//
//  ========================================================================
//  Copyright (c) 1995-2020 Mort Bay Consulting Pty Ltd and others.
//  ------------------------------------------------------------------------
//  All rights reserved. This program and the accompanying materials
//  are made available under the terms of the Eclipse Public License v1.0
//  and Apache License v2.0 which accompanies this distribution.
//
//      The Eclipse Public License is available at
//      http://www.eclipse.org/legal/epl-v10.html
//
//      The Apache License v2.0 is available at
//      http://www.opensource.org/licenses/apache2.0.php
//
//  You may elect to redistribute this code under either of these licenses.
//  ========================================================================
//

package org.eclipse.jetty.util;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.nio.BufferOverflowException;
import java.nio.ByteBuffer;
import java.util.Arrays;
import java.util.concurrent.ThreadLocalRandom;

import org.eclipse.jetty.util.log.Log;
import org.eclipse.jetty.util.log.Logger;
import org.junit.jupiter.api.Disabled;
import org.junit.jupiter.api.Test;

import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.Matchers.containsString;
import static org.hamcrest.Matchers.is;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.junit.jupiter.api.Assertions.assertTrue;

public class BufferUtilTest
{
    @Test
    public void testToInt() throws Exception
    {
        ByteBuffer[] buf =
            {
                BufferUtil.toBuffer("0"),
                BufferUtil.toBuffer(" 42 "),
                BufferUtil.toBuffer("   43abc"),
                BufferUtil.toBuffer("-44"),
                BufferUtil.toBuffer(" - 45;"),
                BufferUtil.toBuffer("-2147483648"),
                BufferUtil.toBuffer("2147483647"),
            };

        int[] val =
            {
                0, 42, 43, -44, -45, -2147483648, 2147483647
            };

        for (int i = 0; i < buf.length; i++)
        {
            assertEquals(val[i], BufferUtil.toInt(buf[i]), "t" + i);
        }
    }

    @Test
    public void testPutInt() throws Exception
    {
        int[] val =
            {
                0, 42, 43, -44, -45, Integer.MIN_VALUE, Integer.MAX_VALUE
            };

        String[] str =
            {
                "0", "42", "43", "-44", "-45", "" + Integer.MIN_VALUE, "" + Integer.MAX_VALUE
            };

        ByteBuffer buffer = ByteBuffer.allocate(24);

        for (int i = 0; i < val.length; i++)
        {
            BufferUtil.clearToFill(buffer);
            BufferUtil.putDecInt(buffer, val[i]);
            BufferUtil.flipToFlush(buffer, 0);
            assertEquals(str[i], BufferUtil.toString(buffer), "t" + i);
        }
    }

    @Test
    public void testPutLong() throws Exception
    {
        long[] val =
            {
                0L, 42L, 43L, -44L, -45L, Long.MIN_VALUE, Long.MAX_VALUE
            };

        String[] str =
            {
                "0", "42", "43", "-44", "-45", "" + Long.MIN_VALUE, "" + Long.MAX_VALUE
            };

        ByteBuffer buffer = ByteBuffer.allocate(50);

        for (int i = 0; i < val.length; i++)
        {
            BufferUtil.clearToFill(buffer);
            BufferUtil.putDecLong(buffer, val[i]);
            BufferUtil.flipToFlush(buffer, 0);
            assertEquals(str[i], BufferUtil.toString(buffer), "t" + i);
        }
    }

    @Test
    public void testPutHexInt() throws Exception
    {
        int[] val =
            {
                0, 42, 43, -44, -45, -2147483648, 2147483647
            };

        String[] str =
            {
                "0", "2A", "2B", "-2C", "-2D", "-80000000", "7FFFFFFF"
            };

        ByteBuffer buffer = ByteBuffer.allocate(50);

        for (int i = 0; i < val.length; i++)
        {
            BufferUtil.clearToFill(buffer);
            BufferUtil.putHexInt(buffer, val[i]);
            BufferUtil.flipToFlush(buffer, 0);
            assertEquals(str[i], BufferUtil.toString(buffer), "t" + i);
        }
    }

