// ==UserScript==
// @name         Hide Single-Post IDs
// @namespace    user-hide-single-posts
// @version      1.3
// @description  Hides users with only one post. Unhides them when they post again. Includes toggle + live updates.
// @match        https://8chan.moe/*/res/*.html*
// @match        https://8chan.se/*/res/*.html*
// @grant        none
// ==/UserScript==

(() => {
  const idNorm = s => (s.match(/^[0-9a-f]{6}/i) || [''])[0].toLowerCase();
  const QSA = (s, r = document) => [...r.querySelectorAll(s)];

  const idUsageCountMap = new Map(); // ID → count
  const singlePostIdMap = new Map(); // ID → { postId }

  const SETTINGS_KEY = 'hideSinglePostIDs';
  let hideEnabled = localStorage.getItem(SETTINGS_KEY) !== 'false';

  function handlePost(post) {
    const idEl = post.querySelector('.labelId');
    if (!idEl) return;

    const id = idNorm(idEl.textContent);
    if (!id) return;

    const count = (idUsageCountMap.get(id) || 0) + 1;
    idUsageCountMap.set(id, count);

    if (count === 1) {
      singlePostIdMap.set(id, { postId: post.id });
      if (hideEnabled) post.style.display = 'none';
    } else if (count === 2) {
      const firstPostId = singlePostIdMap.get(id)?.postId;
      const firstPost = document.getElementById(firstPostId);
      if (firstPost) firstPost.style.display = '';
      singlePostIdMap.delete(id);
    }
  }

  function scanAllExistingPosts() {
    QSA('.postCell, .opCell').forEach(handlePost);
  }

  function handleNewPosts(mutations) {
    for (const mutation of mutations) {
      for (const node of mutation.addedNodes) {
        if (!(node instanceof HTMLElement)) continue;
        if (node.matches('.postCell, .opCell')) {
          handlePost(node);
        } else {
          QSA('.postCell, .opCell', node).forEach(handlePost);
        }
      }
    }
  }

  function toggleVisibility(enable) {
    hideEnabled = enable;
    localStorage.setItem(SETTINGS_KEY, enable);

    for (const [id, { postId }] of singlePostIdMap.entries()) {
      const post = document.getElementById(postId);
      if (post) post.style.display = enable ? 'none' : '';
    }
  }

  function createToggleUI() {
    const box = document.createElement('div');
    box.style = 'position:fixed;bottom:1rem;right:1rem;z-index:9999;background:#222;color:#fff;padding:6px;border-radius:6px;font:14px sans-serif';
    box.innerHTML = `<label><input type="checkbox" id="toggleHideIds"> Hide Single-Post IDs</label>`;
    document.body.appendChild(box);

    const toggle = box.querySelector('#toggleHideIds');
    toggle.checked = hideEnabled;
    toggle.onchange = () => toggleVisibility(toggle.checked);
  }

  function observeNewPosts() {
    const container = document.querySelector('.divPosts') || document.body;
    const observer = new MutationObserver(handleNewPosts);
    observer.observe(container, { childList: true, subtree: true });
  }

  function waitForPostsAndInit() {
    if (document.querySelector('.postCell, .opCell')) {
      createToggleUI();
      scanAllExistingPosts();
      observeNewPosts();
    } else {
      requestAnimationFrame(waitForPostsAndInit);
    }
  }

  waitForPostsAndInit();
})();