fix:#20 first fix auto dark mode switch

frontend/src/helpers/theme.ts

@@ -0,0 +1,35 @@
+//Calendar implementation for the HTWK Leipzig timetable. Evaluation and display of the individual dates in iCal format.
+//Copyright (C) 2024 HTWKalender support@htwkalender.de
+
+//This program is free software: you can redistribute it and/or modify
+//it under the terms of the GNU Affero General Public License as published by
+//the Free Software Foundation, either version 3 of the License, or
+//(at your option) any later version.
+
+//This program is distributed in the hope that it will be useful,
+//but WITHOUT ANY WARRANTY; without even the implied warranty of
+//MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//GNU Affero General Public License for more details.
+
+//You should have received a copy of the GNU Affero General Public License
+//along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+import { ref } from "vue";
+
+const darkTheme = ref("lara-dark-blue"),
+  lightTheme = ref("lara-light-blue");
+
+
+export function toggleTheme(store, primeVue, emit): void {
+  store.setDarkMode(!store.isDark);
+  setTheme(store, primeVue, emit);
+}
+
+export function setTheme(store, primeVue, emit, shouldBeDark: boolean) {
+  store.setDarkMode(shouldBeDark);
+  const isDark = ref(store.isDark);
+  const newTheme = isDark.value ? darkTheme.value : lightTheme.value,
+    oldTheme = isDark.value ? lightTheme.value : darkTheme.value;
+  primeVue.changeTheme(oldTheme, newTheme, "theme-link", () => {});
+  emit("dark-mode-toggled", isDark.value);
+}