package io.sentry.android.core

import io.sentry.ISpan
import io.sentry.ITransaction
import io.sentry.NoOpSpan
import io.sentry.NoOpTransaction
import io.sentry.SentryNanotimeDate
import io.sentry.SpanContext
import io.sentry.android.core.internal.util.SentryFrameMetricsCollector
import io.sentry.protocol.MeasurementValue
import java.util.UUID
import java.util.concurrent.TimeUnit
import kotlin.test.Test
import kotlin.test.assertEquals
import org.mockito.AdditionalMatchers
import org.mockito.kotlin.any
import org.mockito.kotlin.eq
import org.mockito.kotlin.mock
import org.mockito.kotlin.never
import org.mockito.kotlin.verify
import org.mockito.kotlin.whenever

class SpanFrameMetricsCollectorTest {
  private class Fixture {
    val options = SentryAndroidOptions()
    val frameMetricsCollector = mock<SentryFrameMetricsCollector>()
    var timeNanos = 0L
    var lastKnownChoreographerFrameTimeNanos = 0L

    fun getSut(enabled: Boolean = true): SpanFrameMetricsCollector {
      whenever(frameMetricsCollector.startCollection(any()))
        .thenReturn(UUID.randomUUID().toString())
      whenever(frameMetricsCollector.getLastKnownFrameStartTimeNanos()).thenAnswer {
        return@thenAnswer lastKnownChoreographerFrameTimeNanos
      }
      options.frameMetricsCollector = frameMetricsCollector
      options.isEnableFramesTracking = enabled
      options.isEnablePerformanceV2 = enabled
      options.dateProvider = SentryAndroidDateProvider()

      return SpanFrameMetricsCollector(options, frameMetricsCollector)
    }
  }

  private fun createFakeSpan(
    startTimeStampNanos: Long = 1000,
    endTimeStampNanos: Long? = 2000,
  ): ISpan {
    val span = mock<ISpan>()
    val spanContext = SpanContext("op.fake")
    whenever(span.spanContext).thenReturn(spanContext)
    whenever(span.startDate)
      .thenReturn(SentryNanotimeDate(System.currentTimeMillis(), startTimeStampNanos))
    whenever(span.finishDate)
      .thenReturn(
        if (endTimeStampNanos != null) {
          SentryNanotimeDate(System.currentTimeMillis(), endTimeStampNanos)
        } else {
          null
        }
      )
    return span
  }

  private fun createFakeTxn(
    startTimeStampNanos: Long = 1000,
    endTimeStampNanos: Long? = 2000,
  ): ITransaction {
    val span = mock<ITransaction>()
    val spanContext = SpanContext("op.fake")
    whenever(span.spanContext).thenReturn(spanContext)
    whenever(span.startDate)
      .thenReturn(SentryNanotimeDate(System.currentTimeMillis(), startTimeStampNanos))
    whenever(span.finishDate)
      .thenReturn(
        if (endTimeStampNanos != null) {
          SentryNanotimeDate(System.currentTimeMillis(), endTimeStampNanos)
        } else {
          null
        }
      )
    return span
  }

  private val fixture = Fixture()

  @Test
  fun `When AndroidSlowFrozenFrameCollector is initialized, it doesn't register any listener`() {
    fixture.getSut()
    verify(fixture.frameMetricsCollector, never()).startCollection(any())
  }

  @Test
  fun `If disabled but a span is launched, it doesn't register a listener`() {
    val sut = fixture.getSut(enabled = false)

    // when a span is started
    val span = createFakeSpan()
    sut.onSpanStarted(span)

    // then it doesn't register for frame metrics
    verify(fixture.frameMetricsCollector, never()).startCollection(any())

    // nor unregisters when span is finished
    sut.onSpanFinished(span)
    verify(fixture.frameMetricsCollector, never()).stopCollection(any())
  }

