/*

 * Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package jdk.internal.net.http;

import java.io.IOException;

import java.net.InetSocketAddress;

import java.net.Proxy;

import java.net.ProxySelector;

import java.net.URI;

import java.security.AccessControlContext;

import java.security.AccessController;

import java.security.PrivilegedAction;

import java.time.Duration;

import java.util.List;

import java.util.Locale;

import java.util.Objects;

import java.util.Optional;

import java.net.http.HttpClient;

import java.net.http.HttpHeaders;

import java.net.http.HttpRequest;

import jdk.internal.net.http.common.HttpHeadersBuilder;

import jdk.internal.net.http.common.Utils;

import jdk.internal.net.http.websocket.OpeningHandshake;

import jdk.internal.net.http.websocket.WebSocketRequest;

import static jdk.internal.net.http.common.Utils.ALLOWED_HEADERS;

public class HttpRequestImpl extends HttpRequest implements WebSocketRequest {

    private final HttpHeaders userHeaders;

    private final HttpHeadersBuilder systemHeadersBuilder;

    private final URI uri;

    private volatile Proxy proxy; // ensure safe publishing

    private final InetSocketAddress authority; // only used when URI not specified

    private final String method;

    final BodyPublisher requestPublisher;

    final boolean secure;

    final boolean expectContinue;

    private volatile boolean isWebSocket;

    private volatile AccessControlContext acc;

    private final Duration timeout;  // may be null

    private final Optional<HttpClient.Version> version;

    private static String userAgent() {

        PrivilegedAction<String> pa = () -> System.getProperty("java.version");

        String version = AccessController.doPrivileged(pa);

        return "Java-http-client/" + version;

    }

    /** The value of the User-Agent header for all requests sent by the client. */

    public static final String USER_AGENT = userAgent();

    /**

     * Creates an HttpRequestImpl from the given builder.

     */

    public HttpRequestImpl(HttpRequestBuilderImpl builder) {

        String method = builder.method();

        this.method = method == null ? "GET" : method;

        this.userHeaders = HttpHeaders.of(builder.headersBuilder().map(), ALLOWED_HEADERS);

        this.systemHeadersBuilder = new HttpHeadersBuilder();

        this.uri = builder.uri();

        assert uri != null;

        this.proxy = null;

        this.expectContinue = builder.expectContinue();

        this.secure = uri.getScheme().toLowerCase(Locale.US).equals("https");

        this.requestPublisher = builder.bodyPublisher();  // may be null

        this.timeout = builder.timeout();

        this.version = builder.version();

        this.authority = null;

    }

    /**

     * Creates an HttpRequestImpl from the given request.

     */

    public HttpRequestImpl(HttpRequest request, ProxySelector ps) {

        String method = request.method();

        if (method != null && !Utils.isValidName(method))

            throw new IllegalArgumentException("illegal method \""

                    + method.replace("\n","\\n")

                    .replace("\r", "\\r")

                    .replace("\t", "\\t")

                    + "\"");

        URI requestURI = Objects.requireNonNull(request.uri(),

                "uri must be non null");

        Duration timeout = request.timeout().orElse(null);

        this.method = method == null ? "GET" : method;

        this.userHeaders = HttpHeaders.of(request.headers().map(), Utils.VALIDATE_USER_HEADER);

        if (request instanceof HttpRequestImpl) {

            // all cases exception WebSocket should have a new system headers

            this.isWebSocket = ((HttpRequestImpl) request).isWebSocket;

            if (isWebSocket) {

                this.systemHeadersBuilder = ((HttpRequestImpl)request).systemHeadersBuilder;

            } else {

                this.systemHeadersBuilder = new HttpHeadersBuilder();

            }

        } else {

            HttpRequestBuilderImpl.checkURI(requestURI);

            checkTimeout(timeout);

            this.systemHeadersBuilder = new HttpHeadersBuilder();

        }

        if (!userHeaders.firstValue("User-Agent").isPresent()) {

            this.systemHeadersBuilder.setHeader("User-Agent", USER_AGENT);

        }

        this.uri = requestURI;

        if (isWebSocket) {

            // WebSocket determines and sets the proxy itself

            this.proxy = ((HttpRequestImpl) request).proxy;

        } else {

            if (ps != null)

                this.proxy = retrieveProxy(ps, uri);

            else

                this.proxy = null;