    @Test
    public void testPut() throws Exception
    {
        ByteBuffer to = BufferUtil.allocate(10);
        ByteBuffer from = BufferUtil.toBuffer("12345");

        BufferUtil.clear(to);
        assertEquals(5, BufferUtil.append(to, from));
        assertTrue(BufferUtil.isEmpty(from));
        assertEquals("12345", BufferUtil.toString(to));

        from = BufferUtil.toBuffer("XX67890ZZ");
        from.position(2);

        assertEquals(5, BufferUtil.append(to, from));
        assertEquals(2, from.remaining());
        assertEquals("1234567890", BufferUtil.toString(to));
    }

    @Test
    public void testAppend() throws Exception
    {
        ByteBuffer to = BufferUtil.allocate(8);
        ByteBuffer from = BufferUtil.toBuffer("12345");

        BufferUtil.append(to, from.array(), 0, 3);
        assertEquals("123", BufferUtil.toString(to));
        BufferUtil.append(to, from.array(), 3, 2);
        assertEquals("12345", BufferUtil.toString(to));

        assertThrows(BufferOverflowException.class, () ->
        {
            BufferUtil.append(to, from.array(), 0, 5);
        });
    }

    @Test
    public void testPutDirect() throws Exception
    {
        ByteBuffer to = BufferUtil.allocateDirect(10);
        ByteBuffer from = BufferUtil.toBuffer("12345");

        BufferUtil.clear(to);
        assertEquals(5, BufferUtil.append(to, from));
        assertTrue(BufferUtil.isEmpty(from));
        assertEquals("12345", BufferUtil.toString(to));

        from = BufferUtil.toBuffer("XX67890ZZ");
        from.position(2);

        assertEquals(5, BufferUtil.append(to, from));
        assertEquals(2, from.remaining());
        assertEquals("1234567890", BufferUtil.toString(to));
    }

    @Test
    public void testToBufferArray()
    {
        byte[] arr = new byte[128];
        Arrays.fill(arr, (byte)0x44);
        ByteBuffer buf = BufferUtil.toBuffer(arr);

        int count = 0;
        while (buf.remaining() > 0)
        {
            byte b = buf.get();
            assertEquals(b, 0x44);
            count++;
        }

        assertEquals(arr.length, count, "Count of bytes");
    }

    @Test
    public void testToBufferArrayOffsetLength()
    {
        byte[] arr = new byte[128];
        Arrays.fill(arr, (byte)0xFF); // fill whole thing with FF
        int offset = 10;
        int length = 100;
        Arrays.fill(arr, offset, offset + length, (byte)0x77); // fill partial with 0x77
        ByteBuffer buf = BufferUtil.toBuffer(arr, offset, length);

        int count = 0;
        while (buf.remaining() > 0)
        {
            byte b = buf.get();
            assertEquals(b, 0x77);
            count++;
        }

        assertEquals(length, count, "Count of bytes");
    }

    private static final Logger LOG = Log.getLogger(BufferUtilTest.class);

    @Test
    @Disabled("Very simple microbenchmark to compare different writeTo implementations. Only for development thus " +
        "ignored.")
    public void testWriteToMicrobenchmark() throws IOException
    {
        int capacity = 1024 * 128;
        int iterations = 100;
        int testRuns = 10;
        byte[] bytes = new byte[capacity];
        ThreadLocalRandom.current().nextBytes(bytes);
        ByteBuffer buffer = BufferUtil.allocate(capacity);
        BufferUtil.append(buffer, bytes, 0, capacity);
        long startTest = System.nanoTime();
        for (int i = 0; i < testRuns; i++)
        {
            long start = System.nanoTime();
            for (int j = 0; j < iterations; j++)
            {
                ByteArrayOutputStream out = new ByteArrayOutputStream();
                long startRun = System.nanoTime();
                BufferUtil.writeTo(buffer.asReadOnlyBuffer(), out);
                long elapsedRun = System.nanoTime() - startRun;
//                LOG.warn("run elapsed={}ms", elapsedRun / 1000);
                assertThat("Bytes in out equal bytes in buffer", Arrays.equals(bytes, out.toByteArray()), is(true));
            }
            long elapsed = System.nanoTime() - start;
            LOG.warn("elapsed={}ms average={}ms", elapsed / 1000, elapsed / iterations / 1000);
        }
        LOG.warn("overall average: {}ms", (System.nanoTime() - startTest) / testRuns / iterations / 1000);
    }

