the-algorithm/product-mixer/component-library/src/main/scala/com/twitter/product_mixer/component_library/selector/InsertRelativePositionResults.scala
twitter-team ef4c5eb65e Twitter Recommendation Algorithm
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2023-03-31 17:36:31 -05:00

59 lines
2.5 KiB
Scala

package com.twitter.product_mixer.component_library.selector
import com.twitter.product_mixer.core.functional_component.common.CandidateScope
import com.twitter.product_mixer.core.functional_component.selector.Selector
import CandidateScope.PartitionedCandidates
import com.twitter.product_mixer.core.functional_component.common.SpecificPipelines
import com.twitter.product_mixer.core.functional_component.selector.SelectorResult
import com.twitter.product_mixer.core.model.common.identifier.CandidatePipelineIdentifier
import com.twitter.product_mixer.core.model.common.presentation.CandidateWithDetails
import com.twitter.product_mixer.core.pipeline.PipelineQuery
import com.twitter.timelines.configapi.Param
/**
* Insert all candidates from a candidate pipeline at a position below, relative to the last
* selection of the relative to candidate pipeline. If the relative to candidate pipeline does not
* contain candidates, then the candidates will be inserted with padding relative to position zero.
* If the current results are a shorter length than the requested padding, then the candidates will
* be appended to the results.
*/
case class InsertRelativePositionResults(
candidatePipeline: CandidatePipelineIdentifier,
relativeToCandidatePipeline: CandidatePipelineIdentifier,
paddingAboveParam: Param[Int])
extends Selector[PipelineQuery] {
override val pipelineScope: CandidateScope = SpecificPipelines(candidatePipeline)
override def apply(
query: PipelineQuery,
remainingCandidates: Seq[CandidateWithDetails],
result: Seq[CandidateWithDetails]
): SelectorResult = {
val paddingAbove = query.params(paddingAboveParam)
assert(paddingAbove >= 0, "Padding above must be equal to or greater than zero")
val PartitionedCandidates(selectedCandidates, otherCandidates) =
pipelineScope.partition(remainingCandidates)
val resultUpdated = if (selectedCandidates.nonEmpty) {
// If the relativeToCandidatePipeline has zero candidates, lastIndexWhere will return -1 which
// will start padding from the zero position
val relativePosition = result.lastIndexWhere(_.source == relativeToCandidatePipeline) + 1
val position = relativePosition + paddingAbove
if (position < result.length) {
val (left, right) = result.splitAt(position)
left ++ selectedCandidates ++ right
} else {
result ++ selectedCandidates
}
} else {
result
}
SelectorResult(remainingCandidates = otherCandidates, result = resultUpdated)
}
}