(child.kill).toHaveBeenCalledWith("SIGKILL");
    expect(instance.api.pendingChild).toBeNull();
  });

  it("rejects platforms that cannot record", async () => {
    try {
      await screenRecordingSessionBlueprint.factory({}, iosDevice, {
        device: { id: "chromium-1", platform: "chromium", kind: "app" },
      } as never);
      expect.unreachable();
    } catch (err) {
      expect(getFailureSignal(err)?.error_code).toBe(FAILURE_CODES.SCREEN_RECORDING_WRONG_PLATFORM);
    }
  });

  it("dispose stops the pump, closes the stream and finalizes via stdin EOF", async () => {
    const instance = await screenRecordingSessionBlueprint.factory({}, iosDevice, {
      device: iosDevice,
    } as never);
    const api = instance.api;
    const stream = fakeStream();
    const child = fakeChild();
    child.exitOnStdinEnd();
    await startAndSettle(api);

    await instance.dispose();

    expect(child.stdin.ended).toBe(true);
    expect(stream.close).toHaveBeenCalled();
    expect(api.pumpTimer).toBeNull();
    expect(getActiveScreenRecordings()).toHaveLength(0);
  });

  it("removes the watermark temp file it would otherwise abandon", async () => {
    const instance = await screenRecordingSessionBlueprint.factory({}, iosDevice, {
      device: iosDevice,
    } as never);
    const api = instance.api;
    fakeStream();
    const child = fakeChild();
    child.exitOnStdinEnd();
    // Use a real temp file so the removal is observable.
    const logo = path.join(os.tmpdir(), `argent-test-logo-${process.pid}.png`);
    await fs.writeFile(logo, Buffer.alloc(8, 1));
    vi.mocked(writeLogoTemp).mockResolvedValueOnce(logo);
    await startAndSettle(api, { watermark: true });
    expect(api.logoFile).toBe(logo);

    await instance.dispose();

    await expect(fs.access(logo)).rejects.toThrow();
    expect(api.logoFile).toBeNull();
  });

  describe("a capture reaped by stop-all-simulator-servers", () => {
    // The teardown sequence from the review: start a recording, let
    // `stop-all-simulator-servers` reap the device (which is what disposes this
    // service), then call `screen-recording-stop`. `Registry._teardown` nulls
    // the node's instance, so that stop resolves a BRAND NEW session — modelled
    // here by building a second one for the same device.
    async function reapDuringCapture(): Promise<{
      output: string;
      fresh: ScreenRecordingSessionApi;
    }> {
      const instance = await screenRecordingSessionBlueprint.factory({}, iosDevice, {
        device: iosDevice,
      } as never);
      fakeStream();
      fakeChild().exitOnStdinEnd();
      await startAndSettle(instance.api);
      const output = instance.api.outputFile!;

      await instance.dispose();

      return { output, fresh: await makeSession(iosDevice) };
    }

    it("tells the owner the recording was torn down, and where the video landed", async () => {
      const { output, fresh } = await reapDuringCapture();

      const err = await stopCapture(fresh).catch((e: unknown) => e);

      const message = (err as Error).message;
      // The bug: this used to be "No active screen recording … Call
      // `screen-recording-start` first." while a finalized video sat on disk.
      expect(message).not.toMatch(/Call `screen-recording-start` first/);
      expect(message).toContain("torn down");
      expect(message).toContain("stop-all-simulator-servers");
      // Nothing else in the process still knows this path exists.
      expect(message).toContain(output);
      expect(getFailureSignal(err)?.error_code).toBe(
        FAILURE_CODES.SCREEN_RECORDING_SERVER_SHUTTING_DOWN
      );
    });

    it("tells the owner when the teardown hit a CAPPED capture awaiting retrieval", async () => {
      // `hadUnretrievedCapture` has three arms and only `recordingActive` was
      // covered. This is the likeliest real sequence of the three: the time
      // limit fires, the video is finalized and waiting to be handed over, and
      // the teardown lands in that window. The caller is owed a video just as
      // much as in the mid-capture case.
      const instance = await screenRecordingSessionBlueprint.factory({}, iosDevice, {
        device: iosDevice,
      } as never);
      fakeStream();
      fakeChild().exitOnStdinEnd();
      await startAndSettle(instance.api, { timeLimitSeconds: 5 });
      await vi.advanceTimersByTimeAsync(5_000);
      expect(instance.api.recordingActive).toBe(false);
      expect(instance.api.pendingRetrieval).toBe(true);
      const output = instance.api.outputFile!;

      await instance.dispose();
      const err = await stopCapture(await makeSession(iosDevice)).catch((e: unknown) => e);

      const message = (err as Error).message;
      expect(message).not.toMatch(/Call `screen-recording-start` first/);
      expect(message).toContain("torn down");
      expect(message).toContain(output);
      expect(getFailureSignal(err)?.error_code).toBe(
        FAILURE_CODES.SCREEN_RECORDING_SERVER_SHUTTING_DOWN
      );
    });

    it("tells the owner when the teardown hit a start still mid-readiness", async () => {
      // The third arm. `startPending` is set synchronously before start's first
      // await, so a teardown here destroys a capture whose child may already be
      // spawned — reported as a teardown, not as "you never started one".
      const instance = await screenRecordingSessionBlueprint.factory({}, iosDevice, {
        device: iosDevice,
      } as never);
      fakeStream();
      fakeChild();
      const pending = startCapture(instance.api, {
        streamUrl: STREAM_URL,
        timeLimitSeconds: 180,
        watermark: false,
        trimStatic: false,
      });
      pending.catch(() => {});
      expect(instance.api.startPending).toBe(true);

      await instance.dispose();
      await pending.catch(() => {});
      const err = await stopCapture(await makeSession(iosDevice)).catch((e: unknown) => e);

      expect((err as Error).message).not.toMatch(/Call `screen-recording-start` first/);
      expect((err as Error).message).toContain("torn down");
      expect(getFailureSignal(err)?.error_code).toBe(
        FAILURE_CODES.SCREEN_RECORDING_SERVER_SHUTTING_DOWN
      );
    });

