YouTube Playback Error Auto-Refresh script for tampermonkey (Firefox)

youtube-playback-error-refresh.user

// ==UserScript==
// @name         YouTube Playback Error Auto-Refresh
// @namespace    https://local.userscripts/youtube-error-refresh
// @version      3.0.0
// @description  When YouTube's "An error occurred, please try again later" playback overlay appears, clears the per-tab sessionStorage (mimicking a fresh tab) and reloads the SAME tab, until the video is playable. Language-independent. Does NOT autoplay. No new tabs.
// @author       Antonio Santoro
// @match        https://www.youtube.com/*
// @match        https://m.youtube.com/*
// @run-at       document-start
// @grant        none
// @noframes
// ==/UserScript==

(function () {
  'use strict';

  // ------------------------- Config (tweak freely) -------------------------
  const MAX_ATTEMPTS    = 6;     // Stop after this many resets for the same video (prevents infinite loops).
  const CONFIRM_MS      = 1200;  // Error must stay visible this long before acting (ignores a flicker).
  const RELOAD_DELAY_MS = 300;   // Small pause before reloading.
  const POLL_MS         = 1000;  // How often we check while watching.
  const STABLE_MS       = 10000; // Go idle / reset counter after this much error-free, loaded time.
  const MAX_WATCH_MS    = 90000; // Absolute safety cutoff for polling after (re)start.
  const CLEAR_SESSION   = true;  // The key trick: wipe sessionStorage before reloading (emulates a fresh tab).
  const VERBOSE         = true;  // Set false to silence routine logs.
  // -------------------------------------------------------------------------

  // The transient playback error overlay — same class in every language.
  // The "video unavailable / private" screen is a DIFFERENT element, not matched here.
  const ERROR_SELECTOR = '.ytp-error';

  const log = (...a) => { if (VERBOSE) console.log('[YT auto-refresh]', ...a); };

  let confirmTimer = null;
  let reloading    = false;
  let pollId       = null;
  let watchStart   = 0;
  let cleanSince   = 0;

  function videoKey() {
    try {
      const u = new URL(location.href);
      return u.searchParams.get('v') || location.pathname;
    } catch (e) {
      return location.pathname;
    }
  }

  // Counter lives in localStorage so wiping sessionStorage doesn't erase it.
  const key        = () => 'ytErrRefresh:' + videoKey();
  const getCount   = () => { try { return parseInt(localStorage.getItem(key()) || '0', 10) || 0; } catch (e) { return 0; } };
  const setCount   = (n) => { try { localStorage.setItem(key(), String(n)); } catch (e) {} };
  const clearCount = ()  => { try { localStorage.removeItem(key()); } catch (e) {} };

  function isVisible(el) {
    if (!el) return false;
    const cs = getComputedStyle(el);
    if (cs.display === 'none' || cs.visibility === 'hidden' || cs.opacity === '0') return false;
    return el.getClientRects().length > 0;
  }

  const errorShowing = () => isVisible(document.querySelector(ERROR_SELECTOR));

  function playerLooksLoaded() {
    const v = document.querySelector('video.html5-main-video') || document.querySelector('video');
    return !!v && (v.readyState >= 1 || v.duration > 0);
  }

  function startPolling() {
    watchStart = Date.now();
    cleanSince = 0;
    if (pollId == null) pollId = setInterval(check, POLL_MS);
  }
  function stopPolling(reason) {
    if (pollId != null) { clearInterval(pollId); pollId = null; log('idle —', reason); }
  }
  function cancelPending() {
    if (confirmTimer) { clearTimeout(confirmTimer); confirmTimer = null; }
  }

  function scheduleReload() {
    if (reloading || confirmTimer) return;
    log('error overlay detected — confirming for ' + CONFIRM_MS + 'ms...');
    confirmTimer = setTimeout(() => {
      confirmTimer = null;
      if (!errorShowing()) { log('overlay cleared on its own; not reloading'); return; }

      const count = getCount();
      if (count >= MAX_ATTEMPTS) {
        console.warn('[YT auto-refresh] Giving up after ' + count + ' resets for this video.');
        stopPolling('max attempts reached');
        return;
      }

      setCount(count + 1);
      reloading = true;

      if (CLEAR_SESSION) {
        try { sessionStorage.clear(); log('sessionStorage cleared (fresh-tab emulation)'); }
        catch (e) { log('could not clear sessionStorage:', e); }
      }

      log('reloading (attempt ' + (count + 1) + '/' + MAX_ATTEMPTS +
          ') — enable "Persist Logs" to keep this visible across the reload');
      setTimeout(() => location.reload(), RELOAD_DELAY_MS);
    }, CONFIRM_MS);
  }

  function check() {
    if (reloading) return;

    if (errorShowing()) {
      cleanSince = 0;
      watchStart = Date.now();
      scheduleReload();
      return;
    }

    cancelPending();

    if (playerLooksLoaded()) {
      if (!cleanSince) cleanSince = Date.now();
      if (Date.now() - cleanSince > STABLE_MS) { clearCount(); stopPolling('video stable'); }
    } else {
      cleanSince = 0;
      if (Date.now() - watchStart > MAX_WATCH_MS) stopPolling('watch window elapsed');
    }
  }

  log('active on', location.href);
  startPolling();
  document.addEventListener('DOMContentLoaded', check);
  window.addEventListener('load', check);
  window.addEventListener('yt-navigate-finish', () => { reloading = false; startPolling(); check(); });
})();