* Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved.

import java.io.IOException;

import java.net.InetSocketAddress;

import java.net.URI;

import static java.net.http.SettingsFrame.INITIAL_WINDOW_SIZE;

import static java.net.http.SettingsFrame.ENABLE_PUSH;

import static java.net.http.SettingsFrame.HEADER_TABLE_SIZE;

import static java.net.http.SettingsFrame.MAX_CONCURRENT_STREAMS;

import static java.net.http.SettingsFrame.MAX_FRAME_SIZE;

import java.util.Base64;

import java.util.Collections;

import java.util.HashMap;

import java.util.HashSet;

import java.util.Map;

import java.util.Set;

/**

 *  Http2 specific aspects of HttpClientImpl

 */

    final private HttpClientImpl client;

    Http2ClientImpl(HttpClientImpl client) {

        this.client = client;

    }

    /* Map key is "scheme:host:port" */

    final private Map<String,Http2Connection> connections =

            Collections.synchronizedMap(new HashMap<>());

    final private Set<String> opening = Collections.synchronizedSet(new HashSet<>());

    synchronized boolean haveConnectionFor(URI uri, InetSocketAddress proxy) {

        return connections.containsKey(Http2Connection.keyFor(uri,proxy));

    }

    /**

     * If a https request then blocks and waits until a connection is opened.

     * Returns null if the request is 'http' as a different (upgrade)

     * mechanism is used.

     *

     * Only one connection per destination is created. Blocks when opening

     * connection, or when waiting for connection to be opened.

     * First thread opens the connection and notifies the others when done.

     *

     * If the request is secure (https) then we open the connection here.

     * If not, then the more complicated upgrade from 1.1 to 2 happens (not here)

     * In latter case, when the Http2Connection is connected, putConnection() must

     * be called to store it.

     */

    Http2Connection getConnectionFor(HttpRequestImpl req)

            throws IOException, InterruptedException {

        URI uri = req.uri();

        InetSocketAddress proxy = req.proxy();

        String key = Http2Connection.keyFor(uri, proxy);

        Http2Connection connection;

        synchronized (opening) {

            while ((connection = connections.get(key)) == null) {

                if (!req.secure()) {

                    return null;

                }

                if (!opening.contains(key)) {

                    opening.add(key);

                    break;

                } else {

                    opening.wait();

                }

            }

        }

        if (connection != null) {

            return connection;

        }

        // we are opening the connection here blocking until it is done.

        connection = new Http2Connection(req);

        synchronized (opening) {

            connections.put(key, connection);

            opening.remove(key);

            opening.notifyAll();

        }

        return connection;

    }

    /*

     * TODO: If there isn't a connection to the same destination, then

     * store it. If there is already a connection, then close it

     */

    synchronized void putConnection(Http2Connection c) {

        String key = c.key();

        connections.put(key, c);

    }

    synchronized void deleteConnection(Http2Connection c) {

        String key = c.key();

        connections.remove(key);

    }

    HttpClientImpl client() {

        return client;

    }

    /** Returns the client settings as a base64 (url) encoded string */

    String getSettingsString() {

        SettingsFrame sf = getClientSettings();

        ByteBufferGenerator bg = new ByteBufferGenerator(client);

        sf.writeOutgoing(bg);

        byte[] settings = bg.asByteArray(9); // without the header

        Base64.Encoder encoder = Base64.getUrlEncoder()

                                       .withoutPadding();

        return encoder.encodeToString(settings);

    }

    private static final int K = 1024;

    SettingsFrame getClientSettings() {

        SettingsFrame frame = new SettingsFrame();

        frame.setParameter(HEADER_TABLE_SIZE, Utils.getIntegerNetProperty(

            "java.net.httpclient.hpack.maxheadertablesize", 16 * K));

        frame.setParameter(ENABLE_PUSH, Utils.getIntegerNetProperty(

            "java.net.httpclient.enablepush", 1));

        frame.setParameter(MAX_CONCURRENT_STREAMS, Utils.getIntegerNetProperty(

            "java.net.httpclient.maxstreams", 16));

        frame.setParameter(INITIAL_WINDOW_SIZE, Utils.getIntegerNetProperty(

            "java.net.httpclient.windowsize", 32 * K));

        frame.setParameter(MAX_FRAME_SIZE, Utils.getIntegerNetProperty(

            "java.net.httpclient.maxframesize", 16 * K));

        frame.computeLength();

        return frame;