siftlode/frontend/src/components/PlayerModal.dom.test.tsx

// @vitest-environment jsdom
//
// The YouTube player modal, rendered for real. Its pure helpers (afterRemoval, the progress cache)
// had tests; what the modal DOES with them had none — a deep-review of the 2026-09 bug hunt found
// that deleting the lines that apply them left every lane green.
//
// `window.YT` is a fake installed before the module's API loader first runs (that loader memoises
// its promise in a module-level singleton, so this file must not share a module instance with a
// test that leaves `window.YT` unset). Each item the modal plays constructs a new YT.Player, and the
// fake records what it was asked for — that is how these tests see where playback starts.
import { describe, it, expect, vi, afterEach, beforeAll, beforeEach } from "vitest";
import { render, screen, fireEvent, waitFor, cleanup, act } from "@testing-library/react";
import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
import type { ReactNode } from "react";

vi.mock("react-i18next", async (importOriginal) => {
  const actual = await importOriginal<typeof import("react-i18next")>();
  return {
    ...actual,
    useTranslation: () => ({
      t: (key: string, o?: Record<string, unknown>) => (o?.title ? `${key}:${o.title}` : key),
      i18n: { language: "en" },
    }),
  };
});
vi.mock("./NavigationProvider", () => ({ useNavigationActions: () => ({ openChannel: vi.fn() }) }));
// Their own queries and popovers are not what is under test here.
vi.mock("./AddToPlaylist", () => ({ default: () => null }));
vi.mock("./DownloadButton", () => ({ default: () => null }));

import PlayerModal from "./PlayerModal";
import { ConfirmProvider, useConfirm } from "./ConfirmProvider";
import { api, type Video } from "../lib/api";
import { clearAll, notify } from "../lib/notifications";

beforeAll(() => {
  class Stub {
    observe() {}
    unobserve() {}
    disconnect() {}
    takeRecords() {
      return [];
    }
  }
  globalThis.ResizeObserver ??= Stub as unknown as typeof ResizeObserver;
  globalThis.IntersectionObserver ??= Stub as unknown as typeof IntersectionObserver;
});

// --- the fake IFrame API ------------------------------------------------------------------------
const clock = { current: 0, duration: 3000 };
const started: { videoId: string; start: number | undefined }[] = [];
const base = {
  getCurrentTime: () => clock.current,
  getDuration: () => clock.duration,
  getVideoData: () => null,
};
// Anything else the modal calls on the player (volume, rate, destroy…) is a no-op. Not `then`:
// a thenable would be swallowed by the first `await` that touched it.
const fakePlayer = new Proxy(base, {
  get: (t, k) => (k in t ? t[k as keyof typeof t] : k === "then" ? undefined : () => undefined),
});
window.YT = {
  Player: function (_el: unknown, opts: { videoId: string; playerVars: { start?: number } }) {
    started.push({ videoId: opts.videoId, start: opts.playerVars.start });
    return fakePlayer;
  } as never,
};

const vid = (id: string, position_seconds: number): Video =>
  ({
    id,
    title: `Video ${id}`,
    channel_id: "UCx",
    channel_title: "Channel",
    status: "new",
    position_seconds,
    duration_seconds: 3000,
    watch_url: `https://www.youtube.com/watch?v=${id}`,
  }) as unknown as Video;

function renderModal(ui: ReactNode) {
  const qc = new QueryClient({ defaultOptions: { queries: { retry: false } } });
  return render(<QueryClientProvider client={qc}>{ui}</QueryClientProvider>);
}

afterEach(() => {
  cleanup();
  vi.restoreAllMocks();
  started.length = 0;
});

const lastStart = () => started[started.length - 1];

