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/*
 * Copyright © 2021-present Arcade Data Ltd ([email protected])
 *
 * 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.
 *
 * SPDX-FileCopyrightText: 2021-present Arcade Data Ltd ([email protected])
 * SPDX-License-Identifier: Apache-2.0
 */
package com.arcadedb.query.sql.executor;

import com.arcadedb.exception.TimeoutException;
import com.arcadedb.query.sql.parser.Expression;
import com.arcadedb.query.sql.parser.Identifier;

/**
 * Created by luigidellaquila on 03/08/16.
 */
public class GlobalLetExpressionStep extends AbstractExecutionStep {
  private final Identifier varname;
  private final Expression expression;

  boolean executed = false;

  public GlobalLetExpressionStep(final Identifier varName, final Expression expression, final CommandContext context, final boolean profilingEnabled) {
    super(context, profilingEnabled);
    this.varname = varName;
    this.expression = expression;
  }

  @Override
  public ResultSet syncPull(final CommandContext context, final int nRecords) throws TimeoutException {
    pullPrevious(context, nRecords);

    calculate(context);
    return new InternalResultSet();
  }

  private void calculate(final CommandContext context) {
    if (executed) {
      return;
    }
    final Object value = expression.execute((Result) null, context);
    context.setVariable(varname.getStringValue(), value);
    executed = true;
  }

  @Override
  public String prettyPrint(final int depth, final int indent) {
    final String spaces = ExecutionStepInternal.getIndent(depth, indent);
    return spaces + "+ LET (once)\n" + spaces + "  " + varname + " = " + expression;
  }
}