code: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You under the Apache License, Version 2.0
   * (the "License"); you may not use this file except in compliance with
   * the License.  You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   *
   */
  
  package org.apache.skywalking.oap.server.core.management.ui.menu;
  
  import com.google.common.cache.CacheBuilder;
  import com.google.common.cache.CacheLoader;
  import com.google.common.cache.LoadingCache;
  import com.google.common.reflect.TypeToken;
  import com.google.gson.Gson;
  import lombok.SneakyThrows;
  import lombok.extern.slf4j.Slf4j;
  import org.apache.skywalking.oap.server.core.CoreModule;
  import org.apache.skywalking.oap.server.core.CoreModuleConfig;
  import org.apache.skywalking.oap.server.core.query.MetadataQueryService;
  import org.apache.skywalking.oap.server.core.query.type.MenuItem;
  import org.apache.skywalking.oap.server.core.storage.StorageModule;
  import org.apache.skywalking.oap.server.core.storage.management.UIMenuManagementDAO;
  import org.apache.skywalking.oap.server.library.module.ModuleManager;
  import org.apache.skywalking.oap.server.library.module.Service;
  import org.apache.skywalking.oap.server.library.util.CollectionUtils;
  import org.apache.skywalking.oap.server.library.util.StringUtil;
  
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  import java.util.concurrent.TimeUnit;
  
  @Slf4j
  public class UIMenuManagementService implements Service {
      private static final String MENU_ID = "1";
      private static final Gson GSON = new Gson();
  
      private final LoadingCache<Boolean, List<MenuItem>> menuItemCache;
      private UIMenuManagementDAO menuDAO;
      private ModuleManager moduleManager;
      private MetadataQueryService metadataQueryService;
  
      public UIMenuManagementService(ModuleManager moduleManager, CoreModuleConfig moduleConfig) {
          this.moduleManager = moduleManager;
          this.menuItemCache = CacheBuilder.newBuilder()
              .maximumSize(1)
              .refreshAfterWrite(moduleConfig.getUiMenuRefreshInterval(), TimeUnit.SECONDS)
              .build(new CacheLoader<>() {
                  @Override
                  public List<MenuItem> load(Boolean key) throws Exception {
                      return fetchMenuItems();
                  }
              });
      }
  
      private UIMenuManagementDAO getMenuDAO() {
          if (menuDAO == null) {
              menuDAO = moduleManager.find(StorageModule.NAME).provider().getService(UIMenuManagementDAO.class);
          }
          return menuDAO;
      }
  
      private MetadataQueryService getMetadataQueryService() {
          if (metadataQueryService == null) {
              metadataQueryService = moduleManager.find(CoreModule.NAME).provider().getService(MetadataQueryService.class);
          }
          return metadataQueryService;
      }
  
      public void saveMenu(List<UIMenuItemSetting> menuItems) throws IOException {
          // ignore if already existing
          if (getMenuDAO().getMenu(MENU_ID) != null) {
              this.getMenuItems();
              return;
          }
  
          UIMenu menu = new UIMenu();
          menu.setMenuId(MENU_ID);
          menu.setUpdateTime(System.currentTimeMillis());
          menu.setConfigurationJson(GSON.toJson(menuItems));
  
          getMenuDAO().saveMenu(menu);
          this.getMenuItems();
      }
  
      @SneakyThrows
      public List<MenuItem> getMenuItems() {
          return menuItemCache.get(true);
      }
  
      private List<MenuItem> fetchMenuItems() throws IOException {
          UIMenu menu = getMenuDAO().getMenu(MENU_ID);
          if (menu == null) {
              throw new IllegalStateException("cannot found UI menu");
          }
  
          List<UIMenuItemSetting> menuItems = GSON.fromJson(menu.getConfigurationJson(), new TypeToken<List<UIMenuItemSetting>>() {
          }.getType());
          return this.convertToMenuItems(menuItems);
      }
  
      private List<MenuItem> convertToMenuItems(List<UIMenuItemSetting> settings) throws IOException {
          List<MenuItem> items = new ArrayList<>();
          for (UIMenuItemSetting setting : settings) {
              final MenuItem item = new MenuItem();
              boolean shouldActivate = true;
              if (CollectionUtils.isNotEmpty(setting.getMenus())) {
                  // check should activate by sub items
                  List<MenuItem> subItems = this.convertToMenuItems(setting.getMenus());
                  shouldActivate = subItems.stream().anyMatch(MenuItem::isActivate);
                  item.setSubItems(subItems);
              } else if (StringUtil.isNotEmpty(setting.getLayer())) {
                  // check should active by dashboard
                  shouldActivate = CollectionUtils.isNotEmpty(getMetadataQueryService().listServices(setting.getLayer(), null));
              }
  
              item.setTitle(setting.getTitle());
              item.setIcon(setting.getIcon());
              item.setLayer(StringUtil.isEmpty(setting.getLayer()) ? "" : setting.getLayer());
              item.setDescription(setting.getDescription());
              item.setDocumentLink(setting.getDocumentLink());
              item.setI18nKey(setting.getI18nKey());
              item.setActivate(shouldActivate);
              if (CollectionUtils.isEmpty(item.getSubItems())) {
                  item.setSubItems(Collections.emptyList());
              }
              items.add(item);
          }
          return items;
      }
  
  }
  