/*
 * Copyright 2002-2018 the original author or authors.
 *
 * 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.
 */

package org.springframework.http.client.reactive;

import java.net.URI;
import java.util.function.Consumer;
import java.util.function.Function;

import org.eclipse.jetty.client.HttpClient;
import org.eclipse.jetty.reactive.client.ContentChunk;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.core.io.buffer.DataBufferFactory;
import org.springframework.core.io.buffer.DefaultDataBufferFactory;
import org.springframework.http.HttpMethod;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;

ClientHttpConnector for the Jetty Reactive Streams HttpClient. 
Author:
Sebastien Deleuze
See Also:
Jetty ReactiveStreams HttpClient
Since:
5.1/**
 * {@link ClientHttpConnector} for the Jetty Reactive Streams HttpClient.
 *
 * @author Sebastien Deleuze
 * @since 5.1
 * @see <a href="https://github.com/jetty-project/jetty-reactive-httpclient">Jetty ReactiveStreams HttpClient</a>
 */
public class JettyClientHttpConnector implements ClientHttpConnector {

	private final HttpClient httpClient;

	private DataBufferFactory bufferFactory = new DefaultDataBufferFactory();


	
Default constructor that creates a new instance of HttpClient. /**
	 * Default constructor that creates a new instance of {@link HttpClient}.
	 */
	public JettyClientHttpConnector() {
		this(new HttpClient());
	}

	
Constructor with an JettyResourceFactory that will manage shared resources. 
Params:
resourceFactory – the JettyResourceFactory to use
customizer – the lambda used to customize the HttpClient/**
	 * Constructor with an {@link JettyResourceFactory} that will manage shared resources.
	 * @param resourceFactory the {@link JettyResourceFactory} to use
	 * @param customizer the lambda used to customize the {@link HttpClient}
	 */
	public JettyClientHttpConnector(
			JettyResourceFactory resourceFactory, @Nullable Consumer<HttpClient> customizer) {

		HttpClient httpClient = new HttpClient();
		httpClient.setExecutor(resourceFactory.getExecutor());
		httpClient.setByteBufferPool(resourceFactory.getByteBufferPool());
		httpClient.setScheduler(resourceFactory.getScheduler());
		if (customizer != null) {
			customizer.accept(httpClient);
		}
		this.httpClient = httpClient;
	}

	
Constructor with an initialized HttpClient. /**
	 * Constructor with an initialized {@link HttpClient}.
	 */
	public JettyClientHttpConnector(HttpClient httpClient) {
		Assert.notNull(httpClient, "HttpClient is required");
		this.httpClient = httpClient;
	}


	public void setBufferFactory(DataBufferFactory bufferFactory) {
		this.bufferFactory = bufferFactory;
	}


	@Override
	public Mono<ClientHttpResponse> connect(HttpMethod method, URI uri,
			Function<? super ClientHttpRequest, Mono<Void>> requestCallback) {

		if (!uri.isAbsolute()) {
			return Mono.error(new IllegalArgumentException("URI is not absolute: " + uri));
		}

		if (!this.httpClient.isStarted()) {
			try {
				this.httpClient.start();
			}
			catch (Exception ex) {
				return Mono.error(ex);
			}
		}

		JettyClientHttpRequest clientHttpRequest = new JettyClientHttpRequest(
				this.httpClient.newRequest(uri).method(method.toString()), this.bufferFactory);

		return requestCallback.apply(clientHttpRequest).then(Mono.from(
				clientHttpRequest.getReactiveRequest().response((response, chunks) -> {
					Flux<DataBuffer> content = Flux.from(chunks).map(this::toDataBuffer);
					return Mono.just(new JettyClientHttpResponse(response, content));
				})));
	}

	private DataBuffer toDataBuffer(ContentChunk chunk) {

		// We must copy until this is resolved:
		// https://github.com/eclipse/jetty.project/issues/2429

		// Use copy instead of buffer wrapping because Callback#succeeded() is
		// used not only to release the buffer but also to request more data
		// which is a problem for codecs that buffer data.

		DataBuffer buffer = this.bufferFactory.allocateBuffer(chunk.buffer.capacity());
		buffer.write(chunk.buffer);
		chunk.callback.succeeded();
		return buffer;
	}

}