    it("still reports a plain absence when no capture was reaped", async () => {
      // The breadcrumb must not turn every "you never started one" into an
      // accusation: disposing an idle session leaves nothing behind.
      const instance = await screenRecordingSessionBlueprint.factory({}, iosDevice, {
        device: iosDevice,
      } as never);
      await instance.dispose();

      const err = await stopCapture(await makeSession(iosDevice)).catch((e: unknown) => e);

      expect((err as Error).message).toContain("No active screen recording");
      expect(getFailureSignal(err)?.error_code).toBe(
        FAILURE_CODES.SCREEN_RECORDING_NO_ACTIVE_SESSION
      );
    });

    it("is consumed once, so it cannot blame a later unrelated absence", async () => {
      const { fresh } = await reapDuringCapture();
      await stopCapture(fresh).catch(() => {});

      const err = await stopCapture(await makeSession(iosDevice)).catch((e: unknown) => e);

      expect((err as Error).message).toContain("No active screen recording");
    });

    it("is dropped by a new recording, which would otherwise never consume it", async () => {
      const { fresh } = await reapDuringCapture();
      fakeStream();
      fakeChild().exitOnStdinEnd();
      await startAndSettle(fresh);
      await fs.writeFile(fresh.outputFile!, Buffer.alloc(16, 1));
      await stopCapture(fresh);

      const err = await stopCapture(await makeSession(iosDevice)).catch((e: unknown) => e);

      expect((err as Error).message).toContain("No active screen recording");
    });
  });
});

describe("screen recording capture", () => {
  it("encodes the paced frame pipe, stamps the session and registers the reminder", async () => {
    const api = await makeSession(iosDevice);
    fakeStream();
    const child = fakeChild();

    const result = await startAndSettle(api, { timeLimitSeconds: 60 });

    expect(result).toMatchObject({ status: "recording", timeLimitSeconds: 60 });
    expect(mockOpenStream).toHaveBeenCalledWith(STREAM_URL, expect.any(Number));
    const [bin, args] = mockSpawn.mock.calls[0]!;
    expect(bin).toBe("/fake/ffmpeg");
    expect(args).toEqual(expect.arrayContaining(["-f", "image2pipe", "-framerate", "30"]));
    // Output must be the file the caller was told about.
    expect((args as string[]).at(-1)).toBe(result.outputFile);
    expect(api.recordingActive).toBe(true);
    expect(api.captureProcess).toBe(child as unknown as ChildProcess);
    expect(getActiveScreenRecordings()).toHaveLength(1);
  });

  it("stamps the watermark in the same pass when the flag is on", async () => {
    const api = await makeSession(iosDevice);
    fakeStream();
    fakeChild();

    await startAndSettle(api, { watermark: true });

    const args = mockSpawn.mock.calls[0]![1] as string[];
    expect(args).toContain("-filter_complex");
    // Geometry comes from the first frame's JPEG header (1320x2868), so the
    // graph must carry a concrete crop box rather than a placeholder.
    expect(args[args.indexOf("-filter_complex") + 1]).toContain("crop=378:116:40:2728");
    expect(args).toContain("/tmp/fake-logo.png");
  });

  it("still records, and says so, when the frame size cannot be read", async () => {
    const api = await makeSession(iosDevice);
    // A frame whose JPEG header carries no SOF marker: nothing to size the
    // watermark box from.
    const headerless = Buffer.from([0xff, 0xd8, 0xff, 0xd9]);
    fakeStream({ latest: headerless, waitForFirstFrame: vi.fn(async () => headerless) });
    const child = fakeChild();
    child.exitOnStdinEnd();

    await startAndSettle(api, { watermark: true });
    const args = mockSpawn.mock.calls[0]![1] as string[];
    expect(args).not.toContain("-filter_complex");

    await fs.writeFile(api.outputFile!, Buffer.alloc(32, 1));
    const outputFile = api.outputFile!;
    const result = await stopCapture(api);

    expect(result.warning).toContain("watermark was not applied");
    await fs.rm(outputFile, { force: true });
  });

  it("omits the filter graph entirely when the watermark is disabled", async () => {
    const api = await makeSession(iosDevice);
    fakeStream();
    fakeChild();

    await startAndSettle(api, { watermark: false });

    const args = mockSpawn.mock.calls[0]![1] as string[];
    expect(args).not.toContain("-filter_complex");
  });

  it("evens the raw base so an odd device resolution still encodes (no watermark)", () => {
    // The watermark-off path has no filter graph to normalize the base, so the
    // frame reaches libx264 directly. yuv420p rejects an odd width/height and
    // leaves a 0-byte file (iPhone 16 / 15 Pro / 15 / 14 Pro stream at
    // 1179x2556); the crop drops the odd edge pixel so any resolution records.
    const args = ffmpegArgs({ outputFile: "/tmp/out.mp4", logoFile: null, graph: null });
    const vf = args.indexOf("-vf");
    expect(vf).toBeGreaterThan(-1);
    expect(args[vf + 1]).toBe("crop=trunc(iw/2)*2:trunc(ih/2)*2:0:0");
    expect(args).not.toContain("-filter_complex");
    // the crop must precede the output file, not trail it
    expect(vf).toBeLessThan(args.length - 1);
  });

  it("does not add a second base filter when a watermark graph already evens it", () => {
    // buildWatermarkGraph handles the even-base crop itself, so the args must not
    // also carry a -vf (ffmpeg rejects -vf alongside -filter_complex on one map).
    const args = ffmpegArgs({
      outputFile: "/tmp/out.mp4",
      logoFile: "/tmp/logo.png",
      graph: "[0:v]fps=30,split=2[base][under];[base][x]overlay[out]",
    });
    expect(args).not.toContain("-vf");
    expect(args).toContain("-filter_complex");
  });

  it("fails the start when ffmpeg is not installed", async () => {
    const api = await makeSession(iosDevice);
    mockResolveFfmpeg.mockResolvedValue(null);

