Allow reactions also with other combined emojis

Honerful copying the EmojiService from UserStatus for now
I think this should be put into a decent place and then reused,
but I couldn't find somethin short term before beta1

Signed-off-by: Joas Schilling <coding@schilljs.com>

2 files changed, 109 insertions, 2 deletions

diff --git a/lib/private/Comments/EmojiHelper.php b/lib/private/Comments/EmojiHelper.php
new file mode 100644
index 00000000000..a75919edbc9
--- /dev/null
+++ b/lib/private/Comments/EmojiHelper.php
@@ -0,0 +1,101 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright Copyright (c) 2020, Georg Ehrke
+ *
+ * @author Georg Ehrke <oc.list@georgehrke.com>
+ * @author Joas Schilling <coding@schilljs.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 OC\Comments;
+
+use OCP\IDBConnection;
+
+/**
+ * Copied OCA\UserStatus\Service\EmojiService
+ * Needs to be unified later
+ */
+class EmojiHelper {
+
+	/** @var IDBConnection */
+	private $db;
+
+	/**
+	 * EmojiService constructor.
+	 *
+	 * @param IDBConnection $db
+	 */
+	public function __construct(IDBConnection $db) {
+		$this->db = $db;
+	}
+
+	/**
+	 * @return bool
+	 */
+	public function doesPlatformSupportEmoji(): bool {
+		return $this->db->supports4ByteText() &&
+			\class_exists(\IntlBreakIterator::class);
+	}
+
+	/**
+	 * @param string $emoji
+	 * @return bool
+	 */
+	public function isValidEmoji(string $emoji): bool {
+		$intlBreakIterator = \IntlBreakIterator::createCharacterInstance();
+		$intlBreakIterator->setText($emoji);
+
+		$characterCount = 0;
+		while ($intlBreakIterator->next() !== \IntlBreakIterator::DONE) {
+			$characterCount++;
+		}
+
+		if ($characterCount !== 1) {
+			return false;
+		}
+
+		$codePointIterator = \IntlBreakIterator::createCodePointInstance();
+		$codePointIterator->setText($emoji);
+
+		foreach ($codePointIterator->getPartsIterator() as $codePoint) {
+			$codePointType = \IntlChar::charType($codePoint);
+
+			// If the current code-point is an emoji or a modifier (like a skin-tone)
+			// just continue and check the next character
+			if ($codePointType === \IntlChar::CHAR_CATEGORY_MODIFIER_SYMBOL ||
+				$codePointType === \IntlChar::CHAR_CATEGORY_MODIFIER_LETTER ||
+				$codePointType === \IntlChar::CHAR_CATEGORY_OTHER_SYMBOL ||
+				$codePointType === \IntlChar::CHAR_CATEGORY_GENERAL_OTHER_TYPES) {
+				continue;
+			}
+
+			// If it's neither a modifier nor an emoji, we only allow
+			// a zero-width-joiner or a variation selector 16
+			$codePointValue = \IntlChar::ord($codePoint);
+			if ($codePointValue === 8205 || $codePointValue === 65039) {
+				continue;
+			}
+
+			return false;
+		}
+
+		return true;
+	}
+}
diff --git a/lib/private/Comments/Manager.php b/lib/private/Comments/Manager.php
index 384187accf3..123e4f6988d 100644
--- a/lib/private/Comments/Manager.php
+++ b/lib/private/Comments/Manager.php
@@ -59,6 +59,9 @@ class Manager implements ICommentsManager {
 	/** @var ITimeFactory */
 	protected $timeFactory;
 
+	/** @var EmojiHelper */
+	protected $emojiHelper;
+
 	/** @var IInitialStateService */
 	protected $initialStateService;
 
@@ -78,11 +81,13 @@ class Manager implements ICommentsManager {
 								LoggerInterface $logger,
 								IConfig $config,
 								ITimeFactory $timeFactory,
+								EmojiHelper $emojiHelper,
 								IInitialStateService $initialStateService) {
 		$this->dbConn = $dbConn;
 		$this->logger = $logger;
 		$this->config = $config;
 		$this->timeFactory = $timeFactory;
+		$this->emojiHelper = $emojiHelper;
 		$this->initialStateService = $initialStateService;
 	}
 
@@ -148,8 +153,9 @@ class Manager implements ICommentsManager {
 			throw new \UnexpectedValueException('Actor, Object and Verb information must be provided for saving');
 		}
 
-		if ($comment->getVerb() === 'reaction' && mb_strlen($comment->getMessage()) > 2) {
-			throw new \UnexpectedValueException('Reactions cannot be longer than 2 chars (emoji with skin tone have two chars)');
+		if ($comment->getVerb() === 'reaction' && !$this->emojiHelper->isValidEmoji($comment->getMessage())) {
+			// 4 characters: laptop + person + gender + skin color => "🧑🏽‍💻" is a single emoji from the picker
+			throw new \UnexpectedValueException('Reactions can only be a single emoji');
 		}
 
 		if ($comment->getId() === '') {