package com.twitter.frigate.pushservice.adaptor

import com.twitter.events.recos.thriftscala.DisplayLocation
import com.twitter.events.recos.thriftscala.TrendsContext
import com.twitter.finagle.stats.StatsReceiver
import com.twitter.frigate.common.base.CandidateSource
import com.twitter.frigate.common.base.CandidateSourceEligible
import com.twitter.frigate.common.base.TrendTweetCandidate
import com.twitter.frigate.common.base.TrendsCandidate
import com.twitter.frigate.common.candidate.RecommendedTrendsCandidateSource
import com.twitter.frigate.common.candidate.RecommendedTrendsCandidateSource.Query
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.adaptor.TrendsCandidatesAdaptor._
import com.twitter.frigate.pushservice.params.PushFeatureSwitchParams
import com.twitter.frigate.pushservice.params.PushParams
import com.twitter.frigate.pushservice.predicate.TargetPredicates
import com.twitter.frigate.pushservice.util.PushDeviceUtil
import com.twitter.frigate.thriftscala.CommonRecommendationType
import com.twitter.geoduck.common.thriftscala.Location
import com.twitter.gizmoduck.thriftscala.UserType
import com.twitter.hermit.store.tweetypie.UserTweet
import com.twitter.stitch.tweetypie.TweetyPie.TweetyPieResult
import com.twitter.storehaus.ReadableStore
import com.twitter.util.Future
import scala.collection.Map

object TrendsCandidatesAdaptor {
  type TweetId = Long
  type EventId = Long
}

case class TrendsCandidatesAdaptor(
  softUserGeoLocationStore: ReadableStore[Long, Location],
  recommendedTrendsCandidateSource: RecommendedTrendsCandidateSource,
  tweetyPieStore: ReadableStore[Long, TweetyPieResult],
  tweetyPieStoreNoVF: ReadableStore[Long, TweetyPieResult],
  safeUserTweetTweetyPieStore: ReadableStore[UserTweet, TweetyPieResult],
  statsReceiver: StatsReceiver)
    extends CandidateSource[Target, RawCandidate]
    with CandidateSourceEligible[Target, RawCandidate] {
  override val name = this.getClass.getSimpleName

  private val trendAdaptorStats = statsReceiver.scope("TrendsCandidatesAdaptor")
  private val trendTweetCandidateNumber = trendAdaptorStats.counter("trend_tweet_candidate")
  private val nonReplyTweetsCounter = trendAdaptorStats.counter("non_reply_tweets")

  private def getQuery(target: Target): Future[Query] = {
    def getUserCountryCode(target: Target): Future[Option[String]] = {
      target.targetUser.flatMap {
        case Some(user) if user.userType == UserType.Soft =>
          softUserGeoLocationStore
            .get(user.id)
            .map(_.flatMap(_.simpleRgcResult.flatMap(_.countryCodeAlpha2)))

        case _ => target.accountCountryCode
      }
    }

    for {
      countryCode <- getUserCountryCode(target)
      inferredLanguage <- target.inferredUserDeviceLanguage
    } yield {
      Query(
        userId = target.targetId,
        displayLocation = DisplayLocation.MagicRecs,
        languageCode = inferredLanguage,
        countryCode = countryCode,
        maxResults = target.params(PushFeatureSwitchParams.MaxRecommendedTrendsToQuery)
      )
    }
  }

  /**
   * Query candidates only if sent at most [[PushFeatureSwitchParams.MaxTrendTweetNotificationsInDuration]]
   * trend tweet notifications in [[PushFeatureSwitchParams.TrendTweetNotificationsFatigueDuration]]
   */
  val trendTweetFatiguePredicate = TargetPredicates.pushRecTypeFatiguePredicate(
    CommonRecommendationType.TrendTweet,
    PushFeatureSwitchParams.TrendTweetNotificationsFatigueDuration,
    PushFeatureSwitchParams.MaxTrendTweetNotificationsInDuration,
    trendAdaptorStats
  )

  private val recommendedTrendsWithTweetsCandidateSource: CandidateSource[
    Target,
    RawCandidate with TrendsCandidate
  ] = recommendedTrendsCandidateSource
    .convert[Target, TrendsCandidate](
      getQuery,
      recommendedTrendsCandidateSource.identityCandidateMapper
    )
    .batchMapValues[Target, RawCandidate with TrendsCandidate](
      trendsCandidatesToTweetCandidates(_, _, getTweetyPieResults))