    try {
      await startAndSettle(api);
      expect.unreachable();
    } catch (err) {
      expect(getFailureSignal(err)?.error_code).toBe(
        FAILURE_CODES.SCREEN_RECORDING_FFMPEG_NOT_FOUND
      );
    }
    expect(mockSpawn).not.toHaveBeenCalled();
    expect(getActiveScreenRecordings()).toHaveLength(0);
    expect(api.startPending).toBe(false);
  });

  it("fails the start (and closes the stream) when no frame ever arrives", async () => {
    const api = await makeSession(iosDevice);
    const streamError = new Error("no frame");
    const stream = fakeStream({
      waitForFirstFrame: vi.fn(async () => {
        throw streamError;
      }),
    });

    await expect(startAndSettle(api)).rejects.toThrow("no frame");
    expect(stream.close).toHaveBeenCalled();
    expect(mockSpawn).not.toHaveBeenCalled();
    expect(api.recordingActive).toBe(false);
  });

  it("fails the start when ffmpeg dies inside the fail-fast grace", async () => {
    const api = await makeSession(iosDevice);
    const stream = fakeStream();
    const child = fakeChild();

    const promise = startCapture(api, {
      streamUrl: STREAM_URL,
      timeLimitSeconds: 30,
      watermark: false,
      trimStatic: false,
    });
    await vi.advanceTimersByTimeAsync(1);
    child.stderr.emit("data", Buffer.from("Unrecognized option 'bogus'\n"));
    child.exit(1);

    try {
      await promise;
      expect.unreachable();
    } catch (err) {
      expect(getFailureSignal(err)?.error_code).toBe(FAILURE_CODES.SCREEN_RECORDING_START_EXITED);
      expect((err as Error).message).toContain("Unrecognized option");
    }
    expect(stream.close).toHaveBeenCalled();
    expect(api.recordingActive).toBe(false);
    expect(getActiveScreenRecordings()).toHaveLength(0);
  });

  it("rejects a second start while a recording is active", async () => {
    const api = await makeSession(iosDevice);
    fakeStream();
    fakeChild();
    await startAndSettle(api);

    fakeStream();
    fakeChild();
    try {
      await startAndSettle(api);
      expect.unreachable();
    } catch (err) {
      expect(getFailureSignal(err)?.error_code).toBe(FAILURE_CODES.SCREEN_RECORDING_ALREADY_ACTIVE);
    }
  });

  it("rejects a start that overlaps another start's readiness window", async () => {
    const api = await makeSession(iosDevice);
    fakeStream();
    fakeChild();
    const first = startCapture(api, {
      streamUrl: STREAM_URL,
      timeLimitSeconds: 30,
      watermark: false,
      trimStatic: false,
    });

    // Second start lands while the first is still inside its grace.
    await expect(
      startCapture(api, {
        streamUrl: STREAM_URL,
        timeLimitSeconds: 30,
        watermark: false,
        trimStatic: false,
      })
    ).rejects.toThrow(/already in flight|already running/i);

    await vi.advanceTimersByTimeAsync(READY_GRACE_MS);
    await first;
  });

  it("rejects a stop while a start is still in flight on the session", async () => {
    const api = await makeSession(iosDevice);
    fakeStream();
    fakeChild();
    const first = startCapture(api, {
      streamUrl: STREAM_URL,
      timeLimitSeconds: 30,
      watermark: false,
      trimStatic: false,
    });

    try {
      await stopCapture(api);
      expect.unreachable();
    } catch (err) {
      expect(getFailureSignal(err)?.error_code).toBe(FAILURE_CODES.SCREEN_RECORDING_ALREADY_ACTIVE);
    }

    await vi.advanceTimersByTimeAsync(READY_GRACE_MS);
    await first;
  });

  it("a superseded capture's exit no longer touches the new capture's session", async () => {
    const api = await makeSession(iosDevice);
    fakeStream();
    const first = fakeChild();
    await startAndSettle(api);

    // Simulate the first capture ending and being stopped, then a fresh start.
    first.exitOnStdinEnd();
    await fs.writeFile(api.outputFile!, Buffer.alloc(16, 1));
    const firstOutput = api.outputFile!;
    await stopCapture(api);
    await fs.rm(firstOutput, { force: true });

    fakeStream();
    const second = fakeChild();
    await startAndSettle(api);
    const secondOutput = api.outputFile;

    first.exit(0);

    expect(api.recordingActive).toBe(true);
    expect(api.captureProcess).toBe(second as unknown as ChildProcess);
    expect(api.outputFile).toBe(secondOutput);
  });

  it("aborts a start (no spawn) once the session has been disposed", async () => {
    const instance = await screenRecordingSessionBlueprint.factory({}, iosDevice, {
      device: iosDevice,
    } as never);
    const api = instance.api;
    api.disposed = true;
    const stream = fakeStream();

    try {
      await startAndSettle(api);
      expect.unreachable();
    } catch (err) {
      expect(getFailureSignal(err)?.error_code).toBe(
        FAILURE_CODES.SCREEN_RECORDING_SERVER_SHUTTING_DOWN
      );
      // The error CODE is not the behaviour here — its enum name still says
      // "shutting down", which is exactly the claim the message stopped making.
      // A dispose is now far more often a `stop-all-simulator-servers` reaping
      // this device than a process shutdown, and the two are indistinguishable
      // from `api.disposed`. So the message must name both, and must not tell
      // the caller a retry is pointless: on the teardown branch the device is
      // usually still up. Asserted here because reverting the whole rewrite to
      // the old one-liner otherwise leaves the suite green.
      const message = (err as Error).message;
      expect(message).toContain("stop-all-simulator-servers");
      expect(message).toContain("nothing was recorded");
      expect(message).toContain("start the recording again");
      expect(message).toContain(IOS_UDID);
    }
    expect(mockSpawn).not.toHaveBeenCalled();
    expect(stream.close).toHaveBeenCalled();
  });
});

describe("frame pump", () => {
  it("tops the encoder up to the frame count the elapsed time calls for", () => {
    expect(framesDue(1_000, 1_000)).toBe(0);
    expect(framesDue(1_000, 1_033)).toBe(0);
    expect(framesDue(1_000, 1_034)).toBe(1);
    expect(framesDue(1_000, 2_000)).toBe(30);
  });

  it("keeps re-emitting the last frame while the screen is static", async () => {
    const api = await makeSession(iosDevice);
    // A still screen produces exactly one frame and then nothing.
    const stream = fakeStream({ frameCount: 1 });
    const child = fakeChild();
    await startAndSettle(api);
    child.stdin.writes.length = 0;

    await vi.advanceTimersByTimeAsync(1_000);

