content: /*
   *
   *  * Copyright 2020 Alibaba Group Holding Limited.
   *  *
   *  * Licensed 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 com.alibaba.graphscope.common.ir.rel;
  
  import com.alibaba.graphscope.common.ir.tools.AliasInference;
  import com.alibaba.graphscope.common.ir.tools.Utils;
  
  import org.apache.calcite.plan.GraphOptCluster;
  import org.apache.calcite.plan.RelTraitSet;
  import org.apache.calcite.rel.RelNode;
  import org.apache.calcite.rel.RelShuttle;
  import org.apache.calcite.rel.RelWriter;
  import org.apache.calcite.rel.SingleRel;
  import org.apache.calcite.rel.type.*;
  import org.apache.calcite.rex.RexNode;
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.util.List;
  import java.util.stream.Collectors;
  
  public class GraphLogicalUnfold extends SingleRel {
      private final RexNode key;
      private final String aliasName;
      private final int aliasId;
  
      public GraphLogicalUnfold(
              GraphOptCluster cluster, RelNode input, RexNode key, @Nullable String aliasName) {
          super(cluster, RelTraitSet.createEmpty(), input);
          this.key = key;
          this.aliasName =
                  AliasInference.inferDefault(
                          aliasName, AliasInference.getUniqueAliasList(input, true));
          this.aliasId = cluster.getIdGenerator().generate(this.aliasName);
      }
  
      public RexNode getUnfoldKey() {
          return this.key;
      }
  
      @Override
      public RelWriter explainTerms(RelWriter pw) {
          return super.explainTerms(pw).item("key", key).item("alias", aliasName);
      }
  
      @Override
      public RelDataType deriveRowType() {
          RelDataType inputOutputType = Utils.getOutputType(input);
          List<RelDataTypeField> fields =
                  inputOutputType.getFieldList().stream()
                          .filter(k -> k.getIndex() != AliasInference.DEFAULT_ID)
                          .collect(Collectors.toList());
          fields.add(
                  new RelDataTypeFieldImpl(
                          this.aliasName, this.aliasId, key.getType().getComponentType()));
          return new RelRecordType(StructKind.FULLY_QUALIFIED, fields);
      }
  
      @Override
      public GraphLogicalUnfold copy(RelTraitSet traitSet, List<RelNode> inputs) {
          return new GraphLogicalUnfold(
                  (GraphOptCluster) getCluster(), inputs.get(0), this.key, this.aliasName);
      }
  
      @Override
      public RelNode accept(RelShuttle shuttle) {
          if (shuttle instanceof GraphShuttle) {
              return ((GraphShuttle) shuttle).visit(this);
          }
          return shuttle.visit(this);
      }
  
      public String getAliasName() {
          return this.aliasName;
      }
  
      public int getAliasId() {
          return this.aliasId;
      }
  }
  