Add new icon files for Nebulae project

- Added PNG icon for model in `src/main/resources/nebulae_icons/model/icon.png`
- Added ICO icon for script in `src/main/resources/nebulae_icons/script/icon.ico`
- Added PNG icon for script in `src/main/resources/nebulae_icons/script/icon.png`

Author: Niwer1525

src/main/java/niwer/nebulae/NebulaeEngine.java

@@ -43,4 +43,6 @@ public class NebulaeEngine {
      * @return An instance of the requested NebulaeProcessor.
      */
     public static NebulaeProcessor forVersion(NebulaeVersion version, byte[] key) { return version.getProcessor(key); }
+
+    
 }

src/main/java/niwer/nebulae/NebulaeFormat.java

@@ -17,4 +17,5 @@ public class NebulaeFormat {
     public static final byte TYPE_SCRIPT = 0x05; // For script files (e.g. Lua or JavaScript)
     public static final byte TYPE_FONT = 0x06; // For font files (e.g. TTF/OTF)
     public static final byte TYPE_DATA  = 0x07; // For generic data files (e.g. JSON, binary blobs)
+    public static final byte TYPE_ARCHIVE  = 0x08; // For archive files (e.g. ZIP, RAR)
 }

src/main/java/niwer/nebulae/NebulaeIcons.java

@@ -0,0 +1,24 @@
+package niwer.nebulae.icons;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.StandardCopyOption;
+
+public abstract class AbstractFileIconHandler implements FileIconHandler {
+
+    private static final Path ICON_DIRECTORY = Paths.get(System.getProperty("user.home"), ".nebulae_register", "icons");
+
+    protected Path saveIcon(String fileType, NebulaeIcons icon, String extension) throws IOException {
+        Files.createDirectories(ICON_DIRECTORY);
+
+        Path iconPath = ICON_DIRECTORY.resolve(fileType + extension);
+        Files.copy(icon.asStream(), iconPath, StandardCopyOption.REPLACE_EXISTING);
+        return iconPath;
+    }
+
+    protected void run(String... command) throws IOException, InterruptedException {
+        if (new ProcessBuilder(command).inheritIO().start().waitFor() != 0) throw new IOException("Command failed: " + String.join(" ", command));
+    }
+}

src/main/java/niwer/nebulae/icons/AbstractFileIconHandler.java

@@ -0,0 +1,6 @@
+package niwer.nebulae.icons;
+
+public interface FileIconHandler {
+
+    void registerFileIcon(String extension, String fileType, String description, NebulaeIcons iconStream) throws Exception;
+}

src/main/java/niwer/nebulae/icons/FileIconHandler.java

@@ -0,0 +1,29 @@
+package niwer.nebulae.icons;
+
+import java.util.Locale;
+
+public final class FileIconRegistryManager {
+
+    private static final FileIconHandler HANDLER = createHandler();
+
+    private FileIconRegistryManager() {}
+
+    private static FileIconHandler createHandler() {
+        String os = System.getProperty("os.name").toLowerCase(Locale.ROOT).trim();
+        if (os.contains("win")) return new WindowsFileIconHandler();
+        if (os.contains("linux")) return new LinuxFileIconHandler();
+        if (os.contains("mac")) return new MacOSFileIconHandler();
+        throw new UnsupportedOperationException("Unsupported OS: " + os);
+    }
+
+    /**
+     * Registers a custom file icon for the given extension. The file type will be "niwer.nebulae.[extension]", and the description will be the one provided by the icon.
+     * 
+     * @param extension The file extension, including the dot (e.g. ".txt")
+     * @param icon The icon to use for this file type
+     * @throws Exception if an error occurs while registering the icon (e.g. insufficient permissions, unsupported OS, etc.)
+     */
+    public static void register(String extension, NebulaeIcons icon) throws Exception {
+        HANDLER.registerFileIcon(extension, "niwer.nebulae." + extension.replace(".", ""), icon.description(), icon);
+    }
+}

