/*
 * 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.planner.assertions;

import org.apache.iotdb.db.queryengine.common.SessionInfo;
import org.apache.iotdb.db.queryengine.plan.planner.plan.node.PlanNode;
import org.apache.iotdb.db.queryengine.plan.relational.metadata.Metadata;
import org.apache.iotdb.db.queryengine.plan.relational.planner.Symbol;

import java.util.Optional;

import static java.lang.String.format;
import static java.util.Objects.requireNonNull;
import static org.apache.iotdb.db.queryengine.plan.relational.planner.assertions.MatchResult.match;

public class AliasMatcher implements Matcher {
  private final Optional<String> alias;
  private final RvalueMatcher matcher;

  AliasMatcher(Optional<String> alias, RvalueMatcher matcher) {
    this.alias = requireNonNull(alias, "alias is null");
    this.matcher = requireNonNull(matcher, "matcher is null");
  }

  @Override
  public boolean shapeMatches(PlanNode node) {
    return true;
  }

  /*
   * Aliases must be collected on the way back up the tree for several reasons:
   * 1) The rvalue may depend on previously bound aliases (in the case of an
   *    Expression or FunctionCall)
   * 2) Scope: aliases bound in a node are only in scope in nodes higher up
   *    the tree, just as symbols in a node's output are only in scope in nodes
   *    higher up the tree.
   */
  @Override
  public MatchResult detailMatches(
      PlanNode node, SessionInfo sessionInfo, Metadata metadata, SymbolAliases symbolAliases) {
    Optional<Symbol> symbol = matcher.getAssignedSymbol(node, sessionInfo, metadata, symbolAliases);
    if (symbol.isPresent() && alias.isPresent()) {
      return match(alias.get(), symbol.get().toSymbolReference());
    }
    return new MatchResult(symbol.isPresent());
  }

  @Override
  public String toString() {
    if (alias.isPresent()) {
      return format("bind %s -> %s", alias.get(), matcher);
    }
    return format("bind %s", matcher);
  }
}
