package com.twitter.frigate.pushservice.adaptor

import com.twitter.finagle.stats.Stat
import com.twitter.finagle.stats.StatsReceiver
import com.twitter.frigate.common.base._
import com.twitter.frigate.common.candidate._
import com.twitter.frigate.common.predicate.CommonOutNetworkTweetCandidatesSourcePredicates.filterOutReplyTweet
import com.twitter.frigate.pushservice.model.PushTypes.RawCandidate
import com.twitter.frigate.pushservice.model.PushTypes.Target
import com.twitter.frigate.pushservice.params.PushFeatureSwitchParams
import com.twitter.frigate.pushservice.params.PushParams
import com.twitter.frigate.pushservice.util.PushDeviceUtil
import com.twitter.hermit.store.tweetypie.UserTweet
import com.twitter.recos.recos_common.thriftscala.SocialProofType
import com.twitter.search.common.features.thriftscala.ThriftSearchResultFeatures
import com.twitter.stitch.tweetypie.TweetyPie.TweetyPieResult
import com.twitter.storehaus.ReadableStore
import com.twitter.timelines.configapi.Param
import com.twitter.util.Future
import com.twitter.util.Time
import scala.collection.Map

case class EarlyBirdFirstDegreeCandidateAdaptor(
  earlyBirdFirstDegreeCandidates: CandidateSource[
    EarlybirdCandidateSource.Query,
    EarlybirdCandidate
  ],
  tweetyPieStore: ReadableStore[Long, TweetyPieResult],
  tweetyPieStoreNoVF: ReadableStore[Long, TweetyPieResult],
  userTweetTweetyPieStore: ReadableStore[UserTweet, TweetyPieResult],
  maxResultsParam: Param[Int],
  globalStats: StatsReceiver)
    extends CandidateSource[Target, RawCandidate]
    with CandidateSourceEligible[Target, RawCandidate] {

  type EBCandidate = EarlybirdCandidate with TweetDetails
  private val stats = globalStats.scope("EarlyBirdFirstDegreeAdaptor")
  private val earlyBirdCandsStat: Stat = stats.stat("early_bird_cands_dist")
  private val emptyEarlyBirdCands = stats.counter("empty_early_bird_candidates")
  private val seedSetEmpty = stats.counter("empty_seedset")
  private val seenTweetsStat = stats.stat("filtered_by_seen_tweets")
  private val emptyTweetyPieResult = stats.stat("empty_tweetypie_result")
  private val nonReplyTweetsCounter = stats.counter("non_reply_tweets")
  private val enableRetweets = stats.counter("enable_retweets")
  private val f1withoutSocialContexts = stats.counter("f1_without_social_context")
  private val userTweetTweetyPieStoreCounter = stats.counter("user_tweet_tweetypie_store")

  override val name: String = earlyBirdFirstDegreeCandidates.name

  private def getAllSocialContextActions(
    socialProofTypes: Seq[(SocialProofType, Seq[Long])]
  ): Seq[SocialContextAction] = {
    socialProofTypes.flatMap {
      case (SocialProofType.Favorite, scIds) =>
        scIds.map { scId =>
          SocialContextAction(
            scId,
            Time.now.inMilliseconds,
            socialContextActionType = Some(SocialContextActionType.Favorite)
          )
        }
      case (SocialProofType.Retweet, scIds) =>
        scIds.map { scId =>
          SocialContextAction(
            scId,
            Time.now.inMilliseconds,
            socialContextActionType = Some(SocialContextActionType.Retweet)
          )
        }
      case (SocialProofType.Reply, scIds) =>
        scIds.map { scId =>
          SocialContextAction(
            scId,
            Time.now.inMilliseconds,
            socialContextActionType = Some(SocialContextActionType.Reply)
          )
        }
      case (SocialProofType.Tweet, scIds) =>
        scIds.map { scId =>
          SocialContextAction(
            scId,
            Time.now.inMilliseconds,
            socialContextActionType = Some(SocialContextActionType.Tweet)
          )
        }
      case _ => Nil
    }
  }

