lila/modules/game/src/main/Game.scala

package lila.game

import chess.Color.{ Black, White }
import chess.format.{ FEN, Uci }
import chess.opening.{ FullOpening, FullOpeningDB }
import chess.variant.{ FromPosition, Standard, Variant }
import chess.{ Castles, Centis, CheckCount, Clock, Color, Mode, MoveOrDrop, Speed, Status, Game => ChessGame }
import org.joda.time.DateTime

import lila.common.Sequence
import lila.db.ByteArray
import lila.rating.PerfType
import lila.rating.PerfType.Classical
import lila.user.User

case class Game(
    id: Game.ID,
    whitePlayer: Player,
    blackPlayer: Player,
    chess: ChessGame,
    loadClockHistory: Clock => Option[ClockHistory] = _ => Game.someEmptyClockHistory,
    status: Status,
    daysPerTurn: Option[Int],
    binaryMoveTimes: Option[ByteArray] = None,
    mode: Mode = Mode.default,
    bookmarks: Int = 0,
    createdAt: DateTime = DateTime.now,
    movedAt: DateTime = DateTime.now,
    metadata: Metadata
) {
  lazy val clockHistory = chess.clock flatMap loadClockHistory

  def situation = chess.situation
  def board     = chess.situation.board
  def history   = chess.situation.board.history
  def variant   = chess.situation.board.variant
  def turns     = chess.turns
  def clock     = chess.clock
  def pgnMoves  = chess.pgnMoves

  val players = List(whitePlayer, blackPlayer)

  def player(color: Color): Player = color.fold(whitePlayer, blackPlayer)

  def player(playerId: Player.ID): Option[Player] =
    players find (_.id == playerId)

  def player(user: User): Option[Player] =
    players find (_ isUser user)

  def player(c: Color.type => Color): Player = player(c(Color))

  def isPlayerFullId(player: Player, fullId: String): Boolean =
    (fullId.lengthIs == Game.fullIdSize) && player.id == (fullId drop Game.gameIdSize)

  def player: Player = player(turnColor)

  def playerByUserId(userId: User.ID): Option[Player]   = players.find(_.userId contains userId)
  def opponentByUserId(userId: User.ID): Option[Player] = playerByUserId(userId) map opponent

  def hasUserIds(userId1: User.ID, userId2: User.ID) =
    playerByUserId(userId1).isDefined && playerByUserId(userId2).isDefined

  def hasUserId(userId: User.ID) = playerByUserId(userId).isDefined

  def opponent(p: Player): Player = opponent(p.color)

  def opponent(c: Color): Player = player(!c)

  lazy val naturalOrientation =
    if (variant.racingKings) White else Color.fromWhite(whitePlayer before blackPlayer)

  def turnColor = chess.player

  def turnOf(p: Player): Boolean = p == player
  def turnOf(c: Color): Boolean  = c == turnColor
  def turnOf(u: User): Boolean   = player(u) ?? turnOf

  def playedTurns = turns - chess.startedAtTurn

  def flagged = (status == Status.Outoftime).option(turnColor)

  def fullIdOf(player: Player): Option[String] =
    (players contains player) option s"$id${player.id}"

  def fullIdOf(color: Color): String = s"$id${player(color).id}"

  def tournamentId = metadata.tournamentId
  def simulId      = metadata.simulId
  def swissId      = metadata.swissId

  def isTournament = tournamentId.isDefined
  def isSimul      = simulId.isDefined
  def isSwiss      = swissId.isDefined
  def isMandatory  = isTournament || isSimul || isSwiss
  def isClassical  = perfType contains Classical
  def nonMandatory = !isMandatory

  def hasChat = !isTournament && !isSimul && nonAi

  // we can't rely on the clock,
  // because if moretime was given,
  // elapsed time is no longer representing the game duration
  def durationSeconds: Option[Int] =
    movedAt.getSeconds - createdAt.getSeconds match {
      case seconds if seconds > 60 * 60 * 12 => none // no way it lasted more than 12 hours, come on.
      case seconds                           => seconds.toInt.some
    }

  private def everyOther[A](l: List[A]): List[A] =
    l match {
      case a :: _ :: tail => a :: everyOther(tail)
      case _              => l
    }

  def moveTimes(color: Color): Option[List[Centis]] = {
    for {
      clk <- clock
      inc = clk.incrementOf(color)
      history <- clockHistory
      clocks = history(color)
    } yield Centis(0) :: {
      val pairs = clocks.iterator zip clocks.iterator.drop(1)

