Adds methods for getting head skins from id

src/main/java/net/knarcraft/knargui/item/PlayerHeadGUIItemFactory.java

@@ -7,7 +7,12 @@ import org.bukkit.inventory.ItemStack;
 import org.bukkit.inventory.meta.SkullMeta;
 import org.bukkit.profile.PlayerProfile;
 
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.util.Base64;
 import java.util.UUID;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 /**
  * An item factory for generating player head-based icons
@@ -15,6 +20,9 @@ import java.util.UUID;
 @SuppressWarnings("unused")
 public class PlayerHeadGUIItemFactory extends AbstractGUIItemFactory<PlayerHeadGUIItemFactory> {
 
+    private static final String textureBaseURL = "https://textures.minecraft.net/texture/";
+    private static final Pattern texturePattern = Pattern.compile("/texture/([0-9a-z]+)");
+
     /**
      * Instantiates a player head gui item factory
      */
@@ -53,4 +61,43 @@ public class PlayerHeadGUIItemFactory extends AbstractGUIItemFactory<PlayerHeadG
         return useSkin(Bukkit.getOfflinePlayer(uuid));
     }
 
+    /**
+     * Uses the skin from the given texture id
+     *
+     * <p>This methods takes the id after "<a href="https://textures.minecraft.net/texture/">
+     * https://textures.minecraft.net/texture/</a>" as input. A base64 JSON value can also be used, though it's not
+     * recommended.</p>
+     *
+     * @param textureId <p>The id of the texture to use</p>
+     * @return <p>The factory. Used for chaining commands</p>
+     */
+    public PlayerHeadGUIItemFactory useSkin(String textureId) {
+        //Get the texture id from a Base64 encoded JSON string
+        if (!textureId.isBlank() && textureId.length() % 4 == 0) {
+            String decoded = new String(Base64.getDecoder().decode(textureId));
+            Matcher matcher = texturePattern.matcher(decoded);
+            if (matcher.find()) {
+                textureId = matcher.group(1);
+            }
+        }
+
+        try {
+            return useSkin(new URL(textureBaseURL + textureId));
+        } catch (MalformedURLException exception) {
+            throw new IllegalArgumentException("Texture id resulted in invalid URL");
+        }
+    }
+
+    /**
+     * Uses the head skin from the given URL
+     *
+     * @param url <p>The URL to use</p>
+     * @return <p>The factory. Used for chaining commands</p>
+     */
+    public PlayerHeadGUIItemFactory useSkin(URL url) {
+        PlayerProfile profile = Bukkit.createPlayerProfile(UUID.randomUUID());
+        profile.getTextures().setSkin(url);
+        return changeItemMeta(SkullMeta.class, (meta) -> meta.setOwnerProfile(profile));
+    }
+
 }