/*
 *  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.commons.compress.archivers.zip;

import static org.junit.jupiter.api.Assertions.assertArrayEquals;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.junit.jupiter.api.Assertions.assertTrue;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.Map;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.function.Consumer;
import java.util.function.Function;
import java.util.zip.Deflater;
import java.util.zip.ZipEntry;

import org.apache.commons.compress.AbstractTempDirTest;
import org.apache.commons.compress.AbstractTest;
import org.apache.commons.compress.parallel.FileBasedScatterGatherBackingStore;
import org.apache.commons.compress.parallel.InputStreamSupplier;
import org.apache.commons.compress.parallel.ScatterGatherBackingStoreSupplier;
import org.apache.commons.io.IOUtils;
import org.junit.jupiter.api.Disabled;
import org.junit.jupiter.api.Test;

public class ParallelScatterZipCreatorTest extends AbstractTempDirTest {

    private interface CallableConsumer extends Consumer<Callable<? extends ScatterZipOutputStream>> {
        // empty
    }

    private interface CallableConsumerSupplier extends Function<ParallelScatterZipCreator, CallableConsumer> {
        // empty
    }

    private static final long EXPECTED_FILE_SIZE = 1024 * 1024; // 1MB

    private static final int EXPECTED_FILES_NUMBER = 50;
    private final int NUMITEMS = 5000;

    private void callableApi(final CallableConsumerSupplier consumerSupplier, final File result) throws Exception {
        callableApi(consumerSupplier, Deflater.DEFAULT_COMPRESSION, result);
    }

    private void callableApi(final CallableConsumerSupplier consumerSupplier, final int compressionLevel, final File result) throws Exception {
        final Map<String, byte[]> entries;
        final ParallelScatterZipCreator zipCreator;
        try (ZipArchiveOutputStream zos = new ZipArchiveOutputStream(result)) {
            zos.setEncoding(StandardCharsets.UTF_8.name());
            final ExecutorService es = Executors.newFixedThreadPool(1);

            final ScatterGatherBackingStoreSupplier supp = () -> new FileBasedScatterGatherBackingStore(createTempFile("parallelscatter", "n1"));

            zipCreator = new ParallelScatterZipCreator(es, supp, compressionLevel);
            entries = writeEntriesAsCallable(zipCreator, consumerSupplier.apply(zipCreator));
            zipCreator.writeTo(zos);
        }

        removeEntriesFoundInZipFile(result, entries);
        assertTrue(entries.isEmpty());
        assertNotNull(zipCreator.getStatisticsMessage());
    }

    private void callableApiWithTestFiles(final CallableConsumerSupplier consumerSupplier, final int compressionLevel, final File result) throws Exception {
        final ParallelScatterZipCreator zipCreator;
        final Map<String, byte[]> entries;
        try (ZipArchiveOutputStream zos = new ZipArchiveOutputStream(result)) {
            zos.setEncoding(StandardCharsets.UTF_8.name());
            final ExecutorService es = Executors.newFixedThreadPool(1);

            final ScatterGatherBackingStoreSupplier supp = () -> new FileBasedScatterGatherBackingStore(createTempFile("parallelscatter", "n1"));

            zipCreator = new ParallelScatterZipCreator(es, supp, compressionLevel);
            entries = writeTestFilesAsCallable(zipCreator, consumerSupplier.apply(zipCreator));
            zipCreator.writeTo(zos);
        }

        // validate the content of the compressed files
        try (ZipFile zf = ZipFile.builder().setFile(result).get()) {
            final Enumeration<ZipArchiveEntry> entriesInPhysicalOrder = zf.getEntriesInPhysicalOrder();
            while (entriesInPhysicalOrder.hasMoreElements()) {
                final ZipArchiveEntry zipArchiveEntry = entriesInPhysicalOrder.nextElement();
                try (InputStream inputStream = zf.getInputStream(zipArchiveEntry)) {
                    final byte[] actual = IOUtils.toByteArray(inputStream);
                    final byte[] expected = entries.remove(zipArchiveEntry.getName());
                    assertArrayEquals(expected, actual, "For " + zipArchiveEntry.getName());
                }
            }
        }
        assertNotNull(zipCreator.getStatisticsMessage());
    }

    private ZipArchiveEntry createZipArchiveEntry(final Map<String, byte[]> entries, final int i, final byte[] payloadBytes) {
        final ZipArchiveEntry za = new ZipArchiveEntry("file" + i);
        entries.put(za.getName(), payloadBytes);
        za.setMethod(ZipEntry.DEFLATED);
        za.setSize(payloadBytes.length);
        za.setUnixMode(UnixStat.FILE_FLAG | 0664);
        return za;
    }

