From a25b57cd7b98f876f880c4f361e8b3e224524a70 Mon Sep 17 00:00:00 2001
From: Marco <marco@delight.im>
Date: Fri, 16 Aug 2024 06:44:17 +0200
Subject: [PATCH] Create function 'EmailAddress::mask'

---
 src/EmailAddress.php | 59 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)
 create mode 100644 src/EmailAddress.php

diff --git a/src/EmailAddress.php b/src/EmailAddress.php
new file mode 100644
index 0000000..969babf
--- /dev/null
+++ b/src/EmailAddress.php
@@ -0,0 +1,59 @@
+<?php
+
+/*
+ * PHP-Auth (https://github.com/delight-im/PHP-Auth)
+ * Copyright (c) delight.im (https://www.delight.im/)
+ * Licensed under the MIT License (https://opensource.org/licenses/MIT)
+ */
+
+namespace Delight\Auth;
+
+final class EmailAddress {
+
+	/**
+	 * Returns a masked version of the given email address that can be used for privacy reasons and data safety reasons
+	 *
+	 * @param string $emailAddress
+	 * @return string
+	 */
+	public static function mask($emailAddress) {
+		if (empty($emailAddress)) {
+			return $emailAddress;
+		}
+
+		// split the email address into local part and domain part and then split the domain part into individual segments
+		$emailAddress = \trim((string) $emailAddress);
+		$partsSeparatedByAtSymbol = \explode('@', $emailAddress);
+		$domainPart = \array_pop($partsSeparatedByAtSymbol);
+		$localPart = \implode('@', $partsSeparatedByAtSymbol);
+		$localPart = \str_replace('"', '', $localPart);
+		$localPart = \str_replace("'", "", $localPart);
+		$parts = \explode('.', $domainPart);
+		\array_unshift($parts, $localPart);
+
+		// mask the individual parts of the address one by one
+		for ($i = 0; $i < \count($parts); $i++) {
+			$parts[$i] = \trim($parts[$i]);
+
+			if (\mb_strlen($parts[$i]) >= 5) {
+				$parts[$i] = \mb_substr($parts[$i], 0, 1) . '***' . \mb_substr($parts[$i], -1);
+			}
+			elseif (\mb_strlen($parts[$i]) === 4) {
+				$parts[$i] = \mb_substr($parts[$i], 0, 1) . '**' . \mb_substr($parts[$i], -1);
+			}
+			elseif (\mb_strlen($parts[$i]) === 3 && $i <= 1) {
+				$parts[$i] = \mb_substr($parts[$i], 0, 1) . '*' . \mb_substr($parts[$i], -1);
+			}
+			elseif (\mb_strlen($parts[$i]) === 2 && $i <= 1) {
+				$parts[$i] = \mb_substr($parts[$i], 0, 1) . '*';
+			}
+			elseif (\mb_strlen($parts[$i]) === 1 && $i <= 1) {
+				$parts[$i] = '*';
+			}
+		}
+
+		// join the individual parts back together
+		return \array_shift($parts) . '@' . \implode('.', $parts);
+	}
+
+}