/*******************************************************************************
 * Copyright 2020 Graz University of Technology
 * MOA ZS has been developed in a cooperation between EGIZ
 * and Graz University of Technology.
 * Licensed under the EUPL, Version 1.2 or - as soon they will be approved by
 * the European Commission - subsequent versions of the EUPL (the "Licence");
 * You may not use this work except in compliance with the Licence.
 * You may obtain a copy of the Licence at:
 * https://joinup.ec.europa.eu/news/understanding-eupl-v12
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the Licence is distributed on an "AS IS" basis,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the Licence for the specific language governing permissions and
 * limitations under the Licence.
 *
 * This product combines work with different licenses. See the "NOTICE" text
 * file for details on the various modules and licenses.
 * The "NOTICE" text file is part of the distribution. Any derivative works
 * that you distribute must include a readable copy of the "NOTICE" text file.
 *******************************************************************************/
package at.gv.egiz.moazs.util;

import org.apache.cxf.helpers.IOUtils;
import org.apache.cxf.io.CachedOutputStream;
import org.apache.cxf.io.CachedWriter;
import org.apache.cxf.io.DelegatingInputStream;
import org.apache.cxf.message.Message;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;

import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.io.SequenceInputStream;

/**
 * @author Christof Rabensteiner
 *
 */
@Component
public class CXFMessageUtils {

    private static final Logger LOG = LoggerFactory.getLogger(CXFMessageUtils.class);

    /**
     * Copy and return content of org.apache.cxf.message.Message; Restore InputStream / Reader from
     * message.getContent() after consuming it.
     * @param message
     * @return
     * @throws IOException
     */
    public byte[] copyContent(Message message) throws IOException {

        if (message.getContent(InputStream.class) != null) {
            return streamMessageContentToByteArray(message);
        } else if (message.getContent(Reader.class) != null) {
            return readMessageContentToByteArray(message);
        } else {
            LOG.warn("Message Content is neither Reader nor InputStream; will return empty content.");
            return new byte[0];
        }
    }

    /**
     * Source: Adapted from ApacheCXF 3.3.0 / LoggingInInterceptor.logInputStream()
     * @param message
     * @return copy of message content
     * @throws IOException
     */
    private byte[] streamMessageContentToByteArray(Message message) throws IOException {

        var in = message.getContent(InputStream.class);

        try (var out = new CachedOutputStream()) {

            // use the appropriate input stream and restore it later
            InputStream bis = in instanceof DelegatingInputStream
                    ? ((DelegatingInputStream)in).getInputStream() : in;

            //only copy up to the limit since that's all we need to log
            //we can stream the rest
            IOUtils.copy(bis, out);
            out.flush();
            bis = new SequenceInputStream(out.getInputStream(), bis);

            // restore the delegating input stream or the input stream
            if (in instanceof DelegatingInputStream) {
                ((DelegatingInputStream)in).setInputStream(bis);
            } else {
                message.setContent(InputStream.class, bis);
            }

            return out.getBytes();
        }

    }

    /**
     * Source: Adapted from ApacheCXF 3.3.0 / LoggingInInterceptor.logReader()
     * @param message
     * @return copy of message content
     * @throws IOException
     */
    private byte[] readMessageContentToByteArray(Message message) throws IOException {
        var reader = message.getContent(Reader.class);
        var writer = new CachedWriter();
        IOUtils.copyAndCloseInput(reader, writer);
        message.setContent(Reader.class, writer.getReader());

        var buffer = new StringBuilder();
        writer.writeCacheTo(buffer);
        return buffer.toString().getBytes();
    }

}