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   *  to you under the Apache License, Version 2.0 (the
   *  "License"); you may not use this file except in compliance
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   *
   *        http://www.apache.org/licenses/LICENSE-2.0
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  package org.apache.causeway.core.metamodel.methods;
  
  import java.lang.annotation.Annotation;
  import java.util.Arrays;
  import java.util.Optional;
  import java.util.function.Predicate;
  import java.util.stream.Stream;
  
  import org.jspecify.annotations.Nullable;
  
  import org.apache.causeway.applib.annotation.Domain;
  import org.apache.causeway.applib.annotation.Introspection.EncapsulationPolicy;
  import org.apache.causeway.applib.annotation.Introspection.IntrospectionPolicy;
  import org.apache.causeway.commons.collections.Can;
  import org.apache.causeway.commons.internal.functions._Predicates;
  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._Reflect;
  import org.apache.causeway.core.config.progmodel.ProgrammingModelConstants;
  import org.apache.causeway.core.config.progmodel.ProgrammingModelConstants.ConflictingAnnotations;
  import org.apache.causeway.core.metamodel.commons.MethodUtil;
  
  import org.jspecify.annotations.NonNull;
  
  public record MethodFinder(
          @NonNull Class<?> correspondingClass,
          @NonNull Can<String> methodNameCandidates,
          @NonNull EncapsulationPolicy encapsulationPolicy,
          @NonNull Predicate<ResolvedMethod> mustSatisfy) {
  
      public static final Can<String> ANY_NAME = Can.of(""); // arbitrary marker
      public static final Class<?>[] NO_ARG = new Class<?>[0];
  
      public static MethodFinder of(
              final @NonNull Class<?> correspondingClass,
              final @NonNull Can<String> methodNameCandidatesPossiblyDuplicated,
              final @NonNull EncapsulationPolicy encapsulationPolicy,
              final @NonNull Predicate<ResolvedMethod> mustSatisfy) {
  
          final Predicate<ResolvedMethod> isNotStatic = MethodUtil::isNotStatic;
          var methodNameCandidates = methodNameCandidatesPossiblyDuplicated.distinct();
  
          return new MethodFinder(
                  correspondingClass,
                  methodNameCandidates,
                  encapsulationPolicy,
                  methodNameCandidates.equals(ANY_NAME)
                          ? isNotStatic.and(mustSatisfy)
                          : isNotStatic
                              .and(method->methodNameCandidates.contains(method.name()))
                              .and(mustSatisfy));
      }
  
      public static MethodFinder notNecessarilyPublic(
              final Class<?> correspondingClass,
              final Can<String> methodNameCandidates) {
          return of(
                  correspondingClass,
                  methodNameCandidates,
                  EncapsulationPolicy.ENCAPSULATED_MEMBERS_SUPPORTED,
                  _Predicates.alwaysTrue());
      }
  
      public static MethodFinder publicOnly(
              final Class<?> correspondingClass,
              final Can<String> methodNameCandidates) {
          return of(
                  correspondingClass,
                  methodNameCandidates,
                  EncapsulationPolicy.ONLY_PUBLIC_MEMBERS_SUPPORTED,
                  _Predicates.alwaysTrue());
      }
  
      public static MethodFinder accessor(
              final Class<?> correspondingClass,
              final Can<String> methodNameCandidates,
              final IntrospectionPolicy memberIntrospectionPolicy) {
          return havingAnyOrNoAnnotation(
                  correspondingClass,
                  methodNameCandidates,
                  memberIntrospectionPolicy);
      }
  
      public static MethodFinder objectSupport(
              final Class<?> correspondingClass,
              final Can<String> methodNameCandidates,
              final IntrospectionPolicy memberIntrospectionPolicy) {
          return supportMethod(
                  correspondingClass,
                  methodNameCandidates,
                  memberIntrospectionPolicy,
                  Domain.Include.class,
                  ProgrammingModelConstants.ConflictingAnnotations.OBJECT_SUPPORT);
      }
  
      public static MethodFinder livecycleCallback(
              final Class<?> correspondingClass,
              final Can<String> methodNameCandidates,
              final IntrospectionPolicy memberIntrospectionPolicy) {
          return supportMethod(
                  correspondingClass,
                  methodNameCandidates,
                  memberIntrospectionPolicy,
                  Domain.Include.class,
                  ProgrammingModelConstants.ConflictingAnnotations.OBJECT_LIFECYCLE);
      }
  
      public static MethodFinder memberSupport(
              final Class<?> correspondingClass,
              final Can<String> methodNameCandidates,
              final IntrospectionPolicy memberIntrospectionPolicy) {
          return supportMethod(
                  correspondingClass,
                  methodNameCandidates,
                  memberIntrospectionPolicy,
                  Domain.Include.class,
                  ProgrammingModelConstants.ConflictingAnnotations.MEMBER_SUPPORT);
      }
  
      public Stream<ResolvedMethod> streamMethodsMatchingSignature(
              final @Nullable Class<?>[] paramTypes) {
  
          if(paramTypes==null) return streamMethodsIgnoringSignature();
  
