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.object;
  
  import java.util.Objects;
  import java.util.Optional;
  import java.util.function.Supplier;
  import java.util.stream.Stream;
  
  import org.jspecify.annotations.NonNull;
  import org.jspecify.annotations.Nullable;
  
  import org.springframework.util.ClassUtils;
  
  import org.apache.causeway.applib.services.bookmark.Bookmark;
  import org.apache.causeway.applib.services.i18n.TranslatableString;
  import org.apache.causeway.applib.services.i18n.TranslationContext;
  import org.apache.causeway.commons.collections.Can;
  import org.apache.causeway.commons.functional.Try;
  import org.apache.causeway.commons.internal.base._NullSafe;
  import org.apache.causeway.commons.internal.exceptions._Exceptions;
  import org.apache.causeway.commons.internal.reflection._GenericResolver.ResolvedMethod;
  import org.apache.causeway.core.metamodel.commons.ClassExtensions;
  import org.apache.causeway.core.metamodel.consent.InteractionInitiatedBy;
  import org.apache.causeway.core.metamodel.spec.ObjectSpecification;
  
  import lombok.experimental.UtilityClass;
  import lombok.extern.log4j.Log4j2;
  
  /**
   * A collection of utilities for {@link ManagedObject}.
   * @since 2.0
   *
   */
  @UtilityClass
  @Log4j2
  public final class ManagedObjects {
  
      // -- CATEGORISATION
  
      /** is null or has no ObjectSpecification or has no value (pojo) */
      public boolean isNullOrUnspecifiedOrEmpty(final @Nullable ManagedObject adapter) {
          if(adapter==null
                  || adapter==ManagedObject.unspecified()
                  || adapter.specialization()==null
                  || adapter.specialization().isEmpty()) {
              return true;
          }
          if(adapter instanceof PackedManagedObject) {
              return ((PackedManagedObject)adapter).unpack().isEmpty();
          }
          return adapter.getPojo()==null;
      }
  
      /**
       * Optionally given adapter, based on whether it is not null AND specified AND not empty.
       */
      public Optional<ManagedObject> whenNonEmpty(final ManagedObject adapter) {
          return isNullOrUnspecifiedOrEmpty(adapter)
                  ? Optional.empty()
                  : Optional.of(adapter);
      }
  
      /** whether has at least a spec */
      public boolean isSpecified(final @Nullable ManagedObject adapter) {
          return adapter!=null
                  && adapter!=ManagedObject.unspecified();
      }
  
      /** Optionally the corresponding class, based on whether is specified. */
      public Optional<Class<?>> correspondingClass(final @Nullable ManagedObject adapter) {
          return isSpecified(adapter)
                  ? Optional.ofNullable(adapter.getCorrespondingClass()) // null is not expected here, but just in case
                  : Optional.empty();
      }
  
      /**
       * Optionally given adapter, based on whether it is specified
       * (even if empty, that is, representing null.)
       * @return SPECIFIED
       */
      public Optional<ManagedObject> asSpecified(final @Nullable ManagedObject adapter) {
          return isSpecified(adapter)
                  ? Optional.of(adapter)
                  : Optional.empty();
      }
  
      /**
       * Optionally given adapter, based on whether it is specified and scalar (not packed)
       * (even if empty, that is, representing null.)
       * @return SCALAR or EMTPY
       */
      public Optional<ManagedObject> asScalar(final @Nullable ManagedObject adapter) {
          return asSpecified(adapter)
                  .filter(obj->!obj.specialization().isPacked());
      }
  
      /**
       * Optionally given adapter, based on whether it is specified
       * (even if empty, that is, representing null.)
       * @return SCALAR and NOT_EMTPY
       */
      public Optional<ManagedObject> asScalarNonEmpty(final @Nullable ManagedObject adapter) {
          return asScalar(adapter)
                  .filter(obj->!obj.specialization().isEmpty());
      }
  
      /**
       * whether the corresponding type can be mapped onto a REFERENCE (schema) or an Oid,
       * that is, the type is 'identifiable' (aka 'referencable' or 'bookmarkable')
       * <p>
       * returns <code>false</code> for non-scalar objects
       */
      public boolean isIdentifiable(final @Nullable ManagedObject managedObject) {
          return (managedObject instanceof PackedManagedObject)
                  ? false
                  : spec(managedObject)
                      .map(ObjectSpecification::isIdentifiable)
                      .orElse(false);
      }
  
      public boolean isEntity(final ManagedObject managedObject) {
          return spec(managedObject)
                  .map(ObjectSpecification::isEntity)
                  .orElse(false);
      }
  
      public boolean isValue(final ManagedObject managedObject) {
          return spec(managedObject)
                  .map(ObjectSpecification::isValue)
                  .orElse(false);
      }
  
      public Optional<String> getDomainType(final ManagedObject managedObject) {
          return spec(managedObject)
                  .map(ObjectSpecification::logicalTypeName);
      }
  
      // -- INSTANCE-OF CHECKS
  
      public boolean isPacked(final @Nullable ManagedObject managedObject) {
          return managedObject instanceof PackedManagedObject;
      }
  
