Improve implementation

Author: nyamsprod

interfaces/Encoder.php

@@ -30,6 +30,7 @@
 use function rawurldecode;
 use function rawurlencode;
 use function sprintf;
+use function str_starts_with;
 use function strtolower;
 use function strtoupper;
 
@@ -300,8 +301,8 @@ public static function normalizeHost(Stringable|string|null $host): ?string
             return $host;
         }
 
-        if (($newHost = IPv6Converter::normalize($host)) !== $host) {
-            return $newHost;
+        if (str_starts_with($host, '[')) {
+            return IPv6Converter::normalize($host);
         }
 
         $host = strtolower($host);

interfaces/IPv6/Converter.php

@@ -100,8 +100,6 @@ public static function build(array $components): string
     }
 
     /**
-     * @param Stringable|string|null $host
-     *
      * @return array{ipAddress:string|null, zoneIdentifier:string|null}
      */
     private static function parse(Stringable|string|null $host): array
@@ -145,9 +143,14 @@ public static function isIpv6(Stringable|string|null $host): bool
 
     public static function normalize(Stringable|string|null $host): ?string
     {
+        if (null === $host || '' === $host) {
+            return $host;
+        }
+
+        $host = (string) $host;
         $components = self::parse($host);
         if (null === $components['ipAddress']) {
-            return $host;
+            return strtolower($host);
         }
 
         $components['ipAddress'] = strtolower($components['ipAddress']);

interfaces/UriString.php

@@ -298,12 +298,12 @@ public static function parseNormalized(Stringable|string $uri): array
 
         $host = $components['host'];
         if (null !== $host && false === filter_var($host, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4)) {
-            $host = IPv6Converter::normalize($host);
+            $host = (string) IPv6Converter::normalize($host);
             if ($host === $components['host']) {
                 $host = (string) preg_replace_callback(
                     '/%[0-9A-F]{2}/i',
                     fn (array $matches): string => strtoupper($matches[0]),
-                    strtolower($components['host'])
+                    strtolower($host)
                 );
                 if ($isSupported) {
                     $idnaHost = IdnaConverter::toAscii(rawurldecode($components['host']));