describe("PlayerModal — where each item starts", () => {
  it("resumes an item played earlier in the SAME session where this session left it", async () => {
    // The launch queue is frozen at mount, so its rows keep the position they were snapshotted
    // with (748). Stepping next→prev back to an item already watched to 830 used to start it at
    // 748 — and the next checkpoint then wrote 748 over the 830 the server held.
    vi.spyOn(api, "videoDetail").mockReturnValue(new Promise(() => {}));
    vi.spyOn(api, "saveProgress").mockImplementation(async (id: string) => ({
      video_id: id,
      position_seconds: id === "A" ? 830 : 0,
    }));
    const A = vid("A", 748);
    const B = vid("B", 0);
    clock.current = 830;
    renderModal(
      <PlayerModal video={A} queue={[A, B]} startIndex={0} onClose={() => {}} onState={() => {}} />,
    );
    await waitFor(() => expect(lastStart()).toEqual({ videoId: "A", start: 748 }));
    fireEvent.click(screen.getAllByRole("button", { name: "player.next" })[0]!);
    await waitFor(() => expect(lastStart()?.videoId).toBe("B"));
    fireEvent.click(screen.getAllByRole("button", { name: "player.previous" })[0]!);
    await waitFor(() => expect(lastStart()?.videoId).toBe("A"));
    expect(lastStart()?.start).toBe(830);
  });
});

// --- "remove from this playlist", from inside the player ----------------------------------------
const trash = (title: string) =>
  screen.getByRole("button", { name: `playlists.removeItemOf:Video ${title}` });
const next = () => fireEvent.click(screen.getAllByRole("button", { name: "player.next" })[0]!);
const prev = () => fireEvent.click(screen.getAllByRole("button", { name: "player.previous" })[0]!);
const settle = () => act(async () => {});

describe("PlayerModal — removing the playing video from its playlist", () => {
  const [A, B, C, D] = ["A", "B", "C", "D"].map((id) => vid(id, 0));
  beforeEach(() => {
    vi.spyOn(api, "videoDetail").mockReturnValue(new Promise(() => {}));
    vi.spyOn(api, "saveProgress").mockImplementation(async (id: string) => ({
      video_id: id,
      position_seconds: 0,
    }));
    clock.current = 0;
  });

  it("steps to the item that followed, and the removed one is gone from the queue", async () => {
    renderModal(
      <PlayerModal
        video={B!}
        queue={[A!, B!, C!]}
        startIndex={1}
        onClose={() => {}}
        onState={() => {}}
        onRemoveFromList={async () => true}
      />,
    );
    await waitFor(() => expect(lastStart()?.videoId).toBe("B"));
    fireEvent.click(trash("B"));
    await waitFor(() => expect(lastStart()?.videoId).toBe("C"));
    prev(); // …straight back to A: B is no longer there to step onto
    await waitFor(() => expect(lastStart()?.videoId).toBe("A"));
  });

  it("closes the player when the last item goes", async () => {
    const onClose = vi.fn();
    renderModal(
      <PlayerModal
        video={A!}
        queue={[A!]}
        startIndex={0}
        onClose={onClose}
        onState={() => {}}
        onRemoveFromList={async () => true}
      />,
    );
    await waitFor(() => expect(lastStart()?.videoId).toBe("A"));
    fireEvent.click(trash("A"));
    await waitFor(() => expect(onClose).toHaveBeenCalled());
  });

  it("leaves playback and the queue alone when the removal did not happen", async () => {
    const onClose = vi.fn();
    renderModal(
      <PlayerModal
        video={A!}
        queue={[A!, B!]}
        startIndex={0}
        onClose={onClose}
        onState={() => {}}
        onRemoveFromList={async () => false}
      />,
    );
    await waitFor(() => expect(lastStart()?.videoId).toBe("A"));
    fireEvent.click(trash("A"));
    await settle();
    expect(onClose).not.toHaveBeenCalled();
    expect(started.map((s) => s.videoId)).toEqual(["A"]);
    next();
    await waitFor(() => expect(lastStart()?.videoId).toBe("B"));
    prev(); // A is still in the queue
    await waitFor(() => expect(lastStart()?.videoId).toBe("A"));
  });

