content: /*
   *  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.causeway.core.metamodel.spec.impl;
  
  import java.util.Optional;
  import java.util.stream.Stream;
  
  import org.apache.causeway.applib.annotation.ParameterTuple;
  import org.apache.causeway.commons.collections.Can;
  import org.apache.causeway.commons.internal.reflection._Annotations;
  import org.apache.causeway.commons.internal.reflection._ClassCache;
  import org.apache.causeway.commons.internal.reflection._GenericResolver.ResolvedMethod;
  import org.apache.causeway.commons.internal.reflection._MethodFacades;
  import org.apache.causeway.commons.internal.reflection._MethodFacades.MethodFacade;
  import org.apache.causeway.core.config.progmodel.ProgrammingModelConstants.MessageTemplate;
  import org.apache.causeway.core.metamodel.facetapi.FacetHolder;
  import org.apache.causeway.core.metamodel.specloader.validator.ValidationFailure;
  
  import lombok.experimental.UtilityClass;
  
  @UtilityClass
  class _MethodFacadeAutodetect {
  
      /**
       * Detects whether an action uses the {@link ParameterTuple} annotation on its single argument.
       * If so, we follow Parameters as Tuple (PAT) semantics.
       */
      MethodFacade autodetect(final ResolvedMethod method, final FacetHolder inspectedTypeSpec) {
          final long paramTupleCount = Stream.of(method.method().getParameters())
              .map(parameter->_Annotations.synthesize(parameter, ParameterTuple.class))
              .filter(Optional::isPresent)
              .count();
          if(paramTupleCount == 0) {
              return _MethodFacades.regular(method);
          }
          if(paramTupleCount > 1
                  || method.paramCount() > 1) {
              // invalid
              ValidationFailure.raiseFormatted(inspectedTypeSpec,
                      MessageTemplate.PARAMETER_TUPLE_INVALID_USE_OF_ANNOTATION
                          .builder()
                          .addVariable("type", inspectedTypeSpec.getFeatureIdentifier().className())
                          .addVariable("member", method.name())
                          .buildMessage());
          }
          var patType = method.paramType(0);
          var patConstructors = _ClassCache.getInstance().streamPublicConstructors(patType)
              .collect(Can.toCan());
          if(!patConstructors.isCardinalityOne()) {
              // invalid
              ValidationFailure.raiseFormatted(inspectedTypeSpec,
                      MessageTemplate.PARAMETER_TUPLE_TYPE_WITH_AMBIGUOUS_CONSTRUCTORS
                          .builder()
                          .addVariable("type", inspectedTypeSpec.getFeatureIdentifier().className())
                          .addVariable("member", method.name())
                          .addVariable("patType", patType.getName())
                          .buildMessage());
          }
          return _MethodFacades.paramsAsTuple(method, patConstructors.getFirstElseFail());
      }
  
  }
  