コンテンツ情報取得の実装をapi.phpから剥がした

app/MetadataResolver/MetadataResolver.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace App\MetadataResolver;
+
+class MetadataResolver implements Resolver
+{
+    public $rules = [
+        '~(((sp\.)?seiga\.nicovideo\.jp/seiga(/#!)?|nico\.ms))/im~' => NicoSeigaResolver::class,
+        '~nijie\.info/view\.php~' => NijieResolver::class,
+        '/.*/' => OGPResolver::class
+    ];
+
+    public function resolve(string $url): Metadata
+    {
+        foreach ($this->rules as $pattern => $class) {
+            if (preg_match($pattern, $url) === 1) {
+                $resolver = new $class;
+                return $resolver->resolve($url);
+            }
+        }
+
+        throw new \UnexpectedValueException('URL not matched.');
+    }
+}