docs: add DocsVersion component to navigate through different docs versions

docs/astro.config.mjs

@@ -15,6 +15,10 @@ export default defineConfig({
       title: "Castopod Docs",
       description:
         "Check out the Castopod documentation! Install your own free & open-source podcast host, help make it better by contributing, or simply learn more about Castopod!",
+      components: {
+        Header: "./src/components/Header.astro",
+        MobileMenuFooter: "./src/components/MobileMenuFooter.astro",
+      },
       logo: {
         src: "./src/assets/castopod-logo-inline.svg",
         replacesTitle: true,

docs/src/components/DocsVersionSelect.astro

@@ -0,0 +1,34 @@
+---
+import Select from '@astrojs/starlight/components/Select.astro';
+import type { Props } from '@astrojs/starlight/props';
+---
+
+<docs-version-select>
+    <Select
+		icon="starlight"
+		label="version"
+		value="develop"
+		options={[
+			{ label: 'develop', selected: import.meta.env.BASE_URL === '/develop', value: '/develop' },
+			{ label: 'next', selected: import.meta.env.BASE_URL === '/next', value: '/next' },
+		]}
+		width="7em"
+	/>
+</docs-version-select>
+
+<script>
+	class DocsVersionSelect extends HTMLElement {
+		constructor() {
+			super();
+			const select = this.querySelector('select');
+			if (select) {
+				select.addEventListener('change', (e) => {
+					if (e.currentTarget instanceof HTMLSelectElement) {
+						window.location.pathname = e.currentTarget.value;
+					}
+				});
+			}
+		}
+	}
+	customElements.define('docs-version-select', DocsVersionSelect);
+</script>

docs/src/components/Header.astro

@@ -0,0 +1,90 @@
+---
+import config from 'virtual:starlight/user-config';
+import type { Props } from '../props';
+
+import LanguageSelect from 'virtual:starlight/components/LanguageSelect';
+import Search from 'virtual:starlight/components/Search';
+import SiteTitle from 'virtual:starlight/components/SiteTitle';
+import SocialIcons from 'virtual:starlight/components/SocialIcons';
+import ThemeSelect from 'virtual:starlight/components/ThemeSelect';
+import VersionSelect from './DocsVersionSelect.astro';
+
+/**
+ * Render the `Search` component if Pagefind is enabled or the default search component has been overridden.
+ */
+const shouldRenderSearch =
+	config.pagefind || config.components.Search !== '@astrojs/starlight/components/Search.astro';
+---
+
+<div class="header sl-flex">
+	<div class="title-wrapper sl-flex">
+		<SiteTitle {...Astro.props} />
+	</div>
+	<div class="sl-flex">
+		{shouldRenderSearch && <Search {...Astro.props} />}
+	</div>
+	<div class="sl-hidden md:sl-flex right-group">
+		<div class="sl-flex social-icons">
+			<SocialIcons {...Astro.props} />
+		</div>
+		<ThemeSelect {...Astro.props} />
+		<VersionSelect {...Astro.props} />
+		<LanguageSelect {...Astro.props} />
+	</div>
+</div>
+
+<style>
+	.header {
+		gap: var(--sl-nav-gap);
+		justify-content: space-between;
+		align-items: center;
+		height: 100%;
+	}
+
+	.title-wrapper {
+		/* Prevent long titles overflowing and covering the search and menu buttons on narrow viewports. */
+		overflow: hidden;
+	}
+
+	.right-group,
+	.social-icons {
+		gap: 1rem;
+		align-items: center;
+	}
+	.social-icons::after {
+		content: '';
+		height: 2rem;
+		border-inline-end: 1px solid var(--sl-color-gray-5);
+	}
+
+	@media (min-width: 50rem) {
+		:global(:root[data-has-sidebar]) {
+			--__sidebar-pad: calc(2 * var(--sl-nav-pad-x));
+		}
+		:global(:root:not([data-has-toc])) {
+			--__toc-width: 0rem;
+		}
+		.header {
+			--__sidebar-width: max(0rem, var(--sl-content-inline-start, 0rem) - var(--sl-nav-pad-x));
+			--__main-column-fr: calc(
+				(
+						100% + var(--__sidebar-pad, 0rem) - var(--__toc-width, var(--sl-sidebar-width)) -
+							(2 * var(--__toc-width, var(--sl-nav-pad-x))) - var(--sl-content-inline-start, 0rem) -
+							var(--sl-content-width)
+					) / 2
+			);
+			display: grid;
+			grid-template-columns:
+        /* 1 (site title): runs up until the main content column’s left edge or the width of the title, whichever is the largest  */
+				minmax(
+					calc(var(--__sidebar-width) + max(0rem, var(--__main-column-fr) - var(--sl-nav-gap))),
+					auto
+				)
+				/* 2 (search box): all free space that is available. */
+				1fr
+				/* 3 (right items): use the space that these need. */
+				auto;
+			align-content: center;
+		}
+	}
+</style>

docs/src/components/MobileMenuFooter.astro

@@ -0,0 +1,35 @@
+---
+import LanguageSelect from 'virtual:starlight/components/LanguageSelect';
+import SocialIcons from 'virtual:starlight/components/SocialIcons';
+import ThemeSelect from 'virtual:starlight/components/ThemeSelect';
+import type { Props } from '../props';
+import VersionSelect from './DocsVersionSelect.astro';
+---
+
+<div class="mobile-preferences sl-flex">
+	<div class="sl-flex social-icons">
+		<SocialIcons {...Astro.props} />
+	</div>
+	<ThemeSelect {...Astro.props} />
+    <VersionSelect {...Astro.props} />
+	<LanguageSelect {...Astro.props} />
+</div>
+
+<style>
+	.social-icons {
+		margin-inline-end: auto;
+		gap: 1rem;
+		align-items: center;
+		padding-block: 1rem;
+	}
+	.social-icons:empty {
+		display: none;
+	}
+	.mobile-preferences {
+		justify-content: space-between;
+		flex-wrap: wrap;
+		border-top: 1px solid var(--sl-color-gray-6);
+		column-gap: 1rem;
+		padding: 0.5rem 0;
+	}
+</style>