      // We need to determine if this color's last clock had inc applied.
      // if finished and history.size == playedTurns then game was ended
      // by a players move, such as with mate or autodraw. In this case,
      // the last move of the game, and the only one without inc, is the
      // last entry of the clock history for !turnColor.
      //
      // On the other hand, if history.size is more than playedTurns,
      // then the game ended during a players turn by async event, and
      // the last recorded time is in the history for turnColor.
      val noLastInc = finished && (history.size <= playedTurns) == (color != turnColor)

      pairs map { case (first, second) =>
        {
          val d = first - second
          if (pairs.hasNext || !noLastInc) d + inc else d
        } nonNeg
      } toList
    }
  } orElse binaryMoveTimes.map { binary =>
    // TODO: make movetime.read return List after writes are disabled.
    val base = BinaryFormat.moveTime.read(binary, playedTurns)
    val mts  = if (color == startColor) base else base.drop(1)
    everyOther(mts.toList)
  }

  def moveTimes: Option[Vector[Centis]] =
    for {
      a <- moveTimes(startColor)
      b <- moveTimes(!startColor)
    } yield Sequence.interleave(a, b)

  def bothClockStates: Option[Vector[Centis]] = clockHistory.map(_ bothClockStates startColor)

  def pgnMoves(color: Color): PgnMoves = {
    val pivot = if (color == startColor) 0 else 1
    pgnMoves.zipWithIndex.collect {
      case (e, i) if (i % 2) == pivot => e
    }
  }

  // apply a move
  def update(
      game: ChessGame, // new chess position
      moveOrDrop: MoveOrDrop,
      blur: Boolean = false
  ): Progress = {

    def copyPlayer(player: Player) =
      if (blur && moveOrDrop.fold(_.color, _.color) == player.color)
        player.copy(
          blurs = player.blurs.add(playerMoves(player.color))
        )
      else player

    // This must be computed eagerly
    // because it depends on the current time
    val newClockHistory = for {
      clk <- game.clock
      ch  <- clockHistory
    } yield ch.record(turnColor, clk)

    val updated = copy(
      whitePlayer = copyPlayer(whitePlayer),
      blackPlayer = copyPlayer(blackPlayer),
      chess = game,
      binaryMoveTimes = (!isPgnImport && chess.clock.isEmpty).option {
        BinaryFormat.moveTime.write {
          binaryMoveTimes.?? { t =>
            BinaryFormat.moveTime.read(t, playedTurns)
          } :+ Centis(nowCentis - movedAt.getCentis).nonNeg
        }
      },
      loadClockHistory = _ => newClockHistory,
      status = game.situation.status | status,
      movedAt = DateTime.now
    )

    val state = Event.State(
      color = game.situation.color,
      turns = game.turns,
      status = (status != updated.status) option updated.status,
      winner = game.situation.winner,
      whiteOffersDraw = whitePlayer.isOfferingDraw,
      blackOffersDraw = blackPlayer.isOfferingDraw
    )

    val clockEvent = updated.chess.clock map Event.Clock.apply orElse {
      updated.playableCorrespondenceClock map Event.CorrespondenceClock.apply
    }

    val events = moveOrDrop.fold(
      Event.Move(_, game.situation, state, clockEvent, updated.board.crazyData),
      Event.Drop(_, game.situation, state, clockEvent, updated.board.crazyData)
    ) :: {
      // abstraction leak, I know.
      (updated.board.variant.threeCheck && game.situation.check) ?? List(
        Event.CheckCount(
          white = updated.history.checkCount.white,
          black = updated.history.checkCount.black
        )
      )
    }

