/*
 * 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.iotdb.db.queryengine.plan.relational.sql.ast;

import com.google.common.collect.ImmutableList;
import org.apache.tsfile.utils.RamUsageEstimator;
import org.apache.tsfile.utils.ReadWriteIOUtils;

import java.io.DataOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.List;
import java.util.Objects;

public class SymbolReference extends Expression {

  private static final long INSTANCE_SIZE =
      RamUsageEstimator.shallowSizeOfInstance(SymbolReference.class);

  private final String name;

  public SymbolReference(String name) {
    super(null);
    this.name = name;
  }

  public String getName() {
    return name;
  }

  @Override
  public <R, C> R accept(AstVisitor<R, C> visitor, C context) {
    return visitor.visitSymbolReference(this, context);
  }

  @Override
  public List<Node> getChildren() {
    return ImmutableList.of();
  }

  @Override
  public boolean equals(Object o) {
    if (this == o) {
      return true;
    }
    if (o == null || getClass() != o.getClass()) {
      return false;
    }
    SymbolReference that = (SymbolReference) o;
    return Objects.equals(name, that.name);
  }

  @Override
  public int hashCode() {
    return Objects.hash(name);
  }

  // =============== serialize =================

  @Override
  public TableExpressionType getExpressionType() {
    return TableExpressionType.SYMBOL_REFERENCE;
  }

  @Override
  public void serialize(DataOutputStream stream) throws IOException {
    ReadWriteIOUtils.write(this.name, stream);
  }

  public SymbolReference(ByteBuffer byteBuffer) {
    super(null);
    this.name = ReadWriteIOUtils.readString(byteBuffer);
  }

  @Override
  public long ramBytesUsed() {
    return INSTANCE_SIZE
        + AstMemoryEstimationHelper.getEstimatedSizeOfNodeLocation(getLocationInternal())
        + RamUsageEstimator.sizeOf(name);
  }
}
