From 9938d4649b51d2be7a8b1f13862a1c3cfb8de4ff Mon Sep 17 00:00:00 2001
From: Rodrigo Verdiani <rocverdiani@gmail.com>
Date: Tue, 14 Jul 2026 14:11:44 -0300
Subject: [PATCH] refactor(image): extract shared SHA-256 hash utility

Move computeHash from ImageFetchService into reusable ImageHashUtil
to avoid duplication when other services need image hashing.
---
 .../image/service/ImageFetchService.java      | 22 ++--------------
 .../magamochi/image/util/ImageHashUtil.java   | 26 +++++++++++++++++++
 2 files changed, 28 insertions(+), 20 deletions(-)
 create mode 100644 src/main/java/com/magamochi/image/util/ImageHashUtil.java

diff --git a/src/main/java/com/magamochi/image/service/ImageFetchService.java b/src/main/java/com/magamochi/image/service/ImageFetchService.java
index 4849a0c..68c9037 100644
--- a/src/main/java/com/magamochi/image/service/ImageFetchService.java
+++ b/src/main/java/com/magamochi/image/service/ImageFetchService.java
@@ -4,12 +4,12 @@ import static java.util.Objects.nonNull;
 
 import com.google.common.util.concurrent.RateLimiter;
 import com.magamochi.common.model.enumeration.ContentType;
+import com.magamochi.image.util.ImageHashUtil;
 import java.io.IOException;
 import java.net.URI;
 import java.net.http.HttpClient;
 import java.net.http.HttpRequest;
 import java.net.http.HttpResponse;
-import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
 import java.util.UUID;
 import lombok.RequiredArgsConstructor;
@@ -54,7 +54,7 @@ public class ImageFetchService {
       throws NoSuchAlgorithmException {
     var fileContentType = resolveContentType(httpResponse, imageBytes);
 
-    var fileHash = computeHash(imageBytes);
+    var fileHash = ImageHashUtil.computeSha256(imageBytes);
 
     return imageManagerService.upload(
         imageBytes, fileContentType, contentType.name().toLowerCase(), fileHash);
@@ -76,22 +76,4 @@ public class ImageFetchService {
 
     return tika.detect(fileBytes);
   }
-
-  private String computeHash(byte[] content) throws NoSuchAlgorithmException {
-    var digest = MessageDigest.getInstance("SHA-256");
-    var hashBytes = digest.digest(content);
-    var hexString = new StringBuilder(2 * hashBytes.length);
-
-    for (byte b : hashBytes) {
-      var hex = Integer.toHexString(0xff & b);
-
-      if (hex.length() == 1) {
-        hexString.append('0');
-      }
-
-      hexString.append(hex);
-    }
-
-    return hexString.toString();
-  }
 }
diff --git a/src/main/java/com/magamochi/image/util/ImageHashUtil.java b/src/main/java/com/magamochi/image/util/ImageHashUtil.java
new file mode 100644
index 0000000..48ad9fc
--- /dev/null
+++ b/src/main/java/com/magamochi/image/util/ImageHashUtil.java
@@ -0,0 +1,26 @@
+package com.magamochi.image.util;
+
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import lombok.NoArgsConstructor;
+
+@NoArgsConstructor(access = lombok.AccessLevel.PRIVATE)
+public class ImageHashUtil {
+  public static String computeSha256(byte[] content) throws NoSuchAlgorithmException {
+    var digest = MessageDigest.getInstance("SHA-256");
+    var hashBytes = digest.digest(content);
+    var hexString = new StringBuilder(2 * hashBytes.length);
+
+    for (byte b : hashBytes) {
+      var hex = Integer.toHexString(0xff & b);
+
+      if (hex.length() == 1) {
+        hexString.append('0');
+      }
+
+      hexString.append(hex);
+    }
+
+    return hexString.toString();
+  }
+}