/*-
 * ============LICENSE_START=======================================================
 * ONAP - SO
 * ================================================================================
 * Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
 * ================================================================================
 * Licensed 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.
 * ============LICENSE_END=========================================================
 */

package org.openecomp.mso.client.policy;

import java.io.BufferedInputStream;

import java.io.ByteArrayOutputStream;
import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.logging.Logger;
import javax.annotation.Priority;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.client.ClientRequestContext;
import javax.ws.rs.client.ClientRequestFilter;
import javax.ws.rs.client.ClientResponseContext;
import javax.ws.rs.client.ClientResponseFilter;
import javax.ws.rs.ext.WriterInterceptor;
import javax.ws.rs.ext.WriterInterceptorContext;

@Priority(Integer.MIN_VALUE)
public class LoggingFilter implements ClientRequestFilter, ClientResponseFilter, WriterInterceptor {

	private static final Logger logger = Logger.getLogger(LoggingFilter.class.getName());
	private static final String ENTITY_STREAM_PROPERTY = "LoggingFilter.entityStream";
	private static final Charset DEFAULT_CHARSET = StandardCharsets.UTF_8;
	private final int maxEntitySize = 1024 * 8;

	private void log(StringBuilder sb) {
		logger.info(sb.toString());
	}

	private InputStream logInboundEntity(final StringBuilder b, InputStream stream, final Charset charset)
			throws IOException {
		InputStream inputStream = stream;
		if (!inputStream.markSupported()) {
			inputStream = new BufferedInputStream(inputStream);
		}
		inputStream.mark(maxEntitySize + 1);
		final byte[] entity = new byte[maxEntitySize + 1];
		final int entitySize = inputStream.read(entity);
		b.append(new String(entity, 0, Math.min(entitySize, maxEntitySize), charset));
		if (entitySize > maxEntitySize) {
			b.append("...more...");
		}
		b.append('\n');
		inputStream.reset();
		return inputStream;
	}

	@Override
	public void filter(ClientRequestContext requestContext) throws IOException {
		if (requestContext.hasEntity()) {
			final OutputStream stream = new LoggingStream(requestContext.getEntityStream());
			requestContext.setEntityStream(stream);
			requestContext.setProperty(ENTITY_STREAM_PROPERTY, stream);
		}
	}

	@Override
	public void filter(ClientRequestContext requestContext, ClientResponseContext responseContext) throws IOException {
		final StringBuilder sb = new StringBuilder();
		if (responseContext.hasEntity()) {
			responseContext.setEntityStream(logInboundEntity(sb, responseContext.getEntityStream(), DEFAULT_CHARSET));
			log(sb);
		}

	}

	@Override
	public void aroundWriteTo(WriterInterceptorContext context) throws IOException, WebApplicationException {
		final LoggingStream stream = (LoggingStream) context.getProperty(ENTITY_STREAM_PROPERTY);
		context.proceed();
		if (stream != null) {
			log(stream.getStringBuilder(DEFAULT_CHARSET));
		}
	}

	private class LoggingStream extends FilterOutputStream {

		private final StringBuilder sb = new StringBuilder();
		private final ByteArrayOutputStream baos = new ByteArrayOutputStream();

		LoggingStream(OutputStream out) {
			super(out);
		}

		StringBuilder getStringBuilder(Charset charset) {
			// write entity to the builder
			final byte[] entity = baos.toByteArray();

			sb.append(new String(entity, 0, entity.length, charset));
			if (entity.length > maxEntitySize) {
				sb.append("...more...");
			}
			sb.append('\n');

			return sb;
		}

		@Override
		public void write(final int i) throws IOException {
			if (baos.size() <= maxEntitySize) {
				baos.write(i);
			}
			out.write(i);
		}
	}
}