  private def generateRetweetCandidate(
    inputTarget: Target,
    candidate: EBCandidate,
    scIds: Seq[Long],
    socialProofTypes: Seq[(SocialProofType, Seq[Long])]
  ): RawCandidate = {
    val scActions = scIds.map { scId => SocialContextAction(scId, Time.now.inMilliseconds) }
    new RawCandidate with TweetRetweetCandidate with EarlybirdTweetFeatures {
      override val socialContextActions = scActions
      override val socialContextAllTypeActions = getAllSocialContextActions(socialProofTypes)
      override val tweetId = candidate.tweetId
      override val target = inputTarget
      override val tweetyPieResult = candidate.tweetyPieResult
      override val features = candidate.features
    }
  }

  private def generateF1CandidateWithoutSocialContext(
    inputTarget: Target,
    candidate: EBCandidate
  ): RawCandidate = {
    f1withoutSocialContexts.incr()
    new RawCandidate with F1FirstDegree with EarlybirdTweetFeatures {
      override val tweetId = candidate.tweetId
      override val target = inputTarget
      override val tweetyPieResult = candidate.tweetyPieResult
      override val features = candidate.features
    }
  }

  private def generateEarlyBirdCandidate(
    id: Long,
    result: Option[TweetyPieResult],
    ebFeatures: Option[ThriftSearchResultFeatures]
  ): EBCandidate = {
    new EarlybirdCandidate with TweetDetails {
      override val tweetyPieResult: Option[TweetyPieResult] = result
      override val tweetId: Long = id
      override val features: Option[ThriftSearchResultFeatures] = ebFeatures
    }
  }

  private def filterOutSeenTweets(seenTweetIds: Seq[Long], inputTweetIds: Seq[Long]): Seq[Long] = {
    inputTweetIds.filterNot(seenTweetIds.contains)
  }

  private def filterInvalidTweets(
    tweetIds: Seq[Long],
    target: Target
  ): Future[Seq[(Long, TweetyPieResult)]] = {

    val resMap = {
      if (target.params(PushFeatureSwitchParams.EnableF1FromProtectedTweetAuthors)) {
        userTweetTweetyPieStoreCounter.incr()
        val keys = tweetIds.map { tweetId =>
          UserTweet(tweetId, Some(target.targetId))
        }

        userTweetTweetyPieStore
          .multiGet(keys.toSet).map {
            case (userTweet, resultFut) =>
              userTweet.tweetId -> resultFut
          }.toMap
      } else {
        (target.params(PushFeatureSwitchParams.EnableVFInTweetypie) match {
          case true => tweetyPieStore
          case false => tweetyPieStoreNoVF
        }).multiGet(tweetIds.toSet)
      }
    }
    Future.collect(resMap).map { tweetyPieResultMap =>
      val cands = filterOutReplyTweet(tweetyPieResultMap, nonReplyTweetsCounter).collect {
        case (id: Long, Some(result)) =>
          id -> result
      }

      emptyTweetyPieResult.add(tweetyPieResultMap.size - cands.size)
      cands.toSeq
    }
  }

  private def getEBRetweetCandidates(
    inputTarget: Target,
    retweets: Seq[(Long, TweetyPieResult)]
  ): Seq[RawCandidate] = {
    retweets.flatMap {
      case (_, tweetypieResult) =>
        tweetypieResult.tweet.coreData.flatMap { coreData =>
          tweetypieResult.sourceTweet.map { sourceTweet =>
            val tweetId = sourceTweet.id
            val scId = coreData.userId
            val socialProofTypes = Seq((SocialProofType.Retweet, Seq(scId)))
            val candidate = generateEarlyBirdCandidate(
              tweetId,
              Some(TweetyPieResult(sourceTweet, None, None)),
              None
            )
            generateRetweetCandidate(
              inputTarget,
              candidate,
              Seq(scId),
              socialProofTypes
            )
          }
        }
    }
  }

  private def getEBFirstDegreeCands(
    tweets: Seq[(Long, TweetyPieResult)],
    ebTweetIdMap: Map[Long, Option[ThriftSearchResultFeatures]]
  ): Seq[EBCandidate] = {
    tweets.map {
      case (id, tweetypieResult) =>
        val features = ebTweetIdMap.getOrElse(id, None)
        generateEarlyBirdCandidate(id, Some(tweetypieResult), features)
    }
  }