    Progress(this, updated, events)
  }

  def lastMoveKeys: Option[String] =
    history.lastMove map {
      case Uci.Drop(target, _) => s"$target$target"
      case m: Uci.Move         => m.keys
    }

  def updatePlayer(color: Color, f: Player => Player) =
    color.fold(
      copy(whitePlayer = f(whitePlayer)),
      copy(blackPlayer = f(blackPlayer))
    )

  def updatePlayers(f: Player => Player) =
    copy(
      whitePlayer = f(whitePlayer),
      blackPlayer = f(blackPlayer)
    )

  def start =
    if (started) this
    else
      copy(
        status = Status.Started,
        mode = Mode(mode.rated && userIds.distinct.size == 2)
      )

  def startClock =
    clock map { c =>
      start.withClock(c.start)
    }

  def correspondenceClock: Option[CorrespondenceClock] =
    daysPerTurn map { days =>
      val increment   = days * 24 * 60 * 60
      val secondsLeft = (movedAt.getSeconds + increment - nowSeconds).toInt max 0
      CorrespondenceClock(
        increment = increment,
        whiteTime = turnColor.fold(secondsLeft, increment).toFloat,
        blackTime = turnColor.fold(increment, secondsLeft).toFloat
      )
    }

  def playableCorrespondenceClock: Option[CorrespondenceClock] =
    playable ?? correspondenceClock

  def speed = Speed(chess.clock.map(_.config))

  def perfKey  = PerfPicker.key(this)
  def perfType = PerfType(perfKey)

  def started = status >= Status.Started

  def notStarted = !started

  def aborted = status == Status.Aborted

  def playedThenAborted = aborted && bothPlayersHaveMoved

  def abort = copy(status = Status.Aborted)

  def playable = status < Status.Aborted && !imported

  def playableEvenImported = status < Status.Aborted

  def playableBy(p: Player): Boolean = playable && turnOf(p)

  def playableBy(c: Color): Boolean = playableBy(player(c))

  def playableByAi: Boolean = playable && player.isAi

  def mobilePushable = isCorrespondence && playable && nonAi

  def alarmable = hasCorrespondenceClock && playable && nonAi

  def continuable = status != Status.Mate && status != Status.Stalemate

  def aiLevel: Option[Int] = players find (_.isAi) flatMap (_.aiLevel)

  def hasAi: Boolean = players.exists(_.isAi)
  def nonAi          = !hasAi

  def aiPov: Option[Pov] = players.find(_.isAi).map(_.color) map pov

  def mapPlayers(f: Player => Player) =
    copy(
      whitePlayer = f(whitePlayer),
      blackPlayer = f(blackPlayer)
    )

  def drawOffers = metadata.drawOffers

  def playerCanOfferDraw(color: Color) =
    started && playable &&
      turns >= 2 &&
      !player(color).isOfferingDraw &&
      !opponent(color).isAi &&
      !playerHasOfferedDrawRecently(color)

  def playerHasOfferedDrawRecently(color: Color) =
    drawOffers.lastBy(color) ?? (_ >= turns - 20)

  def offerDraw(color: Color) = copy(
    metadata = metadata.copy(drawOffers = drawOffers.add(color, turns))
  ).updatePlayer(color, _.offerDraw)

  def playerCouldRematch =
    finishedOrAborted &&
      nonMandatory &&
      !boosted && ! {
        hasAi && variant == FromPosition && clock.exists(_.config.limitSeconds < 60)
      }

  def playerCanProposeTakeback(color: Color) =
    started && playable && !isTournament && !isSimul &&
      bothPlayersHaveMoved &&
      !player(color).isProposingTakeback &&
      !opponent(color).isProposingTakeback

  def boosted = rated && finished && bothPlayersHaveMoved && playedTurns < 10

  def moretimeable(color: Color) =
    playable && nonMandatory && {
      clock.??(_ moretimeable color) || correspondenceClock.??(_ moretimeable color)
    }

  def abortable = status == Status.Started && playedTurns < 2 && nonMandatory

  def berserkable = clock.??(_.config.berserkable) && status == Status.Started && playedTurns < 2

  def goBerserk(color: Color): Option[Progress] =
    clock.ifTrue(berserkable && !player(color).berserk).map { c =>
      val newClock = c goBerserk color
      Progress(
        this,
        copy(
          chess = chess.copy(clock = Some(newClock)),
          loadClockHistory = _ =>
            clockHistory.map(history => {
              if (history(color).isEmpty) history
              else history.reset(color).record(color, newClock)
            })
        ).updatePlayer(color, _.goBerserk)
      ) ++
        List(
          Event.ClockInc(color, -c.config.berserkPenalty),
          Event.Clock(newClock), // BC
          Event.Berserk(color)
        )
    }