    // ~1s of a 30fps timeline, all duplicates of the one frame we ever saw.
    expect(child.stdin.writes.length).toBeGreaterThanOrEqual(25);
    expect(child.stdin.writes.every((w) => w.equals(stream.latest!))).toBe(true);
  });

  it("writes newly arrived frames once the device draws again", async () => {
    const api = await makeSession(iosDevice);
    const stream = fakeStream();
    const child = fakeChild();
    await startAndSettle(api);
    child.stdin.writes.length = 0;

    const nextFrame = fakeJpeg(640, 480);
    stream.latest = nextFrame;
    await vi.advanceTimersByTimeAsync(200);

    expect(child.stdin.writes.at(-1)!.equals(nextFrame)).toBe(true);
  });

  it("skips ticks while ffmpeg's pipe is backed up instead of buffering in Node", async () => {
    const api = await makeSession(iosDevice);
    fakeStream();
    const child = fakeChild();
    await startAndSettle(api);
    child.stdin.writes.length = 0;
    child.stdin.writableLength = 64 * 1024 * 1024; // encoder is far behind

    await vi.advanceTimersByTimeAsync(1_000);

    expect(child.stdin.writes).toHaveLength(0);
  });

  it("stops writing once the capture has been stopped", async () => {
    const api = await makeSession(iosDevice);
    fakeStream();
    const child = fakeChild();
    child.exitOnStdinEnd();
    await startAndSettle(api);
    await fs.writeFile(api.outputFile!, Buffer.alloc(32, 1));
    const outputFile = api.outputFile!;

    await stopCapture(api);
    const writesAtStop = child.stdin.writes.length;
    await vi.advanceTimersByTimeAsync(1_000);

    expect(child.stdin.writes).toHaveLength(writesAtStop);
    await fs.rm(outputFile, { force: true });
  });
});

describe("static-frame trimming", () => {
  it("defaults on for a new session", async () => {
    const api = await makeSession(iosDevice);
    expect(api.trimStatic).toBe(true);
  });

  it("keeps only the grace window of a long static stretch", async () => {
    const api = await makeSession(iosDevice);
    fakeStream({ frameCount: 1 });
    const child = fakeChild();
    await startAndSettle(api, { trimStatic: true });
    child.stdin.writes.length = 0;

    await vi.advanceTimersByTimeAsync(5_000);

    // ~1s of held frames (the grace), then nothing for the remaining 4s.
    expect(child.stdin.writes.length).toBeGreaterThanOrEqual(27);
    expect(child.stdin.writes.length).toBeLessThanOrEqual(34);
  });

  it("does NOT trim when the same stretch is recorded with trimStatic off", async () => {
    const api = await makeSession(iosDevice);
    fakeStream({ frameCount: 1 });
    const child = fakeChild();
    await startAndSettle(api, { trimStatic: false });
    child.stdin.writes.length = 0;

    await vi.advanceTimersByTimeAsync(5_000);

    // Full 5s of the timeline, ~150 frames.
    expect(child.stdin.writes.length).toBeGreaterThanOrEqual(140);
  });

  it("resumes emitting the moment the screen changes after a dead stretch", async () => {
    const api = await makeSession(iosDevice);
    const stream = fakeStream({ frameCount: 1 });
    const child = fakeChild();
    await startAndSettle(api, { trimStatic: true });

    await vi.advanceTimersByTimeAsync(4_000); // long static — trimmed after 1s
    const framesAfterStatic = api.framesWritten;
    child.stdin.writes.length = 0;

    const moved = fakeJpeg(640, 480); // a genuinely different picture
    stream.latest = moved;
    await vi.advanceTimersByTimeAsync(500);

    // New content is written, and the skipped 3s did not become catch-up frames.
    expect(child.stdin.writes.length).toBeGreaterThan(0);
    expect(child.stdin.writes.every((w) => w.equals(moved))).toBe(true);
    expect(api.framesWritten - framesAfterStatic).toBeLessThanOrEqual(20);
  });

  it("treats a byte-identical new frame as no change (stays trimmed)", async () => {
    const api = await makeSession(iosDevice);
    const stream = fakeStream({ frameCount: 1 });
    const child = fakeChild();
    await startAndSettle(api, { trimStatic: true });

    await vi.advanceTimersByTimeAsync(2_000); // trimmed after the grace
    child.stdin.writes.length = 0;

    // A NEW buffer object, but the same pixels: must not un-trim.
    stream.latest = fakeJpeg(1320, 2868);
    await vi.advanceTimersByTimeAsync(1_000);

    expect(child.stdin.writes).toHaveLength(0);
  });

  it("reports the trimmed length plus the wall clock and how much was cut", async () => {
    const api = await makeSession(iosDevice);
    fakeStream({ frameCount: 1 });
    const child = fakeChild();
    child.exitOnStdinEnd();
    await startAndSettle(api, { trimStatic: true });

    await vi.advanceTimersByTimeAsync(5_000); // 5s wall clock, ~1s of kept frames
    await fs.writeFile(api.outputFile!, Buffer.alloc(64, 1));
    const outputFile = api.outputFile!;

    const result = await stopCapture(api);

    expect(result.durationMs).toBeGreaterThanOrEqual(800);
    expect(result.durationMs).toBeLessThanOrEqual(1_300);
    expect(result.wallClockMs).toBeGreaterThanOrEqual(4_800);
    expect(result.trimmedMs).toBeGreaterThan(3_000);
    await fs.rm(outputFile, { force: true });
  });

  it("omits wallClockMs/trimmedMs when trimming is on but nothing was static", async () => {
    const api = await makeSession(iosDevice);
    const stream = fakeStream({ frameCount: 1 });
    const child = fakeChild();
    child.exitOnStdinEnd();
    await startAndSettle(api, { trimStatic: true });

