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   * Licensed to the Apache Software Foundation (ASF) under one
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   * distributed with this work for additional information
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   * 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.
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  package org.apache.cassandra.distributed.test;
  
  import java.io.IOException;
  import java.nio.ByteBuffer;
  import java.util.HashSet;
  import java.util.Set;
  
  import com.google.common.collect.Sets;
  import org.junit.Test;
  
  import org.apache.cassandra.Util;
  import org.apache.cassandra.db.ColumnFamilyStore;
  import org.apache.cassandra.db.Keyspace;
  import org.apache.cassandra.dht.Bounds;
  import org.apache.cassandra.dht.Murmur3Partitioner;
  import org.apache.cassandra.dht.Token;
  import org.apache.cassandra.distributed.Cluster;
  import org.apache.cassandra.distributed.api.ConsistencyLevel;
  import org.apache.cassandra.distributed.api.IIsolatedExecutor;
  import org.apache.cassandra.io.sstable.format.SSTableReader;
  import org.apache.cassandra.service.snapshot.TableSnapshot;
  import org.apache.cassandra.utils.concurrent.Refs;
  
  import static java.util.concurrent.TimeUnit.MILLISECONDS;
  import static java.util.concurrent.TimeUnit.MINUTES;
  import static org.apache.cassandra.distributed.api.Feature.GOSSIP;
  import static org.apache.cassandra.distributed.api.Feature.NETWORK;
  import static org.awaitility.Awaitility.await;
  import static org.hamcrest.Matchers.emptyString;
  import static org.hamcrest.Matchers.not;
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertFalse;
  
  public class PreviewRepairSnapshotTest extends TestBaseImpl
  {
      /**
       * Makes sure we only snapshot sstables containing the mismatching token
       * <p>
       * 1. create 100 sstables per instance, compaction disabled, one token per sstable
       * 2. make 3 tokens mismatching on node2, one token per sstable
       * 3. run preview repair
       * 4. make sure that only the sstables containing the token are in the snapshot
       */
      @Test
      public void testSnapshotOfSStablesContainingMismatchingTokens() throws IOException
      {
          try (Cluster cluster = init(Cluster.build(2).withConfig(config ->
                                                                  config.set("snapshot_on_repaired_data_mismatch", true)
                                                                        .with(GOSSIP)
                                                                        .with(NETWORK)).start()))
          {
              Set<Integer> tokensToMismatch = Sets.newHashSet(1, 50, 99);
              cluster.schemaChange(withKeyspace("create table %s.tbl (id blob primary key) with compaction = {'class' : 'SizeTieredCompactionStrategy', 'enabled':false }"));
              // 1 token per sstable;
              for (int i = 0; i < 100; i++)
              {
                  // BigFormat severely overestimates the number of partitions per range when the sstable size is small.
                  // Do multiple writes per sstable, with the same token, to compensate.
                  for (int j = 0; j < 10; ++j)
                      cluster.coordinator(1).execute(withKeyspace("insert into %s.tbl (id) values (?)"), ConsistencyLevel.ALL, matchingHashBlob(i, j));
                  cluster.stream().forEach(instance -> instance.flush(KEYSPACE));
              }
              cluster.stream().forEach(instance -> instance.flush(KEYSPACE));
              for (int i = 1; i <= 2; i++)
                  markRepaired(cluster, i);
  
              cluster.get(1)
                     .nodetoolResult("repair", "-vd", "-pr", KEYSPACE, "tbl")
                     .asserts()
                     .success()
                     .stdoutContains("Repaired data is in sync");
  
              Set<Token> mismatchingTokens = new HashSet<>();
              for (Integer token : tokensToMismatch)
              {
                  final ByteBuffer b = matchingHashBlob(token, 0);
                  cluster.get(2).executeInternal(withKeyspace("insert into %s.tbl (id) values (?)"), b);
                  cluster.get(2).flush(KEYSPACE);
                  Object[][] res = cluster.get(2).executeInternal(withKeyspace("select token(id) from %s.tbl where id = ?"), b);
                  mismatchingTokens.add(new Murmur3Partitioner.LongToken((long) res[0][0]));
              }
  
              markRepaired(cluster, 2);
  
              cluster.get(1)
                     .nodetoolResult("repair", "-vd", KEYSPACE, "tbl")
                     .asserts()
                     .success()
                     .stdoutContains("Repaired data is inconsistent");
  
              cluster.get(1).runOnInstance(checkSnapshot(mismatchingTokens, 3));
              // node2 got the duplicate mismatch-tokens above, so it should exist in exactly 6 sstables
              cluster.get(2).runOnInstance(checkSnapshot(mismatchingTokens, 6));
          }
      }
  
      private ByteBuffer matchingHashBlob(int hashAffectingComponent, int hashUnaffectingComponent)
      {
          // Generate blobs with mathing hash for the same i, but different for the different j
          ByteBuffer base = ByteBuffer.wrap(Integer.toHexString(hashAffectingComponent).getBytes());
          return Util.generateMurmurCollision(base, Integer.toHexString(hashUnaffectingComponent).getBytes());
      }
  
      private IIsolatedExecutor.SerializableRunnable checkSnapshot(Set<Token> mismatchingTokens, int expectedSnapshotSize)
      {
          return () -> {
              ColumnFamilyStore cfs = Keyspace.open(KEYSPACE).getColumnFamilyStore("tbl");
  
              String snapshotTag = await().atMost(1, MINUTES)
                                          .pollInterval(100, MILLISECONDS)
                                          .until(() -> {
                                              for (String tag : Util.listSnapshots(cfs).keySet())
                                              {
                                                  // we create the snapshot schema file last, so when this exists we know the snapshot is complete;
                                                  if (cfs.getDirectories().getSnapshotSchemaFile(tag).exists())
                                                      return tag;
                                              }
  
                                              return "";
                                          }, not(emptyString()));
  
              Set<SSTableReader> inSnapshot = new HashSet<>();
  
              try (Refs<SSTableReader> sstables = TableSnapshot.getSnapshotSSTableReaders(cfs.getKeyspaceName(), cfs.name, snapshotTag))
              {
                  inSnapshot.addAll(sstables);
              }
              catch (IOException e)
              {
                  throw new RuntimeException(e);
              }
              assertEquals(expectedSnapshotSize, inSnapshot.size());
  
              for (SSTableReader sstable : cfs.getLiveSSTables())
              {
                  Bounds<Token> sstableBounds = new Bounds<>(sstable.getFirst().getToken(), sstable.getLast().getToken());
                  boolean shouldBeInSnapshot = false;
                  for (Token mismatchingToken : mismatchingTokens)
                  {
                      if (sstableBounds.contains(mismatchingToken))
                      {
                          assertFalse(shouldBeInSnapshot);
                          shouldBeInSnapshot = true;
                      }
                  }
                  assertEquals(shouldBeInSnapshot, inSnapshot.contains(sstable));
              }
          };
      }
  
      private void markRepaired(Cluster cluster, int instance)
      {
          cluster.get(instance).runOnInstance(() -> {
              ColumnFamilyStore cfs = Keyspace.open(KEYSPACE).getColumnFamilyStore("tbl");
              for (SSTableReader sstable : cfs.getLiveSSTables())
              {
                  try
                  {
                      sstable.descriptor.getMetadataSerializer().mutateRepairMetadata(sstable.descriptor,
                                                                                      System.currentTimeMillis(),
                                                                                      null,
                                                                                      false);
                      sstable.reloadSSTableMetadata();
                  }
                  catch (IOException e)
                  {
                      throw new RuntimeException(e);
                  }
              }
          });
      }
  }
  