package com.twitter.product_mixer.component_library.selector

import com.twitter.product_mixer.core.functional_component.common.AllPipelines
import com.twitter.product_mixer.core.functional_component.common.CandidateScope
import com.twitter.product_mixer.core.functional_component.common.CandidateScope.PartitionedCandidates
import com.twitter.product_mixer.core.functional_component.selector.Selector
import com.twitter.product_mixer.core.functional_component.selector.SelectorResult
import com.twitter.product_mixer.core.model.common.presentation.CandidateWithDetails
import com.twitter.product_mixer.core.pipeline.PipelineQuery

/**
 * Drops all Candidates on the `remainingCandidates` side which are in the [[pipelineScope]]
 *
 * This is typically used as a placeholder when templating out a new pipeline or
 * as a simple filter to drop candidates based only on the [[CandidateScope]]
 */
case class DropAllCandidates(override val pipelineScope: CandidateScope = AllPipelines)
    extends Selector[PipelineQuery] {

  override def apply(
    query: PipelineQuery,
    remainingCandidates: Seq[CandidateWithDetails],
    result: Seq[CandidateWithDetails]
  ): SelectorResult = {
    val PartitionedCandidates(inScope, outOfScope) = pipelineScope.partition(remainingCandidates)

    SelectorResult(remainingCandidates = outOfScope, result = result)
  }
}