/*
 * 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 java.time.Duration;
import java.util.EnumSet;
import java.util.Map;

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.IteratorSetting;
import org.apache.accumulo.core.client.Scanner;
import org.apache.accumulo.core.client.TableNotFoundException;
import org.apache.accumulo.core.client.admin.NewTableConfiguration;
import org.apache.accumulo.core.conf.Property;
import org.apache.accumulo.core.data.Mutation;
import org.apache.accumulo.core.iterators.IteratorUtil.IteratorScope;
import org.apache.accumulo.core.security.Authorizations;
import org.apache.accumulo.harness.AccumuloClusterHarness;
import org.apache.accumulo.miniclusterImpl.MiniAccumuloConfigImpl;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.Text;
import org.junit.jupiter.api.Test;

import com.google.common.collect.Iterators;

public class ConcurrencyIT extends AccumuloClusterHarness {

  static class ScanTask extends Thread {

    int count = 0;
    AccumuloClient client;
    String tableName;
    long time;

    ScanTask(AccumuloClient client, String tableName, long time) {
      this.client = client;
      this.tableName = tableName;
      this.time = time;
    }

    @Override
    public void run() {
      try (Scanner scanner = client.createScanner(tableName, Authorizations.EMPTY)) {
        IteratorSetting slow = new IteratorSetting(30, "slow", SlowIterator.class);
        SlowIterator.setSleepTime(slow, time);
        scanner.addScanIterator(slow);
        count = Iterators.size(scanner.iterator());
      } catch (TableNotFoundException e) {
        throw new IllegalStateException(e);
      }
    }
  }

  @Override
  protected Duration defaultTimeout() {
    return Duration.ofMinutes(2);
  }

  @Override
  public void configureMiniCluster(MiniAccumuloConfigImpl cfg, Configuration hadoopCoreSite) {
    Map<String,String> siteConfig = cfg.getSiteConfig();
    cfg.setSiteConfig(siteConfig);
  }

  // @formatter:off
  // Below is a diagram of the operations in this test over time.
  //
  // Scan 0 |------------------------------|
  // Scan 1 |----------|
  // Minc 1  |-----|
  // Scan 2   |----------|
  // Scan 3               |---------------|
  // Minc 2                |-----|
  // Majc 1                       |-----|
  // @formatter:on
  @Test
  public void run() throws Exception {
    try (AccumuloClient c = Accumulo.newClient().from(getClientProps()).build()) {
      runTest(c, getUniqueNames(1)[0]);
    }
  }

  static void runTest(AccumuloClient c, String tableName) throws Exception {
    NewTableConfiguration ntc = new NewTableConfiguration();
    ntc.setProperties(Map.of(Property.TABLE_MAJC_RATIO.getKey(), "1.0"));
    IteratorSetting is = new IteratorSetting(10, SlowIterator.class);
    SlowIterator.setSleepTime(is, 50);
    ntc.attachIterator(is, EnumSet.of(IteratorScope.minc, IteratorScope.majc));
    c.tableOperations().create(tableName, ntc);

    BatchWriter bw = c.createBatchWriter(tableName);
    for (int i = 0; i < 50; i++) {
      Mutation m = new Mutation(new Text(String.format("%06d", i)));
      m.put("cf1", "cq1", "foo");
      bw.addMutation(m);
    }
    bw.flush();

    ScanTask st0 = new ScanTask(c, tableName, 300);
    st0.start();

    ScanTask st1 = new ScanTask(c, tableName, 100);
    st1.start();

    Thread.sleep(50);
    c.tableOperations().flush(tableName, null, null, true);

    for (int i = 0; i < 50; i++) {
      Mutation m = new Mutation(new Text(String.format("%06d", i)));
      m.put("cf1", "cq1", "foo");
      bw.addMutation(m);
    }

    bw.flush();

    ScanTask st2 = new ScanTask(c, tableName, 100);
    st2.start();

    st1.join();
    st2.join();
    if (st1.count != 50) {
      throw new Exception("Thread 1 did not see 50, saw " + st1.count);
    }

    if (st2.count != 50) {
      throw new Exception("Thread 2 did not see 50, saw " + st2.count);
    }

    ScanTask st3 = new ScanTask(c, tableName, 150);
    st3.start();

    Thread.sleep(50);
    c.tableOperations().flush(tableName, null, null, false);

    st3.join();
    if (st3.count != 50) {
      throw new Exception("Thread 3 did not see 50, saw " + st3.count);
    }

    st0.join();
    if (st0.count != 50) {
      throw new Exception("Thread 0 did not see 50, saw " + st0.count);
    }

    bw.close();
  }
}