    // Drive continuous motion: a fresh, distinct frame every tick so the pump
    // never crosses the static grace and trims nothing.
    const frameIntervalMs = 1000 / 30;
    for (let i = 0; i < 90; i++) {
      // A distinct picture each tick (trailing byte differs) — never static.
      stream.latest = Buffer.concat([fakeJpeg(1320, 2868), Buffer.from([i])]);
      await vi.advanceTimersByTimeAsync(frameIntervalMs);
    }
    await fs.writeFile(api.outputFile!, Buffer.alloc(64, 1));
    const outputFile = api.outputFile!;

    const result = await stopCapture(api);

    // Nothing was trimmed, so the trim-only fields must be absent — a small
    // rounding gap between framesWritten and the wall clock is not "trimming".
    expect(result.wallClockMs).toBeUndefined();
    expect(result.trimmedMs).toBeUndefined();
    await fs.rm(outputFile, { force: true });
  });

  it("omits wallClockMs/trimmedMs when trimming is off", async () => {
    const api = await makeSession(iosDevice);
    fakeStream({ frameCount: 1 });
    const child = fakeChild();
    child.exitOnStdinEnd();
    await startAndSettle(api, { trimStatic: false });

    await vi.advanceTimersByTimeAsync(2_000);
    await fs.writeFile(api.outputFile!, Buffer.alloc(64, 1));
    const outputFile = api.outputFile!;

    const result = await stopCapture(api);

    expect(result.wallClockMs).toBeUndefined();
    expect(result.trimmedMs).toBeUndefined();
    await fs.rm(outputFile, { force: true });
  });
});

describe("touch visualizer", () => {
  it("enables the overlay at start and restores it to off at stop", async () => {
    const api = await makeSession(iosDevice);
    fakeStream();
    const child = fakeChild();
    child.exitOnStdinEnd();
    const pointer = fakePointer();

    await startAndSettle(api, { pointer });
    expect(pointer.enable).toHaveBeenCalledTimes(1);
    expect(pointer.disable).not.toHaveBeenCalled();
    expect(api.pointerFailed).toBe(false);
    expect(api.pointerDisable).toBe(pointer.disable);

    await fs.writeFile(api.outputFile!, Buffer.alloc(64, 1));
    const outputFile = api.outputFile!;
    const result = await stopCapture(api);

    expect(pointer.disable).toHaveBeenCalledTimes(1);
    expect(api.pointerDisable).toBeNull();
    expect(result.warning).toBeUndefined();
    await fs.rm(outputFile, { force: true });
  });

  it("restores the overlay when the time-limit cap fires", async () => {
    const api = await makeSession(iosDevice);
    fakeStream();
    const child = fakeChild();
    child.exitOnStdinEnd();
    const pointer = fakePointer();

    await startAndSettle(api, { timeLimitSeconds: 5, pointer });
    await vi.advanceTimersByTimeAsync(5_000); // cap fires

    expect(pointer.disable).toHaveBeenCalledTimes(1);
    expect(api.recordingTimedOut).toBe(true);
  });

  it("restores the overlay when the encoder dies unexpectedly", async () => {
    const api = await makeSession(iosDevice);
    fakeStream();
    const child = fakeChild();
    const pointer = fakePointer();
    await startAndSettle(api, { pointer });

    child.exit(1); // crash mid-capture

    expect(pointer.disable).toHaveBeenCalledTimes(1);
    expect(api.recordingExitedUnexpectedly).toBe(true);
  });

  it("observes an encoder crash that lands during the pointer-enable await", async () => {
    const api = await makeSession(iosDevice);
    fakeStream();
    const child = fakeChild();

    // Park enable() in flight so the start suspends exactly in the window
    // between ffmpeg readiness and the exit-handler registration — the gap where
    // a crash would go unobserved unless the `exit` listener is armed first.
    let releaseEnable!: () => void;
    const enableParked = new Promise<void>((resolve) => (releaseEnable = resolve));
    const enable = vi.fn(async () => {
      await enableParked;
      return true;
    });
    const pointer = { enable, disable: vi.fn(async () => {}) } satisfies PointerControl;

    const promise = startCapture(api, {
      streamUrl: STREAM_URL,
      timeLimitSeconds: 180,
      watermark: false,
      trimStatic: false,
      pointer,
    });
    promise.catch(() => {});
    // Clear the fail-fast grace so readiness resolves and the start parks at
    // `await enable()`.
    await vi.advanceTimersByTimeAsync(READY_GRACE_MS);
    expect(enable).toHaveBeenCalledTimes(1); // enable is now parked in flight

    child.exit(1); // ffmpeg dies WHILE the enable await is still suspended

    // The death must be seen: with the exit listener armed before the await, the
    // crash flips the recording into its unexpected-exit recovery state so a
    // later stop warns and returns the (truncated) file instead of a silent one.
    expect(api.recordingExitedUnexpectedly).toBe(true);
    expect(api.pendingRetrieval).toBe(true);

    releaseEnable();
    await promise;
  });

  it("restores the overlay on session dispose", async () => {
    const instance = await screenRecordingSessionBlueprint.factory({}, iosDevice, {
      device: iosDevice,
    } as never);
    const api = instance.api;
    fakeStream();
    const child = fakeChild();
    child.exitOnStdinEnd();
    const pointer = fakePointer();
    await startAndSettle(api, { pointer });

    await instance.dispose();

    expect(pointer.disable).toHaveBeenCalledTimes(1);
    expect(api.pointerDisable).toBeNull();
  });

  it("warns at stop when the overlay could not be enabled", async () => {
    const api = await makeSession(iosDevice);
    fakeStream();
    const child = fakeChild();
    child.exitOnStdinEnd();
    const pointer = fakePointer(false); // sim-server refused the toggle

    await startAndSettle(api, { pointer });
    expect(api.pointerFailed).toBe(true);

    await fs.writeFile(api.outputFile!, Buffer.alloc(64, 1));
    const outputFile = api.outputFile!;
    const result = await stopCapture(api);