        }

        this.expectContinue = request.expectContinue();

        this.secure = uri.getScheme().toLowerCase(Locale.US).equals("https");

        this.requestPublisher = request.bodyPublisher().orElse(null);

        this.timeout = timeout;

        this.version = request.version();

        this.authority = null;

    }

    private static void checkTimeout(Duration duration) {

        if (duration != null) {

            if (duration.isNegative() || Duration.ZERO.equals(duration))

                throw new IllegalArgumentException("Invalid duration: " + duration);

        }

    }

    /** Returns a new instance suitable for redirection. */

    public static HttpRequestImpl newInstanceForRedirection(URI uri,

                                                            String method,

                                                            HttpRequestImpl other,

                                                            boolean mayHaveBody) {

        return new HttpRequestImpl(uri, method, other, mayHaveBody);

    }

    /** Returns a new instance suitable for authentication. */

    public static HttpRequestImpl newInstanceForAuthentication(HttpRequestImpl other) {

        HttpRequestImpl request = new HttpRequestImpl(other.uri(), other.method(), other, true);

        if (request.isWebSocket()) {

            Utils.setWebSocketUpgradeHeaders(request);

        }

        return request;

    }

    /**

     * Creates a HttpRequestImpl using fields of an existing request impl.

     * The newly created HttpRequestImpl does not copy the system headers.

     */

    private HttpRequestImpl(URI uri,

                            String method,

                            HttpRequestImpl other,

                            boolean mayHaveBody) {

        assert method == null || Utils.isValidName(method);

        this.method = method == null? "GET" : method;

        this.userHeaders = other.userHeaders;

        this.isWebSocket = other.isWebSocket;

        this.systemHeadersBuilder = new HttpHeadersBuilder();

        if (!userHeaders.firstValue("User-Agent").isPresent()) {

            this.systemHeadersBuilder.setHeader("User-Agent", USER_AGENT);

        }

        this.uri = uri;

        this.proxy = other.proxy;

        this.expectContinue = other.expectContinue;

        this.secure = uri.getScheme().toLowerCase(Locale.US).equals("https");

        this.requestPublisher = mayHaveBody ? publisher(other) : null; // may be null

        this.acc = other.acc;

        this.timeout = other.timeout;

        this.version = other.version();

        this.authority = null;

    }

    private BodyPublisher publisher(HttpRequestImpl other) {

        BodyPublisher res = other.requestPublisher;

        if (!Objects.equals(method, other.method)) {

            res = null;

        }

        return res;

    }

    /* used for creating CONNECT requests  */

    HttpRequestImpl(String method, InetSocketAddress authority, HttpHeaders headers) {

        // TODO: isWebSocket flag is not specified, but the assumption is that

        // such a request will never be made on a connection that will be returned

        // to the connection pool (we might need to revisit this constructor later)

        assert "CONNECT".equalsIgnoreCase(method);

        this.method = method;

        this.systemHeadersBuilder = new HttpHeadersBuilder();

        this.userHeaders = headers;

        this.uri = URI.create("socket://" + authority.getHostString() + ":"

                              + Integer.toString(authority.getPort()) + "/");

        this.proxy = null;

        this.requestPublisher = null;

        this.authority = authority;

        this.secure = false;

        this.expectContinue = false;

        this.timeout = null;

        // The CONNECT request sent for tunneling is only used in two cases:

        //   1. websocket, which only supports HTTP/1.1

        //   2. SSL tunneling through a HTTP/1.1 proxy

        // In either case we do not want to upgrade the connection to the proxy.

        // What we want to possibly upgrade is the tunneled connection to the

        // target server (so not the CONNECT request itself)

        this.version = Optional.of(HttpClient.Version.HTTP_1_1);

    }

    final boolean isConnect() {

        return "CONNECT".equalsIgnoreCase(method);

    }

    /**

     * Creates a HttpRequestImpl from the given set of Headers and the associated

     * "parent" request. Fields not taken from the headers are taken from the

     * parent.