    private void removeEntriesFoundInZipFile(final File result, final Map<String, byte[]> entries) throws IOException {
        try (ZipFile zf = ZipFile.builder().setFile(result).get()) {
            final Enumeration<ZipArchiveEntry> entriesInPhysicalOrder = zf.getEntriesInPhysicalOrder();
            int i = 0;
            while (entriesInPhysicalOrder.hasMoreElements()) {
                final ZipArchiveEntry zipArchiveEntry = entriesInPhysicalOrder.nextElement();
                try (InputStream inputStream = zf.getInputStream(zipArchiveEntry)) {
                    final byte[] actual = IOUtils.toByteArray(inputStream);
                    final byte[] expected = entries.remove(zipArchiveEntry.getName());
                    assertArrayEquals(expected, actual, "For " + zipArchiveEntry.getName());
                }
                // check order of ZIP entries vs order of addition to the parallel ZIP creator
                assertEquals("file" + i++, zipArchiveEntry.getName(), "For " + zipArchiveEntry.getName());
            }
        }
    }

    @Test
    @Disabled("[COMPRESS-639]")
    public void sameZipArchiveEntryNullPointerException() throws IOException, ExecutionException, InterruptedException {
        final ByteArrayOutputStream testOutputStream = new ByteArrayOutputStream();

        final String fileContent = "A";
        final int NUM_OF_FILES = 100;
        final LinkedList<InputStream> inputStreams = new LinkedList<>();
        for (int i = 0; i < NUM_OF_FILES; i++) {
            inputStreams.add(new ByteArrayInputStream(fileContent.getBytes(StandardCharsets.UTF_8)));
        }

        final ParallelScatterZipCreator zipCreator = new ParallelScatterZipCreator();
        try (ZipArchiveOutputStream zipArchiveOutputStream = new ZipArchiveOutputStream(testOutputStream)) {
            zipArchiveOutputStream.setUseZip64(Zip64Mode.Always);

            for (final InputStream inputStream : inputStreams) {
                final ZipArchiveEntry zipArchiveEntry = new ZipArchiveEntry("./dir/myfile.txt");
                zipArchiveEntry.setMethod(ZipEntry.DEFLATED);
                zipCreator.addArchiveEntry(zipArchiveEntry, () -> inputStream);
            }

            zipCreator.writeTo(zipArchiveOutputStream);
        } // Throws NullPointerException on close()
    }

    @Test
    public void testCallableApiUsingSubmit() throws Exception {
        final File result = createTempFile("parallelScatterGather2", "");
        callableApi(zipCreator -> zipCreator::submit, result);
    }

    @Test
    public void testCallableApiUsingSubmitStreamAwareCallable() throws Exception {
        final File result = createTempFile("parallelScatterGather3", "");
        callableApi(zipCreator -> zipCreator::submitStreamAwareCallable, result);
    }

    @Test
    public void testCallableApiWithHighestLevelUsingSubmitStreamAwareCallable() throws Exception {
        final File result = createTempFile("parallelScatterGather5", "");
        callableApiWithTestFiles(zipCreator -> zipCreator::submitStreamAwareCallable, Deflater.BEST_COMPRESSION, result);
    }

    @Test
    public void testCallableWithLowestLevelApiUsingSubmit() throws Exception {
        final File result = createTempFile("parallelScatterGather4", "");
        callableApiWithTestFiles(zipCreator -> zipCreator::submit, Deflater.NO_COMPRESSION, result);
    }

    @Test
    public void testConcurrentCustomTempFolder() throws Exception {
        final File result = createTempFile("parallelScatterGather1", "");
        final ParallelScatterZipCreator zipCreator;
        final Map<String, byte[]> entries;
        try (ZipArchiveOutputStream zos = new ZipArchiveOutputStream(result)) {
            zos.setEncoding(StandardCharsets.UTF_8.name());

            // Formatter:off
            final Path dir = Paths.get("target/custom-temp-dir");
            Files.createDirectories(dir);
            zipCreator = new ParallelScatterZipCreator(Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors()),
                    new DefaultBackingStoreSupplier(dir));
            // Formatter:on

            entries = writeEntries(zipCreator);
            zipCreator.writeTo(zos);
        }
        removeEntriesFoundInZipFile(result, entries);
        assertTrue(entries.isEmpty());
        assertNotNull(zipCreator.getStatisticsMessage());
    }

    @Test
    public void testConcurrentDefaultTempFolder() throws Exception {
        final File result = createTempFile("parallelScatterGather1", "");
        final ParallelScatterZipCreator zipCreator;
        final Map<String, byte[]> entries;
        try (ZipArchiveOutputStream zos = new ZipArchiveOutputStream(result)) {
            zos.setEncoding(StandardCharsets.UTF_8.name());
            zipCreator = new ParallelScatterZipCreator();

            entries = writeEntries(zipCreator);
            zipCreator.writeTo(zos);
        }
        removeEntriesFoundInZipFile(result, entries);
        assertTrue(entries.isEmpty());
        assertNotNull(zipCreator.getStatisticsMessage());
    }

