feat: implement bootstrap theme switcher (#36)

* feat: implement bootstrap theme switcher

* chore: german translations

src/js/darkmode.js

@@ -1,50 +1,90 @@
-function updateDarkmodeIcons() {
-  const isDarkmode = document.documentElement.hasAttribute('data-bs-theme')
+;(() => {
+  'use strict'
 
-  document.querySelectorAll('[toggle-dark-mode] i').forEach((icon) => {
-    const remove = isDarkmode ? 'bi-moon-fill' : 'bi-sun-fill'
-    const add = isDarkmode ? 'bi-sun-fill' : 'bi-moon-fill'
+  const getStoredTheme = () => localStorage.getItem('theme')
+  const setStoredTheme = (theme) => localStorage.setItem('theme', theme)
 
-    icon.classList.remove(remove)
-    icon.classList.add(add)
-  })
-}
-
-function removeDarkmode() {
-  document.documentElement.removeAttribute('data-bs-theme')
-  localStorage.removeItem('theme')
-  updateDarkmodeIcons()
-}
-
-function setDarkmode() {
-  document.documentElement.setAttribute('data-bs-theme', 'dark')
-  localStorage.setItem('theme', 'dark')
-  updateDarkmodeIcons()
-}
-
-function toggleDarkmode() {
-  if (document.documentElement.hasAttribute('data-bs-theme')) {
-    removeDarkmode()
-  } else {
-    setDarkmode()
+  const getPreferredTheme = () => {
+    const storedTheme = getStoredTheme()
+    if (storedTheme) {
+      return storedTheme
+    }
+
+    return window.matchMedia('(prefers-color-scheme: dark)').matches
+      ? 'dark'
+      : 'light'
+  }
+
+  const setTheme = (theme) => {
+    if (theme === 'auto') {
+      document.documentElement.setAttribute(
+        'data-bs-theme',
+        window.matchMedia('(prefers-color-scheme: dark)').matches
+          ? 'dark'
+          : 'light'
+      )
+    } else {
+      document.documentElement.setAttribute('data-bs-theme', theme)
+    }
   }
-}
 
-function loadTheme() {
-  const theme = localStorage.getItem('theme')
+  setTheme(getPreferredTheme())
+
+  const showActiveTheme = (theme, focus = false) => {
+    const themeSwitcher = document.querySelector('#bd-theme')
+
+    if (!themeSwitcher) {
+      return
+    }
+
+    const themeSwitcherText = document.querySelector('#bd-theme-text')
+    const activeThemeIcon = document.querySelector('.theme-icon-active')
+    const btnToActive = document.querySelector(
+      `[data-bs-theme-value="${theme}"]`
+    )
+    const svgOfActiveBtn = btnToActive.querySelector('i[data-bs-theme-icon]')
+      .dataset.bsThemeIcon
 
-  if (theme) {
-    setDarkmode()
-  } else {
-    removeDarkmode()
+    document.querySelectorAll('[data-bs-theme-value]').forEach((element) => {
+      element.classList.remove('active')
+      element.setAttribute('aria-pressed', 'false')
+    })
+
+    const allIcons = Array.from(
+      document.querySelectorAll('[data-bs-theme-value] > i[data-bs-theme-icon]')
+    ).map((i) => i.dataset.bsThemeIcon)
+    allIcons.forEach((i) => activeThemeIcon.classList.remove(i))
+
+    btnToActive.classList.add('active')
+    btnToActive.setAttribute('aria-pressed', 'true')
+    activeThemeIcon.classList.add(svgOfActiveBtn)
+    const themeSwitcherLabel = `${themeSwitcherText.textContent} (${btnToActive.textContent})`
+    themeSwitcher.setAttribute('aria-label', themeSwitcherLabel)
+
+    if (focus) {
+      themeSwitcher.focus()
+    }
   }
-}
 
-document.addEventListener('DOMContentLoaded', () => {
-  updateDarkmodeIcons()
-  document.querySelectorAll('[toggle-dark-mode]').forEach((button) => {
-    button.addEventListener('click', toggleDarkmode)
-  })
-})
+  window
+    .matchMedia('(prefers-color-scheme: dark)')
+    .addEventListener('change', () => {
+      const storedTheme = getStoredTheme()
+      if (storedTheme !== 'light' && storedTheme !== 'dark') {
+        setTheme(getPreferredTheme())
+      }
+    })
+
+  window.addEventListener('DOMContentLoaded', () => {
+    showActiveTheme(getPreferredTheme())
 
