/*
 *  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
 *
 *    https://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.grails.web.converters.marshaller.json;

import java.text.Format;
import java.time.format.DateTimeFormatter;
import java.util.Calendar;

import grails.converters.JSON;
import org.grails.web.converters.exceptions.ConverterException;
import org.grails.web.converters.marshaller.ObjectMarshaller;
import org.grails.web.json.JSONException;

/**
 * JSON ObjectMarshaller which converts a Calendar Object to an RFC 3339 / ISO 8601
 * UTC instant string (e.g. {@code 2024-06-15T14:30:45.123Z}).
 *
 * @since 7.0
 */
public class CalendarMarshaller implements ObjectMarshaller<JSON> {

    private final Format legacyFormatter;

    /**
     * Constructor with a custom formatter.
     * @param formatter the formatter
     */
    public CalendarMarshaller(Format formatter) {
        this.legacyFormatter = formatter;
    }

    /**
     * Default constructor — uses {@link DateTimeFormatter#ISO_INSTANT}.
     */
    public CalendarMarshaller() {
        this(null);
    }

    public boolean supports(Object object) {
        return object instanceof Calendar;
    }

    public void marshalObject(Object object, JSON converter) throws ConverterException {
        try {
            Calendar calendar = (Calendar) object;
            String formatted = legacyFormatter != null ?
                    legacyFormatter.format(calendar.getTime()) :
                    DateTimeFormatter.ISO_INSTANT.format(calendar.toInstant());
            converter.getWriter().value(formatted);
        }
        catch (JSONException e) {
            throw new ConverterException(e);
        }
    }
}
