/*
 * 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
 *
 *   https://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.accumulo.test.functional;

import static java.nio.charset.StandardCharsets.UTF_8;
import static org.apache.accumulo.core.util.UtilWaitThread.sleepUninterruptibly;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotEquals;
import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertNull;
import static org.junit.jupiter.api.Assertions.assertTrue;
import static org.junit.jupiter.api.Assertions.fail;

import java.io.UncheckedIOException;
import java.time.Duration;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map.Entry;
import java.util.concurrent.TimeUnit;
import java.util.stream.Collectors;
import java.util.stream.Stream;

import org.apache.accumulo.core.Constants;
import org.apache.accumulo.core.client.Accumulo;
import org.apache.accumulo.core.client.AccumuloClient;
import org.apache.accumulo.core.client.BatchWriter;
import org.apache.accumulo.core.client.Scanner;
import org.apache.accumulo.core.conf.Property;
import org.apache.accumulo.core.data.Key;
import org.apache.accumulo.core.data.Mutation;
import org.apache.accumulo.core.data.TableId;
import org.apache.accumulo.core.data.Value;
import org.apache.accumulo.core.fate.zookeeper.ServiceLock;
import org.apache.accumulo.core.fate.zookeeper.ZooReaderWriter;
import org.apache.accumulo.core.fate.zookeeper.ZooUtil;
import org.apache.accumulo.core.gc.GcCandidate;
import org.apache.accumulo.core.gc.ReferenceFile;
import org.apache.accumulo.core.metadata.MetadataTable;
import org.apache.accumulo.core.metadata.StoredTabletFile;
import org.apache.accumulo.core.metadata.schema.Ample;
import org.apache.accumulo.core.metadata.schema.Ample.DataLevel;
import org.apache.accumulo.core.metadata.schema.MetadataSchema.DeletesSection;
import org.apache.accumulo.core.metadata.schema.MetadataSchema.DeletesSection.SkewedKeyValue;
import org.apache.accumulo.core.security.Authorizations;
import org.apache.accumulo.core.security.TablePermission;
import org.apache.accumulo.core.util.ServerServices;
import org.apache.accumulo.core.util.ServerServices.Service;
import org.apache.accumulo.gc.SimpleGarbageCollector;
import org.apache.accumulo.minicluster.MemoryUnit;
import org.apache.accumulo.minicluster.ServerType;
import org.apache.accumulo.miniclusterImpl.MiniAccumuloClusterImpl.ProcessInfo;
import org.apache.accumulo.miniclusterImpl.MiniAccumuloConfigImpl;
import org.apache.accumulo.miniclusterImpl.ProcessNotFoundException;
import org.apache.accumulo.miniclusterImpl.ProcessReference;
import org.apache.accumulo.server.ServerOpts;
import org.apache.accumulo.test.TestIngest;
import org.apache.accumulo.test.VerifyIngest;
import org.apache.accumulo.test.VerifyIngest.VerifyParams;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.RawLocalFileSystem;
import org.apache.hadoop.io.Text;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.KeeperException.NoNodeException;
import org.junit.jupiter.api.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.collect.Iterators;

public class GarbageCollectorIT extends ConfigurableMacBase {
  private static final String OUR_SECRET = "itsreallysecret";
  public static final Logger log = LoggerFactory.getLogger(GarbageCollectorIT.class);

  @Override
  protected Duration defaultTimeout() {
    return Duration.ofMinutes(5);
  }

  @Override
  public void configure(MiniAccumuloConfigImpl cfg, Configuration hadoopCoreSite) {
    cfg.setProperty(Property.INSTANCE_ZK_TIMEOUT, "15s");
    cfg.setProperty(Property.INSTANCE_SECRET, OUR_SECRET);
    cfg.setProperty(Property.GC_CYCLE_START, "1");
    cfg.setProperty(Property.GC_CYCLE_DELAY, "1");
    cfg.setProperty(Property.GC_PORT, "0");
    cfg.setProperty(Property.TSERV_MAXMEM, "5K");
    cfg.setProperty(Property.TSERV_MAJC_DELAY, "1");
    // reduce the batch size significantly in order to cause the integration tests to have
    // to process many batches of deletion candidates.
    cfg.setProperty(Property.GC_CANDIDATE_BATCH_SIZE, "256K");