  @Test
  fun `No-op txn and spans are ignored`() {
    val sut = fixture.getSut()

    // when fake transactions and spans are provided
    val txn = NoOpTransaction.getInstance()
    val span = NoOpSpan.getInstance()

    sut.onSpanStarted(txn)
    sut.onSpanStarted(span)

    // then it never registers for frame metrics
    verify(fixture.frameMetricsCollector, never()).startCollection(any())
  }

  @Test
  fun `Once a span is launched, it registers for frame metrics`() {
    val sut = fixture.getSut()

    // when a span is started
    fixture.timeNanos = 1000
    val span = createFakeSpan(1000, 2000)
    sut.onSpanStarted(span)

    // then it registers for frame metrics
    verify(fixture.frameMetricsCollector).startCollection(any())

    // when the span is finished
    fixture.timeNanos = 2000
    sut.onSpanFinished(span)

    // then it unregisters from frame metrics
    verify(fixture.frameMetricsCollector).stopCollection(any())
  }

  @Test
  fun `If multiple spans are launched, unregister is called after the last span finishes`() {
    val sut = fixture.getSut()

    // when 2 spans are started
    val span0 = createFakeSpan()
    val span1 = createFakeSpan()
    sut.onSpanStarted(span0)
    sut.onSpanStarted(span1)

    // and one finishes, but not the other one
    sut.onSpanFinished(span0)

    // then it doesn't unregister from frame metrics
    verify(fixture.frameMetricsCollector, never()).stopCollection(any())

    // but if the other one finishes
    sut.onSpanFinished(span1)

    // then it unregisters from frame metrics
    verify(fixture.frameMetricsCollector).stopCollection(any())
  }

  @Test
  fun `slow and frozen frames are calculated per span`() {
    val sut = fixture.getSut()

    // when the first span starts
    fixture.timeNanos = 0
    val span0 = createFakeSpan(0, 800)
    sut.onSpanStarted(span0)

    // and one fast, two slow frames and one frozen is are recorded
    sut.onFrameMetricCollected(0, 10, 10, 0, false, false, 60.0f)
    sut.onFrameMetricCollected(16, 48, 32, 16, true, false, 60.0f)
    sut.onFrameMetricCollected(60, 92, 32, 16, true, false, 60.0f)
    sut.onFrameMetricCollected(100, 800, 700, 784, true, true, 60.0f)

    // then a second span starts
    fixture.timeNanos = 800
    sut.onSpanFinished(span0)

    fixture.timeNanos = 820
    val span1 = createFakeSpan(820, 840)
    sut.onSpanStarted(span1)

    // and another slow frame is recorded
    fixture.timeNanos = 840
    sut.onFrameMetricCollected(820, 840, 20, 4, true, false, 60.0f)
    sut.onSpanFinished(span1)

    // then the metrics are set on the spans
    verify(span0).setData("frames.total", 4)
    verify(span0).setData("frames.slow", 2)
    verify(span0).setData("frames.frozen", 1)

    verify(span1).setData("frames.total", 1)
    verify(span1).setData("frames.slow", 1)
    verify(span1).setData("frames.frozen", 0)
  }

  @Test
  fun `slow and frozen frames are calculated even when spans overlap`() {
    val sut = fixture.getSut()

    // when 4 spans are running at the same time
    fixture.timeNanos = 0
    val span0 = createFakeSpan(0, 2000)
    val span1 = createFakeSpan(200, 2200)
    val span2 = createFakeSpan(400, 2400)
    val span3 = createFakeSpan(600, 2600)

    fixture.timeNanos = 0
    sut.onSpanStarted(span0)

    fixture.timeNanos = 200
    sut.onSpanStarted(span1)

    fixture.timeNanos = 400
    sut.onSpanStarted(span2)

    fixture.timeNanos = 600
    sut.onSpanStarted(span3)

