/*
    * 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.shadow.route.engine.dml;
  
  import org.apache.shardingsphere.infra.binder.context.statement.dml.UpdateStatementContext;
  import org.apache.shardingsphere.shadow.api.shadow.ShadowOperationType;
  import org.apache.shardingsphere.shadow.condition.ShadowColumnCondition;
  import org.apache.shardingsphere.shadow.route.engine.util.ShadowExtractor;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.dml.column.ColumnSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.dml.expr.ExpressionSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.dml.predicate.AndPredicate;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.dml.predicate.WhereSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.util.ColumnExtractor;
  import org.apache.shardingsphere.sql.parser.sql.common.util.ExpressionExtractUtils;
  
  import java.util.Collection;
  import java.util.LinkedList;
  import java.util.List;
  
  /**
   * Shadow update statement routing engine.
   */
  public final class ShadowUpdateStatementRoutingEngine extends AbstractShadowDMLStatementRouteEngine {
      
      private final UpdateStatementContext sqlStatementContext;
      
      private final List<Object> parameters;
      
      public ShadowUpdateStatementRoutingEngine(final UpdateStatementContext sqlStatementContext, final List<Object> parameters) {
          super(sqlStatementContext, ShadowOperationType.UPDATE);
          this.sqlStatementContext = sqlStatementContext;
          this.parameters = parameters;
      }
      
      @Override
      protected Collection<ShadowColumnCondition> getShadowColumnConditions(final String shadowColumnName) {
          Collection<ShadowColumnCondition> result = new LinkedList<>();
          for (ExpressionSegment each : getWhereSegment()) {
              Collection<ColumnSegment> columns = ColumnExtractor.extract(each);
              if (1 != columns.size()) {
                  continue;
              }
              ShadowExtractor.extractValues(each, parameters).map(values -> new ShadowColumnCondition(getSingleTableName(), shadowColumnName, values)).ifPresent(result::add);
          }
          return result;
      }
      
      private Collection<ExpressionSegment> getWhereSegment() {
          Collection<ExpressionSegment> result = new LinkedList<>();
          for (WhereSegment each : sqlStatementContext.getWhereSegments()) {
              for (AndPredicate predicate : ExpressionExtractUtils.getAndPredicates(each.getExpr())) {
                  result.addAll(predicate.getPredicates());
              }
          }
          return result;
      }
  }