userscript.js

// ==UserScript==
// @name         KIT Moodle utils
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  try to take over the world!
// @author       You
// @match        https://moodle.cis.kit.ac.jp/*
// @grant        none
// ==/UserScript==

(function () {
  'use strict';

  function toggleTopicList() {
    const topics = document.querySelector('.topics');
    if (!topics || topics.classList.contains('expand-topics')) return;
    topics.classList.add('expand-topics');

    const classId = location.search.match(/id=(\d+)/) ? Number(RegExp.$1) : -1;

    const sections = topics.querySelectorAll('li.section.main');
    const openedIndexes =
      localStorage
        .getItem(`toggle_topic_${classId}`)
        ?.split(',')
        .filter((n) => n.length > 0)
        .map((n) => Number(n)) || [];

    sections.forEach((section, index) => {
      section.style.paddingBottom = 0;

      section.querySelector('div.left.side')?.remove();
      section.querySelector('div.right.side')?.remove();

      const content = section.querySelector('.content');

      const sectionName = content.querySelector('.sectionname > span');
      if (!sectionName) return;

      const summary = document.createElement('summary');
      const newSectionName = document.createElement('b');
      newSectionName.append(sectionName.textContent);
      summary.append(newSectionName);
      sectionName.remove();

      const details = document.createElement('details');
      details.appendChild(summary);
      details.appendChild(content.cloneNode(true));

      if (
        content.querySelector('.summary')?.childNodes.length === 0 &&
        content.querySelector('.section')?.childNodes.length === 0
      ) {
        summary.style.color = '#aaa';
      }

      if (openedIndexes.includes(index)) {
        details.open = true;
      }

      details.addEventListener('toggle', () => {
        const openedIndexes =
          localStorage
            .getItem(`toggle_topic_${classId}`)
            ?.split(',')
            .filter((n) => n.length > 0)
            .map((n) => Number(n)) || [];

        if (openedIndexes.includes(index) && !details.open) {
          localStorage.setItem(
            `toggle_topic_${classId}`,
            openedIndexes.filter((id) => id !== index).join(','),
          );
        } else if (!openedIndexes.includes(index) && details.open) {
          localStorage.setItem(
            `toggle_topic_${classId}`,
            [...openedIndexes, index].join(','),
          );
        }
      });

      content.replaceWith(details);
    });
  }

  if (location.href.match(/\/course\/view\.php/)) {
    toggleTopicList();
  }
})();