/*
 * Copyright 2002-2020 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
 *
 *      https://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.server.reactive;

import java.net.InetSocketAddress;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.concurrent.atomic.AtomicLong;

import javax.net.ssl.SSLSession;

import io.netty.channel.Channel;
import io.netty.handler.codec.http.HttpHeaderNames;
import io.netty.handler.codec.http.cookie.Cookie;
import io.netty.handler.ssl.SslHandler;
import reactor.core.publisher.Flux;
import reactor.netty.Connection;
import reactor.netty.http.server.HttpServerRequest;

import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.core.io.buffer.NettyDataBufferFactory;
import org.springframework.http.HttpCookie;
import org.springframework.http.HttpHeaders;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;

/**
 * Adapt {@link ServerHttpRequest} to the Reactor {@link HttpServerRequest}.
 *
 * @author Stephane Maldini
 * @author Rossen Stoyanchev
 * @since 5.0
 */
class ReactorServerHttpRequest extends AbstractServerHttpRequest {

	private static final AtomicLong logPrefixIndex = new AtomicLong(0);


	private final HttpServerRequest request;

	private final NettyDataBufferFactory bufferFactory;


	public ReactorServerHttpRequest(HttpServerRequest request, NettyDataBufferFactory bufferFactory)
			throws URISyntaxException {

		super(initUri(request), "", initHeaders(request));
		Assert.notNull(bufferFactory, "DataBufferFactory must not be null");
		this.request = request;
		this.bufferFactory = bufferFactory;
	}

	private static URI initUri(HttpServerRequest request) throws URISyntaxException {
		Assert.notNull(request, "HttpServerRequest must not be null");
		return new URI(resolveBaseUrl(request).toString() + resolveRequestUri(request));
	}

	private static URI resolveBaseUrl(HttpServerRequest request) throws URISyntaxException {
		String scheme = getScheme(request);
		String header = request.requestHeaders().get(HttpHeaderNames.HOST);
		if (header != null) {
			final int portIndex;
			if (header.startsWith("[")) {
				portIndex = header.indexOf(':', header.indexOf(']'));
			}
			else {
				portIndex = header.indexOf(':');
			}
			if (portIndex != -1) {
				try {
					return new URI(scheme, null, header.substring(0, portIndex),
							Integer.parseInt(header.substring(portIndex + 1)), null, null, null);
				}
				catch (NumberFormatException ex) {
					throw new URISyntaxException(header, "Unable to parse port", portIndex);
				}
			}
			else {
				return new URI(scheme, header, null, null);
			}
		}
		else {
			InetSocketAddress localAddress = request.hostAddress();
			Assert.state(localAddress != null, "No host address available");
			return new URI(scheme, null, localAddress.getHostString(),
					localAddress.getPort(), null, null, null);
		}
	}

	private static String getScheme(HttpServerRequest request) {
		return request.scheme();
	}

	private static String resolveRequestUri(HttpServerRequest request) {
		String uri = request.uri();
		for (int i = 0; i < uri.length(); i++) {
			char c = uri.charAt(i);
			if (c == '/' || c == '?' || c == '#') {
				break;
			}
			if (c == ':' && (i + 2 < uri.length())) {
				if (uri.charAt(i + 1) == '/' && uri.charAt(i + 2) == '/') {
					for (int j = i + 3; j < uri.length(); j++) {
						c = uri.charAt(j);
						if (c == '/' || c == '?' || c == '#') {
							return uri.substring(j);
						}
					}
					return "";
				}
			}
		}
		return uri;
	}

	private static HttpHeaders initHeaders(HttpServerRequest channel) {
		NettyHeadersAdapter headersMap = new NettyHeadersAdapter(channel.requestHeaders());
		return new HttpHeaders(headersMap);
	}


	@Override
	public String getMethodValue() {
		return this.request.method().name();
	}

	@Override
	protected MultiValueMap<String, HttpCookie> initCookies() {
		MultiValueMap<String, HttpCookie> cookies = new LinkedMultiValueMap<>();
		for (CharSequence name : this.request.cookies().keySet()) {
			for (Cookie cookie : this.request.cookies().get(name)) {
				HttpCookie httpCookie = new HttpCookie(name.toString(), cookie.value());
				cookies.add(name.toString(), httpCookie);
			}
		}
		return cookies;
	}

	@Override
	@Nullable
	public InetSocketAddress getLocalAddress() {
		return this.request.hostAddress();
	}

	@Override
	@Nullable
	public InetSocketAddress getRemoteAddress() {
		return this.request.remoteAddress();
	}

	@Override
	@Nullable
	protected SslInfo initSslInfo() {
		Channel channel = ((Connection) this.request).channel();
		SslHandler sslHandler = channel.pipeline().get(SslHandler.class);
		if (sslHandler == null && channel.parent() != null) { // HTTP/2
			sslHandler = channel.parent().pipeline().get(SslHandler.class);
		}
		if (sslHandler != null) {
			SSLSession session = sslHandler.engine().getSession();
			return new DefaultSslInfo(session);
		}
		return null;
	}

	@Override
	public Flux<DataBuffer> getBody() {
		return this.request.receive().retain().map(this.bufferFactory::wrap);
	}

	@SuppressWarnings("unchecked")
	@Override
	public <T> T getNativeRequest() {
		return (T) this.request;
	}

	@Override
	@Nullable
	protected String initId() {
		if (this.request instanceof Connection) {
			return ((Connection) this.request).channel().id().asShortText() +
					"-" + logPrefixIndex.incrementAndGet();
		}
		return null;
	}

}