  def resignable      = playable && !abortable
  def drawable        = playable && !abortable
  def forceResignable = resignable && nonAi && !fromFriend && hasClock && !isSwiss

  def finish(status: Status, winner: Option[Color]) = {
    val newClock = clock map { _.stop }
    Progress(
      this,
      copy(
        status = status,
        whitePlayer = whitePlayer.finish(winner contains White),
        blackPlayer = blackPlayer.finish(winner contains Black),
        chess = chess.copy(clock = newClock),
        loadClockHistory = clk =>
          clockHistory map { history =>
            // If not already finished, we're ending due to an event
            // in the middle of a turn, such as resignation or draw
            // acceptance. In these cases, record a final clock time
            // for the active color. This ensures the end time in
            // clockHistory always matches the final clock time on
            // the board.
            if (!finished) history.record(turnColor, clk)
            else history
          }
      ),
      // Events here for BC.
      List(Event.End(winner)) ::: newClock.??(c => List(Event.Clock(c)))
    )
  }

  def rated  = mode.rated
  def casual = !rated

  def finished = status >= Status.Mate

  def finishedOrAborted = finished || aborted

  def accountable = playedTurns >= 2 || isTournament

  def replayable = isPgnImport || finished || (aborted && bothPlayersHaveMoved)

  def analysable =
    replayable && playedTurns > 4 &&
      Game.analysableVariants(variant) &&
      !Game.isOldHorde(this)

  def ratingVariant =
    if (isTournament && variant.fromPosition) Standard
    else variant

  def fromPosition = variant.fromPosition || source.??(Source.Position ==)

  def imported = source contains Source.Import

  def fromPool   = source contains Source.Pool
  def fromLobby  = source contains Source.Lobby
  def fromFriend = source contains Source.Friend
  def fromApi    = source contains Source.Api

  def winner = players find (_.wins)

  def loser = winner map opponent

  def winnerColor: Option[Color] = winner map (_.color)

  def winnerUserId: Option[String] = winner flatMap (_.userId)

  def loserUserId: Option[String] = loser flatMap (_.userId)

  def wonBy(c: Color): Option[Boolean] = winner map (_.color == c)

  def lostBy(c: Color): Option[Boolean] = winner map (_.color != c)

  def drawn = finished && winner.isEmpty

  def outoftime(withGrace: Boolean): Boolean =
    if (isCorrespondence) outoftimeCorrespondence else outoftimeClock(withGrace)

  private def outoftimeClock(withGrace: Boolean): Boolean =
    clock ?? { c =>
      started && playable && {
        c.outOfTime(turnColor, withGrace) || {
          !c.isRunning && c.players.exists(_.elapsed.centis > 0)
        }
      }
    }

  private def outoftimeCorrespondence: Boolean =
    playableCorrespondenceClock ?? { _ outoftime turnColor }

  def isCorrespondence = speed == Speed.Correspondence

  def isSwitchable = nonAi && (isCorrespondence || isSimul)

  def hasClock = clock.isDefined

  def hasCorrespondenceClock = daysPerTurn.isDefined

  def isUnlimited = !hasClock && !hasCorrespondenceClock

  def isClockRunning = clock ?? (_.isRunning)

  def withClock(c: Clock) = Progress(this, copy(chess = chess.copy(clock = Some(c))))

  def correspondenceGiveTime = Progress(this, copy(movedAt = DateTime.now))

  def estimateClockTotalTime = clock.map(_.estimateTotalSeconds)

  def estimateTotalTime =
    estimateClockTotalTime orElse
      correspondenceClock.map(_.estimateTotalTime) getOrElse 1200

  def timeForFirstMove: Centis =
    Centis ofSeconds {
      import Speed._
      val base = if (isTournament) speed match {
        case UltraBullet => 11
        case Bullet      => 16
        case Blitz       => 21
        case Rapid       => 25
        case _           => 30
      }
      else
        speed match {
          case UltraBullet => 15
          case Bullet      => 20
          case Blitz       => 25
          case Rapid       => 30
          case _           => 35
        }
      if (variant.chess960) base * 5 / 4
      else base
    }

  def expirable =
    !bothPlayersHaveMoved && source.exists(Source.expirable.contains) && playable && nonAi && clock.exists(
      !_.isRunning
    )

