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.fhirpath.function.provider;
  
  import static java.util.Objects.nonNull;
  
  import au.csiro.pathling.fhirpath.annotations.SqlOnFhirConformance;
  import au.csiro.pathling.fhirpath.annotations.SqlOnFhirConformance.Profile;
  import au.csiro.pathling.fhirpath.collection.BooleanCollection;
  import au.csiro.pathling.fhirpath.collection.Collection;
  import au.csiro.pathling.fhirpath.function.CollectionTransform;
  import au.csiro.pathling.fhirpath.function.FhirPathFunction;
  import jakarta.annotation.Nonnull;
  import jakarta.annotation.Nullable;
  
  /**
   * Contains functions for evaluating the existence of elements in a collection.
   *
   * @author Piotr Szul
   * @author John Grimes
   * @see <a href="https://build.fhir.org/ig/HL7/FHIRPath/#existence">FHIRPath Specification -
   * Existence</a>
   */
  @SuppressWarnings("unused")
  public class ExistenceFunctions {
  
    private ExistenceFunctions() {
    }
  
    /**
     * Returns {@code true} if the input collection has any elements (optionally filtered by the
     * criteria), and {@code false} otherwise. This is the opposite of {@code empty()}, and as such is
     * a shorthand for {@code empty().not()}. If the input collection is empty, the result is
     * {@code false}.
     * <p>
     * Using the optional criteria can be considered a shorthand for
     * {@code where(criteria).exists()}.
     *
     * @param input The input collection
     * @param criteria The criteria to apply to the input collection
     * @return A {@link BooleanCollection} containing the result
     * @see <a
     * href="https://build.fhir.org/ig/HL7/FHIRPath/#existscriteria--expression--boolean">FHIRPath
     * Specification - exists</a>
     */
    @FhirPathFunction
    @SqlOnFhirConformance(Profile.SHARABLE)
    @Nonnull
    public static BooleanCollection exists(@Nonnull final Collection input,
        @Nullable final CollectionTransform criteria) {
      return BooleanLogicFunctions.not(empty(nonNull(criteria)
                                             ? FilteringAndProjectionFunctions.where(input, criteria)
                                             : input));
  
    }
  
    /**
     * Returns {@code true} if the input collection is empty and {@code false} otherwise.
     *
     * @param input The input collection
     * @return A {@link BooleanCollection} containing the result
     * @see <a href="https://build.fhir.org/ig/HL7/FHIRPath/#empty--boolean">FHIRPath Specification -
     * empty</a>
     */
    @FhirPathFunction
    @SqlOnFhirConformance(Profile.SHARABLE)
    @Nonnull
    public static BooleanCollection empty(@Nonnull final Collection input) {
      return BooleanCollection.build(input.getColumn().isEmpty());
    }
  }
  