Allow using Emoji ZWJ Sequences

Signed-off-by: Georg Ehrke <developer@georgehrke.com>

apps/user_status/lib/Service/StatusService.php

@@ -118,7 +118,7 @@ public function setStatus(string $userId,
 			throw new InvalidStatusTypeException('Status-type "' . $statusType . '" is not supported');
 		}
 		// Check if statusIcon contains only one character
-		if (\mb_strlen($statusIcon) > 1) {
+		if ($statusIcon !== null && !$this->isValidEmoji($statusIcon)) {
 			throw new InvalidStatusIconException('Status-Icon is longer than one character');
 		}
 		// Check for maximum length of custom message
@@ -158,4 +158,48 @@ public function removeUserStatus(string $userId): bool {
 		$this->mapper->delete($userStatus);
 		return true;
 	}
+
+	/**
+	 * @param string $emoji
+	 * @return bool
+	 */
+	private 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) {
+				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;
+	}
 }

apps/user_status/tests/Unit/Service/StatusServiceTest.php

@@ -199,6 +199,12 @@ public function setStatusDataProvider(): array {
 			// Clear at is in the past
 			['john.doe', 'busy', '📱', 'In a phone call', 10, true, false, true, InvalidClearAtException::class, 'ClearAt is in the past'],
 			['john.doe', 'busy', '📱', 'In a phone call', 10, false, false, true, InvalidClearAtException::class, 'ClearAt is in the past'],
+			// Test some more complex emojis with modifiers and zero-width-joiner
+			['john.doe', 'busy', '👩🏿‍💻', 'In a phone call', 42, true, true, false, null, null],
+			['john.doe', 'busy', '🤷🏼‍♀️', 'In a phone call', 42, true, true, false, null, null],
+			['john.doe', 'busy', '🏳️‍🌈', 'In a phone call', 42, true, true, false, null, null],
+			['john.doe', 'busy', '👨‍👨‍👦‍👦', 'In a phone call', 42, true, true, false, null, null],
+			['john.doe', 'busy', '👩‍❤️‍👩', 'In a phone call', 42, true, true, false, null, null],
 		];
 	}