content: /*
   * Copyright © 2018-2025 Commonwealth Scientific and Industrial Research
   * Organisation (CSIRO) ABN 41 687 119 230.
   *
   * 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 au.csiro.pathling.projection;
  
  import static java.util.stream.Collectors.joining;
  
  import jakarta.annotation.Nonnull;
  import java.util.List;
  
  /**
   * Groups multiple selections together using a cross join.
   *
   * @param components the list of projection clauses to be grouped
   * @author John Grimes
   * @author Piotr Szul
   */
  public record GroupingSelection(@Nonnull List<ProjectionClause> components) implements
      ProjectionClause {
  
    @Override
    @Nonnull
    public ProjectionResult evaluate(@Nonnull final ProjectionContext context) {
      // evaluate and cross join the subcomponents
      final List<ProjectionResult> subResults = components.stream().map(c -> c.evaluate(context))
          .toList();
      return ProjectionResult.combine(subResults);
    }
  
    @Nonnull
    @Override
    public String toString() {
      return "GroupingSelection{" +
          "components=[" + components.stream()
          .map(ProjectionClause::toString)
          .collect(joining(", ")) +
          "]}";
    }
  
    /**
     * Returns a string expression representation of this grouping selection.
     *
     * @return the string expression "group"
     */
    @Nonnull
    public String toExpression() {
      return "group";
    }
  
    @Override
    @Nonnull
    public String toTreeString(final int level) {
      final String indent = "  ".repeat(level);
      return indent + toExpression() + "\n" +
          components.stream()
              .map(c -> c.toTreeString(level + 1))
              .collect(joining("\n"));
    }
  }
  