richdocuments/lib/Service/FontService.php

<?php
/**
 * @copyright Copyright (c) 2022 Julien Veyssier <eneiluj@posteo.net>
 *
 * @author Julien Veyssier <eneiluj@posteo.net>
 *
 * @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\Richdocuments\Service;

use OCA\Richdocuments\AppInfo\Application;
use OCP\Files\IAppData;
use OCP\Files\NotFoundException;
use OCP\Files\SimpleFS\ISimpleFile;
use OCP\Files\SimpleFS\ISimpleFolder;
use OCP\ICacheFactory;
use OCP\IConfig;
use OCP\IURLGenerator;

class FontService {
	private const INVALIDATE_FONT_LIST_CACHE_AFTER_SECONDS = 3600;

	/**
	 * @var IAppData
	 */
	private $appData;
	/**
	 * @var \OCP\ICache
	 */
	private $cache;
	/**
	 * @var IURLGenerator
	 */
	private $url;
	/**
	 * @var IConfig
	 */
	private $config;

	public function __construct(IAppData $appData,
								ICacheFactory $cacheFactory,
								IURLGenerator $url,
								IConfig $config) {
		$this->appData = $appData;
		$this->cache = $cacheFactory->createDistributed(Application::APPNAME);
		$this->url = $url;
		$this->config = $config;
	}

	/**
	 * @return ISimpleFolder
	 * @throws \OCP\Files\NotPermittedException
	 */
	private function getFontAppDataDir(): ISimpleFolder {
		try {
			return $this->appData->getFolder('fonts');
		} catch (NotFoundException $e) {
			return $this->appData->newFolder('fonts');
		}
	}

	/**
	 * @return ISimpleFolder
	 * @throws \OCP\Files\NotPermittedException
	 */
	private function getFontOverviewAppDataDir(): ISimpleFolder {
		try {
			return $this->appData->getFolder('font-overviews');
		} catch (NotFoundException $e) {
			return $this->appData->newFolder('font-overviews');
		}
	}

	/**
	 * Get the list of available font files
	 *
	 * @return array
	 * @throws \OCP\Files\NotPermittedException
	 */
	public function getFontFiles(): array {
		$fontDir = $this->getFontAppDataDir();
		return $fontDir->getDirectoryListing();
	}

	/**
	 * Get the list of available font file names
	 *
	 * @return array
	 * @throws \OCP\Files\NotPermittedException
	 */
	public function getFontFileNames(): array {
		$cacheKey = 'fontFileNames';
		$cachedNames = $this->cache->get($cacheKey);
		if ($cachedNames === null) {
			$files = $this->getFontFiles();
			$cachedNames = array_map(
				static function (ISimpleFile $f) {
					return $f->getName();
				},
				$files
			);
			$this->cache->set($cacheKey, $cachedNames, self::INVALIDATE_FONT_LIST_CACHE_AFTER_SECONDS);
		}

		return $cachedNames;
	}

	/**
	 * Get the formatted list of available fonts
	 *
	 * @param array $fontFiles
	 * @return array
	 */
	public function getFontList(array $fontFiles): array {
		$url = $this->url;
		$list = array_map(
			static function (ISimpleFile $f) use ($url) {
				return [
					'uri' => $url->linkToRouteAbsolute(Application::APPNAME . '.settings.getFontFile', ['name' => $f->getName()]),
					'stamp' => $f->getETag(),
				];
			},
			$fontFiles
		);

		$instanceName = $this->config->getAppValue('theming', 'name');
		return [
			'kind' => 'fontconfiguration',
			'server' => $instanceName . ' (' . $this->url->getBaseUrl() . ')',
			'fonts' => $list,
		];
	}

	/**
	 * @param string $fileName
	 * @param $newFileResource
	 * @return array
	 * @throws \OCP\Files\NotPermittedException
	 */
	public function uploadFontFile(string $fileName, $newFileResource): array {
		$fontDir = $this->getFontAppDataDir();
		$newFile = $fontDir->newFile($fileName, $newFileResource);
		$this->generateFontOverview($newFile);
		$this->cache->remove('fontFileNames');
		return [
			'size' => $newFile->getSize(),
		];
	}

	/**
	 * @param string $fileName
	 * @return ISimpleFile
	 * @throws NotFoundException
	 * @throws \OCP\Files\NotPermittedException
	 */
	public function getFontFile(string $fileName): ISimpleFile {
		$fontDir = $this->getFontAppDataDir();
		return $fontDir->getFile($fileName);
	}

	/**
	 * @param string $fileName
	 * @return string
	 * @throws NotFoundException
	 * @throws \OCP\Files\NotPermittedException
	 */
	public function getFontFileOverview(string $fileName): string {
		$fontDir = $this->getFontOverviewAppDataDir();
		return $fontDir->getFile($fileName . '.png')->getContent();
	}

	/**
	 * @param string $fileName
	 * @return void
	 * @throws NotFoundException
	 * @throws \OCP\Files\NotPermittedException
	 */
	public function deleteFontFile(string $fileName): void {
		$fontDir = $this->getFontAppDataDir();
		if ($fontDir->fileExists($fileName)) {
			$fontDir->getFile($fileName)->delete();
		}

		$overviewDir = $this->getFontOverviewAppDataDir();
		if ($overviewDir->fileExists($fileName . '.png')) {
			$overviewDir->getFile($fileName . '.png')->delete();
		}

		$this->cache->remove('fontFileNames');
	}

	/**
	 * @param ISimpleFile $fontFile
	 * @return void
	 */
	private function generateFontOverview(ISimpleFile $fontFile): void {
		try {
			$color = [0, 0, 0];
			$text = 'Lorem ipsum';

			// we need a temp file because imagettftext can't read the font file from a resource
			// but just a file path
			$tmpFontFile = tmpfile();
			$tmpFontFilePath = stream_get_meta_data($tmpFontFile)['uri'];
			fwrite($tmpFontFile, $fontFile->getContent());
			fflush($tmpFontFile);

			$im = imagecreatetruecolor(250, 30);
			$bg_color = imagecolorallocate($im, 255, 255, 255);
			$font_color = imagecolorallocate($im, $color[0], $color[1], $color[2]);
			imagefilledrectangle($im, 0, 0, 399, 29, $bg_color);
			$ttfResult = imagettftext($im, 20, 0, 0, 22, $font_color, $tmpFontFilePath, $text);
			// this happens with invalid ttf fonts
			if ($ttfResult === false) {
				return;
			}

			$overviewDir = $this->getFontOverviewAppDataDir();
			$imageFileResource = $overviewDir->newFile($fontFile->getName() . '.png')->write();
			if (is_resource($imageFileResource)) {
				imagepng($im, $imageFileResource);
				imagedestroy($im);
			}
		} catch (\Exception | \Throwable $e) {
			// do nothing if there was any kind of error during overview generation
			// the /apps/richdocuments/settings/fonts/FILE_NAME/overview request will fail with 404
			// in the UI and display a fallback message
		}
	}
}