/*
 *  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.isis.viewer.restfulobjects.server.resources.serialization;

import java.util.List;

import javax.ws.rs.core.MediaType;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.module.jaxb.JaxbAnnotationModule;

import org.apache.isis.viewer.restfulobjects.applib.RepresentationType;

public enum SerializationStrategy {
    XML {
        @Override public Object entity(final Object jaxbAnnotatedObject) {
            return jaxbAnnotatedObject;
        }

        @Override public MediaType type(final RepresentationType representationType) {
            return representationType.getXmlMediaType();
        }
    },
    JSON {
        @Override public Object entity(final Object jaxbAnnotatedObject) {
            final JaxbAnnotationModule jaxbAnnotationModule = new JaxbAnnotationModule();
            final ObjectMapper objectMapper = new ObjectMapper()
                    .disable(SerializationFeature.WRITE_NULL_MAP_VALUES) // doesn't seem to work...
                    .disable(SerializationFeature.WRITE_EMPTY_JSON_ARRAYS)
                    ;
            objectMapper.registerModule(jaxbAnnotationModule);
            try {
                String gridJson = objectMapper
                        .writer()
                        .writeValueAsString(jaxbAnnotatedObject);
                return gridJson;
            } catch (JsonProcessingException e) {
                throw new RuntimeException(e);
            }
        }


        @Override
        public MediaType type(final RepresentationType representationType) {
            return representationType.getJsonMediaType();
        }
    };

    public abstract Object entity(final Object jaxbAnnotatedObject);

    public abstract MediaType type(final RepresentationType representationType);

    public static SerializationStrategy determineFrom(final List<MediaType> acceptableMediaTypes) {
        for (MediaType acceptableMediaType : acceptableMediaTypes) {
            if(acceptableMediaType.isCompatible(MediaType.APPLICATION_JSON_TYPE)) {
                return SerializationStrategy.JSON;
            }
            if(acceptableMediaType.isCompatible(MediaType.APPLICATION_XML_TYPE)) {
                return SerializationStrategy.XML;
            }
        }
        return SerializationStrategy.JSON;
    }
}
