WhyIsTheDLRShut.Today/script.js

/* Why is the DLR shut today?
 * Picks a random message on load and on demand, and handles the
 * colour-scheme toggle. Messages live in messages.js (MESSAGES). */

(function () {
  "use strict";

  const FALLBACK = "Add some reasons in messages.js";
  const messageEl = document.getElementById("message");
  const refreshButton = document.getElementById("refresh");
  const themeButtons = document.querySelectorAll("[data-set-theme]");
  const THEME_KEY = "dlr-theme";

  function pickMessage() {
    if (!Array.isArray(MESSAGES) || MESSAGES.length === 0) {
      return FALLBACK;
    }
    const index = Math.floor(Math.random() * MESSAGES.length);
    return MESSAGES[index];
  }

  function showMessage() {
    messageEl.textContent = pickMessage();
  }

  function applyTheme(theme) {
    document.body.setAttribute("data-theme", theme);
    themeButtons.forEach(function (button) {
      const isActive = button.dataset.setTheme === theme;
      button.setAttribute("aria-pressed", String(isActive));
    });
    try {
      localStorage.setItem(THEME_KEY, theme);
    } catch (err) {
      /* localStorage unavailable; theme simply won't persist. */
    }
  }

  function initTheme() {
    let saved = null;
    try {
      saved = localStorage.getItem(THEME_KEY);
    } catch (err) {
      /* ignore */
    }
    applyTheme(saved === "original" ? "original" : "modern");
  }

  themeButtons.forEach(function (button) {
    button.addEventListener("click", function () {
      applyTheme(button.dataset.setTheme);
    });
  });

  refreshButton.addEventListener("click", showMessage);

  initTheme();
  showMessage();
})();