import { describe, it, expect } from "vitest";
import { ParentMediaManager, type ProxyEntry } from "./parent-media";

// A fake media element whose paused state is driven by play()/pause() stubs.
function makeFakeAudio(initiallyPaused: boolean): HTMLMediaElement {
  const el = new Audio();
  let paused = initiallyPaused;
  Object.defineProperty(el, "paused", { get: () => paused });
  el.pause = () => {
    paused = true;
  };
  el.play = () => {
    paused = false;
    return Promise.resolve();
  };
  el.src = "https://example.test/music.mp3";
  return el;
}

function makeManager(overrides: Partial<{ isPaused: boolean; owner: "runtime" | "parent" }> = {}) {
  const mgr = new ParentMediaManager({
    dispatchEvent: () => {},
    getMuted: () => false,
    getVolume: () => 1,
    getPlaybackRate: () => 1,
    getCurrentTime: () => 0,
    isPaused: () => overrides.isPaused ?? true,
  });
  return mgr;
}

describe("ParentMediaManager audio-src proxy lifecycle", () => {
  it("replaces the audio-src proxy instead of stacking a second one", () => {
    const mgr = makeManager();
    mgr.setupFromUrl("https://example.test/a.mp3");
    expect(mgr.entries).toHaveLength(1);

    mgr.setupFromUrl("https://example.test/b.mp3");
    // The old proxy must be gone, not accumulated alongside the new one.
    expect(mgr.entries).toHaveLength(1);
    expect(mgr.entries[0].el.src).toBe("https://example.test/b.mp3");
  });

  it("is a no-op when the same audio-src URL is set again", () => {
    const mgr = makeManager();
    mgr.setupFromUrl("https://example.test/a.mp3");
    const first = mgr.entries[0];

    mgr.setupFromUrl("https://example.test/a.mp3");
    expect(mgr.entries).toHaveLength(1);
    // Same element reference — not torn down and rebuilt.
    expect(mgr.entries[0]).toBe(first);
  });

  it("clears the audio-src proxy on teardownUrlAudio", () => {
    const mgr = makeManager();
    mgr.setupFromUrl("https://example.test/a.mp3");
    const el = mgr.entries[0].el;

    mgr.teardownUrlAudio();
    expect(mgr.entries).toHaveLength(0);
    // The proxy's source is reset so it stops preloading.
    expect(el.src).not.toBe("https://example.test/a.mp3");
  });

  it("teardownUrlAudio removes only the url proxy, leaving other entries", () => {
    const mgr = makeManager();
    // Simulate an iframe-adopted entry already in the pool.
    const adopted: ProxyEntry = {
      el: new Audio(),
      start: 0,
      duration: Infinity,
      driftSamples: 0,
    };
    adopted.el.src = "https://example.test/iframe-clip.mp4";
    mgr.entries.push(adopted);

    mgr.setupFromUrl("https://example.test/a.mp3");
    expect(mgr.entries).toHaveLength(2);

    mgr.teardownUrlAudio();
    expect(mgr.entries).toHaveLength(1);
    expect(mgr.entries[0]).toBe(adopted);
  });

  it("teardownUrlAudio is safe to call with no audio-src set", () => {
    const mgr = makeManager();
    expect(() => mgr.teardownUrlAudio()).not.toThrow();
    expect(mgr.entries).toHaveLength(0);
  });

  it("pauses a proxy once the playhead passes the clip end (trimmed clip)", () => {
    const mgr = makeManager({ owner: "parent", isPaused: false });
    const el = makeFakeAudio(false); // already playing within the clip
    mgr.entries.push({ el, start: 0, duration: 5, driftSamples: 0 });

    mgr.mirrorTime(3); // inside [0, 5) — stays playing
    expect(el.paused).toBe(false);

    mgr.mirrorTime(6); // past the trimmed end — must pause
    expect(el.paused).toBe(true);
  });

  it("re-reads the source element's live data-duration so trims bound the proxy", () => {
    const mgr = makeManager({ owner: "parent", isPaused: false });
    const source = new Audio();
    source.setAttribute("data-start", "0");
    source.setAttribute("data-duration", "30");
    // jsdom reports isConnected=false unless attached; attach it.
    document.body.appendChild(source);

    const el = makeFakeAudio(false);
    mgr.entries.push({ el, start: 0, duration: 30, driftSamples: 0, source });

    mgr.mirrorTime(20); // within 30 → playing
    expect(el.paused).toBe(false);

    // User trims the clip to 10s; the proxy must pick it up and pause at 20s.
    source.setAttribute("data-duration", "10");
    mgr.mirrorTime(20);
    expect(el.paused).toBe(true);
    source.remove();
  });

  it("does not duplicate or hijack a clip the composition already owns", () => {
    const mgr = makeManager();
    // The composition already adopted a clip with this URL.
    const adopted: ProxyEntry = {
      el: new Audio(),
      start: 0,
      duration: Infinity,
      driftSamples: 0,
    };
    adopted.el.src = "https://example.test/shared.mp3";
    mgr.entries.push(adopted);

    // Pointing audio-src at the same URL must not create a second proxy...
    mgr.setupFromUrl("https://example.test/shared.mp3");
    expect(mgr.entries).toHaveLength(1);
    expect(mgr.entries[0]).toBe(adopted);

    // ...and removing audio-src must not tear down the composition's own clip
    // (teardown targets the tracked proxy by reference, not by URL match).
    mgr.teardownUrlAudio();
    expect(mgr.entries).toHaveLength(1);
    expect(mgr.entries[0]).toBe(adopted);
  });
});