    @Test
    public void testThrowsExceptionWithCompressionLevelTooBig() {
        final int compressLevelTooBig = Deflater.BEST_COMPRESSION + 1;
        final ExecutorService es = Executors.newFixedThreadPool(1);
        assertThrows(IllegalArgumentException.class, () -> new ParallelScatterZipCreator(es,
                () -> new FileBasedScatterGatherBackingStore(createTempFile("parallelscatter", "n1")), compressLevelTooBig));
        es.shutdownNow();
    }

    @Test
    public void testThrowsExceptionWithCompressionLevelTooSmall() {
        final int compressLevelTooSmall = Deflater.DEFAULT_COMPRESSION - 1;
        final ExecutorService es = Executors.newFixedThreadPool(1);
        assertThrows(IllegalArgumentException.class, () -> new ParallelScatterZipCreator(es,
                () -> new FileBasedScatterGatherBackingStore(createTempFile("parallelscatter", "n1")), compressLevelTooSmall));
        es.shutdownNow();
    }

    private Map<String, byte[]> writeEntries(final ParallelScatterZipCreator zipCreator) {
        final Map<String, byte[]> entries = new HashMap<>();
        for (int i = 0; i < NUMITEMS; i++) {
            final byte[] payloadBytes = ("content" + i).getBytes();
            final ZipArchiveEntry za = createZipArchiveEntry(entries, i, payloadBytes);
            final InputStreamSupplier iss = () -> new ByteArrayInputStream(payloadBytes);
            if (i % 2 == 0) {
                zipCreator.addArchiveEntry(za, iss);
            } else {
                final ZipArchiveEntryRequestSupplier zaSupplier = () -> ZipArchiveEntryRequest.createZipArchiveEntryRequest(za, iss);
                zipCreator.addArchiveEntry(zaSupplier);
            }
        }
        return entries;
    }

    private Map<String, byte[]> writeEntriesAsCallable(final ParallelScatterZipCreator zipCreator, final CallableConsumer consumer) {
        final Map<String, byte[]> entries = new HashMap<>();
        for (int i = 0; i < NUMITEMS; i++) {
            final byte[] payloadBytes = ("content" + i).getBytes();
            final ZipArchiveEntry za = createZipArchiveEntry(entries, i, payloadBytes);
            final InputStreamSupplier iss = () -> new ByteArrayInputStream(payloadBytes);
            final Callable<ScatterZipOutputStream> callable;
            if (i % 2 == 0) {
                callable = zipCreator.createCallable(za, iss);
            } else {
                final ZipArchiveEntryRequestSupplier zaSupplier = () -> ZipArchiveEntryRequest.createZipArchiveEntryRequest(za, iss);
                callable = zipCreator.createCallable(zaSupplier);
            }

            consumer.accept(callable);
        }
        return entries;
    }

    /**
     * Try to compress the files in src/test/resources with size no bigger than {@value #EXPECTED_FILES_NUMBER} and with a mount of files no bigger than
     * {@value #EXPECTED_FILES_NUMBER}
     *
     * @param zipCreator The ParallelScatterZipCreator
     * @param consumer   The parallel consumer
     * @return A map using file name as key and file content as value
     * @throws IOException if exceptions occur when opening files
     */
    private Map<String, byte[]> writeTestFilesAsCallable(final ParallelScatterZipCreator zipCreator, final CallableConsumer consumer) throws IOException {
        final Map<String, byte[]> entries = new HashMap<>();
        final File baseDir = AbstractTest.getFile("");
        int filesCount = 0;
        for (final File file : baseDir.listFiles()) {
            // do not compress too many files
            if (filesCount >= EXPECTED_FILES_NUMBER) {
                break;
            }

            // skip files that are too large
            if (file.isDirectory() || file.length() > EXPECTED_FILE_SIZE) {
                continue;
            }

            entries.put(file.getName(), Files.readAllBytes(file.toPath()));

            final ZipArchiveEntry zipArchiveEntry = new ZipArchiveEntry(file.getName());
            zipArchiveEntry.setMethod(ZipEntry.DEFLATED);
            zipArchiveEntry.setSize(file.length());
            zipArchiveEntry.setUnixMode(UnixStat.FILE_FLAG | 0664);

            final InputStreamSupplier iss = () -> {
                try {
                    return Files.newInputStream(file.toPath());
                } catch (final IOException e) {
                    return null;
                }
            };

            final Callable<ScatterZipOutputStream> callable;
            if (filesCount % 2 == 0) {
                callable = zipCreator.createCallable(zipArchiveEntry, iss);
            } else {
                final ZipArchiveEntryRequestSupplier zaSupplier = () -> ZipArchiveEntryRequest.createZipArchiveEntryRequest(zipArchiveEntry, iss);
                callable = zipCreator.createCallable(zaSupplier);
            }

            consumer.accept(callable);
            filesCount++;
        }
        return entries;
    }
}
