/*
    * 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.shardingsphere.transaction.rule;
  
  import lombok.AccessLevel;
  import lombok.Getter;
  import lombok.extern.slf4j.Slf4j;
  import org.apache.shardingsphere.database.connector.core.type.DatabaseType;
  import org.apache.shardingsphere.infra.metadata.database.ShardingSphereDatabase;
  import org.apache.shardingsphere.infra.rule.attribute.RuleAttributes;
  import org.apache.shardingsphere.infra.rule.scope.GlobalRule;
  import org.apache.shardingsphere.sql.parser.statement.core.statement.SQLStatement;
  import org.apache.shardingsphere.sql.parser.statement.core.statement.type.dml.DMLStatement;
  import org.apache.shardingsphere.sql.parser.statement.core.statement.type.dml.SelectStatement;
  import org.apache.shardingsphere.transaction.ConnectionTransaction;
  import org.apache.shardingsphere.transaction.ShardingSphereTransactionManagerEngine;
  import org.apache.shardingsphere.transaction.api.TransactionType;
  import org.apache.shardingsphere.transaction.config.TransactionRuleConfiguration;
  import org.apache.shardingsphere.transaction.constant.TransactionOrder;
  
  import javax.sql.DataSource;
  import java.util.Collection;
  import java.util.LinkedHashMap;
  import java.util.Map;
  import java.util.Properties;
  import java.util.concurrent.atomic.AtomicReference;
  
  /**
   * Transaction rule.
   */
  @Getter
  @Slf4j
  public final class TransactionRule implements GlobalRule, AutoCloseable {
      
      private final TransactionRuleConfiguration configuration;
      
      private final TransactionType defaultType;
      
      private final String providerType;
      
      private final Properties props;
      
      @Getter(AccessLevel.NONE)
      private final AtomicReference<ShardingSphereTransactionManagerEngine> resource;
      
      private final RuleAttributes attributes;
      
      public TransactionRule(final TransactionRuleConfiguration ruleConfig, final Collection<ShardingSphereDatabase> databases) {
          configuration = ruleConfig;
          defaultType = TransactionType.valueOf(ruleConfig.getDefaultType().toUpperCase());
          providerType = ruleConfig.getProviderType();
          props = ruleConfig.getProps();
          resource = new AtomicReference<>(createTransactionManagerEngine(databases));
          attributes = new RuleAttributes();
      }
      
      private synchronized ShardingSphereTransactionManagerEngine createTransactionManagerEngine(final Collection<ShardingSphereDatabase> databases) {
          ShardingSphereTransactionManagerEngine result = new ShardingSphereTransactionManagerEngine(defaultType);
          if (databases.isEmpty()) {
              return result;
          }
          Map<String, DatabaseType> databaseTypes = new LinkedHashMap<>(databases.size(), 1F);
          Map<String, DataSource> dataSourceMap = new LinkedHashMap<>(databases.size(), 1F);
          for (ShardingSphereDatabase each : databases) {
              each.getResourceMetaData().getStorageUnits().forEach((key, value) -> {
                  databaseTypes.put(each.getName() + "." + key, value.getStorageType());
                  dataSourceMap.put(each.getName() + "." + key, value.getDataSource());
              });
          }
          result.init(databaseTypes, dataSourceMap, providerType);
          return result;
      }
      
      /**
       * Get resource.
       *
       * @return got resource
       */
      public ShardingSphereTransactionManagerEngine getResource() {
          return resource.get();
      }
      
      /**
       * Judge whether to implicit commit transaction.
      *
      * @param sqlStatement sql statement
      * @param multiExecutionUnits is multiple execution units
      * @param connectionTransaction connection transaction
      * @param isAutoCommit is auto commit
      * @return is implicit commit transaction or not
      */
     public boolean isImplicitCommitTransaction(final SQLStatement sqlStatement, final boolean multiExecutionUnits, final ConnectionTransaction connectionTransaction, final boolean isAutoCommit) {
         if (!isAutoCommit) {
             return false;
         }
         if (!TransactionType.isDistributedTransaction(defaultType) || connectionTransaction.isInDistributedTransaction()) {
             return false;
         }
         return isWriteDMLStatement(sqlStatement) && multiExecutionUnits;
     }
     
     private boolean isWriteDMLStatement(final SQLStatement sqlStatement) {
         return sqlStatement instanceof DMLStatement && !(sqlStatement instanceof SelectStatement);
     }
     
     @Override
     public void refresh(final Collection<ShardingSphereDatabase> databases, final GlobalRuleChangedType changedType) {
         if (GlobalRuleChangedType.DATABASE_CHANGED != changedType) {
             return;
         }
         ShardingSphereTransactionManagerEngine previousEngine = resource.get();
         close(previousEngine);
         resource.set(createTransactionManagerEngine(databases));
     }
     
     @Override
     public void close() {
         // TODO Consider shutting down the transaction manager gracefully
         ShardingSphereTransactionManagerEngine engine = resource.get();
         if (null != engine) {
             resource.set(null);
             close(engine);
         }
     }
     
     private void close(final ShardingSphereTransactionManagerEngine engine) {
         try {
             engine.close();
             // CHECKSTYLE:OFF
         } catch (final RuntimeException ex) {
             // CHECKSTYLE:ON
             log.error("Close transaction engine failed.", ex);
         }
     }
     
     @Override
     public int getOrder() {
         return TransactionOrder.ORDER;
     }
 }