  it("keeps playback where the viewer went while the confirm was open", async () => {
    // prev/next keep working under the confirm dialog; deciding from the cursor as it was when the
    // button was pressed threw the viewer back onto a video they had already moved past.
    let answer!: (ok: boolean) => void;
    renderModal(
      <PlayerModal
        video={A!}
        queue={[A!, B!, C!, D!]}
        startIndex={0}
        onClose={() => {}}
        onState={() => {}}
        onRemoveFromList={() => new Promise<boolean>((r) => (answer = r))}
      />,
    );
    await waitFor(() => expect(lastStart()?.videoId).toBe("A"));
    fireEvent.click(trash("A"));
    next();
    await waitFor(() => expect(lastStart()?.videoId).toBe("B"));
    next();
    await waitFor(() => expect(lastStart()?.videoId).toBe("C"));
    await act(async () => answer(true));
    expect(lastStart()?.videoId).toBe("C");
    prev();
    await waitFor(() => expect(lastStart()?.videoId).toBe("B"));
    // …and A is gone from the queue, not just skipped over: B is its head now, so stepping back
    // again goes nowhere. (One step back lands on B either way — it took the second to tell.)
    prev();
    await settle();
    expect(lastStart()?.videoId).toBe("B");
    expect(started.filter((s) => s.videoId === "A")).toHaveLength(1); // never played again
  });

  it("gives focus back to the Remove button when the confirm is cancelled", async () => {
    // The button used to be disabled for the confirm's whole lifetime, so the dialog's focus
    // restore landed on a disabled element — a no-op — and a keyboard user was left on <body>,
    // outside the aria-modal player.
    function WithConfirm() {
      const confirm = useConfirm();
      return (
        <PlayerModal
          video={A!}
          queue={[A!, B!]}
          startIndex={0}
          onClose={() => {}}
          onState={() => {}}
          onRemoveFromList={(v) =>
            confirm({ title: "t", message: v.title, confirmLabel: "remove", danger: true })
          }
        />
      );
    }
    renderModal(
      <ConfirmProvider>
        <WithConfirm />
      </ConfirmProvider>,
    );
    await waitFor(() => expect(lastStart()?.videoId).toBe("A"));
    trash("A").focus();
    fireEvent.click(trash("A"));
    fireEvent.click(await screen.findByRole("button", { name: "common.cancel" }));
    await waitFor(() => expect(document.activeElement).toBe(trash("A")));
  });
});

describe("PlayerModal — toasts raised while it is open", () => {
  afterEach(() => act(() => clearAll()));

  it("shows them inside the player, not under its scrim", async () => {
    // The app's Toaster is in a stacking context below this body-level portal: a failed Remove
    // reported by a toast was drawn under the 80% black scrim, i.e. still silent.
    vi.spyOn(api, "videoDetail").mockReturnValue(new Promise(() => {}));
    const A = vid("A", 0);
    renderModal(
      <PlayerModal video={A} queue={[A]} startIndex={0} onClose={() => {}} onState={() => {}} />,
    );
    act(() => void notify({ level: "error", message: "Couldn't remove the video." }));
    expect(screen.getByTestId("player-modal").textContent).toContain("Couldn't remove the video.");
  });

  it("shows them inside the stage in true fullscreen — the element holding the lock", async () => {
    // Anything outside the fullscreen element is painted under it. The player's host sat beside the
    // card, so in fullscreen a lost connection was reported to nobody.
    vi.spyOn(api, "videoDetail").mockReturnValue(new Promise(() => {}));
    const A = vid("A", 0);
    renderModal(
      <PlayerModal video={A} queue={[A]} startIndex={0} onClose={() => {}} onState={() => {}} />,
    );
    const stage = document.querySelector(".player-stage")!;
    Object.defineProperty(document, "fullscreenElement", { configurable: true, get: () => stage });
    try {
      act(() => void document.dispatchEvent(new Event("fullscreenchange")));
      act(() => void notify({ level: "error", message: "Connection lost" }));
      await waitFor(() => expect(stage.textContent).toContain("Connection lost"));
    } finally {
      delete (document as { fullscreenElement?: unknown }).fullscreenElement;
    }
  });
});