    // Even a failed enable is still restored to off, best-effort.
    expect(pointer.disable).toHaveBeenCalled();
    expect(result.warning).toContain("touch visualizer could not be enabled");
    expect(api.pointerFailed).toBe(false); // reset for the next recording
    await fs.rm(outputFile, { force: true });
  });

  it("leaves the pointer untouched when no control is supplied", async () => {
    const api = await makeSession(iosDevice);
    fakeStream();
    const child = fakeChild();
    child.exitOnStdinEnd();

    await startAndSettle(api); // showTouches off → no PointerControl
    expect(api.pointerDisable).toBeNull();
    expect(api.pointerFailed).toBe(false);

    await fs.writeFile(api.outputFile!, Buffer.alloc(64, 1));
    const outputFile = api.outputFile!;
    const result = await stopCapture(api);

    expect(result.warning).toBeUndefined();
    await fs.rm(outputFile, { force: true });
  });

  it("clears a stale failed-enable flag at start so a later showTouches:false recording is clean", async () => {
    const api = await makeSession(iosDevice);

    // A cap- or crash-ended recording leaves `pointerFailed` set: only stop and a
    // fresh start clear it, and neither the cap nor the crash path runs stop's
    // reset. Set that residue directly instead of driving a real cap-then-start.
    // On this branch such a start is still admitted (assertNoActiveRecording gates
    // only on recordingActive/startPending/stopPending), but #517's guard — already
    // on origin/feat/screen-recording, not yet in this base — additionally rejects a
    // start while a finalized recording awaits retrieval (`pendingRetrieval`), so a
    // cap-then-start would throw once the stack rebases. Driving the flag in
    // directly keeps this test valid under both guards; it asserts only that a fresh
    // start scrubs the flag, so an overlay-free recording never inherits a spurious
    // touch-visualizer warning.
    api.pointerFailed = true;

    fakeStream();
    const child = fakeChild();
    child.exitOnStdinEnd();
    await startAndSettle(api); // showTouches off → no PointerControl
    expect(api.pointerFailed).toBe(false); // start's reset scrubbed the stale flag

    await fs.writeFile(api.outputFile!, Buffer.alloc(64, 1));
    const outputFile = api.outputFile!;
    const result = await stopCapture(api);
    expect(result.warning).toBeUndefined();
    await fs.rm(outputFile, { force: true });
  });
});

describe("touch visualizer wire protocol", () => {
  const fakeApi = { apiUrl: "http://127.0.0.1:65500" } as SimulatorServerApi;

  afterEach(() => {
    vi.unstubAllGlobals();
  });

  it("setPointerVisible POSTs {show} and reads status ok", async () => {
    const fetchMock = vi.fn(
      async (_url: string, _init?: RequestInit) => new Response(JSON.stringify({ status: "ok" }))
    );
    vi.stubGlobal("fetch", fetchMock);

    await expect(setPointerVisible(fakeApi, true)).resolves.toBe(true);

    const [url, init] = fetchMock.mock.calls[0]!;
    expect(url).toBe("http://127.0.0.1:65500/api/pointer");
    expect(init).toMatchObject({ method: "POST" });
    expect(JSON.parse(init!.body as string)).toEqual({ show: true });
  });

  it("setPointerTrail POSTs {trail}", async () => {
    const fetchMock = vi.fn(
      async (_url: string, _init?: RequestInit) => new Response(JSON.stringify({ status: "ok" }))
    );
    vi.stubGlobal("fetch", fetchMock);

    await expect(setPointerTrail(fakeApi, 8)).resolves.toBe(true);
    expect(JSON.parse(fetchMock.mock.calls[0]![1]!.body as string)).toEqual({ trail: 8 });
  });

  it("returns false on an error response body", async () => {
    vi.stubGlobal(
      "fetch",
      vi.fn(async () => new Response(JSON.stringify({ error: "pointer feature disabled" })))
    );
    await expect(setPointerVisible(fakeApi, true)).resolves.toBe(false);
  });

  it("returns false when the request throws (unreachable / aborted)", async () => {
    vi.stubGlobal(
      "fetch",
      vi.fn(async () => {
        throw new Error("ECONNREFUSED");
      })
    );
    await expect(setPointerVisible(fakeApi, false)).resolves.toBe(false);
  });

  it("issues disable's show:false only after an in-flight enable's show:true", async () => {
    // Model a dispose racing the enable await: enable's `show:true` is parked
    // in flight when disable is called. The control must serialize them so the
    // overlay ends OFF — otherwise disable's `show:false` is issued first and is
    // overtaken by the later `show:true`, leaving the overlay stuck on.
    const ops: Array<Record<string, unknown>> = [];
    let releaseShowTrue!: () => void;
    const showTrueParked = new Promise<void>((resolve) => (releaseShowTrue = resolve));
    const fetchMock = vi.fn(async (_url: string, init?: RequestInit) => {
      const body = JSON.parse(init!.body as string) as Record<string, unknown>;
      if (body.show === true) await showTrueParked; // hold enable's overlay toggle
      ops.push(body);
      return new Response(JSON.stringify({ status: "ok" }));
    });
    vi.stubGlobal("fetch", fetchMock);

    const control = makePointerControl(fakeApi);
    const enablePromise = control.enable();
    // enable's trail POST resolves; its show:true is now parked. Race disable in.
    const disablePromise = control.disable();
    // Flush microtasks: an unserialized disable would fire show:false here.
    for (let i = 0; i < 20; i++) await Promise.resolve();
    expect(ops).toEqual([{ trail: 8 }]); // no show yet

    releaseShowTrue();
    await Promise.all([enablePromise, disablePromise]);