  /**
   * Returns a combination of raw candidates made of: f1 recs, topic social proof recs, sc recs and retweet candidates
   */
  def buildRawCandidates(
    inputTarget: Target,
    firstDegreeCandidates: Seq[EBCandidate],
    retweetCandidates: Seq[RawCandidate]
  ): Seq[RawCandidate] = {
    val hydratedF1Recs =
      firstDegreeCandidates.map(generateF1CandidateWithoutSocialContext(inputTarget, _))
    hydratedF1Recs ++ retweetCandidates
  }

  override def get(inputTarget: Target): Future[Option[Seq[RawCandidate]]] = {
    inputTarget.seedsWithWeight.flatMap { seedsetOpt =>
      val seedsetMap = seedsetOpt.getOrElse(Map.empty)

      if (seedsetMap.isEmpty) {
        seedSetEmpty.incr()
        Future.None
      } else {
        val maxResultsToReturn = inputTarget.params(maxResultsParam)
        val maxTweetAge = inputTarget.params(PushFeatureSwitchParams.F1CandidateMaxTweetAgeParam)
        val earlybirdQuery = EarlybirdCandidateSource.Query(
          maxNumResultsToReturn = maxResultsToReturn,
          seedset = seedsetMap,
          maxConsecutiveResultsByTheSameUser = Some(1),
          maxTweetAge = maxTweetAge,
          disableTimelinesMLModel = false,
          searcherId = Some(inputTarget.targetId),
          isProtectTweetsEnabled =
            inputTarget.params(PushFeatureSwitchParams.EnableF1FromProtectedTweetAuthors),
          followedUserIds = Some(seedsetMap.keySet.toSeq)
        )

        Future
          .join(inputTarget.seenTweetIds, earlyBirdFirstDegreeCandidates.get(earlybirdQuery))
          .flatMap {
            case (seenTweetIds, Some(candidates)) =>
              earlyBirdCandsStat.add(candidates.size)

              val ebTweetIdMap = candidates.map { cand => cand.tweetId -> cand.features }.toMap

              val ebTweetIds = ebTweetIdMap.keys.toSeq

              val tweetIds = filterOutSeenTweets(seenTweetIds, ebTweetIds)
              seenTweetsStat.add(ebTweetIds.size - tweetIds.size)

              filterInvalidTweets(tweetIds, inputTarget)
                .map { validTweets =>
                  val (retweets, tweets) = validTweets.partition {
                    case (_, tweetypieResult) =>
                      tweetypieResult.sourceTweet.isDefined
                  }

                  val firstDegreeCandidates = getEBFirstDegreeCands(tweets, ebTweetIdMap)

                  val retweetCandidates = {
                    if (inputTarget.params(PushParams.EarlyBirdSCBasedCandidatesParam) &&
                      inputTarget.params(PushParams.MRTweetRetweetRecsParam)) {
                      enableRetweets.incr()
                      getEBRetweetCandidates(inputTarget, retweets)
                    } else Nil
                  }

                  Some(
                    buildRawCandidates(
                      inputTarget,
                      firstDegreeCandidates,
                      retweetCandidates
                    ))
                }

            case _ =>
              emptyEarlyBirdCands.incr()
              Future.None
          }
      }
    }
  }

  override def isCandidateSourceAvailable(target: Target): Future[Boolean] = {
    PushDeviceUtil.isRecommendationsEligible(target)
  }
}