    // use raw local file system so walogs sync and flush will work
    hadoopCoreSite.set("fs.file.impl", RawLocalFileSystem.class.getName());
  }

  private void killMacGc() throws ProcessNotFoundException, InterruptedException, KeeperException {
    // kill gc started by MAC
    getCluster().killProcess(ServerType.GARBAGE_COLLECTOR,
        getCluster().getProcesses().get(ServerType.GARBAGE_COLLECTOR).iterator().next());
    // delete lock in zookeeper if there, this will allow next GC to start quickly
    String path = getServerContext().getZooKeeperRoot() + Constants.ZGC_LOCK;
    ZooReaderWriter zk = getServerContext().getZooReaderWriter();
    try {
      ServiceLock.deleteLock(zk, path, Service.GC_CLIENT, hostAndPort -> true, log::debug, false);
    } catch (IllegalStateException e) {
      log.error("Unable to delete ZooLock for mini accumulo-gc", e);
    }

    assertNull(getCluster().getProcesses().get(ServerType.GARBAGE_COLLECTOR));
  }

  @Test
  public void gcTest() throws Exception {
    killMacGc();
    final String table = "test_ingest";
    try (AccumuloClient c = Accumulo.newClient().from(getClientProperties()).build()) {
      c.tableOperations().create(table);
      c.tableOperations().setProperty(table, Property.TABLE_SPLIT_THRESHOLD.getKey(), "5K");
      VerifyParams params = new VerifyParams(getClientProperties(), table, 10_000);
      params.cols = 1;
      log.info("Ingesting files to {}", table);
      TestIngest.ingest(c, cluster.getFileSystem(), params);
      log.info("Compacting the table {}", table);
      c.tableOperations().compact(table, null, null, true, true);
      String pathString = cluster.getConfig().getDir() + "/accumulo/tables/1/*/*.rf";
      log.info("Counting files in path: {}", pathString);

      int before = countFiles(pathString);
      log.info("Counted {} files in path: {}", before, pathString);

      while (true) {
        sleepUninterruptibly(1, TimeUnit.SECONDS);
        int more = countFiles(pathString);
        if (more <= before) {
          break;
        }
        before = more;
      }

      // restart GC
      log.info("Restarting GC...");
      getCluster().start();
      sleepUninterruptibly(15, TimeUnit.SECONDS);
      log.info("Again Counting files in path: {}", pathString);

      int after = countFiles(pathString);
      log.info("Counted {} files in path: {}", after, pathString);

      VerifyIngest.verifyIngest(c, params);
      assertTrue(after < before, "After count " + after + " was not less than " + before);
    }
  }

  @Test
  public void gcLotsOfCandidatesIT() throws Exception {
    killMacGc();

    log.info("Filling metadata table with bogus delete flags");
    try (AccumuloClient c = Accumulo.newClient().from(getClientProperties()).build()) {
      addEntries(c);
      cluster.getConfig().setDefaultMemory(32, MemoryUnit.MEGABYTE);
      ProcessInfo gc = cluster.exec(SimpleGarbageCollector.class);
      sleepUninterruptibly(20, TimeUnit.SECONDS);
      String output = "";
      while (!output.contains("has exceeded the threshold")) {
        try {
          output = gc.readStdOut();
        } catch (UncheckedIOException ex) {
          log.error("IO error reading the IT's accumulo-gc STDOUT", ex);
          break;
        }
      }
      gc.getProcess().destroy();
      assertTrue(output.contains("has exceeded the threshold"));
    }
  }

  @Test
  public void dontGCRootLog() throws Exception {
    killMacGc();
    // dirty metadata
    try (AccumuloClient c = Accumulo.newClient().from(getClientProperties()).build()) {
      String table = getUniqueNames(1)[0];
      c.tableOperations().create(table);
      // let gc run for a bit
      cluster.start();
      sleepUninterruptibly(20, TimeUnit.SECONDS);
      killMacGc();
      // kill tservers
      for (ProcessReference ref : cluster.getProcesses().get(ServerType.TABLET_SERVER)) {
        cluster.killProcess(ServerType.TABLET_SERVER, ref);
      }
      // run recovery
      cluster.start();
      // did it recover?
      try (Scanner scanner = c.createScanner(MetadataTable.NAME, Authorizations.EMPTY)) {
        scanner.forEach((k, v) -> {});
      }
    }
  }

  private Mutation createDelMutation(String path, String cf, String cq, String val) {
    Text row = new Text(DeletesSection.encodeRow(path));
    Mutation delFlag = new Mutation(row);
    delFlag.put(cf, cq, val);
    return delFlag;
  }

