/*
 * 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;

import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.List;
import java.util.Map;

import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.util.FileCopyUtils;
import org.springframework.util.StringUtils;

/**
 * {@link ClientHttpRequest} implementation that uses standard JDK facilities to
 * execute buffered requests. Created via the {@link SimpleClientHttpRequestFactory}.
 *
 * @author Arjen Poutsma
 * @author Juergen Hoeller
 * @since 3.0
 * @see SimpleClientHttpRequestFactory#createRequest(java.net.URI, HttpMethod)
 */
final class SimpleBufferingClientHttpRequest extends AbstractBufferingClientHttpRequest {

	private final HttpURLConnection connection;

	private final boolean outputStreaming;


	SimpleBufferingClientHttpRequest(HttpURLConnection connection, boolean outputStreaming) {
		this.connection = connection;
		this.outputStreaming = outputStreaming;
	}


	@Override
	public HttpMethod getMethod() {
		return HttpMethod.resolve(this.connection.getRequestMethod());
	}

	@Override
	public URI getURI() {
		try {
			return this.connection.getURL().toURI();
		}
		catch (URISyntaxException ex) {
			throw new IllegalStateException("Could not get HttpURLConnection URI: " + ex.getMessage(), ex);
		}
	}

	@Override
	protected ClientHttpResponse executeInternal(HttpHeaders headers, byte[] bufferedOutput) throws IOException {
		addHeaders(this.connection, headers);
		// JDK <1.8 doesn't support getOutputStream with HTTP DELETE
		if (getMethod() == HttpMethod.DELETE && bufferedOutput.length == 0) {
			this.connection.setDoOutput(false);
		}
		if (this.connection.getDoOutput() && this.outputStreaming) {
			this.connection.setFixedLengthStreamingMode(bufferedOutput.length);
		}
		this.connection.connect();
		if (this.connection.getDoOutput()) {
			FileCopyUtils.copy(bufferedOutput, this.connection.getOutputStream());
		}
		else {
			// Immediately trigger the request in a no-output scenario as well
			this.connection.getResponseCode();
		}
		return new SimpleClientHttpResponse(this.connection);
	}


	/**
	 * Add the given headers to the given HTTP connection.
	 * @param connection the connection to add the headers to
	 * @param headers the headers to add
	 */
	static void addHeaders(HttpURLConnection connection, HttpHeaders headers) {
		for (Map.Entry<String, List<String>> entry : headers.entrySet()) {
			String headerName = entry.getKey();
			if (HttpHeaders.COOKIE.equalsIgnoreCase(headerName)) {  // RFC 6265
				String headerValue = StringUtils.collectionToDelimitedString(entry.getValue(), "; ");
				connection.setRequestProperty(headerName, headerValue);
			}
			else {
				for (String headerValue : entry.getValue()) {
					String actualHeaderValue = headerValue != null ? headerValue : "";
					connection.addRequestProperty(headerName, actualHeaderValue);
				}
			}
		}
	}

}
