/*
    * 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.sharding.rewrite.token.generator.impl;
  
  import lombok.Setter;
  import org.apache.shardingsphere.infra.annotation.HighFrequencyInvocation;
  import org.apache.shardingsphere.infra.rewrite.sql.token.common.generator.aware.RouteContextAware;
  import org.apache.shardingsphere.sharding.rewrite.token.pojo.ShardingInsertValue;
  import org.apache.shardingsphere.sharding.rewrite.token.pojo.ShardingInsertValuesToken;
  import org.apache.shardingsphere.infra.binder.context.segment.insert.values.InsertValueContext;
  import org.apache.shardingsphere.infra.binder.context.statement.SQLStatementContext;
  import org.apache.shardingsphere.infra.binder.context.statement.type.dml.InsertStatementContext;
  import org.apache.shardingsphere.sql.parser.statement.core.segment.dml.assignment.InsertValuesSegment;
  import org.apache.shardingsphere.sql.parser.statement.core.segment.dml.expr.ExpressionSegment;
  import org.apache.shardingsphere.infra.datanode.DataNode;
  import org.apache.shardingsphere.infra.rewrite.sql.token.common.generator.OptionalSQLTokenGenerator;
  import org.apache.shardingsphere.infra.rewrite.sql.token.common.pojo.generic.InsertValuesToken;
  import org.apache.shardingsphere.infra.route.context.RouteContext;
  
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.List;
  
  /**
   * Insert values token generator for sharding.
   */
  @HighFrequencyInvocation
  @Setter
  public final class ShardingInsertValuesTokenGenerator implements OptionalSQLTokenGenerator<InsertStatementContext>, RouteContextAware {
      
      private RouteContext routeContext;
      
      @Override
      public boolean isGenerateSQLToken(final SQLStatementContext sqlStatementContext) {
          return sqlStatementContext instanceof InsertStatementContext && !(((InsertStatementContext) sqlStatementContext).getSqlStatement()).getValues().isEmpty();
      }
      
      @Override
      public InsertValuesToken generateSQLToken(final InsertStatementContext insertStatementContext) {
          Collection<InsertValuesSegment> insertValuesSegments = insertStatementContext.getSqlStatement().getValues();
          InsertValuesToken result = new ShardingInsertValuesToken(getStartIndex(insertValuesSegments), getStopIndex(insertValuesSegments));
          Iterator<Collection<DataNode>> dataNodesIterator = routeContext.getOriginalDataNodes().isEmpty() ? Collections.emptyIterator() : routeContext.getOriginalDataNodes().iterator();
          for (InsertValueContext each : insertStatementContext.getInsertValueContexts()) {
              List<ExpressionSegment> expressionSegments = each.getValueExpressions();
              Collection<DataNode> dataNodes = dataNodesIterator.hasNext() ? dataNodesIterator.next() : Collections.emptyList();
              result.getInsertValues().add(new ShardingInsertValue(expressionSegments, dataNodes));
          }
          return result;
      }
      
      private int getStartIndex(final Collection<InsertValuesSegment> segments) {
          int result = segments.iterator().next().getStartIndex();
          for (InsertValuesSegment each : segments) {
              result = Math.min(result, each.getStartIndex());
          }
          return result;
      }
      
      private int getStopIndex(final Collection<InsertValuesSegment> segments) {
          int result = segments.iterator().next().getStopIndex();
          for (InsertValuesSegment each : segments) {
              result = Math.max(result, each.getStopIndex());
          }
          return result;
      }
  }