     */

    static HttpRequestImpl createPushRequest(HttpRequestImpl parent,

                                             HttpHeaders headers)

        throws IOException

    {

        return new HttpRequestImpl(parent, headers);

    }

    // only used for push requests

    private HttpRequestImpl(HttpRequestImpl parent, HttpHeaders headers)

        throws IOException

    {

        this.method = headers.firstValue(":method")

                .orElseThrow(() -> new IOException("No method in Push Promise"));

        String path = headers.firstValue(":path")

                .orElseThrow(() -> new IOException("No path in Push Promise"));

        String scheme = headers.firstValue(":scheme")

                .orElseThrow(() -> new IOException("No scheme in Push Promise"));

        String authority = headers.firstValue(":authority")

                .orElseThrow(() -> new IOException("No authority in Push Promise"));

        StringBuilder sb = new StringBuilder();

        sb.append(scheme).append("://").append(authority).append(path);

        this.uri = URI.create(sb.toString());

        this.proxy = null;

        this.userHeaders = HttpHeaders.of(headers.map(), ALLOWED_HEADERS);

        this.systemHeadersBuilder = parent.systemHeadersBuilder;

        this.expectContinue = parent.expectContinue;

        this.secure = parent.secure;

        this.requestPublisher = parent.requestPublisher;

        this.acc = parent.acc;

        this.timeout = parent.timeout;

        this.version = parent.version;

        this.authority = null;

    }

    @Override

    public String toString() {

        return (uri == null ? "" : uri.toString()) + " " + method;

    }

    @Override

    public HttpHeaders headers() {

        return userHeaders;

    }

    InetSocketAddress authority() { return authority; }

    void setH2Upgrade(Http2ClientImpl h2client) {

        systemHeadersBuilder.setHeader("Connection", "Upgrade, HTTP2-Settings");

        systemHeadersBuilder.setHeader("Upgrade", "h2c");

        systemHeadersBuilder.setHeader("HTTP2-Settings", h2client.getSettingsString());

    }

    @Override

    public boolean expectContinue() { return expectContinue; }

    /** Retrieves the proxy, from the given ProxySelector, if there is one. */

    private static Proxy retrieveProxy(ProxySelector ps, URI uri) {

        Proxy proxy = null;

        List<Proxy> pl = ps.select(uri);

        if (!pl.isEmpty()) {

            Proxy p = pl.get(0);

            if (p.type() == Proxy.Type.HTTP)

                proxy = p;

        }

        return proxy;

    }

    InetSocketAddress proxy() {

        if (proxy == null || proxy.type() != Proxy.Type.HTTP

                || method.equalsIgnoreCase("CONNECT")) {

            return null;

        }

        return (InetSocketAddress)proxy.address();

    }

    boolean secure() { return secure; }

    @Override

    public void setProxy(Proxy proxy) {

        assert isWebSocket;

        this.proxy = proxy;

    }

    @Override

    public void isWebSocket(boolean is) {

        isWebSocket = is;

    }

    boolean isWebSocket() {

        return isWebSocket;

    }

    @Override

    public Optional<BodyPublisher> bodyPublisher() {

        return requestPublisher == null ? Optional.empty()

                                        : Optional.of(requestPublisher);

    }

    /**

     * Returns the request method for this request. If not set explicitly,

     * the default method for any request is "GET".

     */

    @Override

    public String method() { return method; }

    @Override

    public URI uri() { return uri; }

    @Override

    public Optional<Duration> timeout() {

        return timeout == null ? Optional.empty() : Optional.of(timeout);

    }

    HttpHeaders getUserHeaders() { return userHeaders; }

    HttpHeadersBuilder getSystemHeadersBuilder() { return systemHeadersBuilder; }

    @Override

    public Optional<HttpClient.Version> version() { return version; }

    void addSystemHeader(String name, String value) {

        systemHeadersBuilder.addHeader(name, value);

    }

    @Override

    public void setSystemHeader(String name, String value) {

        systemHeadersBuilder.setHeader(name, value);

    }

    InetSocketAddress getAddress() {

        URI uri = uri();

        if (uri == null) {

            return authority();

        }

        int p = uri.getPort();

        if (p == -1) {

            if (uri.getScheme().equalsIgnoreCase("https")) {

                p = 443;

            } else {

                p = 80;

            }

        }

        final String host = uri.getHost();

        final int port = p;

        if (proxy() == null) {

            PrivilegedAction<InetSocketAddress> pa = () -> new InetSocketAddress(host, port);

            return AccessController.doPrivileged(pa);

        } else {

            return InetSocketAddress.createUnresolved(host, port);

        }

    }

}