      /**
       * Whether given {@code object} is an instance of given {@code elementType}.
       */
      public boolean isInstanceOf(
              final @Nullable ManagedObject object,
              final @NonNull ObjectSpecification elementType) {
          var upperBound = ClassUtils.resolvePrimitiveIfNecessary(elementType.getCorrespondingClass());
          if(ManagedObjects.isNullOrUnspecifiedOrEmpty(object)) {
              return true;
          }
          if(object instanceof PackedManagedObject) {
              return ((PackedManagedObject)object).unpack().stream()
              .allMatch(element->isInstanceOf(element, elementType));
          }
          var objectActualType = ClassUtils.resolvePrimitiveIfNecessary(object.objSpec().getCorrespondingClass());
          return upperBound.isAssignableFrom(objectActualType);
      }
  
      // -- IDENTIFICATION
  
      public Optional<ObjectSpecification> spec(final @Nullable ManagedObject managedObject) {
          return isSpecified(managedObject) ? Optional.of(managedObject.objSpec()) : Optional.empty();
      }
  
      public Optional<Bookmark> bookmark(final @Nullable ManagedObject managedObject) {
          return isSpecified(managedObject) ? managedObject.getBookmark() : Optional.empty();
      }
  
      public Bookmark bookmarkElseFail(final @Nullable ManagedObject managedObject) {
          return bookmark(managedObject)
                  .orElseThrow(()->_Exceptions.illegalArgument("Object provides no Bookmark: %s", managedObject));
      }
  
  //    /**
  //     * eg. transient entities have no bookmark, so can fallback to UUID
  //     */
  //    public Bookmark bookmarkElseUUID(final @Nullable ManagedObject managedObject) {
  //        return bookmark(managedObject)
  //                .orElseGet(()->managedObject.createBookmark(UUID.randomUUID().toString()));
  //    }
  
      /**
       * @param managedObject
       * @return optionally a String representing a reference to the <em>identifiable</em>
       * {@code managedObject}, usually made up of the object's type and its ID.
       */
      public Optional<String> stringify(final @Nullable ManagedObject managedObject) {
          return bookmark(managedObject)
                  .map(Bookmark::stringify);
      }
  
      public String stringifyElseFail(final @Nullable ManagedObject managedObject) {
          return stringify(managedObject)
                  .orElseThrow(()->_Exceptions.illegalArgument("cannot stringify %s", managedObject));
      }
  
      /**
       *
       * @param managedObject
       * @param separator custom separator
       * @return optionally a String representing a reference to the <em>identifiable</em>
       * {@code managedObject}, made of the form &lt;object-type&gt; &lt;separator&gt; &lt;object-id&gt;.
       */
      public Optional<String> stringify(
              final @Nullable ManagedObject managedObject,
              final @NonNull String separator) {
          return bookmark(managedObject)
                  .map(oid->oid.logicalTypeName() + separator + oid.identifier());
      }
  
      public String stringifyElseFail(
              final @Nullable ManagedObject managedObject,
              final @NonNull String separator) {
          return stringify(managedObject, separator)
                  .orElseThrow(()->_Exceptions.illegalArgument("cannot stringify %s", managedObject));
      }
  
      public String stringifyElseUnidentified(
              final @Nullable ManagedObject managedObject,
              final @NonNull String separator) {
          return stringify(managedObject, separator)
                  .orElseGet(()->isSpecified(managedObject)
                          ? managedObject.objSpec().logicalTypeName() + separator + "?"
                          : "?" + separator + "?");
      }
  
      // -- PACKING
  
      /**
       * If {@code any} is a {@link PackedManagedObject} then returns its unpacked elements,
       * otherwise collects {@code any} into a {@link Can} unaltered.
       * <p>
       * Results in an empty Can if {@code any} is {@code null}.
       * @param any - nullable
       */
      public Can<ManagedObject> unpack(
              final @Nullable ManagedObject any) {
          return any instanceof PackedManagedObject
                      ? ((PackedManagedObject)any).unpack()
                      : Can.of(any);
      }
  
      /**
       * Flattens given {@link ManagedObject} into a {@link Stream}
       * (also flattening any {@link PackedManagedObject}).
       */
      public Stream<ManagedObject> stream(
              final @Nullable ManagedObject any) {
          return any instanceof PackedManagedObject
                  ? ((PackedManagedObject)any).unpack().stream()
                  : Stream.of(any);
      }
  
      /**
       * Flattens given {@link ManagedObject}(s) into a {@link Stream}
       * (also flattening any {@link PackedManagedObject}).
       */
      public Stream<ManagedObject> stream(
              final @Nullable Can<ManagedObject> many) {
          if(many==null
                  || many.isEmpty()) {
              return Stream.empty();
          }
          return many.stream().flatMap(ManagedObjects::stream);
      }
  
