/*
    * 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.infra.connection.refresher.type.view;
  
  import org.apache.shardingsphere.infra.config.props.ConfigurationProperties;
  import org.apache.shardingsphere.infra.connection.refresher.MetaDataRefresher;
  import org.apache.shardingsphere.infra.connection.refresher.util.TableRefreshUtils;
  import org.apache.shardingsphere.infra.database.core.type.DatabaseType;
  import org.apache.shardingsphere.infra.instance.mode.ModeContextManager;
  import org.apache.shardingsphere.infra.metadata.database.ShardingSphereDatabase;
  import org.apache.shardingsphere.infra.metadata.database.rule.RuleMetaData;
  import org.apache.shardingsphere.infra.metadata.database.schema.builder.GenericSchemaBuilder;
  import org.apache.shardingsphere.infra.metadata.database.schema.builder.GenericSchemaBuilderMaterial;
  import org.apache.shardingsphere.infra.metadata.database.schema.model.ShardingSphereSchema;
  import org.apache.shardingsphere.infra.metadata.database.schema.model.ShardingSphereTable;
  import org.apache.shardingsphere.infra.metadata.database.schema.model.ShardingSphereView;
  import org.apache.shardingsphere.infra.metadata.database.schema.pojo.AlterSchemaMetaDataPOJO;
  import org.apache.shardingsphere.infra.rule.attribute.datanode.MutableDataNodeRuleAttribute;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.generic.table.SimpleTableSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.statement.ddl.AlterViewStatement;
  import org.apache.shardingsphere.sql.parser.sql.dialect.handler.ddl.AlterViewStatementHandler;
  
  import java.sql.SQLException;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.LinkedList;
  import java.util.Map;
  import java.util.Optional;
  
  /**
   * Schema refresher for alter view statement.
   */
  public final class AlterViewStatementSchemaRefresher implements MetaDataRefresher<AlterViewStatement> {
      
      @Override
      public void refresh(final ModeContextManager modeContextManager, final ShardingSphereDatabase database, final Collection<String> logicDataSourceNames,
                          final String schemaName, final DatabaseType databaseType, final AlterViewStatement sqlStatement, final ConfigurationProperties props) throws SQLException {
          String viewName = TableRefreshUtils.getTableName(databaseType, sqlStatement.getView().getTableName().getIdentifier());
          AlterSchemaMetaDataPOJO alterSchemaMetaDataPOJO = new AlterSchemaMetaDataPOJO(database.getName(), schemaName, logicDataSourceNames);
          Optional<SimpleTableSegment> renameView = AlterViewStatementHandler.getRenameView(sqlStatement);
          if (renameView.isPresent()) {
              String renameViewName = renameView.get().getTableName().getIdentifier().getValue();
              String originalView = database.getSchema(schemaName).getView(viewName).getViewDefinition();
              ShardingSphereSchema schema = getSchema(database, logicDataSourceNames, schemaName, renameViewName, originalView, props);
              alterSchemaMetaDataPOJO.getAlteredTables().add(schema.getTable(renameViewName));
              alterSchemaMetaDataPOJO.getAlteredViews().add(schema.getView(renameViewName));
              alterSchemaMetaDataPOJO.getDroppedTables().add(viewName);
              alterSchemaMetaDataPOJO.getDroppedViews().add(viewName);
          }
          Optional<String> viewDefinition = AlterViewStatementHandler.getViewDefinition(sqlStatement);
          if (viewDefinition.isPresent()) {
              ShardingSphereSchema schema = getSchema(database, logicDataSourceNames, schemaName, viewName, viewDefinition.get(), props);
              alterSchemaMetaDataPOJO.getAlteredTables().add(schema.getTable(viewName));
              alterSchemaMetaDataPOJO.getAlteredViews().add(schema.getView(viewName));
          }
          modeContextManager.alterSchemaMetaData(alterSchemaMetaDataPOJO);
      }
      
      private ShardingSphereSchema getSchema(final ShardingSphereDatabase database, final Collection<String> logicDataSourceNames,
                                             final String schemaName, final String viewName, final String viewDefinition, final ConfigurationProperties props) throws SQLException {
          RuleMetaData ruleMetaData = new RuleMetaData(new LinkedList<>(database.getRuleMetaData().getRules()));
          if (TableRefreshUtils.isSingleTable(viewName, database)) {
              ruleMetaData.getAttributes(MutableDataNodeRuleAttribute.class).forEach(each -> each.put(logicDataSourceNames.iterator().next(), schemaName, viewName));
          }
          GenericSchemaBuilderMaterial material = new GenericSchemaBuilderMaterial(
                  database.getProtocolType(), database.getResourceMetaData().getStorageUnits(), ruleMetaData.getRules(), props, schemaName);
          Map<String, ShardingSphereSchema> schemaMap = GenericSchemaBuilder.build(Collections.singletonList(viewName), material);
          Optional<ShardingSphereTable> actualViewMetaData = Optional.ofNullable(schemaMap.get(schemaName)).map(optional -> optional.getTable(viewName));
          ShardingSphereSchema result = new ShardingSphereSchema();
          actualViewMetaData.ifPresent(optional -> result.putTable(viewName, optional));
          result.putView(viewName, new ShardingSphereView(viewName, viewDefinition));
          return result;
      }
      
      @Override
      public Class<AlterViewStatement> getType() {
          return AlterViewStatement.class;
      }
  }