1 files changed, 88 insertions, 0 deletions
diff --git a/apps/theming/lib/Service/ThemeInjectionService.php b/apps/theming/lib/Service/ThemeInjectionService.php
new file mode 100644
index 00000000000..fec14de96cf
--- /dev/null
+++ b/apps/theming/lib/Service/ThemeInjectionService.php
@@ -0,0 +1,88 @@
+<?php
+/**
+ * @copyright Copyright (c) 2022 John Molakvoæ <skjnldsv@protonmail.com>
+ *
+ * @author John Molakvoæ <skjnldsv@protonmail.com>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * 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 <http://www.gnu.org/licenses/>.
+ *
+ */
+namespace OCA\Theming\Service;
+
+use OCA\Theming\Themes\DefaultTheme;
+use OCP\IURLGenerator;
+use OCP\Util;
+
+class ThemeInjectionService {
+
+	private IURLGenerator $urlGenerator;
+	private ThemesService $themesService;
+	private DefaultTheme $defaultTheme;
+
+	public function __construct(IURLGenerator $urlGenerator,
+								ThemesService $themesService,
+								DefaultTheme $defaultTheme) {
+		$this->urlGenerator = $urlGenerator;
+		$this->themesService = $themesService;
+		$this->defaultTheme = $defaultTheme;
+	}
+
+	public function injectHeaders() {
+		$themes = $this->themesService->getThemes();
+		$defaultTheme = $themes[$this->defaultTheme->getId()];
+		$mediaThemes = array_filter($themes, function($theme) {
+			// Check if the theme provides a media query
+			return (bool)$theme->getMediaQuery();
+		});
+
+		// Default theme fallback
+		$this->addThemeHeader($defaultTheme->getId());
+		
+		// Themes applied by media queries
+		foreach($mediaThemes as $theme) {
+			$this->addThemeHeader($theme->getId(), true, $theme->getMediaQuery());
+		}
+
+		// Themes 
+		foreach($this->themesService->getThemes() as $theme) {
+			// Ignore default theme as already processed first
+			if ($theme->getId() === $this->defaultTheme->getId()) {
+				continue;
+			}
+			$this->addThemeHeader($theme->getId(), false);
+		}
+	}
+
+	/**
+	 * Inject theme header into rendered page
+	 * 
+	 * @param string $themeId the theme ID
+	 * @param bool $plain request the :root syntax
+	 * @param string $media media query to use in the <link> element
+	 */
+	private function addThemeHeader(string $themeId, bool $plain = true, string $media = null) {
+		$linkToCSS = $this->urlGenerator->linkToRoute('theming.Theming.getThemeStylesheet', [
+			'themeId' => $themeId,
+			'plain' => $plain,
+		]);
+		Util::addHeader('link', [
+			'rel' => 'stylesheet',
+			'media' => $media,
+			'href' => $linkToCSS,
+			'class' => 'theme'
+		]);
+	}
+}