extract Google logic into separate adapter

src/main/java/com/ddf/vodsystem/security/GoogleVerifierService.java

@@ -0,0 +1,41 @@
+package com.ddf.vodsystem.security;
+
+import com.ddf.vodsystem.dto.GoogleUser;
+import com.ddf.vodsystem.exceptions.NotAuthenticated;
+import com.google.api.client.googleapis.auth.oauth2.GoogleIdToken;
+import com.google.api.client.googleapis.auth.oauth2.GoogleIdTokenVerifier;
+import org.springframework.stereotype.Service;
+
+import java.io.IOException;
+import java.security.GeneralSecurityException;
+
+@Service
+public class GoogleVerifierService {
+    private final GoogleIdTokenVerifier verifier;
+
+    public GoogleVerifierService(GoogleIdTokenVerifier verifier) {
+        this.verifier = verifier;
+    }
+
+    public GoogleUser verify(String idToken) {
+        GoogleIdToken token;
+        try {
+            token = verifier.verify(idToken);
+        } catch (GeneralSecurityException | IOException e) {
+            throw new NotAuthenticated("Invalid ID token: " + e.getMessage());
+        }
+
+        String googleId = token.getPayload().getSubject();
+
+        if (googleId == null) {
+            throw new NotAuthenticated("Google ID does not exist");
+        }
+
+        return new GoogleUser(
+                googleId,
+                token.getPayload().getEmail(),
+                (String) token.getPayload().get("name"),
+                (String) token.getPayload().get("picture")
+        );
+    }
+}