  @Test
  public void testInvalidDelete() throws Exception {
    killMacGc();
    try (AccumuloClient c = Accumulo.newClient().from(getClientProperties()).build()) {
      String table = getUniqueNames(1)[0];
      c.tableOperations().create(table);

      try (BatchWriter bw = c.createBatchWriter(table)) {
        Mutation m1 = new Mutation("r1");
        m1.put("cf1", "cq1", "v1");
        bw.addMutation(m1);
      }

      c.tableOperations().flush(table, null, null, true);

      // ensure an invalid delete entry does not cause GC to go berserk ACCUMULO-2520
      c.securityOperations().grantTablePermission(c.whoami(), MetadataTable.NAME,
          TablePermission.WRITE);
      try (BatchWriter bw = c.createBatchWriter(MetadataTable.NAME)) {
        bw.addMutation(createDelMutation("", "", "", ""));
        bw.addMutation(createDelMutation("", "testDel", "test", "valueTest"));
        // path is invalid but value is expected - only way the invalid entry will come through
        // processing and
        // show up to produce error in output to allow while loop to end
        bw.addMutation(createDelMutation("/", "", "", SkewedKeyValue.STR_NAME));
      }

      ProcessInfo gc = cluster.exec(SimpleGarbageCollector.class);
      try {
        String output = "";
        while (!output.contains("Ignoring invalid deletion candidate")) {
          sleepUninterruptibly(250, TimeUnit.MILLISECONDS);
          try {
            output = gc.readStdOut();
          } catch (UncheckedIOException ioe) {
            log.error("Could not read all from cluster.", ioe);
          }
        }
      } finally {
        gc.getProcess().destroy();
      }

      try (Scanner scanner = c.createScanner(table, Authorizations.EMPTY)) {
        Entry<Key,Value> entry = getOnlyElement(scanner);
        assertEquals("r1", entry.getKey().getRow().toString());
        assertEquals("cf1", entry.getKey().getColumnFamily().toString());
        assertEquals("cq1", entry.getKey().getColumnQualifier().toString());
        assertEquals("v1", entry.getValue().toString());
      }
    }
  }

  @Test
  public void testUserUniqueMutationDelete() throws Exception {
    killMacGc();
    try (AccumuloClient c = Accumulo.newClient().from(getClientProperties()).build()) {
      String table = getUniqueNames(1)[0];
      c.tableOperations().create(table);
      log.info("User GcCandidate Deletion test of table: {}", table);
      log.info("GcCandidates will be added/removed from table: {}", DataLevel.USER.metaTable());
      createAndDeleteUniqueMutation(TableId.of(table), Ample.GcCandidateType.INUSE);
      createAndDeleteUniqueMutation(TableId.of(table), Ample.GcCandidateType.VALID);
    }
  }

  @Test
  public void testMetadataUniqueMutationDelete() throws Exception {
    killMacGc();
    TableId tableId = DataLevel.USER.metaTableId();
    log.info("Metadata GcCandidate Deletion test");
    log.info("GcCandidates will be added/removed from table: {}", DataLevel.METADATA.metaTable());
    createAndDeleteUniqueMutation(tableId, Ample.GcCandidateType.INUSE);
    createAndDeleteUniqueMutation(tableId, Ample.GcCandidateType.VALID);
  }

  /**
   * Root INUSE deletions are not supported in 2.1.x. This test can be migrated to use
   * createAndDeleteUniqueMutation in 3.x
   *
   * @throws Exception may occur when killing the GC process.
   */
  @Test
  public void testRootUniqueMutationDelete() throws Exception {
    killMacGc();
    TableId tableId = DataLevel.METADATA.metaTableId();
    log.info("Root GcCandidate Deletion test");
    log.info("GcCandidates will be added but not removed from Zookeeper");

    Ample ample = cluster.getServerContext().getAmple();
    DataLevel datalevel = DataLevel.ROOT;

    // Ensure that no other candidates exist before starting test.
    Iterator<GcCandidate> cIter = ample.getGcCandidates(datalevel);