  def timeBeforeExpiration: Option[Centis] =
    expirable option {
      Centis.ofMillis(movedAt.getMillis - nowMillis + timeForFirstMove.millis).nonNeg
    }

  def playerWhoDidNotMove: Option[Player] =
    playedTurns match {
      case 0 => player(startColor).some
      case 1 => player(!startColor).some
      case _ => none
    }

  def onePlayerHasMoved    = playedTurns > 0
  def bothPlayersHaveMoved = playedTurns > 1

  def startColor = Color.fromPly(chess.startedAtTurn)

  def playerMoves(color: Color): Int =
    if (color == startColor) (playedTurns + 1) / 2
    else playedTurns / 2

  def playerHasMoved(color: Color) = playerMoves(color) > 0

  def playerBlurPercent(color: Color): Int =
    if (playedTurns > 5) (player(color).blurs.nb * 100) / playerMoves(color)
    else 0

  def isBeingPlayed = !isPgnImport && !finishedOrAborted

  def olderThan(seconds: Int) = movedAt isBefore DateTime.now.minusSeconds(seconds)

  def justCreated = createdAt isAfter DateTime.now.minusSeconds(1)

  def unplayed = !bothPlayersHaveMoved && (createdAt isBefore Game.unplayedDate)

  def abandoned =
    (status <= Status.Started) && {
      movedAt isBefore {
        if (hasAi && hasClock) Game.aiAbandonedDate
        else Game.abandonedDate
      }
    }

  def forecastable = started && playable && isCorrespondence && !hasAi

  def hasBookmarks = bookmarks > 0

  def showBookmarks = hasBookmarks ?? bookmarks.toString

  def userIds = playerMaps(_.userId)

  def twoUserIds: Option[(User.ID, User.ID)] =
    for {
      w <- whitePlayer.userId
      b <- blackPlayer.userId
      if w != b
    } yield w -> b

  def userRatings = playerMaps(_.rating)

  def averageUsersRating =
    userRatings match {
      case a :: b :: Nil => Some((a + b) / 2)
      case a :: Nil      => Some((a + 1500) / 2)
      case _             => None
    }

  def withTournamentId(id: String) = copy(metadata = metadata.copy(tournamentId = id.some))
  def withSwissId(id: String)      = copy(metadata = metadata.copy(swissId = id.some))

  def withSimulId(id: String) = copy(metadata = metadata.copy(simulId = id.some))

  def withId(newId: String) = copy(id = newId)

  def source = metadata.source

  def pgnImport   = metadata.pgnImport
  def isPgnImport = pgnImport.isDefined

  def resetTurns =
    copy(
      chess = chess.copy(turns = 0, startedAtTurn = 0)
    )

  lazy val opening: Option[FullOpening.AtPly] =
    if (fromPosition || !Variant.openingSensibleVariants(variant)) none
    else FullOpeningDB search pgnMoves

  def synthetic = id == Game.syntheticId

  private def playerMaps[A](f: Player => Option[A]): List[A] = players flatMap f

  def pov(c: Color)                                 = Pov(this, c)
  def playerIdPov(playerId: Player.ID): Option[Pov] = player(playerId) map { Pov(this, _) }
  def whitePov                                      = pov(White)
  def blackPov                                      = pov(Black)
  def playerPov(p: Player)                          = pov(p.color)
  def loserPov                                      = loser map playerPov

  def setAnalysed = copy(metadata = metadata.copy(analysed = true))

  def secondsSinceCreation = (nowSeconds - createdAt.getSeconds).toInt

  def drawReason = {
    if (drawOffers.normalizedPlies.exists(turns <=)) DrawReason.MutualAgreement.some
    else if (variant.fiftyMoves(history)) DrawReason.FiftyMoves.some
    else if (history.threefoldRepetition) DrawReason.ThreefoldRepetition.some
    else if (variant.isInsufficientMaterial(board)) DrawReason.InsufficientMaterial.some
    else None
  }

  override def toString = s"""Game($id)"""
}

object Game {

  type ID = String

  case class Id(value: String) extends AnyVal with StringValue {
    def full(playerId: PlayerId) = FullId(s"$value{$playerId.value}")
  }
  case class FullId(value: String) extends AnyVal with StringValue {
    def gameId   = Id(value take gameIdSize)
    def playerId = PlayerId(value drop gameIdSize)
  }
  case class PlayerId(value: String) extends AnyVal with StringValue

