/*
 * 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.
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package org.apache.iotdb.db.queryengine.plan.expression.visitor;

import org.apache.iotdb.commons.path.PartialPath;
import org.apache.iotdb.db.queryengine.plan.analyze.GroupByLevelController;
import org.apache.iotdb.db.queryengine.plan.expression.Expression;
import org.apache.iotdb.db.queryengine.plan.expression.leaf.ConstantOperand;
import org.apache.iotdb.db.queryengine.plan.expression.leaf.TimeSeriesOperand;
import org.apache.iotdb.db.queryengine.plan.expression.leaf.TimestampOperand;
import org.apache.iotdb.db.queryengine.plan.expression.multi.FunctionExpression;

import java.util.ArrayList;
import java.util.List;

import static org.apache.iotdb.db.queryengine.plan.analyze.ExpressionUtils.reconstructFunctionExpression;
import static org.apache.iotdb.db.queryengine.plan.analyze.ExpressionUtils.reconstructTimeSeriesOperand;

public class ReplaceRawPathWithGroupedPathVisitor
    extends ReconstructVisitor<GroupByLevelController.RawPathToGroupedPathMap> {
  @Override
  public Expression visitFunctionExpression(
      FunctionExpression functionExpression,
      GroupByLevelController.RawPathToGroupedPathMap rawPathToGroupedPathMap) {
    List<Expression> childrenExpressions = new ArrayList<>();
    for (Expression childExpression : functionExpression.getExpressions()) {
      childrenExpressions.add(process(childExpression, rawPathToGroupedPathMap));

      // We just process first input Expression of AggregationFunction.
      // If AggregationFunction need more than one input series,
      // we need to reconsider the process of it
      if (functionExpression.isBuiltInAggregationFunctionExpression()) {
        List<Expression> children = functionExpression.getExpressions();
        for (int i = 1; i < children.size(); i++) {
          childrenExpressions.add(children.get(i));
        }
        break;
      }
    }
    return reconstructFunctionExpression(functionExpression, childrenExpressions);
  }

  @Override
  public Expression visitTimeSeriesOperand(
      TimeSeriesOperand timeSeriesOperand,
      GroupByLevelController.RawPathToGroupedPathMap rawPathToGroupedPathMap) {
    PartialPath rawPath = timeSeriesOperand.getPath();
    PartialPath groupedPath = rawPathToGroupedPathMap.get(rawPath);
    return reconstructTimeSeriesOperand(timeSeriesOperand, groupedPath);
  }

  @Override
  public Expression visitTimeStampOperand(
      TimestampOperand timestampOperand, GroupByLevelController.RawPathToGroupedPathMap context) {
    return timestampOperand;
  }

  @Override
  public Expression visitConstantOperand(
      ConstantOperand constantOperand, GroupByLevelController.RawPathToGroupedPathMap context) {
    return constantOperand;
  }
}
