/*

 * Copyright (c) 2018, 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.

 *

 * 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.

 */

import java.io.IOException;

import java.nio.ByteBuffer;

import java.nio.channels.SocketChannel;

import java.nio.charset.StandardCharsets;

import java.util.Arrays;

import java.util.concurrent.CompletableFuture;

import java.util.concurrent.CompletionException;

import java.util.concurrent.CompletionStage;

import java.util.concurrent.TimeUnit;

import java.util.concurrent.TimeoutException;

import static org.testng.Assert.assertThrows;

public class Support {

    private Support() { }

    public static void assertFails(Class<? extends Throwable> clazz,

                                    CompletionStage<?> stage) {

        Support.assertCompletesExceptionally(clazz, stage);

    }

    public static void assertCompletesExceptionally(Class<? extends Throwable> clazz,

                                                    CompletionStage<?> stage) {

        CompletableFuture<?> cf =

                CompletableFuture.completedFuture(null).thenCompose(x -> stage);

        assertThrows(clazz, () -> {

            try {

                cf.join();

            } catch (CompletionException e) {

                throw e.getCause();

            }

        });

    }

    public static void assertHangs(CompletionStage<?> stage) {

        Support.assertDoesNotCompleteWithin(5, TimeUnit.SECONDS, stage);

    }

    public static void assertDoesNotCompleteWithin(long timeout,

                                                   TimeUnit unit,

                                                   CompletionStage<?> stage) {

        CompletableFuture<?> cf =

                CompletableFuture.completedFuture(null).thenCompose(x -> stage);

        assertThrows(TimeoutException.class, () -> cf.get(timeout, unit));

    }

    public static ByteBuffer fullCopy(ByteBuffer src) {

        ByteBuffer copy = ByteBuffer.allocate(src.capacity());

        int p = src.position();

        int l = src.limit();

        src.clear();

        copy.put(src).position(p).limit(l);

        src.position(p).limit(l);

        return copy;

    }

    public static DummyWebSocketServer serverWithCannedData(int... data) {

        byte[] copy = new byte[data.length];

        for (int i = 0; i < data.length; i++) {

            copy[i] = (byte) data[i];

        }

        return serverWithCannedData(copy);

    }

    public static DummyWebSocketServer serverWithCannedData(byte... data) {

        byte[] copy = Arrays.copyOf(data, data.length);

        return new DummyWebSocketServer() {

            @Override

            protected void write(SocketChannel ch) throws IOException {

                int off = 0; int n = 1; // 1 byte at a time

                while (off + n < copy.length + n) {

//                    try {

//                        TimeUnit.MICROSECONDS.sleep(500);

//                    } catch (InterruptedException e) {

//                        return;

//                    }

                    int len = Math.min(copy.length - off, n);

                    ByteBuffer bytes = ByteBuffer.wrap(copy, off, len);

                    off += len;

                    ch.write(bytes);

                }

                super.write(ch);

            }

        };

    }

    /*

     * This server does not read from the wire, allowing its client to fill up

     * their send buffer. Used to test scenarios with outstanding send

     * operations.

     */

    public static DummyWebSocketServer notReadingServer() {

        return new DummyWebSocketServer() {

            @Override

            protected void read(SocketChannel ch) throws IOException {

                try {

                    Thread.sleep(Long.MAX_VALUE);

                } catch (InterruptedException e) {

                    throw new IOException(e);

                }

            }

        };

    }

    public static DummyWebSocketServer writingServer(int... data) {

        byte[] copy = new byte[data.length];

        for (int i = 0; i < data.length; i++) {

            copy[i] = (byte) data[i];

        }

        return new DummyWebSocketServer() {

            @Override

            protected void read(SocketChannel ch) throws IOException {

                try {

                    Thread.sleep(Long.MAX_VALUE);

                } catch (InterruptedException e) {

                    throw new IOException(e);

                }

            }

            @Override

            protected void write(SocketChannel ch) throws IOException {

                int off = 0; int n = 1; // 1 byte at a time

                while (off + n < copy.length + n) {

//                    try {

//                        TimeUnit.MICROSECONDS.sleep(500);

//                    } catch (InterruptedException e) {

//                        return;

//                    }

                    int len = Math.min(copy.length - off, n);

                    ByteBuffer bytes = ByteBuffer.wrap(copy, off, len);

                    off += len;

                    ch.write(bytes);

                }

                super.write(ch);

            }

        };

    }

    public static String stringWith2NBytes(int n) {

        // -- Russian Alphabet (33 characters, 2 bytes per char) --

        char[] abc = {

                0x0410, 0x0411, 0x0412, 0x0413, 0x0414, 0x0415, 0x0401, 0x0416,

                0x0417, 0x0418, 0x0419, 0x041A, 0x041B, 0x041C, 0x041D, 0x041E,

                0x041F, 0x0420, 0x0421, 0x0422, 0x0423, 0x0424, 0x0425, 0x0426,

                0x0427, 0x0428, 0x0429, 0x042A, 0x042B, 0x042C, 0x042D, 0x042E,

                0x042F,

        };

        // repeat cyclically

        StringBuilder sb = new StringBuilder(n);

        for (int i = 0, j = 0; i < n; i++, j = (j + 1) % abc.length) {

            sb.append(abc[j]);

        }

        String s = sb.toString();

        assert s.length() == n && s.getBytes(StandardCharsets.UTF_8).length == 2 * n;

        return s;

    }

    public static String malformedString() {

        return new String(new char[]{0xDC00, 0xD800});

    }

    public static String incompleteString() {

        return new String(new char[]{0xD800});

    }

    public static String stringWithNBytes(int n) {

        char[] chars = new char[n];

        Arrays.fill(chars, 'A');

        return new String(chars);

    }

}