// @vitest-environment jsdom
//
// exposeVideoToBackgroundPlay: Brave iOS's background play hooks only a <video> that shows up as a
// MutationObserver addedNode itself. A video mounted inside a new wrapper in one go never does — this
// locks that the helper makes it one, once per element, without moving it.
import { describe, it, expect } from "vitest";
import { exposeVideoToBackgroundPlay } from "./browserBackgroundPlay";

// Brave's detection rule, re-implemented: count addedNodes that ARE a <video>.
async function videosSeenWhile(act: () => void): Promise<number> {
  let seen = 0;
  const observer = new MutationObserver((records) => {
    for (const r of records) r.addedNodes.forEach((n) => n instanceof HTMLVideoElement && seen++);
  });
  observer.observe(document, { childList: true, subtree: true });
  act();
  await Promise.resolve(); // MutationObserver callbacks are microtasks
  observer.disconnect();
  return seen;
}

function mountWrapped(): { wrapper: HTMLDivElement; video: HTMLVideoElement } {
  const wrapper = document.createElement("div");
  const before = document.createElement("span");
  const video = document.createElement("video");
  const after = document.createElement("span");
  wrapper.append(before, video, after);
  return { wrapper, video };
}

describe("exposeVideoToBackgroundPlay", () => {
  it("a video mounted inside its wrapper is invisible to the rule until exposed", async () => {
    const { wrapper, video } = mountWrapped();
    expect(await videosSeenWhile(() => document.body.append(wrapper))).toBe(0);
    expect(await videosSeenWhile(() => exposeVideoToBackgroundPlay(video))).toBe(1);
    wrapper.remove();
  });

  it("keeps the video exactly where it was", () => {
    const { wrapper, video } = mountWrapped();
    document.body.append(wrapper);
    exposeVideoToBackgroundPlay(video);
    expect([...wrapper.children].map((c) => c.tagName)).toEqual(["SPAN", "VIDEO", "SPAN"]);
    wrapper.remove();
  });

  it("acts once per element, so a ref callback running on every render adds nothing", async () => {
    const { wrapper, video } = mountWrapped();
    document.body.append(wrapper);
    exposeVideoToBackgroundPlay(video);
    expect(await videosSeenWhile(() => exposeVideoToBackgroundPlay(video))).toBe(0);
    wrapper.remove();
  });

  it("ignores null and a detached element", () => {
    expect(() => exposeVideoToBackgroundPlay(null)).not.toThrow();
    expect(() => exposeVideoToBackgroundPlay(document.createElement("video"))).not.toThrow();
  });
});