/*
 * Copyright 2017 HugeGraph Authors
 *
 * 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 com.baidu.hugegraph.computer.core.store;

import java.io.File;
import java.io.IOException;
import java.util.List;
import java.util.NoSuchElementException;

import org.apache.commons.io.FileUtils;
import org.junit.After;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;

import com.baidu.hugegraph.computer.core.config.ComputerOptions;
import com.baidu.hugegraph.computer.core.config.Config;
import com.baidu.hugegraph.computer.core.store.entry.KvEntry;
import com.baidu.hugegraph.computer.core.store.file.hgkvfile.HgkvFile;
import com.baidu.hugegraph.computer.core.store.file.hgkvfile.HgkvFileImpl;
import com.baidu.hugegraph.computer.core.store.file.hgkvfile.builder.HgkvFileBuilder;
import com.baidu.hugegraph.computer.core.store.file.hgkvfile.builder.HgkvFileBuilderImpl;
import com.baidu.hugegraph.computer.core.store.file.hgkvfile.reader.HgkvFileReaderImpl;
import com.baidu.hugegraph.computer.suite.unit.UnitTestBase;
import com.baidu.hugegraph.testutil.Assert;
import com.google.common.collect.ImmutableList;

public class HgkvFileTest {

    private static Config CONFIG;

    @BeforeClass
    public static void init() {
        CONFIG = UnitTestBase.updateWithRequiredOptions(
                ComputerOptions.HGKV_MAX_FILE_SIZE, "32",
                ComputerOptions.HGKV_DATABLOCK_SIZE, "16"
        );
    }

    @Before
    public void setup() throws IOException {
        FileUtils.deleteDirectory(new File(StoreTestUtil.FILE_DIR));
    }

    @After
    public void teardown() throws IOException {
        FileUtils.deleteDirectory(new File(StoreTestUtil.FILE_DIR));
    }

    @Test
    public void testHgkvFileBuilder() throws IOException {
        // The data must be ordered
        List<Integer> data = testData();
        String filePath = StoreTestUtil.availablePathById("1");
        StoreTestUtil.mapToHgkvFile(CONFIG, data, filePath);
    }

    @Test
    public void testOpenFile() throws IOException {
        // The keys in the data must be ordered
        List<Integer> data = testData();
        String filePath = StoreTestUtil.availablePathById("1");
        File file = StoreTestUtil.mapToHgkvFile(CONFIG, data, filePath);
        // Open file
        HgkvFile hgkvFile = HgkvFileImpl.open(file.getPath());
        // Assert magic
        Assert.assertEquals(HgkvFileImpl.MAGIC, hgkvFile.magic());
        // Assert version
        String version = HgkvFileImpl.MAJOR_VERSION + "." +
                         HgkvFileImpl.MINOR_VERSION;
        Assert.assertEquals(version, hgkvFile.version());
        // Assert numEntries
        Assert.assertEquals(5, hgkvFile.numEntries());
        // Assert max key
        int maxKey = StoreTestUtil.byteArrayToInt(hgkvFile.max());
        Assert.assertEquals(6, maxKey);
        // Assert min key
        int minKey = StoreTestUtil.byteArrayToInt(hgkvFile.min());
        Assert.assertEquals(2, minKey);
    }

    @Test
    public void testExceptionCase() throws IOException {
        // Exception to add key/value
        String filePath = StoreTestUtil.availablePathById("1");
        try (HgkvFileBuilder builder = new HgkvFileBuilderImpl(CONFIG,
                                                               filePath)) {
            Assert.assertThrows(IllegalArgumentException.class, () -> {
                builder.add(null);
            }, e -> {
                Assert.assertContains("Parameter entry can't be null",
                                      e.getMessage());
            });
            builder.finish();
            Assert.assertThrows(IllegalStateException.class, () -> {
                builder.add(null);
            }, e -> {
                Assert.assertContains("builder is finished",
                                      e.getMessage());
            });
        }

        // Open not exists file.
        File tempFile = new File(StoreTestUtil.availablePathById("2"));
        Assert.assertThrows(IllegalArgumentException.class, () -> {
            HgkvFileImpl.open(tempFile);
        }, e -> {
            Assert.assertContains("file does not exists", e.getMessage());
        });
    }

    @Test
    public void testHgkvFileReader() throws Exception {
        // The keys in the data must be ordered
        List<Integer> data = testData();
        String filePath = StoreTestUtil.availablePathById("1");
        File file = StoreTestUtil.mapToHgkvFile(CONFIG, data, filePath);

        KvEntryFileReader reader = new HgkvFileReaderImpl(file.getPath(),
                                                          false);
        try (EntryIterator iterator = reader.iterator()) {
            int index = 0;
            while (iterator.hasNext()) {
                KvEntry next = iterator.next();
                int key = StoreTestUtil.byteArrayToInt(next.key().bytes());
                Assert.assertEquals(data.get(index).intValue(), key);
                index += 2;
            }
            Assert.assertThrows(NoSuchElementException.class, iterator::next);
        }
    }

    private static List<Integer> testData() {
        return ImmutableList.of(2, 3,
                                2, 1,
                                5, 2,
                                5, 9,
                                6, 2);
    }
}