// ==UserScript==
// @name         Hide GitHub Flagged Organization Banner
// @namespace    https://github.com/Iamliuxiaozhen/Hide-GitHub-Flagged-Organization-Banner
// @version      1.0.1
// @description  Remove GitHub's flagged organization global error banner.
// @author       Oliver
// @homepageURL  https://github.com/Iamliuxiaozhen/Hide-GitHub-Flagged-Organization-Banner
// @match        https://github.com/*
// @run-at       document-start
// @grant        none
// ==/UserScript==

(function () {
  'use strict';

  const BANNER_SELECTOR = 'section[aria-label="Error"].flash.flash-full.js-notice.flash-error';
  const FLAGGED_ORG_HEADING_PATTERN = /^the\s+.+\s+organization\s+has\s+been\s+flagged\.$/i;

  function isTargetBanner(element) {
    const heading = element.querySelector('h4');
    if (!heading) {
      return false;
    }

    return FLAGGED_ORG_HEADING_PATTERN.test(heading.textContent.trim());
  }

  function removeTargetBanners(root) {
    if (!root || (root.nodeType !== Node.ELEMENT_NODE && root.nodeType !== Node.DOCUMENT_NODE)) {
      return;
    }

    const candidates = [];

    if (root.nodeType === Node.ELEMENT_NODE && root.matches(BANNER_SELECTOR)) {
      candidates.push(root);
    }

    candidates.push(...root.querySelectorAll(BANNER_SELECTOR));

    for (const candidate of candidates) {
      if (isTargetBanner(candidate)) {
        candidate.remove();
      }
    }
  }

  removeTargetBanners(document);

  const observer = new MutationObserver((mutations) => {
    for (const mutation of mutations) {
      for (const node of mutation.addedNodes) {
        removeTargetBanners(node);
      }
    }
  });

  function startObserver() {
    if (!document.documentElement) {
      return;
    }

    removeTargetBanners(document);
    observer.observe(document.documentElement, {
      childList: true,
      subtree: true,
    });
  }

  if (document.documentElement) {
    startObserver();
  } else {
    document.addEventListener('DOMContentLoaded', startObserver, { once: true });
  }
})();