the-algorithm/tweetypie/server/src/main/scala/com/twitter/tweetypie/store/GizmoduckUserCountsUpdatingStore.scala

package com.twitter.tweetypie
package store

import com.twitter.gizmoduck.thriftscala.{CountsUpdateField => Field}
import com.twitter.tweetypie.backends.Gizmoduck

trait GizmoduckUserCountsUpdatingStore
    extends TweetStoreBase[GizmoduckUserCountsUpdatingStore]
    with InsertTweet.Store
    with DeleteTweet.Store {
  def wrap(w: TweetStore.Wrap): GizmoduckUserCountsUpdatingStore =
    new TweetStoreWrapper(w, this)
      with GizmoduckUserCountsUpdatingStore
      with InsertTweet.StoreWrapper
      with DeleteTweet.StoreWrapper
}

/**
 * A TweetStore implementation that sends user-specific count updates to Gizmoduck.
 */
object GizmoduckUserCountsUpdatingStore {
  def isUserTweet(tweet: Tweet): Boolean =
    !TweetLenses.nullcast.get(tweet) && TweetLenses.narrowcast.get(tweet).isEmpty

  def apply(
    incr: Gizmoduck.IncrCount,
    hasMedia: Tweet => Boolean
  ): GizmoduckUserCountsUpdatingStore = {
    def incrField(field: Field, amt: Int): FutureEffect[Tweet] =
      FutureEffect[Tweet](tweet => incr((getUserId(tweet), field, amt)))

    def incrAll(amt: Int): FutureEffect[Tweet] =
      FutureEffect.inParallel(
        incrField(Field.Tweets, amt).onlyIf(isUserTweet),
        incrField(Field.MediaTweets, amt).onlyIf(t => isUserTweet(t) && hasMedia(t))
      )

    new GizmoduckUserCountsUpdatingStore {
      override val insertTweet: FutureEffect[InsertTweet.Event] =
        incrAll(1).contramap[InsertTweet.Event](_.tweet)

      override val deleteTweet: FutureEffect[DeleteTweet.Event] =
        incrAll(-1)
          .contramap[DeleteTweet.Event](_.tweet)
          .onlyIf(!_.isUserErasure)
    }
  }
}