/**
 * =============================================================================
 *
 * ORCID (R) Open Source
 * http://orcid.org
 *
 * Copyright (c) 2012-2014 ORCID, Inc.
 * Licensed under an MIT-Style License (MIT)
 * http://orcid.org/open-source-license
 *
 * This copyright and license information (including a link to the full license)
 * shall be included in its entirety in all copies or substantial portion of
 * the software.
 *
 * =============================================================================
 */
package org.orcid.api.common.writer;

import org.orcid.jaxb.model.message.OrcidMessage;

import javax.ws.rs.Produces;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.ext.MessageBodyWriter;
import javax.ws.rs.ext.Provider;
import java.io.IOException;
import java.io.OutputStream;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;

import static javax.ws.rs.core.MediaType.TEXT_HTML;

/**
 * @author Declan Newman (declan) Date: 02/03/2012
 */
@Provider
@Produces({ TEXT_HTML })
public class HtmlMessageBodyWriter implements MessageBodyWriter<OrcidMessage> {

    /**
     * Ascertain if the MessageBodyWriter supports a particular type.
     * 
     * @param type
     *            the class of object that is to be written.
     * @param genericType
     *            the type of object to be written, obtained either by
     *            reflection of a resource method return type or via inspection
     *            of the returned instance.
     *            {@link javax.ws.rs.core.GenericEntity} provides a way to
     *            specify this information at runtime.
     * @param annotations
     *            an array of the annotations on the resource method that
     *            returns the object.
     * @param mediaType
     *            the media type of the HTTP entity.
     * @return true if the type is supported, otherwise false.
     */
    @Override
    public boolean isWriteable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
        return OrcidMessage.class.isAssignableFrom(type);
    }

    /**
     * Called before <code>writeTo</code> to ascertain the length in bytes of
     * the serialized form of <code>t</code>. A non-negative return value is
     * used in a HTTP <code>Content-Length</code> header.
     * 
     * @param message
     *            the instance to write
     * @param type
     *            the class of object that is to be written.
     * @param genericType
     *            the type of object to be written, obtained either by
     *            reflection of a resource method return type or by inspection
     *            of the returned instance.
     *            {@link javax.ws.rs.core.GenericEntity} provides a way to
     *            specify this information at runtime.
     * @param annotations
     *            an array of the annotations on the resource method that
     *            returns the object.
     * @param mediaType
     *            the media type of the HTTP entity.
     * @return length in bytes or -1 if the length cannot be determined in
     *         advance
     */
    @Override
    public long getSize(OrcidMessage message, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
        return (message != null && message.toString() != null) ? message.toString().getBytes().length : -1;
    }

    /**
     * Write a type to an HTTP response. The response header map is mutable but
     * any changes must be made before writing to the output stream since the
     * headers will be flushed prior to writing the response body.
     * 
     * @param message
     *            the instance to write.
     * @param type
     *            the class of object that is to be written.
     * @param genericType
     *            the type of object to be written, obtained either by
     *            reflection of a resource method return type or by inspection
     *            of the returned instance.
     *            {@link javax.ws.rs.core.GenericEntity} provides a way to
     *            specify this information at runtime.
     * @param annotations
     *            an array of the annotations on the resource method that
     *            returns the object.
     * @param mediaType
     *            the media type of the HTTP entity.
     * @param httpHeaders
     *            a mutable map of the HTTP response headers.
     * @param entityStream
     *            the {@link java.io.OutputStream} for the HTTP entity. The
     *            implementation should not close the output stream.
     * @throws java.io.IOException
     *             if an IO error arises
     * @throws javax.ws.rs.WebApplicationException
     *             if a specific HTTP error response needs to be produced. Only
     *             effective if thrown prior to the response being committed.
     */
    @Override
    public void writeTo(OrcidMessage message, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType, MultivaluedMap<String, Object> httpHeaders,
            OutputStream entityStream) throws IOException, WebApplicationException {
        entityStream.write(message.toString().getBytes());
    }
}