src/main/java/niwer/nebulae/icons/FileIconRegistryManager.java

@@ -0,0 +1,38 @@
+package niwer.nebulae.icons;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.StandardCopyOption;
+
+/**
+ * This should support most Linux desktop environments that follow the XDG standard, but may not work on all distributions or setups.
+ */
+public final class LinuxFileIconHandler extends AbstractFileIconHandler {
+
+    @Override
+    public void registerFileIcon(String extension, String fileType, String description, NebulaeIcons icon) throws Exception {
+        Path iconPath = saveIcon(fileType, icon, ".png");
+
+        Path mimeDir = Paths.get(System.getProperty("user.home"), ".local/share/mime/packages");
+        Files.createDirectories(mimeDir);
+
+        String mime = "application/x-" + fileType.toLowerCase();
+        Path xml = mimeDir.resolve(fileType + ".xml");
+        Files.writeString(xml, """
+                <?xml version="1.0" encoding="UTF-8"?>
+                <mime-info xmlns='http://www.freedesktop.org/standards/shared-mime-info'>
+                  <mime-type type='%s'>
+                    <comment>%s</comment>
+                    <glob pattern='*%s'/>
+                  </mime-type>
+                </mime-info>
+                """.formatted(mime, description, extension));
+
+        run("update-mime-database", System.getProperty("user.home") + "/.local/share/mime");
+
+        Path iconDir = Paths.get(System.getProperty("user.home"), ".local/share/icons/hicolor/256x256/mimetypes");
+        Files.createDirectories(iconDir);
+        Files.copy(iconPath, iconDir.resolve(mime.replace("/", "-") + ".png"), StandardCopyOption.REPLACE_EXISTING);
+    }
+}

src/main/java/niwer/nebulae/icons/LinuxFileIconHandler.java

@@ -0,0 +1,9 @@
+package niwer.nebulae.icons;
+
+public final class MacOSFileIconHandler extends AbstractFileIconHandler {
+
+    @Override
+    public void registerFileIcon(String extension, String fileType, String description, NebulaeIcons icon) {
+        throw new UnsupportedOperationException("Custom file icons are not supported on macOS.");
+    }
+}

src/main/java/niwer/nebulae/icons/MacOSFileIconHandler.java

@@ -0,0 +1,44 @@
+package niwer.nebulae.icons;
+
+import java.io.InputStream;
+import java.util.Locale;
+
+import niwer.nebulae.NebulaeFormat;
+
+public enum NebulaeIcons {
+
+    DEFAULT("data", NebulaeFormat.TYPE_DATA, "Default"), // Default icon for unregistered file types
+
+    MODEL("model", NebulaeFormat.TYPE_MODEL, "Model"),
+    IMAGE("image", NebulaeFormat.TYPE_IMAGE, "Image"),
+    ANIMATION("animation", NebulaeFormat.TYPE_ANIMATION, "Animation"),
+    AUDIO("audio", NebulaeFormat.TYPE_SOUND, "Audio"),
+    SCRIPT("script", NebulaeFormat.TYPE_SCRIPT, "Script"),
+    FONT("font", NebulaeFormat.TYPE_FONT, "Font"),
+    DATA("data", NebulaeFormat.TYPE_DATA, "Data"),
+    ARCHIVE("archive", NebulaeFormat.TYPE_ARCHIVE, "Archive");
+
+    private final String SUB_FOLDER_PATH;
+    public final String DESCRIPTION;
+
+    private InputStream stream;
+
+    NebulaeIcons(String path, byte formatType, String description) {
+        this.SUB_FOLDER_PATH = path;
+        this.DESCRIPTION = description;
+    }
+
+    public String description() { return DESCRIPTION; }
+
+    public InputStream asStream() {
+        if (stream == null) {
+            final String OS = System.getProperty("os.name").toLowerCase(Locale.ROOT).trim();
+            final String EXTENSION = OS.contains("win") ? ".ico" : ".png";
+
+            /* Try getting the icon inside the JAR */
+            stream = getClass().getResourceAsStream("/nebulae_icons/" + SUB_FOLDER_PATH + "/icon" + EXTENSION);
+            if (stream == null) throw new RuntimeException("Icon not found: " + SUB_FOLDER_PATH);
+        }
+        return stream;
+    }
+}

src/main/java/niwer/nebulae/icons/NebulaeIcons.java

@@ -0,0 +1,21 @@
+package niwer.nebulae.icons;
+
+import java.io.IOException;
+import java.nio.file.Path;
+
+public final class WindowsFileIconHandler extends AbstractFileIconHandler {
+
+    @Override
+    public void registerFileIcon(String extension, String fileType, String description, NebulaeIcons icon) throws Exception {
+        Path iconPath = saveIcon(fileType, icon, ".ico");
+        run("reg", "add", "HKCU\\Software\\Classes\\" + extension, "/ve", "/d", fileType, "/f");
+        run("reg", "add", "HKCU\\Software\\Classes\\" + fileType, "/ve", "/d", description, "/f");
+        run("reg", "add", "HKCU\\Software\\Classes\\" + fileType + "\\DefaultIcon", "/ve", "/d", iconPath.toString(), "/f");
+        refreshExplorer();
+    }
+
+    private void refreshExplorer() throws IOException, InterruptedException {
+        run("taskkill", "/f", "/im", "explorer.exe");
+        new ProcessBuilder("cmd", "/c", "start", "explorer").start();
+    }
+}