          var type = correspondingClass();
          var classCache = _ClassCache.getInstance();
          var isEncapsulationSupported = encapsulationPolicy().isEncapsulatedMembersSupported();
  
          if(methodNameCandidates.equals(ANY_NAME)) {
              //stream all
              return (isEncapsulationSupported
                      ? classCache.streamResolvedMethods(type)
                      : classCache.streamPublicMethods(type))
                          .filter(method->Arrays.equals(paramTypes, method.paramTypes()))
                          .filter(mustSatisfy);
          }
  
          return methodNameCandidates.stream()
              .map(name->isEncapsulationSupported
                      ? classCache.lookupResolvedMethod(type, name, paramTypes)
                      : classCache.lookupPublicMethod(type, name, paramTypes))
              .filter(Optional::isPresent)
              .map(Optional::get)
              .filter(mustSatisfy);
      }
  
      public Stream<ResolvedMethod> streamMethodsIgnoringSignature() {
          var type = correspondingClass();
          var classCache = _ClassCache.getInstance();
          var isEncapsulationSupported = encapsulationPolicy().isEncapsulatedMembersSupported();
          return (isEncapsulationSupported
                  ? classCache.streamResolvedMethods(type)
                  : classCache.streamPublicMethods(type))
                      .filter(mustSatisfy);
      }
  
      // -- WITHERS
  
      public MethodFinder withRequiredReturnType(final @NonNull Class<?> requiredReturnType) {
          return new MethodFinder(
                  correspondingClass,
                  methodNameCandidates,
                  encapsulationPolicy,
                  mustSatisfy.and(resolvedMethod->resolvedMethod.isReturnTypeATypeOf(requiredReturnType)));
      }
  
      public MethodFinder withReturnTypeAnyOf(final @NonNull Can<Class<?>> anyOfReturnTypes) {
          return new MethodFinder(
                  correspondingClass,
                  methodNameCandidates,
                  encapsulationPolicy,
                  mustSatisfy.and(resolvedMethod->resolvedMethod.isReturnTypeAnyTypeOf(anyOfReturnTypes)));
      }
  
      // -- HELPER
  
      private static MethodFinder havingAnyOrNoAnnotation(
              final Class<?> correspondingClass,
              final Can<String> methodNameCandidates,
              final IntrospectionPolicy memberIntrospectionPolicy) {
          return of(
                  correspondingClass,
                  methodNameCandidates,
                  memberIntrospectionPolicy.getEncapsulationPolicy(),
                  _Predicates.alwaysTrue());
      }
  
      private static MethodFinder supportMethod(
              final Class<?> correspondingClass,
              final Can<String> methodNameCandidates,
              final IntrospectionPolicy memberIntrospectionPolicy,
              final Class<? extends Annotation> annotationType,
              final ConflictingAnnotations conflictingAnnotations) {
  
          var finder = of(
                  correspondingClass,
                  methodNameCandidates,
                  // support methods are always allowed private
                  EncapsulationPolicy.ENCAPSULATED_MEMBERS_SUPPORTED,
                  havingAnnotationIfEnforcedByPolicyOrAccessibility(
                          memberIntrospectionPolicy.getSupportMethodAnnotationPolicy().isSupportMethodAnnotationsRequired(),
                          annotationType,
                          conflictingAnnotations.getProhibits()));
  
          return finder;
      }
  
      private static Predicate<ResolvedMethod> havingAnnotationIfEnforcedByPolicyOrAccessibility(
              final boolean annotationRequired,
              final Class<? extends Annotation> annotationType,
              final Can<Class<? extends Annotation>> conflictingAnnotations) {
  
          return annotationRequired
                      ? method->havingAnnotation(method, annotationType, conflictingAnnotations)
                      : method->havingAnnotationOrPublic(method, annotationType, conflictingAnnotations);
      }
  
      private static boolean havingAnnotationOrPublic(
              final ResolvedMethod method,
              final Class<? extends Annotation> annotationType,
              final Can<Class<? extends Annotation>> conflictingAnnotations) {
  
          return _Reflect.isPublicNonSynthetic(method.method())
                  ? true
                  : havingAnnotation(method, annotationType, conflictingAnnotations);
      }
  
      //FIXME[CAUSEWAY-2774] if annotation appears on an abstract method that was inherited with given method,
      // its not detected here
      private static boolean havingAnnotation(
              final ResolvedMethod method,
              final Class<? extends Annotation> annotationType,
              final Can<Class<? extends Annotation>> conflictingAnnotations) {
  
          var isMarkerAnnotationPresent = _Annotations.synthesize(method.method(), annotationType).isPresent();
          if(isMarkerAnnotationPresent) {
  
              var isConflictingAnnotationPresent = conflictingAnnotations
              .stream()
              .anyMatch(conflictingAnnotationType->
                      _Annotations.synthesize(method.method(), conflictingAnnotationType).isPresent());
  
              // do not pickup this method if conflicting - so meta-model validation will fail later on
              return !isConflictingAnnotationPresent;
          }
          return isMarkerAnnotationPresent;
      }
  
  }
  