    ArrayList<GcCandidate> tempCandidates = new ArrayList<>();
    while (cIter.hasNext()) {
      GcCandidate cTemp = cIter.next();
      tempCandidates.add(cTemp);
    }
    if (tempCandidates.size() != 0) {
      ample.deleteGcCandidates(datalevel, tempCandidates, Ample.GcCandidateType.VALID);
      tempCandidates.clear();

      cIter = ample.getGcCandidates(datalevel);
      while (cIter.hasNext()) {
        GcCandidate cTemp = cIter.next();
        log.debug("PreExisting Candidate Found: {}", cTemp);
        tempCandidates.add(cTemp);
      }
      assertEquals(0, tempCandidates.size());
    }

    // Create multiple candidate entries
    List<GcCandidate> candidates =
        List.of(new GcCandidate("hdfs://foo.com:6000/user/foo/tables/+r/t-0/F00.rf", 0L),
            new GcCandidate("hdfs://foo.com:6000/user/foo/tables/+r/t-0/F001.rf", 1L));

    List<StoredTabletFile> stfs = new LinkedList<>();
    candidates.stream().forEach(temp -> stfs.add(new StoredTabletFile(temp.getPath())));

    log.debug("Adding root table GcCandidates");
    ample.putGcCandidates(tableId, stfs);

    // Retrieve the recently created entries.
    cIter = ample.getGcCandidates(datalevel);

    int counter = 0;
    while (cIter.hasNext()) {
      // Duplicate these entries back into zookeeper
      ample.putGcCandidates(tableId, List.of(new StoredTabletFile(cIter.next().getPath())));
      counter++;
    }
    // Ensure Zookeeper collapsed the entries and did not support duplicates.
    assertEquals(2, counter);

    cIter = ample.getGcCandidates(datalevel);
    while (cIter.hasNext()) {
      // This should be a noop call. Root inUse candidate deletions are not supported.
      ample.deleteGcCandidates(datalevel, List.of(cIter.next()), Ample.GcCandidateType.INUSE);
    }

    // Check that GcCandidates still exist
    cIter = ample.getGcCandidates(datalevel);

    counter = candidates.size();
    while (cIter.hasNext()) {
      GcCandidate gcC = cIter.next();
      log.debug("Candidate Found: {}", gcC);
      for (GcCandidate cand : candidates) {
        if (gcC.getPath().equals(cand.getPath())) {
          // Candidate uid's will never match as they are randomly generated in 2.1.x
          assertNotEquals(gcC.getUid(), cand.getUid());
          counter--;
        }
      }
    }
    // Ensure that we haven't seen more candidates than we expected.
    assertEquals(0, counter);

    // Delete the candidates as VALID GcCandidates
    cIter = ample.getGcCandidates(datalevel);
    while (cIter.hasNext()) {
      ample.deleteGcCandidates(datalevel, List.of(cIter.next()), Ample.GcCandidateType.VALID);
    }
    // Ensure the GcCandidates have been removed.
    cIter = ample.getGcCandidates(datalevel);

    counter = 0;
    while (cIter.hasNext()) {
      GcCandidate gcC = cIter.next();
      if (gcC != null) {
        log.error("Candidate Found: {}", gcC);
        counter++;
      }
    }
    assertEquals(0, counter);
  }

  @Test
  public void testProperPortAdvertisement() throws Exception {

    try (AccumuloClient client = Accumulo.newClient().from(getClientProperties()).build()) {

      ZooReaderWriter zk = cluster.getServerContext().getZooReaderWriter();
      var path = ServiceLock
          .path(ZooUtil.getRoot(client.instanceOperations().getInstanceId()) + Constants.ZGC_LOCK);
      for (int i = 0; i < 5; i++) {
        List<String> locks;
        try {
          locks = ServiceLock.validateAndSort(path, zk.getChildren(path.toString()));
        } catch (NoNodeException e) {
          Thread.sleep(5000);
          continue;
        }

        if (locks != null && !locks.isEmpty()) {
          String lockPath = path + "/" + locks.get(0);

          String gcLoc = new String(zk.getData(lockPath), UTF_8);

          assertTrue(gcLoc.startsWith(Service.GC_CLIENT.name()),
              "Found unexpected data in zookeeper for GC location: " + gcLoc);
          int loc = gcLoc.indexOf(ServerServices.SEPARATOR_CHAR);
          assertNotEquals(-1, loc, "Could not find split point of GC location for: " + gcLoc);
          String addr = gcLoc.substring(loc + 1);

          int addrSplit = addr.indexOf(':');
          assertNotEquals(-1, addrSplit, "Could not find split of GC host:port for: " + addr);