      // -- SIDE EFFECT FREE POJO GETTER
  
      /**
       * Peeks at the pojo of given {@link ManagedObject}, without triggering refetches of hollow entities.
       */
      @Nullable
      public Object peekAtPojoOf(final @Nullable ManagedObject obj) {
          return isNullOrUnspecifiedOrEmpty(obj)
                  ? null
                  : (obj instanceof ManagedObjectEntity entity)
                      ? entity.peekAtPojo()
                      : obj.getPojo();
      }
  
      // -- EQUALITY
  
      public boolean pojoEquals(final @Nullable ManagedObject a, final @Nullable ManagedObject b) {
          var aPojo = MmUnwrapUtils.single(a);
          var bPojo = MmUnwrapUtils.single(b);
          return Objects.equals(aPojo, bPojo);
      }
  
      // -- DEFAULTS UTILITIES
  
      public ManagedObject nullToEmpty(
              final @NonNull ObjectSpecification elementSpec,
              final @Nullable ManagedObject adapter) {
  
          if(adapter!=null) {
              return adapter;
          }
          return ManagedObject.empty(elementSpec);
      }
  
      public ManagedObject nullOrEmptyToDefault(
              final @NonNull ObjectSpecification elementSpec,
              final @Nullable ManagedObject adapter,
              final @NonNull Supplier<Object> pojoDefaultSupplier) {
          return isNullOrUnspecifiedOrEmpty(adapter)
              ? ManagedObject.adaptSingular(elementSpec, Objects.requireNonNull(pojoDefaultSupplier.get()))
              : adapter;
      }
  
      /**
       * Only applies to value types, otherwise acts as identity operation.
       * <p>
       * @implNote TODO this implementation ignores any registered value-semantics,
       *  which should be used for the non-primitive, mandatory case instead
       */
      public ManagedObject emptyToDefault(
              final ObjectSpecification elementSpec,
              final boolean mandatory,
              final @NonNull ManagedObject input) {
          if(!isSpecified(input)
                  || !elementSpec.isValue()) {
              return input;
          }
          if(input.getPojo()!=null) {
              return input;
          }
  
          // there are 2 cases to handle here
          // 1) if primitive, then don't return null
          // 2) if boxed boolean, that is MANDATORY, then don't return null
  
          var expectedType = elementSpec.getCorrespondingClass();
          if(expectedType.isPrimitive()) {
              return ManagedObject.value(elementSpec, ClassExtensions.toDefault(expectedType));
          }
          if(Boolean.class.equals(expectedType) && mandatory) {
              return ManagedObject.value(elementSpec, Boolean.FALSE);
          }
  
          return input;
      }
  
      // -- ADABT UTILITIES
  
      public Can<ManagedObject> adaptMultipleOfType(
              final @NonNull ObjectSpecification elementSpec,
              final @Nullable Object collectionOrArray) {
  
          return _NullSafe.streamAutodetect(collectionOrArray)
          .map(pojo->ManagedObject.adaptSingular(elementSpec, pojo)) // pojo is nullable here
          .collect(Can.toCan());
      }
  
      /**
       * used eg. to adapt the result of supporting methods, that return choice pojos
       */
      public Can<ManagedObject> adaptMultipleOfTypeThenFilterByVisibility(
              final @NonNull  ObjectSpecification elementSpec,
              final @Nullable Object collectionOrArray,
              final @NonNull  InteractionInitiatedBy interactionInitiatedBy) {
  
          return _NullSafe.streamAutodetect(collectionOrArray)
          .map(pojo->ManagedObject.adaptSingular(elementSpec, pojo)) // pojo is nullable here
          .filter(MmVisibilityUtils.filterOn(interactionInitiatedBy))
          .collect(Can.toCan());
      }
  
      // -- IMPERATIVE TEXT UTILITY
  
      public Try<String> imperativeText(
              final @Nullable ManagedObject object,
              final @NonNull ResolvedMethod method,
              final @Nullable TranslationContext translationContext) {
  
          if(ManagedObjects.isNullOrUnspecifiedOrEmpty(object)) {
              return Try.success(null);
          }
  
          var mmc = object.objSpec().getMetaModelContext();
  
          var result =  Try.call(()->{
              final Object returnValue = MmInvokeUtils.invokeNoArg(method.method(), object);
              if(returnValue instanceof String) {
                  return (String) returnValue;
              }
              if(returnValue instanceof TranslatableString) {
                  final TranslatableString ts = (TranslatableString) returnValue;
                  return ts.translate(mmc.getTranslationService(), translationContext);
              }
              return null;
          });
  
          if(result.isFailure()) {
              var isUnitTesting = mmc.getSystemEnvironment().isUnitTesting();
              if(!isUnitTesting) {
                  log.warn("imperative text failure (context: {})", translationContext, result.getFailure().get());
              }
          }
  
          return result;
      }
  
      // -- VIEWMODEL UTILITIES
  
      public void refreshViewmodel(
              final @Nullable ManagedObject mo,
              final @Nullable Supplier<Bookmark> bookmarkSupplier) {
  
          if(mo instanceof ManagedObjectViewmodel viewmodel) {
              viewmodel.refreshViewmodel(bookmarkSupplier);
          }
      }
  
  }
  