content: package act.app;
  
  /*-
   * #%L
   * ACT Framework
   * %%
   * Copyright (C) 2014 - 2017 ActFramework
   * %%
   * Licensed 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.
   * #L%
   */
  
  import act.Act;
  import act.Destroyable;
  import act.app.event.SysEventId;
  import act.conf.AppConfig;
  import act.db.*;
  import act.db.util.*;
  import act.event.*;
  import act.util.ClassNode;
  import org.osgl.$;
  import org.osgl.exception.ConfigurationException;
  import org.osgl.util.*;
  
  import java.lang.reflect.Modifier;
  import java.util.*;
  import javax.enterprise.context.ApplicationScoped;
  import javax.inject.Inject;
  
  @ApplicationScoped
  public class DbServiceManager extends AppServiceBase<DbServiceManager> implements DaoLocator {
  
      public static final String DEFAULT = DB.DEFAULT;
  
      // map service id to service instance
      private Map<String, DbService> serviceMap = new HashMap<>();
  
      // map model class to dao class
      private Map<Class<?>, Dao> modelDaoMap = new HashMap<>();
  
      private final Dictionary<DbService, DbService> asyncInitializers = new Hashtable<>();
  
      private String firstInstance = DEFAULT;
  
      @Inject
      public DbServiceManager(final App app) {
          super(app);
          EntityClassRepository.init(app);
          initServices(app.config());
          prepareAsyncInitializers();
          configureSequenceGenerator(app);
  
          final Runnable daoInitializer = new Runnable() {
              @Override
              public void run() {
                  app.emit(SysEventId.DB_SVC_LOADED);
                  initDao();
                  app.emit(SysEventId.DB_SVC_PROVISIONED);
                  app.getInstance(AuditHelper.class);
              }
  
              private void initDao() {
                  ClassNode node = app.classLoader().classInfoRepository().node(Dao.class.getName());
                  node.visitPublicNotAbstractTreeNodes(new $.Visitor<ClassNode>() {
                      private boolean isGeneral(Class c) {
                          return Generics.tryGetTypeParamImplementations(c, DaoBase.class).isEmpty();
                      }
  
                      @Override
                      public void visit(ClassNode classNode) throws $.Break {
                          Class<? extends Dao> daoType = app.classForName(classNode.name());
                          if (Modifier.isAbstract(daoType.getModifiers())) {
                              return;
                          }
                          if (isGeneral(daoType)) {
                              if (!daoType.getName().startsWith("act.")) {
                                  warn("Ignore dao type[%s]: no type implementation found", daoType.getName());
                              }
                              return;
                          }
                          try {
                              Dao dao = $.cast(app.getInstance(daoType));
                              Class<?> modelType = dao.modelType();
                              DB db = modelType.getAnnotation(DB.class);
                              String svcId = null == db ? DEFAULT : db.value();
                              DbService dbService = dbService(svcId);
                              E.invalidConfigurationIf(null == dbService, "cannot find db service by id: %s", svcId);
                              dao = dbService.newDaoInstance(daoType);
                              modelDaoMap.put(modelType, dao);
                          } catch (Exception e) {
                              warn(e, "error loading DAO: %s", daoType);
                          }
                      }
                  });
              }
          };
  
          final EventBus eventBus = app.eventBus();
          if (asyncInitializers.isEmpty()) {
              eventBus.bind(SysEventId.SINGLETON_PROVISIONED, new SysEventListenerBase() {
                  @Override
                  public void on(EventObject event) throws Exception {
                      daoInitializer.run();
                  }
              });
          } else {
              eventBus.bind(DbServiceInitialized.class, new ActEventListenerBase<DbServiceInitialized>() {
                  @Override
                  public void on(DbServiceInitialized event) {
                      synchronized (asyncInitializers) {
                          asyncInitializers.remove(event.source());
                          if (asyncInitializers.isEmpty()) {
                              daoInitializer.run();
                          }
                      }
                  }
              });
          }
      }
  
      boolean hasDbService() {
          return !serviceMap.isEmpty();
      }
  
      private void configureSequenceGenerator(final App app) {
          app.jobManager().on(SysEventId.DEPENDENCY_INJECTOR_PROVISIONED, "DbServiceManager:registerSequenceNumberGenerator", new Runnable() {
              @Override
              public void run() {
                  _SequenceNumberGenerator seqGen = app.config().sequenceNumberGenerator();
                  SequenceNumberGenerator.registerImpl(seqGen);
              }
          });
      }
  
      private void prepareAsyncInitializers() {
          for (Map.Entry<String, DbService> entry : serviceMap.entrySet()) {
              DbService service = entry.getValue();
              if (service.initAsynchronously()) {
                  asyncInitializers.put(service, service);
              }
          }
      }
  
      @Override
      protected void releaseResources() {
          Destroyable.Util.tryDestroyAll(C.newSet(serviceMap.values()), ApplicationScoped.class);
          serviceMap.clear();
          Destroyable.Util.tryDestroyAll(C.newSet(modelDaoMap.values()), ApplicationScoped.class);
          modelDaoMap.clear();
          firstInstance = DEFAULT;
      }
  
