package kamon.metric.instrument

import java.time.Duration

import com.typesafe.config.ConfigFactory
import kamon.metric.Entity
import org.scalatest.{Matchers, WordSpec}

class InstrumentFactorySpec extends WordSpec with Matchers{
  val testEntity = Entity("test", "test-category", Map.empty)
  val customEntity = Entity("test", "custom-category", Map.empty)
  val baseConfiguration = ConfigFactory.parseString(
    """
      |default-settings {
      |  histogram {
      |    lowest-discernible-value = 100
      |    highest-trackable-value = 5000
      |    significant-value-digits = 2
      |  }
      |
      |  min-max-counter {
      |    lowest-discernible-value = 200
      |    highest-trackable-value = 6000
      |    significant-value-digits = 3
      |    sample-interval = 647 millis
      |  }
      |}
      |
      |custom-settings {
      |
      |}
    """.stripMargin
  )


  "the metrics InstrumentFactory" should {
    "create instruments using the default configuration settings" in {
      val factory = InstrumentFactory(baseConfiguration)
      val histogram = factory.buildHistogram(testEntity, "my-histogram")
      val mmCounter = factory.buildMinMaxCounter(testEntity, "my-mm-counter")

      histogram.dynamicRange.lowestDiscernibleValue shouldBe(100)
      histogram.dynamicRange.highestTrackableValue shouldBe(5000)
      histogram.dynamicRange.significantValueDigits shouldBe(2)

      mmCounter.dynamicRange.lowestDiscernibleValue shouldBe(200)
      mmCounter.dynamicRange.highestTrackableValue shouldBe(6000)
      mmCounter.dynamicRange.significantValueDigits shouldBe(3)
      mmCounter.sampleInterval shouldBe(Duration.ofMillis(647))
    }

    "accept custom settings when building instruments" in {
      val factory = InstrumentFactory(baseConfiguration)
      val histogram = factory.buildHistogram(testEntity, "my-histogram", DynamicRange.Loose)
      val mmCounter = factory.buildMinMaxCounter(testEntity, "my-mm-counter", DynamicRange.Fine, Duration.ofMillis(500))

      histogram.dynamicRange shouldBe(DynamicRange.Loose)

      mmCounter.dynamicRange shouldBe(DynamicRange.Fine)
      mmCounter.sampleInterval shouldBe(Duration.ofMillis(500))
    }

    "allow overriding any default and provided settings via the custom-settings configuration key" in {
      val customConfig = ConfigFactory.parseString(
        """
          |custom-settings {
          |   custom-category {
          |     modified-histogram {
          |       lowest-discernible-value = 99
          |       highest-trackable-value = 999
          |       significant-value-digits = 4
          |     }
          |
          |     modified-mm-counter {
          |       lowest-discernible-value = 784
          |       highest-trackable-value = 14785
          |       significant-value-digits = 1
          |       sample-interval = 3 seconds
          |     }
          |   }
          |}
        """.stripMargin
      ).withFallback(baseConfiguration)

      val factory = InstrumentFactory(customConfig)
      val defaultHistogram = factory.buildHistogram(customEntity, "default-histogram")
      val modifiedHistogram = factory.buildHistogram(customEntity, "modified-histogram", DynamicRange.Loose)

      defaultHistogram.dynamicRange.lowestDiscernibleValue shouldBe(100)
      defaultHistogram.dynamicRange.highestTrackableValue shouldBe(5000)
      defaultHistogram.dynamicRange.significantValueDigits shouldBe(2)

      modifiedHistogram.dynamicRange.lowestDiscernibleValue shouldBe(99)
      modifiedHistogram.dynamicRange.highestTrackableValue shouldBe(999)
      modifiedHistogram.dynamicRange.significantValueDigits shouldBe(4)


      val defaultMMCounter = factory.buildMinMaxCounter(customEntity, "default-mm-counter")
      val modifiedMMCounter = factory.buildMinMaxCounter(customEntity, "modified-mm-counter", DynamicRange.Loose)

      defaultMMCounter.dynamicRange.lowestDiscernibleValue shouldBe(200)
      defaultMMCounter.dynamicRange.highestTrackableValue shouldBe(6000)
      defaultMMCounter.dynamicRange.significantValueDigits shouldBe(3)
      defaultMMCounter.sampleInterval shouldBe(Duration.ofMillis(647))

      modifiedMMCounter.dynamicRange.lowestDiscernibleValue shouldBe(784)
      modifiedMMCounter.dynamicRange.highestTrackableValue shouldBe(14785)
      modifiedMMCounter.dynamicRange.significantValueDigits shouldBe(1)
      modifiedMMCounter.sampleInterval shouldBe(Duration.ofSeconds(3))
    }
  }
}