refactor: Move EnumGameDirectory into HMCLCore

HMCLCore/src/main/java/org/jackhuang/hmcl/game/DefaultGameRepository.java

@@ -105,9 +105,17 @@ public class DefaultGameRepository implements GameRepository {
         return artifact.getPath(getBaseDirectory().toPath().resolve("libraries"));
     }
 
+    public GameDirectoryType getGameDirectoryType(String id) {
+        return GameDirectoryType.ROOT_FOLDER;
+    }
+
     @Override
     public File getRunDirectory(String id) {
-        return getBaseDirectory();
+        switch (getGameDirectoryType(id)) {
+            case VERSION_FOLDER: return getVersionRoot(id);
+            case ROOT_FOLDER: return getBaseDirectory();
+            default: throw new IllegalStateException();
+        }
     }
 
     @Override

HMCLCore/src/main/java/org/jackhuang/hmcl/game/GameDirectoryType.java

@@ -0,0 +1,38 @@
+/*
+ * Hello Minecraft! Launcher
+ * Copyright (C) 2020  huangyuhui <huanghongxun2008@126.com> and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package org.jackhuang.hmcl.game;
+
+/**
+ * Determines where game runs in and game files such as mods.
+ *
+ * @author huangyuhui
+ */
+public enum GameDirectoryType {
+    /**
+     * .minecraft
+     */
+    ROOT_FOLDER,
+    /**
+     * .minecraft/versions/&lt;version name&gt;
+     */
+    VERSION_FOLDER,
+    /**
+     * user customized directory.
+     */
+    CUSTOM
+}