      @Override
      public Dao dao(Class<?> modelClass) {
          Dao dao = modelDaoMap.get(modelClass);
          if (null == dao) {
              String svcId = dbId(modelClass);
              DbService dbService = dbService(svcId);
              dao = dbService.defaultDao(modelClass);
              modelDaoMap.put(modelClass, dao);
          }
          return dao;
      }
  
      public <T extends DbService> T dbService(String id) {
          return (T)serviceMap.get(id);
      }
  
      public <T extends DbService> List<T> dbServicesByClass(Class<T> dbServiceClass) {
          // It is possible for same service instance link to different name, e.g. `default` a `db1` etc
          // thus we must add it to set first to prevent the same service appears multiple times in the list
          Set<T> set = new HashSet<>();
          for (DbService service : serviceMap.values()) {
              if (dbServiceClass.isInstance(service)) {
                  set.add((T) service);
              }
          }
          return new ArrayList<>(set);
      }
  
      public Iterable<DbService> registeredServices() {
          return serviceMap.values();
      }
  
      private void initServices(AppConfig config) {
          DbManager dbManager = Act.dbManager();
          if (!dbManager.hasPlugin()) {
              info("DB service not initialized: No DB plugin found");
              return;
          }
          DbPlugin db = dbManager.theSolePlugin();
          Map<String, String> dbConf = config.subSet("db.");
          if (dbConf.isEmpty()) {
              if (null == db) {
                  warn("DB service not initialized: need to specify default db service implementation");
                  return;
              } else {
                  info("DB configuration not found. Will try to init default service with the sole db plugin: %s", db);
                  DbService svc = db.initDbService(DEFAULT, app(), new HashMap<String, String>());
                  serviceMap.put(DEFAULT, svc);
                  return;
              }
          }
  
          if (dbConf.containsKey("db.instances")) {
              String instances = dbConf.get("db.instances").toString();
              String[] sa = instances.split("[,\\s;:]+");
              for (String dbId: sa) {
                  initService(dbId, dbConf);
              }
              firstInstance = sa[0];
              app().entityMetaInfoRepo().setDefaultAlias(firstInstance);
              app().service(EntityClassRepository.class).setDefaultAlias(firstInstance);
          }
          if (serviceMap.containsKey(DEFAULT)) return;
          // try init default service if conf found
          String dbId = null;
          if (dbConf.containsKey("db." + DEFAULT +".impl")) {
              dbId = DEFAULT;
          } else if (dbConf.containsKey("db.impl")) {
              dbId = "";
          }
          if (null != dbId) {
              initService(dbId, dbConf);
          } else if (serviceMap.size() == 1) {
              DbService svc = serviceMap.values().iterator().next();
              serviceMap.put(DEFAULT, svc);
              warn("db service configuration not found. Use the sole one db service[%s] as default service", svc.id());
          } else {
              if (serviceMap.isEmpty()) {
                  if (null == db) {
                      warn("DB service not initialized: need to specify default db service implementation");
                  } else {
                      info("Init default service with the sole db plugin: %s", db);
                      Map<String, String> svcConf = new HashMap<>();
                      String prefix = "db.";
                      for (String key : dbConf.keySet()) {
                          if (key.startsWith(prefix)) {
                              String o = dbConf.get(key);
                              svcConf.put(key.substring(prefix.length()), o);
                          }
                      }
                      DbService svc = db.initDbService(DEFAULT, app(), svcConf);
                      serviceMap.put(DEFAULT, svc);
                  }
              } else {
                  warn("Default service not specified. Use the first db instance as default service: %s", firstInstance);
                  serviceMap.put(DEFAULT, serviceMap.get(firstInstance));
              }
          }
      }
  
      private void initService(String dbId, Map<String, String> conf) {
          Map<String, String> svcConf = new HashMap<>();
          String prefix = "db." + (S.blank(dbId) ? "" : dbId + ".");
          for (String key : conf.keySet()) {
              if (key.startsWith(prefix)) {
                  String o = conf.get(key);
                  svcConf.put(key.substring(prefix.length()), o);
              }
          }
          String impl = svcConf.remove("impl");
          String svcId = S.empty(dbId) ? DEFAULT : dbId;
          if (null == impl) {
              throw new ConfigurationException("Cannot init db service[%s]: implementation not specified", svcId);
          }
          DbPlugin plugin = Act.dbManager().plugin(impl);
          if (null == plugin) {
              throw new ConfigurationException("Cannot init db service[%s]: implementation not found: %s", svcId, impl);
          }
          DbService svc = plugin.initDbService(S.blank(dbId) ? DEFAULT : dbId, app(), svcConf);
          serviceMap.put(svcId, svc);
          info("db service[%s] initialized", svcId);
      }
  
      public static String dbId(Class<?> modelClass) {
          DB db = modelClass.getAnnotation(DB.class);
          if (null != db) {
              return db.value();
          }
          return DbServiceManager.DEFAULT;
      }
  
  }
  