/*
 * Copyright 2020 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.pdfbox.io;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertFalse;
import static org.junit.jupiter.api.Assertions.assertTrue;

import java.io.BufferedWriter;
import java.io.File;
import java.io.IOException;
import java.net.URISyntaxException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.StandardOpenOption;

import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;

/**
 * Unittest for {@link org.apache.pdfbox.io.RandomAccessReadMemoryMappedFile}
 */
class RandomAccessReadMemoryMappedFileTest
{
    @Test
    void testPositionSkip() throws IOException, URISyntaxException
    {
        try (RandomAccessRead randomAccessSource = new RandomAccessReadMemoryMappedFile(
                new File(getClass().getResource("RandomAccessReadFile1.txt").toURI())))
        {
            assertEquals(0, randomAccessSource.getPosition());
            randomAccessSource.skip(5);
            assertEquals('5', randomAccessSource.read());
            assertEquals(6, randomAccessSource.getPosition());
        }
    }

    @Test
    void testPositionRead() throws IOException, URISyntaxException
    {
        RandomAccessRead randomAccessSource = new RandomAccessReadMemoryMappedFile(
                new File(getClass().getResource("RandomAccessReadFile1.txt").toURI()));

        assertEquals(0, randomAccessSource.getPosition());
        assertEquals('0', randomAccessSource.read());
        assertEquals('1', randomAccessSource.read());
        assertEquals('2', randomAccessSource.read());
        assertEquals(3, randomAccessSource.getPosition());

        assertFalse(randomAccessSource.isClosed());
        randomAccessSource.close();
        assertTrue(randomAccessSource.isClosed());
    }

    @Test
    void testSeekEOF() throws IOException, URISyntaxException
    {
        RandomAccessRead randomAccessSource = new RandomAccessReadMemoryMappedFile(
                new File(getClass().getResource("RandomAccessReadFile1.txt").toURI()));

        randomAccessSource.seek(3);
        assertEquals(3, randomAccessSource.getPosition());

        Assertions.assertThrows(IOException.class, () -> randomAccessSource.seek(-1),
                "seek should have thrown an IOException");

        assertFalse(randomAccessSource.isEOF());
        randomAccessSource.seek(randomAccessSource.length());
        assertTrue(randomAccessSource.isEOF());
        assertEquals(-1, randomAccessSource.read());
        assertEquals(-1, randomAccessSource.read(new byte[1], 0, 1));

        randomAccessSource.close();
        Assertions.assertThrows(IOException.class, () -> randomAccessSource.read(),
                "checkClosed should have thrown an IOException");
    }

    @Test
    void testPositionReadBytes() throws IOException, URISyntaxException
    {
        try (RandomAccessRead randomAccessSource = new RandomAccessReadMemoryMappedFile(
                new File(getClass().getResource("RandomAccessReadFile1.txt").toURI())))
        {
            assertEquals(0, randomAccessSource.getPosition());
            byte[] buffer = new byte[4];
            randomAccessSource.read(buffer);
            assertEquals('0', buffer[0]);
            assertEquals('3', buffer[3]);
            assertEquals(4, randomAccessSource.getPosition());
            
            randomAccessSource.read(buffer, 1, 2);
            assertEquals('0', buffer[0]);
            assertEquals('4', buffer[1]);
            assertEquals('5', buffer[2]);
            assertEquals('3', buffer[3]);
            assertEquals(6, randomAccessSource.getPosition());
        }
    }

    @Test
    void testPositionPeek() throws IOException, URISyntaxException
    {
        try (RandomAccessRead randomAccessSource = new RandomAccessReadMemoryMappedFile(
                new File(getClass().getResource("RandomAccessReadFile1.txt").toURI())))
        {
            assertEquals(0, randomAccessSource.getPosition());
            randomAccessSource.skip(6);
            assertEquals(6, randomAccessSource.getPosition());
            
            assertEquals('6', randomAccessSource.peek());
            assertEquals(6, randomAccessSource.getPosition());
        }
    }

    @Test
    void testPositionUnreadBytes() throws IOException, URISyntaxException
    {
        try (RandomAccessRead randomAccessSource = new RandomAccessReadMemoryMappedFile(
                new File(getClass().getResource("RandomAccessReadFile1.txt").toURI())))
        {
            assertEquals(0, randomAccessSource.getPosition());
            randomAccessSource.read();
            randomAccessSource.read();
            byte[] readBytes = new byte[6];
            assertEquals(readBytes.length, randomAccessSource.read(readBytes));
            assertEquals(8, randomAccessSource.getPosition());
            randomAccessSource.rewind(readBytes.length);
            assertEquals(2, randomAccessSource.getPosition());
            assertEquals('2', randomAccessSource.read());
            assertEquals(3, randomAccessSource.getPosition());
            randomAccessSource.read(readBytes, 2, 4);
            assertEquals(7, randomAccessSource.getPosition());
            randomAccessSource.rewind(4);
            assertEquals(3, randomAccessSource.getPosition());
        }
    }

    @Test
    void testEmptyBuffer() throws IOException, URISyntaxException
    {
        try (RandomAccessRead randomAccessSource = new RandomAccessReadMemoryMappedFile(
                new File(getClass().getResource("RandomAccessReadEmptyFile.txt").toURI())))
        {
            assertEquals(-1, randomAccessSource.read());
            assertEquals(-1, randomAccessSource.peek());
            byte[] readBytes = new byte[6];
            assertEquals(-1, randomAccessSource.read(readBytes));
            randomAccessSource.seek(0);
            assertEquals(0, randomAccessSource.getPosition());
            randomAccessSource.seek(6);
            assertEquals(0, randomAccessSource.getPosition());
            assertTrue(randomAccessSource.isEOF());
            Assertions.assertThrows(IOException.class, () -> randomAccessSource.rewind(3),
                    "seek should have thrown an IOException");
        }
    }

    @Test
    void testUnmapping() throws IOException
    {
        // This is a special test case for some unmapping issues limited to windows enviroments
        // see https://bugs.openjdk.java.net/browse/JDK-4724038
        Path tempFile = Files.createTempFile("PDFBOX", "txt");
        try (BufferedWriter bufferedWriter = Files.newBufferedWriter(tempFile, StandardOpenOption.WRITE))
        {
            bufferedWriter.write("Apache PDFBox test");
        }

        try (RandomAccessRead randomAccessSource = new RandomAccessReadMemoryMappedFile(
                tempFile.toFile()))
        {
            assertEquals(65, randomAccessSource.read());
        }

        Files.delete(tempFile);
    }

    @Test
    void testView() throws IOException, URISyntaxException
    {
        try (RandomAccessRead randomAccessSource = new RandomAccessReadMemoryMappedFile(
                new File(getClass().getResource("RandomAccessReadFile1.txt").toURI()));
             RandomAccessReadView view = randomAccessSource.createView(3, 10))
        {
            assertEquals(0, view.getPosition());
            assertEquals('3', view.read());
            assertEquals('4', view.read());
            assertEquals('5', view.read());
            assertEquals(3, view.getPosition());
        }
    }
}
