Improves handling of letter case in word censor

Sources/Lang.php

@@ -635,7 +635,35 @@ public static function censorText(string &$text, bool $force = false): string
 		}
 
 		// Censoring isn't so very complicated :P.
-		$text = preg_replace($censor_vulgar, $censor_proper, $text);
+		foreach ($censor_vulgar as $i => $pattern) {
+			$text = preg_replace_callback(
+				$pattern,
+				function ($matches) use ($censor_proper, $i) {
+					// Special case to return the original word unchanged.
+					if ($censor_proper[$i] === '$0') {
+						return $matches[0];
+					}
+
+					// If the replacement contains any letters, try to match case.
+					if (preg_match('/\p{L}/u', $censor_proper[$i])) {
+						// If original was all uppercase, return uppercase.
+						if (Utils::strtoupper($matches[0]) === $matches[0]) {
+							return Utils::strtoupper($censor_proper[$i]);
+						}
+
+						// If original started with a capital letter, return with a capital letter.
+						$first_vulgar_char = Utils::entitySubstr($matches[0], 0, 1);
+
+						if (Utils::ucfirst($first_vulgar_char) === $first_vulgar_char) {
+							return Utils::ucfirst($censor_proper[$i]);
+						}
+					}
+
+					return $censor_proper[$i];
+				},
+				$text,
+			);
+		}
 
 		return $text;
 	}

Sources/Unicode/SpoofDetector.php

@@ -158,6 +158,14 @@ public static function enhanceWordCensor(string $text): void
 		$vulgar = explode("\n", Config::$modSettings['censor_vulgar']);
 		$proper = explode("\n", Config::$modSettings['censor_proper']);
 
+		if (!empty(Config::$modSettings['censorIgnoreCase'])) {
+			$text = Utils::convertCase($text, 'fold');
+
+			foreach ($vulgar as $i => $v) {
+				$vulgar[$i] = Utils::convertCase($v, 'fold');
+			}
+		}
+
 		$text_chars = preg_split('/(.)/su', $text, 0, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
 
 		foreach ($text_chars as $text_char) {