    @Test
    public void testWriteToWithBufferThatDoesNotExposeArrayAndSmallContent() throws IOException
    {
        int capacity = BufferUtil.TEMP_BUFFER_SIZE / 4;
        testWriteToWithBufferThatDoesNotExposeArray(capacity);
    }

    @Test
    public void testWriteToWithBufferThatDoesNotExposeArrayAndContentLengthMatchingTempBufferSize() throws IOException
    {
        int capacity = BufferUtil.TEMP_BUFFER_SIZE;
        testWriteToWithBufferThatDoesNotExposeArray(capacity);
    }

    @Test
    public void testWriteToWithBufferThatDoesNotExposeArrayAndContentSlightlyBiggerThanTwoTimesTempBufferSize()
        throws
        IOException
    {
        int capacity = BufferUtil.TEMP_BUFFER_SIZE * 2 + 1024;
        testWriteToWithBufferThatDoesNotExposeArray(capacity);
    }

    @Test
    @SuppressWarnings("ReferenceEquality")
    public void testEnsureCapacity() throws Exception
    {
        ByteBuffer b = BufferUtil.toBuffer("Goodbye Cruel World");
        assertTrue(b == BufferUtil.ensureCapacity(b, 0));
        assertTrue(b == BufferUtil.ensureCapacity(b, 10));
        assertTrue(b == BufferUtil.ensureCapacity(b, b.capacity()));

        ByteBuffer b1 = BufferUtil.ensureCapacity(b, 64);
        assertTrue(b != b1);
        assertEquals(64, b1.capacity());
        assertEquals("Goodbye Cruel World", BufferUtil.toString(b1));

        b1.position(8);
        b1.limit(13);
        assertEquals("Cruel", BufferUtil.toString(b1));
        ByteBuffer b2 = b1.slice();
        assertEquals("Cruel", BufferUtil.toString(b2));
        System.err.println(BufferUtil.toDetailString(b2));
        assertEquals(8, b2.arrayOffset());
        assertEquals(5, b2.capacity());

        assertTrue(b2 == BufferUtil.ensureCapacity(b2, 5));

        ByteBuffer b3 = BufferUtil.ensureCapacity(b2, 64);
        assertTrue(b2 != b3);
        assertEquals(64, b3.capacity());
        assertEquals("Cruel", BufferUtil.toString(b3));
        assertEquals(0, b3.arrayOffset());
    }

    @Test
    public void testToDetailWithDEL()
    {
        ByteBuffer b = ByteBuffer.allocate(40);
        b.putChar('a').putChar('b').putChar('c');
        b.put((byte)0x7F);
        b.putChar('x').putChar('y').putChar('z');
        b.flip();
        String result = BufferUtil.toDetailString(b);
        assertThat("result", result, containsString("\\x7f"));
    }

    private void testWriteToWithBufferThatDoesNotExposeArray(int capacity) throws IOException
    {
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        byte[] bytes = new byte[capacity];
        ThreadLocalRandom.current().nextBytes(bytes);
        ByteBuffer buffer = BufferUtil.allocate(capacity);
        BufferUtil.append(buffer, bytes, 0, capacity);
        BufferUtil.writeTo(buffer.asReadOnlyBuffer(), out);
        assertThat("Bytes in out equal bytes in buffer", Arrays.equals(bytes, out.toByteArray()), is(true));
    }
}