    // and one frozen frame is captured right when all spans are running
    fixture.timeNanos = 620
    sut.onFrameMetricCollected(620, 1620, 1000, 984, true, true, 60.0f)

    fixture.timeNanos = 2000
    fixture.lastKnownChoreographerFrameTimeNanos = 2000
    sut.onSpanFinished(span0)

    fixture.timeNanos = 2200
    fixture.lastKnownChoreographerFrameTimeNanos = 2200
    sut.onSpanFinished(span1)

    fixture.timeNanos = 2400
    fixture.lastKnownChoreographerFrameTimeNanos = 2400
    sut.onSpanFinished(span2)

    fixture.timeNanos = 2600
    fixture.lastKnownChoreographerFrameTimeNanos = 2600
    sut.onSpanFinished(span3)

    // every span should contain the frozen frame information
    verify(span0).setData("frames.frozen", 1)
    verify(span1).setData("frames.frozen", 1)
    verify(span2).setData("frames.frozen", 1)
    verify(span3).setData("frames.frozen", 1)
  }

  @Test
  fun `when a span finishes which was never started no-op`() {
    val sut = fixture.getSut()

    // when 4 spans are running at the same time
    fixture.timeNanos = 0
    val span = createFakeSpan(0, 2000)

    sut.onFrameMetricCollected(0, 100, 1000, 984, true, true, 60.0f)

    sut.onSpanFinished(span)
    verify(span, never()).setData(any(), any())
  }

  @Test
  fun `measurements are not set on spans`() {
    val sut = fixture.getSut()

    fixture.timeNanos = 900
    val span = createFakeSpan(900, 1110)

    sut.onSpanStarted(span)
    sut.onFrameMetricCollected(1000, 1010, 10, 0, false, false, 60.0f)

    fixture.timeNanos = 1020
    sut.onSpanFinished(span)

    // then the metrics are set on the spans
    verify(span).setData("frames.total", 1)
    verify(span, never()).setMeasurement(MeasurementValue.KEY_FRAMES_TOTAL, 1)
  }

  @Test
  fun `measurements are set on transactions`() {
    val sut = fixture.getSut()

    fixture.timeNanos = 900
    val span = createFakeTxn(900, 1110)

    sut.onSpanStarted(span)
    sut.onFrameMetricCollected(1000, 1010, 10, 0, false, false, 60.0f)

    fixture.timeNanos = 1020
    sut.onSpanFinished(span)

    // then the metrics are set on the spans
    verify(span).setData("frames.total", 1)
    verify(span).setMeasurement(MeasurementValue.KEY_FRAMES_TOTAL, 1)
  }

  @Test
  fun `when no frame data is collected the total count is interpolated`() {
    val sut = fixture.getSut()

    // given a span which lasts for 1 second
    fixture.timeNanos = TimeUnit.SECONDS.toNanos(1)
    val span = createFakeSpan(TimeUnit.SECONDS.toNanos(1), TimeUnit.SECONDS.toNanos(2))

    sut.onSpanStarted(span)
    // but no frames are drawn

    // and the span finishes
    // and the choreographer reports a recent update
    fixture.lastKnownChoreographerFrameTimeNanos = TimeUnit.SECONDS.toNanos(2)
    fixture.timeNanos = TimeUnit.SECONDS.toNanos(2)
    sut.onSpanFinished(span)

    // then still 61 frames should be reported (1 second at 60fps with approximation)
    verify(span).setData("frames.total", 61)
    verify(span).setData("frames.slow", 0)
    verify(span).setData("frames.frozen", 0)
    verify(span).setData("frames.delay", 0.0)
  }

  @Test
  fun `when no frame data is collected the total count is interpolated and frame delay is added`() {
    val sut = fixture.getSut()

