package com.atlassian.activeobjects.confluence;
   
   import com.atlassian.activeobjects.spi.DatabaseType;
   import com.atlassian.activeobjects.spi.DefaultInitExecutorServiceProvider;
   import com.atlassian.activeobjects.spi.InitExecutorServiceProvider;
   import com.atlassian.activeobjects.spi.TenantAwareDataSourceProvider;
   import com.atlassian.sal.api.executor.ThreadLocalDelegateExecutorFactory;
   import com.atlassian.tenancy.api.Tenant;
   import com.google.common.annotations.VisibleForTesting;
  import com.google.common.util.concurrent.MoreExecutors;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import javax.annotation.Nonnull;
  import java.util.concurrent.ExecutorService;
  
  import static com.google.common.base.Preconditions.checkNotNull;
  
  public class ConfluenceInitExecutorServiceProvider implements InitExecutorServiceProvider {
      private static final Logger logger = LoggerFactory.getLogger(DefaultInitExecutorServiceProvider.class);
  
      private final TenantAwareDataSourceProvider tenantAwareDataSourceProvider;
      private final ThreadLocalDelegateExecutorFactory threadLocalDelegateExecutorFactory;
  
      @VisibleForTesting
      final InitExecutorServiceProvider defaultInitExecutorServiceProvider;
  
      public ConfluenceInitExecutorServiceProvider(
              final ThreadLocalDelegateExecutorFactory threadLocalDelegateExecutorFactory,
              final TenantAwareDataSourceProvider tenantAwareDataSourceProvider,
              final InitExecutorServiceProvider defaultInitExecutorServiceProvider) {
          this.threadLocalDelegateExecutorFactory = checkNotNull(threadLocalDelegateExecutorFactory);
          this.tenantAwareDataSourceProvider = checkNotNull(tenantAwareDataSourceProvider);
          this.defaultInitExecutorServiceProvider = checkNotNull(defaultInitExecutorServiceProvider);
      }
  
      /**
       * In the case of HSQL, confluence will dispatch TenantArrivedEvent synchronously. We then execute the init operations
       * in the same thread, so that we don't have multi threads i.e. transactions attempting DDL against the alleged
       * database HSQL.
       *
       * In other cases it will defer to the default.
       *
       * @return same thread executor for HSQL
       */
      @Nonnull
      @Override
      public ExecutorService initExecutorService(@Nonnull Tenant tenant) {
          DatabaseType databaseType = tenantAwareDataSourceProvider.getDatabaseType(tenant);
          if (DatabaseType.HSQL.equals(databaseType)) {
              logger.debug("creating HSQL snowflake init executor");
              return threadLocalDelegateExecutorFactory.createExecutorService(MoreExecutors.sameThreadExecutor());
          } else {
              return defaultInitExecutorServiceProvider.initExecutorService(tenant);
          }
      }
  }