    // Serialized: trail, then show:true, then show:false last → overlay ends off.
    expect(ops).toEqual([{ trail: 8 }, { show: true }, { show: false }]);
  });

  it("disable() still issues show:false when no enable is in flight", async () => {
    // The ordinary stop path: enable() has already resolved (enabling === null),
    // so disable() takes the non-parked branch. It must still send show:false —
    // otherwise a plain stop would leave the overlay on for the next screenshot.
    const ops: Array<Record<string, unknown>> = [];
    const fetchMock = vi.fn(async (_url: string, init?: RequestInit) => {
      ops.push(JSON.parse(init!.body as string) as Record<string, unknown>);
      return new Response(JSON.stringify({ status: "ok" }));
    });
    vi.stubGlobal("fetch", fetchMock);

    const control = makePointerControl(fakeApi);
    await control.enable(); // fully settles → enabling back to null
    await control.disable(); // idle path, nothing to await first

    expect(ops).toEqual([{ trail: 8 }, { show: true }, { show: false }]);
  });

  it("enable() reflects the show result even when the trail request fails", async () => {
    // The trail is only cosmetic, so a non-ok trail must not make enable() report
    // the overlay as failed: enable() returns the show toggle's result. Otherwise
    // stop would warn "touch visualizer could not be enabled" on a video that does
    // show touches.
    vi.stubGlobal(
      "fetch",
      vi.fn(async (_url: string, init?: RequestInit) => {
        const body = JSON.parse(init!.body as string) as Record<string, unknown>;
        const payload = "trail" in body ? { error: "trail unsupported" } : { status: "ok" };
        return new Response(JSON.stringify(payload));
      })
    );

    const control = makePointerControl(fakeApi);
    await expect(control.enable()).resolves.toBe(true);
  });
});

describe("screen recording stop", () => {
  it("finalizes the file, clears the session state and clears the reminder", async () => {
    const api = await makeSession(androidDevice);
    const stream = fakeStream();
    const child = fakeChild();
    child.exitOnStdinEnd();
    await startAndSettle(api);
    await fs.writeFile(api.outputFile!, Buffer.alloc(1024, 1));
    const outputFile = api.outputFile!;

    const result = await stopCapture(api);

    expect(result.outputFile).toBe(outputFile);
    expect(result.sizeBytes).toBe(1024);
    expect(result.durationMs).not.toBeNull();
    expect(result.warning).toBeUndefined();
    expect(child.stdin.ended).toBe(true);
    expect(stream.close).toHaveBeenCalled();
    expect(api.recordingActive).toBe(false);
    expect(api.outputFile).toBeNull();
    expect(api.pumpTimer).toBeNull();
    expect(getActiveScreenRecordings()).toHaveLength(0);

    await fs.rm(outputFile, { force: true });
  });

  it("leaves the finalized video ON DISK after a successful stop", async () => {
    // Invariant: screen-recording-stop registers the artifact AFTER stopCapture
    // returns, so a successful stop must never delete its own output. Guards
    // against any fail-open cleanup (a "delete unless a success flag is set"
    // finally) that a later refactor could trip into wiping every recording.
    const api = await makeSession(iosDevice);
    fakeStream();
    const child = fakeChild();
    child.exitOnStdinEnd();
    await startAndSettle(api);
    const outputFile = api.outputFile!;
    await fs.writeFile(outputFile, Buffer.alloc(4096, 1)); // a real, non-empty video

    const result = await stopCapture(api);
    expect(result.outputFile).toBe(outputFile);

    const sizeOnDisk = await fs
      .stat(outputFile)
      .then((s) => s.size)
      .catch(() => -1);
    await fs.rm(outputFile, { force: true }).catch(() => {});
    expect(sizeOnDisk).toBe(4096);
  });

  it("stop with no session fails with SCREEN_RECORDING_NO_ACTIVE_SESSION", async () => {
    const api = await makeSession(iosDevice);
    try {
      await stopCapture(api);
      expect.unreachable();
    } catch (err) {
      expect(getFailureSignal(err)?.error_code).toBe(
        FAILURE_CODES.SCREEN_RECORDING_NO_ACTIVE_SESSION
      );
    }
  });

  it("ends the capture at the time-limit cap and flips the reminder to finalized", async () => {
    const api = await makeSession(iosDevice);
    const stream = fakeStream();
    const child = fakeChild();
    child.exitOnStdinEnd();
    await startAndSettle(api, { timeLimitSeconds: 5 });

    await vi.advanceTimersByTimeAsync(5_000);

    expect(child.stdin.ended).toBe(true);
    expect(stream.close).toHaveBeenCalled();
    expect(api.recordingActive).toBe(false);
    expect(api.recordingTimedOut).toBe(true);
    expect(api.pendingRetrieval).toBe(true);
    const [reminder] = getActiveScreenRecordings();
    expect(reminder?.finalizedReason).toContain("5s time limit");
  });

  it("rejects a start while a capped recording still awaits retrieval, keeping the first video reachable", async () => {
    const api = await makeSession(iosDevice);
    fakeStream();
    const child = fakeChild();
    child.exitOnStdinEnd();
    await startAndSettle(api, { timeLimitSeconds: 5 });

    await vi.advanceTimersByTimeAsync(5_000); // cap fires -> pendingRetrieval
    expect(api.pendingRetrieval).toBe(true);
    const firstOutput = api.outputFile!;
    const firstLogo = api.logoFile;

    // Admitting a start here would overwrite outputFile/logoFile and orphan the
    // finalized-but-unretrieved video (the state stop still recovers from), so
    // the guard must reject it and point the agent at stop instead.
    fakeStream();
    fakeChild();
    try {
      await startAndSettle(api);
      expect.unreachable();
    } catch (err) {
      expect(getFailureSignal(err)?.error_code).toBe(FAILURE_CODES.SCREEN_RECORDING_ALREADY_ACTIVE);
    }
    // The first recording's session pointers are untouched -> still retrievable.
    expect(api.outputFile).toBe(firstOutput);
    expect(api.logoFile).toBe(firstLogo);
    expect(api.pendingRetrieval).toBe(true);
  });

  it("durationMs reflects the capture length, not the idle time after the cap", async () => {
    const api = await makeSession(iosDevice);
    fakeStream();
    const child = fakeChild();
    child.exitOnStdinEnd();
    await startAndSettle(api, { timeLimitSeconds: 5 });

