/*
 * Copyright (c) 2015, 2016, 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
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package jdk.incubator.http;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.URI;
import java.util.Base64;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;

import jdk.incubator.http.internal.common.Utils;
import jdk.incubator.http.internal.frame.SettingsFrame;
import static jdk.incubator.http.internal.frame.SettingsFrame.INITIAL_WINDOW_SIZE;
import static jdk.incubator.http.internal.frame.SettingsFrame.ENABLE_PUSH;
import static jdk.incubator.http.internal.frame.SettingsFrame.HEADER_TABLE_SIZE;
import static jdk.incubator.http.internal.frame.SettingsFrame.MAX_CONCURRENT_STREAMS;
import static jdk.incubator.http.internal.frame.SettingsFrame.MAX_FRAME_SIZE;

 Http2 specific aspects of HttpClientImpl
/**
 *  Http2 specific aspects of HttpClientImpl
 */
class Http2ClientImpl {

    private final HttpClientImpl client;

    Http2ClientImpl(HttpClientImpl client) {
        this.client = client;
    }

    /* Map key is "scheme:host:port" */
    private final Map<String,Http2Connection> connections = new ConcurrentHashMap<>();

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

    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.
/**
     * 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(client);
        String key = Http2Connection.keyFor(uri, proxy);
        Http2Connection connection = connections.get(key);
        if (connection != null) { // fast path if connection already exists
            return 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.
        try {
            connection = new Http2Connection(req, this);
        } catch (Throwable t) {
            synchronized (opening) {
                opening.remove(key);
                opening.notifyAll();
            }
            throw t;
        }
        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
     */
    void putConnection(Http2Connection c) {
        connections.put(c.key(), c);
    }

    void deleteConnection(Http2Connection c) {
        connections.remove(c.key());
    }

    HttpClientImpl client() {
        return client;
    }

    
Returns the client settings as a base64 (url) encoded string /** Returns the client settings as a base64 (url) encoded string */
    String getSettingsString() {
        SettingsFrame sf = getClientSettings();
        byte[] settings = sf.toByteArray(); // 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(
                "jdk.httpclient.hpack.maxheadertablesize", 16 * K));
        frame.setParameter(ENABLE_PUSH, Utils.getIntegerNetProperty(
            "jdk.httpclient.enablepush", 1));
        frame.setParameter(MAX_CONCURRENT_STREAMS, Utils.getIntegerNetProperty(
            "jdk.httpclient.maxstreams", 16));
        frame.setParameter(INITIAL_WINDOW_SIZE, Utils.getIntegerNetProperty(
            "jdk.httpclient.windowsize", 64 * K - 1));
        frame.setParameter(MAX_FRAME_SIZE, Utils.getIntegerNetProperty(
            "jdk.httpclient.maxframesize", 16 * K));
        return frame;
    }
}