/**
 * 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 kafka.utils

import java.util.{Arrays, Base64, UUID}
import java.util.concurrent.{ConcurrentHashMap, Executors, TimeUnit}
import java.util.concurrent.atomic.AtomicInteger
import java.util.concurrent.locks.ReentrantLock
import java.nio.ByteBuffer
import java.util.regex.Pattern

import org.junit.Assert._
import kafka.utils.CoreUtils.inLock
import org.apache.kafka.common.KafkaException
import org.junit.Test
import org.apache.kafka.common.utils.Utils
import org.slf4j.event.Level

import scala.collection.JavaConverters._
import scala.collection.mutable
import scala.concurrent.duration.Duration
import scala.concurrent.{Await, ExecutionContext, Future}

class CoreUtilsTest extends Logging {

  val clusterIdPattern = Pattern.compile("[a-zA-Z0-9_\\-]+")

  @Test
  def testSwallow(): Unit = {
    CoreUtils.swallow(throw new KafkaException("test"), this, Level.INFO)
  }

  @Test
  def testTryAll(): Unit = {
    case class TestException(key: String) extends Exception

    val recorded = mutable.Map.empty[String, Either[TestException, String]]
    def recordingFunction(v: Either[TestException, String]): Unit = {
      val key = v match {
        case Right(key) => key
        case Left(e) => e.key
      }
      recorded(key) = v
    }

    CoreUtils.tryAll(Seq(
      () => recordingFunction(Right("valid-0")),
      () => recordingFunction(Left(new TestException("exception-1"))),
      () => recordingFunction(Right("valid-2")),
      () => recordingFunction(Left(new TestException("exception-3")))
    ))
    var expected = Map(
      "valid-0" -> Right("valid-0"),
      "exception-1" -> Left(TestException("exception-1")),
      "valid-2" -> Right("valid-2"),
      "exception-3" -> Left(TestException("exception-3"))
    )
    assertEquals(expected, recorded)

    recorded.clear()
    CoreUtils.tryAll(Seq(
      () => recordingFunction(Right("valid-0")),
      () => recordingFunction(Right("valid-1"))
    ))
    expected = Map(
      "valid-0" -> Right("valid-0"),
      "valid-1" -> Right("valid-1")
    )
    assertEquals(expected, recorded)

    recorded.clear()
    CoreUtils.tryAll(Seq(
      () => recordingFunction(Left(new TestException("exception-0"))),
      () => recordingFunction(Left(new TestException("exception-1")))
    ))
    expected = Map(
      "exception-0" -> Left(TestException("exception-0")),
      "exception-1" -> Left(TestException("exception-1"))
    )
    assertEquals(expected, recorded)
  }

  @Test
  def testCircularIterator(): Unit = {
    val l = List(1, 2)
    val itl = CoreUtils.circularIterator(l)
    assertEquals(1, itl.next())
    assertEquals(2, itl.next())
    assertEquals(1, itl.next())
    assertEquals(2, itl.next())
    assertFalse(itl.hasDefiniteSize)

    val s = Set(1, 2)
    val its = CoreUtils.circularIterator(s)
    assertEquals(1, its.next())
    assertEquals(2, its.next())
    assertEquals(1, its.next())
    assertEquals(2, its.next())
    assertEquals(1, its.next())
  }

  @Test
  def testReadBytes(): Unit = {
    for(testCase <- List("", "a", "abcd")) {
      val bytes = testCase.getBytes
      assertTrue(Arrays.equals(bytes, Utils.readBytes(ByteBuffer.wrap(bytes))))
    }
  }

  @Test
  def testAbs(): Unit = {
    assertEquals(0, Utils.abs(Integer.MIN_VALUE))
    assertEquals(1, Utils.abs(-1))
    assertEquals(0, Utils.abs(0))
    assertEquals(1, Utils.abs(1))
    assertEquals(Integer.MAX_VALUE, Utils.abs(Integer.MAX_VALUE))
  }

  @Test
  def testReplaceSuffix(): Unit = {
    assertEquals("blah.foo.text", CoreUtils.replaceSuffix("blah.foo.txt", ".txt", ".text"))
    assertEquals("blah.foo", CoreUtils.replaceSuffix("blah.foo.txt", ".txt", ""))
    assertEquals("txt.txt", CoreUtils.replaceSuffix("txt.txt.txt", ".txt", ""))
    assertEquals("foo.txt", CoreUtils.replaceSuffix("foo", "", ".txt"))
  }

  @Test
  def testReadInt(): Unit = {
    val values = Array(0, 1, -1, Byte.MaxValue, Short.MaxValue, 2 * Short.MaxValue, Int.MaxValue/2, Int.MinValue/2, Int.MaxValue, Int.MinValue, Int.MaxValue)
    val buffer = ByteBuffer.allocate(4 * values.size)
    for(i <- 0 until values.length) {
      buffer.putInt(i*4, values(i))
      assertEquals("Written value should match read value.", values(i), CoreUtils.readInt(buffer.array, i*4))
    }
  }

