/*
 *  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.facets.properties.defaults.fromtype;

import jakarta.inject.Inject;

import org.apache.causeway.core.metamodel.context.MetaModelContext;
import org.apache.causeway.core.metamodel.facetapi.FacetUtil;
import org.apache.causeway.core.metamodel.facetapi.FeatureType;
import org.apache.causeway.core.metamodel.facets.FacetFactoryAbstract;
import org.apache.causeway.core.metamodel.facets.object.defaults.DefaultedFacet;
import org.apache.causeway.core.metamodel.facets.properties.defaults.PropertyDefaultFacet;
import org.apache.causeway.core.metamodel.spec.ObjectSpecification;

public class PropertyDefaultFacetFromTypeFactory
extends FacetFactoryAbstract {

    @Inject
    public PropertyDefaultFacetFromTypeFactory(final MetaModelContext mmc) {
        super(mmc, FeatureType.PROPERTIES_ONLY);
    }

    /**
     * If there is a {@link DefaultedFacet} on the properties return type, then
     * installs a {@link PropertyDefaultFacet} for the property with the same
     * default.
     */
    @Override
    public void process(final ProcessMethodContext processMethodContext) {
        // don't overwrite any defaults that might already picked up
        final PropertyDefaultFacet existingDefaultFacet = processMethodContext.getFacetHolder()
                .lookupNonFallbackFacet(PropertyDefaultFacet.class)
                .orElse(null);
        if (existingDefaultFacet != null) {
            return;
        }

        // try to infer defaults from the underlying return type
        final Class<?> returnType = processMethodContext.getMethod().getReturnType();
        final DefaultedFacet returnTypeDefaultedFacet = getDefaultedFacet(returnType);
        if (returnTypeDefaultedFacet != null) {
            FacetUtil.addFacet(
                    new PropertyDefaultFacetFromDefaultedFacet(
                            returnTypeDefaultedFacet, processMethodContext.getFacetHolder()));
        }
    }

    private DefaultedFacet getDefaultedFacet(final Class<?> paramType) {
        final ObjectSpecification paramTypeSpec = getSpecificationLoader().loadSpecification(paramType);
        return paramTypeSpec.getFacet(DefaultedFacet.class);
    }

}
