Add support for portable settings detection

Introduces logic to detect a preferences.txt file in the same folder as the running executable or jar. If found, settings are loaded from this location, improving portability and allowing users to override default settings without modifying system directories.

Author: Stefterv

app/utils/src/main/java/processing/utils/Settings.java

@@ -3,6 +3,7 @@
 import java.io.BufferedReader;
 import java.io.File;
 import java.io.InputStreamReader;
+import java.util.Optional;
 
 public class Settings {
     public static File getFolder() throws SettingsFolderException {
@@ -23,6 +24,11 @@ private static File getFolderForPlatform() throws SettingsFolderException {
             return new File(settingsOverride);
         }
 
+        var portableSettings = FindPortableSettings();
+        if (portableSettings.isPresent()) {
+            return portableSettings.get();
+        }
+
         if (Platform.isWindows()) {
             var options = new String[]{
                     "APPDATA",
@@ -88,6 +94,32 @@ private static File getFolderForPlatform() throws SettingsFolderException {
         return new File(System.getProperty("user.home"), ".processing");
     }
 
+    /**
+     * find a preferences.txt file in the same folder as the running jar/executable
+     *
+     * @return Optional File pointing to preferences.txt if found, empty otherwise
+     */
+    private static Optional<File> FindPortableSettings() {
+        var command = ProcessHandle.current().info().command();
+        if (command.isEmpty()) return Optional.empty();
+
+        var path = command.get();
+        path = path.replaceAll("/[^/]+$", "");
+
+        if (Platform.isMacOS()) {
+            // On macOS, the executable is inside the .app bundle, so we need to go up to above the .app folder
+            path = path.replaceAll("/[^/]+\\.app/.*$", "");
+        }
+        var file = new File(path, "preferences.txt");
+        if (System.getenv().containsKey("DEBUG"))
+            System.out.println("Looking for portable settings at: " + file.getAbsolutePath());
+        
+        if (!file.exists()) {
+            return Optional.empty();
+        }
+        return Optional.of(new File(path));
+
+    }
 
     public static class SettingsFolderException extends Exception {
         public enum Type {