    await vi.advanceTimersByTimeAsync(5_000); // cap fires
    await vi.advanceTimersByTimeAsync(30_000); // agent notices much later
    await fs.writeFile(api.outputFile!, Buffer.alloc(64, 1));
    const outputFile = api.outputFile!;

    const result = await stopCapture(api);

    expect(result.durationMs).toBeGreaterThanOrEqual(5_000);
    expect(result.durationMs).toBeLessThan(6_000);
    expect(result.warning).toContain("time limit");
    await fs.rm(outputFile, { force: true });
  });

  it("recovers the video when ffmpeg died before stop, with a warning", async () => {
    const api = await makeSession(iosDevice);
    fakeStream();
    const child = fakeChild();
    await startAndSettle(api);
    await fs.writeFile(api.outputFile!, Buffer.alloc(128, 1));
    const outputFile = api.outputFile!;

    child.exit(1); // encoder crashed mid-capture
    expect(api.pendingRetrieval).toBe(true);
    expect(api.recordingExitedUnexpectedly).toBe(true);

    const result = await stopCapture(api);

    expect(result.outputFile).toBe(outputFile);
    expect(result.warning).toContain("exited before stop");
    expect(getActiveScreenRecordings()).toHaveLength(0);
    await fs.rm(outputFile, { force: true });
  });

  it("warns when the frame stream dropped during the recording", async () => {
    const api = await makeSession(iosDevice);
    const stream = fakeStream();
    const child = fakeChild();
    child.exitOnStdinEnd();
    await startAndSettle(api);
    await fs.writeFile(api.outputFile!, Buffer.alloc(64, 1));
    const outputFile = api.outputFile!;
    stream.error = new Error("frame stream aborted");

    const result = await stopCapture(api);

    expect(result.warning).toContain("frame stream");
    await fs.rm(outputFile, { force: true });
  });

  it("still reports a frame-stream drop when the cap fired after the drop", async () => {
    const api = await makeSession(iosDevice);
    const stream = fakeStream();
    const child = fakeChild();
    child.exitOnStdinEnd();
    await startAndSettle(api, { timeLimitSeconds: 5 });
    // Stream drops mid-recording, THEN the cap fires. The cap's finalize nulls
    // api.frameStream, so a stop that reads api.frameStream.error afterwards
    // would lose the drop entirely and never emit the freeze hint.
    stream.error = new Error("frame stream aborted");
    await vi.advanceTimersByTimeAsync(5_000); // cap fires, nulls frameStream
    await fs.writeFile(api.outputFile!, Buffer.alloc(64, 1));
    const outputFile = api.outputFile!;

    const result = await stopCapture(api);

    // Both the cap notice and the freeze hint must survive.
    expect(result.warning).toContain("time limit");
    expect(result.warning).toContain("frame stream");
    await fs.rm(outputFile, { force: true });
  });

  it("stop fails loudly when the recording left no file behind", async () => {
    const api = await makeSession(iosDevice);
    fakeStream();
    const child = fakeChild();
    child.exitOnStdinEnd();
    await startAndSettle(api);

    try {
      await stopCapture(api);
      expect.unreachable();
    } catch (err) {
      expect(getFailureSignal(err)?.error_code).toBe(FAILURE_CODES.SCREEN_RECORDING_OUTPUT_MISSING);
    }
    // The session must still be startable after a failed stop.
    expect(api.recordingActive).toBe(false);
    expect(api.stopPending).toBe(false);
  });

  it("removes the empty container rather than orphaning it when a stop fails", async () => {
    const api = await makeSession(iosDevice);
    fakeStream();
    const child = fakeChild();
    child.exitOnStdinEnd();
    await startAndSettle(api);
    // ffmpeg opened its output with `-y` but wrote nothing (odd-resolution
    // encode abort, disk full mid-header, ...): a real 0-byte file is on disk.
    const outputFile = api.outputFile!;
    await fs.writeFile(outputFile, Buffer.alloc(0));

    try {
      await stopCapture(api);
      expect.unreachable();
    } catch (err) {
      expect(getFailureSignal(err)?.error_code).toBe(FAILURE_CODES.SCREEN_RECORDING_OUTPUT_MISSING);
    }
    // The dead 0-byte temp must not be left behind in os.tmpdir.
    await expect(fs.access(outputFile)).rejects.toThrow();
    expect(api.recordingActive).toBe(false);
    expect(api.stopPending).toBe(false);
  });
});

describe("readJpegDimensions", () => {
  it("reads the frame size from the SOF marker", () => {
    expect(readJpegDimensions(fakeJpeg(1320, 2868))).toEqual({ width: 1320, height: 2868 });
    expect(readJpegDimensions(fakeJpeg(1080, 2220))).toEqual({ width: 1080, height: 2220 });
  });

  it("skips leading segments before the SOF", () => {
    const app0 = Buffer.alloc(20);
    app0.writeUInt16BE(0xffd8, 0);
    app0.writeUInt16BE(0xffe0, 2); // APP0
    app0.writeUInt16BE(16, 4); // segment length, skipped over
    const jpeg = Buffer.concat([app0.subarray(0, 20), fakeJpeg(800, 600).subarray(2)]);
    expect(readJpegDimensions(jpeg)).toEqual({ width: 800, height: 600 });
  });

  it("returns null when there is no frame header", () => {
    expect(readJpegDimensions(Buffer.from([0xff, 0xd8, 0xff, 0xd9]))).toBeNull();
  });

  it("skips 0xFF fill bytes before a marker (T.81 B.1.1.2)", () => {
    // A decoder-valid JPEG may pad any number of 0xFF fill bytes before a
    // marker. Splice extras in ahead of the SOF: ffprobe/libjpeg read this
    // fine, so the dimension reader must too rather than bailing to null and
    // silently dropping the watermark.
    const base = fakeJpeg(640, 480);
    const withFill = Buffer.concat([
      base.subarray(0, 2), // SOI
      Buffer.from([0xff, 0xff, 0xff]), // fill bytes before the SOF marker
      base.subarray(2), // SOF0 + payload + EOI
    ]);
    expect(readJpegDimensions(withFill)).toEqual({ width: 640, height: 480 });
  });
});