  @Test
  def testCsvList(): Unit = {
    val emptyString:String = ""
    val nullString:String = null
    val emptyList = CoreUtils.parseCsvList(emptyString)
    val emptyListFromNullString = CoreUtils.parseCsvList(nullString)
    val emptyStringList = Seq.empty[String]
    assertTrue(emptyList!=null)
    assertTrue(emptyListFromNullString!=null)
    assertTrue(emptyStringList.equals(emptyListFromNullString))
    assertTrue(emptyStringList.equals(emptyList))
  }

  @Test
  def testCsvMap(): Unit = {
    val emptyString: String = ""
    val emptyMap = CoreUtils.parseCsvMap(emptyString)
    val emptyStringMap = Map.empty[String, String]
    assertTrue(emptyMap != null)
    assertTrue(emptyStringMap.equals(emptyStringMap))

    val kvPairsIpV6: String = "a:b:c:v,a:b:c:v"
    val ipv6Map = CoreUtils.parseCsvMap(kvPairsIpV6)
    for (m <- ipv6Map) {
      assertTrue(m._1.equals("a:b:c"))
      assertTrue(m._2.equals("v"))
    }

    val singleEntry:String = "key:value"
    val singleMap = CoreUtils.parseCsvMap(singleEntry)
    val value = singleMap.getOrElse("key", 0)
    assertTrue(value.equals("value"))

    val kvPairsIpV4: String = "192.168.2.1/30:allow, 192.168.2.1/30:allow"
    val ipv4Map = CoreUtils.parseCsvMap(kvPairsIpV4)
    for (m <- ipv4Map) {
      assertTrue(m._1.equals("192.168.2.1/30"))
      assertTrue(m._2.equals("allow"))
    }

    val kvPairsSpaces: String = "key:value      , key:   value"
    val spaceMap = CoreUtils.parseCsvMap(kvPairsSpaces)
    for (m <- spaceMap) {
      assertTrue(m._1.equals("key"))
      assertTrue(m._2.equals("value"))
    }
  }

  @Test
  def testInLock(): Unit = {
    val lock = new ReentrantLock()
    val result = inLock(lock) {
      assertTrue("Should be in lock", lock.isHeldByCurrentThread)
      1 + 1
    }
    assertEquals(2, result)
    assertFalse("Should be unlocked", lock.isLocked)
  }

  @Test
  def testUrlSafeBase64EncodeUUID(): Unit = {

    // Test a UUID that has no + or / characters in base64 encoding [a149b4a3-06e1-4b49-a8cb-8a9c4a59fa46 ->(base64)-> oUm0owbhS0moy4qcSln6Rg==]
    val clusterId1 = Base64.getUrlEncoder.withoutPadding.encodeToString(CoreUtils.getBytesFromUuid(UUID.fromString(
      "a149b4a3-06e1-4b49-a8cb-8a9c4a59fa46")))
    assertEquals(clusterId1, "oUm0owbhS0moy4qcSln6Rg")
    assertEquals(clusterId1.length, 22)
    assertTrue(clusterIdPattern.matcher(clusterId1).matches())

    // Test a UUID that has + or / characters in base64 encoding [d418ec02-277e-4853-81e6-afe30259daec ->(base64)-> 1BjsAid+SFOB5q/jAlna7A==]
    val clusterId2 = Base64.getUrlEncoder.withoutPadding.encodeToString(CoreUtils.getBytesFromUuid(UUID.fromString(
      "d418ec02-277e-4853-81e6-afe30259daec")))
    assertEquals(clusterId2, "1BjsAid-SFOB5q_jAlna7A")
    assertEquals(clusterId2.length, 22)
    assertTrue(clusterIdPattern.matcher(clusterId2).matches())
  }

  @Test
  def testGenerateUuidAsBase64(): Unit = {
    val clusterId = CoreUtils.generateUuidAsBase64()
    assertEquals(clusterId.length, 22)
    assertTrue(clusterIdPattern.matcher(clusterId).matches())
  }

  @Test
  def testAtomicGetOrUpdate(): Unit = {
    val count = 1000
    val nThreads = 5
    val createdCount = new AtomicInteger
    val map = new ConcurrentHashMap[Int, AtomicInteger]().asScala
    implicit val executionContext = ExecutionContext.fromExecutorService(Executors.newFixedThreadPool(nThreads))
    try {
      Await.result(Future.traverse(1 to count) { i =>
        Future {
          CoreUtils.atomicGetOrUpdate(map, 0, {
            createdCount.incrementAndGet
            new AtomicInteger
          }).incrementAndGet()
        }
      }, Duration(1, TimeUnit.MINUTES))
      assertEquals(count, map(0).get)
      val created = createdCount.get
      assertTrue(s"Too many creations $created", created > 0 && created <= nThreads)
    } finally {
      executionContext.shutdownNow()
    }
  }
}