-loadTheme()
+    document.querySelectorAll('[data-bs-theme-value]').forEach((toggle) => {
+      toggle.addEventListener('click', () => {
+        const theme = toggle.getAttribute('data-bs-theme-value')
+        setStoredTheme(theme)
+        setTheme(theme)
+        showActiveTheme(theme, true)
+      })
+    })
+  })
+})()

src/partials/base/b_header.twig

@@ -35,11 +35,9 @@
           </button>
         </div>
         <div class='offcanvas-body d-flex flex-column justify-content-between'>
-          <ul class='nav flex-column align-items-start flex-xl-row fs-5 pb-3 pb-xl-0 border-bottom'>
-            <li>
-              <button toggle-dark-mode class='nav-link rounded-0' aria-label='Toggle dark mode'>
-                <i class='bi bi-moon-fill'></i>
-              </button>
+          <ul class='nav flex-column align-items-start flex-xl-row align-items-xl-center fs-5 pb-3 pb-xl-0 border-bottom'>
+            <li class='nav-item'>
+              {% include 'partials::base/b_theme-switcher.twig' %}
             </li>
             <li><a href='./overview' class='nav-link'>Daten</a></li>
             <li><a href='#' class='nav-link'>News</a></li>

src/partials/base/b_theme-switcher.twig

@@ -0,0 +1,52 @@
+<div class='dropdown'>
+  <button
+    class='btn btn-link nav-link p-2 dropdown-toggle d-flex align-items-center'
+    id='bd-theme'
+    type='button'
+    aria-expanded='false'
+    data-bs-toggle='dropdown'
+    data-bs-display='static'
+    aria-label='Dunkelmodus umschalten (auto)'
+  >
+    <i class='bi bi-sun-fill my-1 theme-icon-active'></i>
+    <span class='d-xl-none ms-2' id='bd-theme-text'>Dunkelmodus umschalten</span>
+  </button>
+  <ul class='dropdown-menu dropdown-menu-end' aria-labelledby='bd-theme-text'>
+    <li>
+      <button
+        type='button'
+        class='dropdown-item d-flex align-items-center active'
+        data-bs-theme-value='light'
+        aria-pressed='true'
+      >
+        <i class='bi bi-sun-fill me-2 opacity-50' data-bs-theme-icon='bi-sun-fill'></i>
+        Hell
+        <i class='bi bi-check2 ms-auto d-none'></i>
+      </button>
+    </li>
+    <li>
+      <button
+        type='button'
+        class='dropdown-item d-flex align-items-center'
+        data-bs-theme-value='dark'
+        aria-pressed='false'
+      >
+        <i class='bi bi-moon-stars-fill me-2 opacity-50' data-bs-theme-icon='bi-moon-stars-fill'></i>
+        Dunkel
+        <i class='bi bi-check2 ms-auto d-none'></i>
+      </button>
+    </li>
+    <li>
+      <button
+        type='button'
+        class='dropdown-item d-flex align-items-center'
+        data-bs-theme-value='auto'
+        aria-pressed='false'
+      >
+        <i class='bi bi-circle-half me-2 opacity-50' data-bs-theme-icon='bi-circle-half'></i>
+        Auto
+        <i class='bi bi-check2 ms-auto d-none'></i>
+      </button>
+    </li>
+  </ul>
+</div>

src/styles/components/_form.scss

@@ -29,6 +29,13 @@
 .dropdown-menu {
   --dropdown-link-active-bg: var(--primary);
   --dropdown-link-active-color: var(--color-on-primary);
+
+  .dropdown-item {
+    &:focus,
+    &:focus-visible {
+      outline: solid var(--focus-ring-width) var(--focus-ring-color);
+    }
+  }
 }
 
 .form-switch .form-check-input {

src/styles/components/_header.scss

@@ -58,6 +58,10 @@
       }
     }
 
+    .dropdown-item {
+      --focus-ring-color: var(--primary);
+    }
+
     .logo {
       filter: brightness(0) invert(1);
     }
@@ -78,6 +82,11 @@
     border: 0;
     padding: 0;
   }
+
+  #bd-theme {
+    padding-top: 4px !important;
+    padding-bottom: 4px !important;
+  }
 }
 
 [data-bs-theme='dark'] .header {