    // given a span which lasts for 2 seconds
    fixture.timeNanos = TimeUnit.SECONDS.toNanos(1)
    val span = createFakeSpan(TimeUnit.SECONDS.toNanos(1), TimeUnit.SECONDS.toNanos(3))

    sut.onSpanStarted(span)
    // but no frames are drawn

    // and the span finishes
    // but the choreographer has no update for the last second
    fixture.lastKnownChoreographerFrameTimeNanos = TimeUnit.SECONDS.toNanos(2)
    fixture.timeNanos = TimeUnit.SECONDS.toNanos(3)
    sut.onSpanFinished(span)

    // then
    // still 61 fps should be reported for 1 seconds (with approximation)
    // and one frame with frame delay should be reported (1s - 16ms)
    verify(span).setData("frames.total", 62)
    verify(span).setData("frames.slow", 0)
    verify(span).setData("frames.frozen", 1)
    verify(span).setData(eq("frames.delay"), AdditionalMatchers.eq(0.983333334, 0.01))
  }

  @Test
  fun `when frame data is only partially collected the total count is still interpolated`() {
    val sut = fixture.getSut()

    // given a span which lasts for 1 second
    val span =
      createFakeSpan(
        startTimeStampNanos = TimeUnit.SECONDS.toNanos(1),
        endTimeStampNanos = TimeUnit.SECONDS.toNanos(2),
      )

    fixture.timeNanos = TimeUnit.SECONDS.toNanos(1)
    sut.onSpanStarted(span)

    // when one frozen frame is recorded
    sut.onFrameMetricCollected(
      TimeUnit.MILLISECONDS.toNanos(1000),
      TimeUnit.MILLISECONDS.toNanos(1800),
      TimeUnit.MILLISECONDS.toNanos(800),
      TimeUnit.MILLISECONDS.toNanos(800 - 16),
      false,
      true,
      60.0f,
    )

    // and the span finishes
    fixture.timeNanos = TimeUnit.SECONDS.toNanos(2)
    sut.onSpanFinished(span)

    // then 13 frames should be reported
    // 1 frame at 800ms + 1 frames at 16ms = 992ms
    verify(span).setData("frames.total", 2)
    verify(span).setData("frames.slow", 0)
    verify(span).setData("frames.frozen", 2)
  }

  @Test
  fun `when frame data is only partially collected the total count is not interpolated in case the span didn't finish`() {
    val sut = fixture.getSut()

    // given a span has no end date
    fixture.timeNanos = TimeUnit.SECONDS.toNanos(1)
    val span =
      createFakeSpan(startTimeStampNanos = TimeUnit.SECONDS.toNanos(1), endTimeStampNanos = null)

    sut.onSpanStarted(span)

    // when one frozen frame is recorded
    sut.onFrameMetricCollected(
      TimeUnit.MILLISECONDS.toNanos(1000),
      TimeUnit.MILLISECONDS.toNanos(1800),
      TimeUnit.MILLISECONDS.toNanos(800),
      TimeUnit.MILLISECONDS.toNanos(800 - 16),
      false,
      true,
      60.0f,
    )

    // and the span finishes without a finish date
    fixture.timeNanos = TimeUnit.MILLISECONDS.toNanos(1800)
    sut.onSpanFinished(span)

    // then no frame stats should be reported
    verify(span, never()).setData(any(), any())
  }

  @Test
  fun `clear unregisters from frame collector`() {
    val sut = fixture.getSut()

    // when a span starts
    val span0 = createFakeSpan()
    sut.onSpanStarted(span0)

    // but clear is called
    sut.clear()

    // then it unregisters from frame metrics
    verify(fixture.frameMetricsCollector).stopCollection(any())

    // and no span data should be attached
    verify(span0, never()).setData(any(), any())
  }

  @Test
  fun `SentryNanoDate diff does nano precision`() {
    // having this in here, as SpanFrameMetricsCollector relies on this behavior
    val a = SentryNanotimeDate(1234, 567)
    val b = SentryNanotimeDate(1234, 0)

    assertEquals(567, a.diff(b))
  }
}