          String host = addr.substring(0, addrSplit), port = addr.substring(addrSplit + 1);
          // We shouldn't have the "bindall" address in zk
          assertNotEquals(ServerOpts.BIND_ALL_ADDRESSES, host);
          // Nor should we have the "random port" in zk
          assertNotEquals(0, Integer.parseInt(port));
          return;
        }

        Thread.sleep(5000);
      }

      fail("Could not find advertised GC address");
    }
  }

  private int countFiles(String pathStr) throws Exception {
    Path path = new Path(pathStr);
    return Iterators.size(Arrays.asList(cluster.getFileSystem().globStatus(path)).iterator());
  }

  private void addEntries(AccumuloClient client) throws Exception {
    Ample ample = getServerContext().getAmple();
    client.securityOperations().grantTablePermission(client.whoami(), MetadataTable.NAME,
        TablePermission.WRITE);
    try (BatchWriter bw = client.createBatchWriter(MetadataTable.NAME)) {
      for (int i = 0; i < 100000; ++i) {
        String longpath = "aaaaaaaaaabbbbbbbbbbccccccccccddddddddddeeeeeeeeee"
            + "ffffffffffgggggggggghhhhhhhhhhiiiiiiiiiijjjjjjjjjj";
        var path = String.format("file:/%020d/%s", i, longpath);
        Mutation delFlag = ample.createDeleteMutation(ReferenceFile.forFile(TableId.of("1"), path));
        bw.addMutation(delFlag);
      }
    }
  }

  private void createAndDeleteUniqueMutation(TableId tableId, Ample.GcCandidateType type) {
    int totalCandidates = 2;
    boolean inUseDelete = true;

    if (type == Ample.GcCandidateType.VALID) {
      totalCandidates = 1;
      inUseDelete = false;
    }
    Ample ample = cluster.getServerContext().getAmple();
    DataLevel datalevel = Ample.DataLevel.of(tableId);

    // Ensure that no other candidates exist before starting test.
    List<GcCandidate> candidates = new ArrayList<>();
    Iterator<GcCandidate> candidate = ample.getGcCandidates(datalevel);

    while (candidate.hasNext()) {
      GcCandidate cTemp = candidate.next();
      log.debug("PreExisting Candidate Found: {}", cTemp);
      candidates.add(cTemp);
    }
    assertEquals(0, candidates.size());

    // Create multiple candidate entries
    List<StoredTabletFile> stfs = Stream
        .of(new StoredTabletFile("hdfs://foo.com:6000/user/foo/tables/a/t-0/F00.rf"),
            new StoredTabletFile("hdfs://foo.com:6000/user/foo/tables/b/t-0/F00.rf"))
        .collect(Collectors.toList());

    log.debug("Adding candidates to table {}", tableId);
    ample.putGcCandidates(tableId, stfs);
    // Retrieve new entries.
    candidate = ample.getGcCandidates(datalevel);

    while (candidate.hasNext()) {
      GcCandidate cTemp = candidate.next();
      log.debug("Candidate Found: {}", cTemp);
      candidates.add(cTemp);
    }
    assertEquals(2, candidates.size());

    GcCandidate deleteCandidate = candidates.get(0);
    assertNotNull(deleteCandidate);
    ample.putGcCandidates(tableId, List.of(new StoredTabletFile(deleteCandidate.getPath())));

    log.debug("Deleting Candidate {}", deleteCandidate);
    ample.deleteGcCandidates(datalevel, List.of(deleteCandidate), type);

    candidate = ample.getGcCandidates(datalevel);

    int counter = 0;
    boolean foundNewCandidate = false;
    while (candidate.hasNext()) {
      GcCandidate gcC = candidate.next();
      log.debug("Candidate Found: {}", gcC);
      if (gcC.getPath().equals(deleteCandidate.getPath())) {
        assertNotEquals(gcC.getUid(), deleteCandidate.getUid());
        foundNewCandidate = true;
      }
      counter++;
    }
    assertEquals(totalCandidates, counter);
    assertEquals(inUseDelete, foundNewCandidate);

    // Cleanup from test
    ample.deleteGcCandidates(datalevel, candidates, Ample.GcCandidateType.VALID);
  }
}
