// ==UserScript==
// @name         Instagram Background Play
// @description  Keep Instagram videos and reels playing when you switch tabs or apps. Stops Instagram from pausing playback the moment you look away, and keeps picture-in-picture live instead of frozen.
// @version      1.0.3
// @author       Zingzy
// @namespace    https://github.com/Zingzy/instagram-background-play
// @homepageURL  https://github.com/Zingzy/instagram-background-play
// @supportURL   https://github.com/Zingzy/instagram-background-play/issues
// @match        https://www.instagram.com/*
// @icon         https://www.google.com/s2/favicons?sz=64&domain=instagram.com
// @license      MIT
// @run-at       document-start
// @grant        none
// @downloadURL  https://raw.githubusercontent.com/Zingzy/instagram-background-play/main/instagram-background-play.user.js
// @updateURL    https://raw.githubusercontent.com/Zingzy/instagram-background-play/main/instagram-background-play.user.js
// ==/UserScript==

(function () {
  'use strict';

  // Instagram pauses playback as soon as the tab or window loses focus.
  // It detects this through the Page Visibility API and focus events,
  // and additionally calls pause() from its own player logic.
  // This script defuses all three paths.

  // Keep a handle on the real visibility getter before spoofing it,
  // so we can still tell when the tab is genuinely hidden.
  const nativeVisibility = Object.getOwnPropertyDescriptor(
    Document.prototype,
    'visibilityState'
  ).get;
  const reallyHidden = () => nativeVisibility.call(document) !== 'visible';

  // 1. Spoof the Page Visibility API: the page always reports "visible".
  Object.defineProperty(Document.prototype, 'visibilityState', {
    get: () => 'visible',
    configurable: true,
  });
  Object.defineProperty(Document.prototype, 'hidden', {
    get: () => false,
    configurable: true,
  });
  document.hasFocus = () => true;

  // 2. Swallow the events Instagram listens to for detecting you leaving.
  //    Capturing on window runs before any page listener can react.
  const block = (e) => e.stopImmediatePropagation();
  for (const type of [
    'visibilitychange',
    'webkitvisibilitychange',
    'blur',
    'focusout',
    'pagehide',
    'freeze',
  ]) {
    window.addEventListener(type, block, true);
  }

  // 3. The hammer: drop programmatic pause() calls while the tab is
  //    actually backgrounded. Manual pauses still work, since they happen
  //    while the tab is visible or go through browser UI (like
  //    picture-in-picture controls) which bypasses this method entirely.
  const nativePause = HTMLMediaElement.prototype.pause;
  HTMLMediaElement.prototype.pause = function () {
    if (reallyHidden()) return;
    return nativePause.call(this);
  };
})();