/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.logging.log4j.core.appender;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.RandomAccessFile;

import org.apache.logging.log4j.core.util.NullOutputStream;
import org.junit.ClassRule;
import org.junit.Test;
import org.junit.rules.TemporaryFolder;

import static org.junit.Assert.*;

/**
 * Tests the RandomAccessFileManager class.
 */
public class RandomAccessFileManagerTest {

    @ClassRule
    public static TemporaryFolder folder = new TemporaryFolder();

    /**
     * Test method for
     * {@link org.apache.logging.log4j.core.appender.RandomAccessFileManager#writeBytes(byte[], int, int)}
     * .
     */
    @Test
    public void testWrite_multiplesOfBufferSize() throws IOException {
        final File file = folder.newFile();
        try (final RandomAccessFile raf = new RandomAccessFile(file, "rw")) {
            final OutputStream os = NullOutputStream.getInstance();
            final RandomAccessFileManager manager = new RandomAccessFileManager(null, raf, file.getName(),
                    os, RandomAccessFileManager.DEFAULT_BUFFER_SIZE, null, null, true);

            final int size = RandomAccessFileManager.DEFAULT_BUFFER_SIZE * 3;
            final byte[] data = new byte[size];
            manager.write(data); // no buffer overflow exception

            // all data is written if exceeds buffer size
            assertEquals(RandomAccessFileManager.DEFAULT_BUFFER_SIZE * 3, raf.length());
        }}

    /**
     * Test method for
     * {@link org.apache.logging.log4j.core.appender.RandomAccessFileManager#writeBytes(byte[], int, int)}
     * .
     */
    @Test
    public void testWrite_dataExceedingBufferSize() throws IOException {
        final File file = folder.newFile();
        try (final RandomAccessFile raf = new RandomAccessFile(file, "rw")) {
            final OutputStream os = NullOutputStream.getInstance();
            final RandomAccessFileManager manager = new RandomAccessFileManager(null, raf, file.getName(),
                    os, RandomAccessFileManager.DEFAULT_BUFFER_SIZE, null, null, true);

            final int size = RandomAccessFileManager.DEFAULT_BUFFER_SIZE * 3 + 1;
            final byte[] data = new byte[size];
            manager.write(data); // no exception
            // all data is written if exceeds buffer size
            assertEquals(RandomAccessFileManager.DEFAULT_BUFFER_SIZE * 3 + 1, raf.length());

            manager.flush();
            assertEquals(size, raf.length()); // all data written to file now
        }}

    @Test
    public void testConfigurableBufferSize() throws IOException {
        final File file = folder.newFile();
        try (final RandomAccessFile raf = new RandomAccessFile(file, "rw")) {
            final OutputStream os = NullOutputStream.getInstance();
            final int bufferSize = 4 * 1024;
            assertNotEquals(bufferSize, RandomAccessFileManager.DEFAULT_BUFFER_SIZE);

            final RandomAccessFileManager manager = new RandomAccessFileManager(null, raf, file.getName(),
                    os, bufferSize, null, null, true);

            // check the resulting buffer size is what was requested
            assertEquals(bufferSize, manager.getBufferSize());
        }}

    @Test
    public void testWrite_dataExceedingMinBufferSize() throws IOException {
        final File file = folder.newFile();
        try (final RandomAccessFile raf = new RandomAccessFile(file, "rw")) {
            final OutputStream os = NullOutputStream.getInstance();
            final int bufferSize = 1;
            final RandomAccessFileManager manager = new RandomAccessFileManager(null, raf, file.getName(),
                    os, bufferSize, null, null, true);

            final int size = bufferSize * 3 + 1;
            final byte[] data = new byte[size];
            manager.write(data); // no exception
            // all data is written if exceeds buffer size
            assertEquals(bufferSize * 3 + 1, raf.length());

            manager.flush();
            assertEquals(size, raf.length()); // all data written to file now
        }}

    @Test
    public void testAppendDoesNotOverwriteExistingFile() throws IOException {
        final boolean isAppend = true;
        final File file = folder.newFile();
        assertEquals(0, file.length());

        final byte[] bytes = new byte[4 * 1024];

        // create existing file
        try (FileOutputStream fos = new FileOutputStream(file)) {
            fos.write(bytes, 0, bytes.length);
            fos.flush();
        }
        assertEquals("all flushed to disk", bytes.length, file.length());

        final RandomAccessFileManager manager = RandomAccessFileManager.getFileManager(
                file.getAbsolutePath(), isAppend, true, RandomAccessFileManager.DEFAULT_BUFFER_SIZE, null, null, null);
        manager.write(bytes, 0, bytes.length, true);
        final int expected = bytes.length * 2;
        assertEquals("appended, not overwritten", expected, file.length());
    }
}