  private def getTweetyPieResults(
    tweetIds: Seq[TweetId],
    target: Target
  ): Future[Map[TweetId, TweetyPieResult]] = {
    if (target.params(PushFeatureSwitchParams.EnableSafeUserTweetTweetypieStore)) {
      Future
        .collect(
          safeUserTweetTweetyPieStore.multiGet(
            tweetIds.toSet.map(UserTweet(_, Some(target.targetId))))).map {
          _.collect {
            case (userTweet, Some(tweetyPieResult)) => userTweet.tweetId -> tweetyPieResult
          }
        }
    } else {
      Future
        .collect((target.params(PushFeatureSwitchParams.EnableVFInTweetypie) match {
          case true => tweetyPieStore
          case false => tweetyPieStoreNoVF
        }).multiGet(tweetIds.toSet)).map { tweetyPieResultMap =>
          filterOutReplyTweet(tweetyPieResultMap, nonReplyTweetsCounter).collect {
            case (tweetId, Some(tweetyPieResult)) => tweetId -> tweetyPieResult
          }
        }
    }
  }

  /**
   *
   * @param _target: [[Target]] object representing notificaion recipient user
   * @param trendsCandidates: Sequence of [[TrendsCandidate]] returned from ERS
   * @return: Seq of trends candidates expanded to associated tweets.
   */
  private def trendsCandidatesToTweetCandidates(
    _target: Target,
    trendsCandidates: Seq[TrendsCandidate],
    getTweetyPieResults: (Seq[TweetId], Target) => Future[Map[TweetId, TweetyPieResult]]
  ): Future[Seq[RawCandidate with TrendsCandidate]] = {

    def generateTrendTweetCandidates(
      trendCandidate: TrendsCandidate,
      tweetyPieResults: Map[TweetId, TweetyPieResult]
    ) = {
      val tweetIds = trendCandidate.context.curatedRepresentativeTweets.getOrElse(Seq.empty) ++
        trendCandidate.context.algoRepresentativeTweets.getOrElse(Seq.empty)

      tweetIds.flatMap { tweetId =>
        tweetyPieResults.get(tweetId).map { _tweetyPieResult =>
          new RawCandidate with TrendTweetCandidate {
            override val trendId: String = trendCandidate.trendId
            override val trendName: String = trendCandidate.trendName
            override val landingUrl: String = trendCandidate.landingUrl
            override val timeBoundedLandingUrl: Option[String] =
              trendCandidate.timeBoundedLandingUrl
            override val context: TrendsContext = trendCandidate.context
            override val tweetyPieResult: Option[TweetyPieResult] = Some(_tweetyPieResult)
            override val tweetId: TweetId = _tweetyPieResult.tweet.id
            override val target: Target = _target
          }
        }
      }
    }

    // collect all tweet ids associated with all trends
    val allTweetIds = trendsCandidates.flatMap { trendsCandidate =>
      val context = trendsCandidate.context
      context.curatedRepresentativeTweets.getOrElse(Seq.empty) ++
        context.algoRepresentativeTweets.getOrElse(Seq.empty)
    }

    getTweetyPieResults(allTweetIds, _target)
      .map { tweetIdToTweetyPieResult =>
        val trendTweetCandidates = trendsCandidates.flatMap { trendCandidate =>
          val allTrendTweetCandidates = generateTrendTweetCandidates(
            trendCandidate,
            tweetIdToTweetyPieResult
          )

          val (tweetCandidatesFromCuratedTrends, tweetCandidatesFromNonCuratedTrends) =
            allTrendTweetCandidates.partition(_.isCuratedTrend)

          tweetCandidatesFromCuratedTrends.filter(
            _.target.params(PushFeatureSwitchParams.EnableCuratedTrendTweets)) ++
            tweetCandidatesFromNonCuratedTrends.filter(
              _.target.params(PushFeatureSwitchParams.EnableNonCuratedTrendTweets))
        }

        trendTweetCandidateNumber.incr(trendTweetCandidates.size)
        trendTweetCandidates
      }
  }

  /**
   *
   * @param target: [[Target]] user
   * @return: true if customer is eligible to receive trend tweet notifications
   *
   */
  override def isCandidateSourceAvailable(target: Target): Future[Boolean] = {
    PushDeviceUtil
      .isRecommendationsEligible(target)
      .map(target.params(PushParams.TrendsCandidateDecider) && _)
  }

  override def get(target: Target): Future[Option[Seq[RawCandidate with TrendsCandidate]]] = {
    recommendedTrendsWithTweetsCandidateSource
      .get(target)
      .flatMap {
        case Some(candidates) if candidates.nonEmpty =>
          trendTweetFatiguePredicate(Seq(target))
            .map(_.head)
            .map { isTargetFatigueEligible =>
              if (isTargetFatigueEligible) Some(candidates)
              else None
            }

        case _ => Future.None
      }
  }
}