package com.twitter.recos.user_tweet_entity_graph

import com.twitter.finagle.stats.StatsReceiver
import com.twitter.frigate.common.util.StatsUtil
import com.twitter.graphjet.algorithms.RecommendationInfo
import com.twitter.graphjet.algorithms.socialproof.{SocialProofResult => SocialProofJavaResult}
import com.twitter.recos.decider.UserTweetEntityGraphDecider
import com.twitter.recos.util.Stats
import com.twitter.recos.util.Stats._
import com.twitter.recos.recos_common.thriftscala.{SocialProofType => SocialProofThriftType}
import com.twitter.recos.user_tweet_entity_graph.thriftscala.TweetRecommendation
import com.twitter.recos.user_tweet_entity_graph.thriftscala.{
  SocialProofRequest => SocialProofThriftRequest
}
import com.twitter.recos.user_tweet_entity_graph.thriftscala.{
  SocialProofResponse => SocialProofThriftResponse
}
import com.twitter.servo.request.RequestHandler
import com.twitter.util.Future
import scala.collection.JavaConverters._

class TweetSocialProofHandler(
  tweetSocialProofRunner: TweetSocialProofRunner,
  decider: UserTweetEntityGraphDecider,
  statsReceiver: StatsReceiver)
    extends RequestHandler[SocialProofThriftRequest, SocialProofThriftResponse] {
  private val stats = statsReceiver.scope(this.getClass.getSimpleName)

  def getThriftSocialProof(
    tweetSocialProof: SocialProofJavaResult
  ): Map[SocialProofThriftType, Seq[Long]] = {
    Option(tweetSocialProof.getSocialProof) match {
      case Some(socialProof) if socialProof.isEmpty =>
        stats.counter(Stats.EmptyResult).incr()
        Map.empty[SocialProofThriftType, Seq[Long]]
      case Some(socialProof) if !socialProof.isEmpty =>
        socialProof.asScala.map {
          case (socialProofType, connectingUsers) =>
            (
              SocialProofThriftType(socialProofType.toInt),
              connectingUsers.asScala.map { Long2long }.toSeq)
        }.toMap
      case _ =>
        throw new Exception("TweetSocialProofHandler gets wrong TweetSocialProof response")
    }
  }

  def apply(request: SocialProofThriftRequest): Future[SocialProofThriftResponse] = {
    StatsUtil.trackBlockStats(stats) {
      if (decider.tweetSocialProof) {
        val socialProofsFuture = tweetSocialProofRunner(request)

        socialProofsFuture map { socialProofs: Seq[RecommendationInfo] =>
          stats.counter(Stats.Served).incr(socialProofs.size)
          SocialProofThriftResponse(
            socialProofs.flatMap { tweetSocialProof: RecommendationInfo =>
              val tweetSocialProofJavaResult = tweetSocialProof.asInstanceOf[SocialProofJavaResult]
              Some(
                TweetRecommendation(
                  tweetSocialProofJavaResult.getNode,
                  tweetSocialProofJavaResult.getWeight,
                  getThriftSocialProof(tweetSocialProofJavaResult)
                )
              )
            }
          )
        }
      } else {
        Future.value(SocialProofThriftResponse())
      }
    }
  }
}