/*

 * Copyright (c) 2015, 2017, 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.nio.ByteBuffer;

import java.util.concurrent.CompletableFuture;

import java.util.concurrent.Executor;

import jdk.incubator.http.internal.common.Log;

import static jdk.incubator.http.HttpClient.Version.HTTP_1_1;

/**

 * Handles a HTTP/1.1 response in two blocking calls. readHeaders() and

 * readBody(). There can be more than one of these per Http exchange.

 */

class Http1Response<T> {

    private volatile ResponseContent content;

    private final HttpRequestImpl request;

    private Response response;

    private final HttpConnection connection;

    private ResponseHeaders headers;

    private int responseCode;

    private ByteBuffer buffer;

    private final Http1Exchange<T> exchange;

    private final boolean redirecting; // redirecting

    private boolean return2Cache; // return connection to cache when finished

    Http1Response(HttpConnection conn, Http1Exchange<T> exchange) {

        this.request = exchange.request();

        this.exchange = exchange;

        this.connection = conn;

        this.redirecting = false;

        buffer = exchange.getBuffer();

    }

    @SuppressWarnings("unchecked")

    public void readHeaders() throws IOException {

        String statusline = readStatusLine();

        if (statusline == null) {

            if (Log.errors()) {

                Log.logError("Connection closed. Retry");

            }

            connection.close();

            // connection was closed

            throw new IOException("Connection closed");

        }

        if (!statusline.startsWith("HTTP/1.")) {

            throw new IOException("Invalid status line: " + statusline);

        }

        if (Log.trace()) {

            Log.logTrace("Statusline: {0}", statusline);

        }

        char c = statusline.charAt(7);

        responseCode = Integer.parseInt(statusline.substring(9, 12));

        headers = new ResponseHeaders(connection, buffer);

        if (Log.headers()) {

            logHeaders(headers);

        }

        response = new Response(

                request, exchange.getExchange(),

                headers, responseCode, HTTP_1_1);

    }

    private boolean finished;

    synchronized void completed() {

        finished = true;

    }

    synchronized boolean finished() {

        return finished;

    }

    ByteBuffer getBuffer() {

        return buffer;

    }

    int fixupContentLen(int clen) {

        if (request.method().equalsIgnoreCase("HEAD")) {

            return 0;

        }

        if (clen == -1) {

            if (headers.firstValue("Transfer-encoding").orElse("")

                       .equalsIgnoreCase("chunked")) {

                return -1;

            }

            return 0;

        }

        return clen;

    }

    public CompletableFuture<T> readBody(

            HttpResponse.BodyProcessor<T> p,

            boolean return2Cache,

            Executor executor) {

        final BlockingPushPublisher<ByteBuffer> publisher = new BlockingPushPublisher<>();

        return readBody(p, return2Cache, publisher, executor);

    }

    private CompletableFuture<T> readBody(

            HttpResponse.BodyProcessor<T> p,

            boolean return2Cache,

            AbstractPushPublisher<ByteBuffer> publisher,

            Executor executor) {

        this.return2Cache = return2Cache;

        final jdk.incubator.http.HttpResponse.BodyProcessor<T> pusher = p;

        final CompletableFuture<T> cf = p.getBody().toCompletableFuture();

        int clen0;

        try {

            clen0 = headers.getContentLength();

        } catch (IOException ex) {

            cf.completeExceptionally(ex);

            return cf;

        }

        final int clen = fixupContentLen(clen0);

        executor.execute(() -> {

            try {

                content = new ResponseContent(

                        connection, clen, headers, pusher,

                        publisher.asDataConsumer(),

                        (t -> {

                            publisher.acceptError(t);

                            connection.close();

                            cf.completeExceptionally(t);

                        }),

                        () -> onFinished()

                );

                publisher.subscribe(p);

                if (cf.isCompletedExceptionally()) {

                    // if an error occurs during subscription

                    connection.close();

                    return;

                }

                content.pushBody(buffer);

            } catch (Throwable t) {

                cf.completeExceptionally(t);

            }

        });

        return cf;

    }

    private void onFinished() {

        if (return2Cache) {

            Log.logTrace("Returning connection to the pool: {0}", connection);

            connection.returnToCache(headers);

        }

    }

    private void logHeaders(ResponseHeaders headers) {

        StringBuilder sb = new StringBuilder("RESPONSE HEADERS:\n");

        Log.dumpHeaders(sb, "    ", headers);

        Log.logHeaders(sb.toString());

    }

    Response response() {

        return response;

    }

    boolean redirecting() {

        return redirecting;

    }

    HttpHeaders responseHeaders() {

        return headers;

    }

    int responseCode() {

        return responseCode;

    }

    static final char CR = '\r';

    static final char LF = '\n';

    private int obtainBuffer() throws IOException {

        int n = buffer.remaining();

        if (n == 0) {

            buffer = connection.read();

            if (buffer == null) {

                return -1;

            }

            n = buffer.remaining();

        }

        return n;

    }

    String readStatusLine() throws IOException {

        boolean cr = false;

        StringBuilder statusLine = new StringBuilder(128);

        while ((obtainBuffer()) != -1) {

            byte[] buf = buffer.array();

            int offset = buffer.position();

            int len = buffer.limit() - offset;

            for (int i = 0; i < len; i++) {

                char c = (char) buf[i+offset];

                if (cr) {

                    if (c == LF) {

                        buffer.position(i + 1 + offset);

                        return statusLine.toString();

                    } else {

                        throw new IOException("invalid status line");

                    }

                }

                if (c == CR) {

                    cr = true;

                } else {

                    statusLine.append(c);

                }

            }

            // unlikely, but possible, that multiple reads required

            buffer.position(buffer.limit());

        }

        return null;

    }

}