  case class WithInitialFen(game: Game, fen: Option[FEN])

  val syntheticId = "synthetic"

  val maxPlayingRealtime = 100 // plus 200 correspondence games

  val maxPlies = 600 // unlimited can cause StackOverflowError

  val analysableVariants: Set[Variant] = Set(
    chess.variant.Standard,
    chess.variant.Crazyhouse,
    chess.variant.Chess960,
    chess.variant.KingOfTheHill,
    chess.variant.ThreeCheck,
    chess.variant.Antichess,
    chess.variant.FromPosition,
    chess.variant.Horde,
    chess.variant.Atomic,
    chess.variant.RacingKings
  )

  val unanalysableVariants: Set[Variant] = Variant.all.toSet -- analysableVariants

  val variantsWhereWhiteIsBetter: Set[Variant] = Set(
    chess.variant.ThreeCheck,
    chess.variant.Atomic,
    chess.variant.Horde,
    chess.variant.RacingKings,
    chess.variant.Antichess
  )

  val blindModeVariants: Set[Variant] = Set(
    chess.variant.Standard,
    chess.variant.Chess960,
    chess.variant.KingOfTheHill,
    chess.variant.ThreeCheck,
    chess.variant.FromPosition,
    chess.variant.Antichess,
    chess.variant.Atomic,
    chess.variant.RacingKings,
    chess.variant.Horde
  )

  val hordeWhitePawnsSince = new DateTime(2015, 4, 11, 10, 0)

  def isOldHorde(game: Game) =
    game.variant == chess.variant.Horde &&
      game.createdAt.isBefore(Game.hordeWhitePawnsSince)

  def allowRated(variant: Variant, clock: Option[Clock.Config]) =
    variant.standard || {
      clock ?? { c =>
        c.estimateTotalTime >= Centis(3000) &&
        c.limitSeconds > 0 || c.incrementSeconds > 1
      }
    }

  val gameIdSize   = 8
  val playerIdSize = 4
  val fullIdSize   = 12
  val tokenSize    = 4

  val unplayedHours = 24
  def unplayedDate  = DateTime.now minusHours unplayedHours

  val abandonedDays = 21
  def abandonedDate = DateTime.now minusDays abandonedDays

  val aiAbandonedHours = 6
  def aiAbandonedDate  = DateTime.now minusHours aiAbandonedHours

  def takeGameId(fullId: String)   = fullId take gameIdSize
  def takePlayerId(fullId: String) = fullId drop gameIdSize

  val idRegex         = """[\w-]{8}""".r
  def validId(id: ID) = idRegex matches id

  def isBoardCompatible(game: Game): Boolean =
    game.clock.fold(true) { c =>
      isBoardCompatible(c.config) || {
        (game.hasAi || game.fromFriend) && chess.Speed(c.config) >= Speed.Blitz
      }
    }

  def isBoardCompatible(clock: Clock.Config): Boolean =
    chess.Speed(clock) >= Speed.Rapid

  def isBotCompatible(game: Game): Boolean = {
    game.hasAi || game.fromFriend || game.fromApi
  } && isBotCompatible(game.speed)

  def isBotCompatible(speed: Speed): Boolean = speed >= Speed.Bullet

  private[game] val emptyCheckCount = CheckCount(0, 0)

  private[game] val someEmptyClockHistory = Some(ClockHistory())

  def make(
      chess: ChessGame,
      whitePlayer: Player,
      blackPlayer: Player,
      mode: Mode,
      source: Source,
      pgnImport: Option[PgnImport],
      daysPerTurn: Option[Int] = None
  ): NewGame = {
    val createdAt = DateTime.now
    NewGame(
      Game(
        id = IdGenerator.uncheckedGame,
        whitePlayer = whitePlayer,
        blackPlayer = blackPlayer,
        chess = chess,
        status = Status.Created,
        daysPerTurn = daysPerTurn,
        mode = mode,
        metadata = metadata(source).copy(pgnImport = pgnImport),
        createdAt = createdAt,
        movedAt = createdAt
      )
    )
  }

  def metadata(source: Source) =
    Metadata(
      source = source.some,
      pgnImport = none,
      tournamentId = none,
      swissId = none,
      simulId = none,
      analysed = false,
      drawOffers = GameDrawOffers.empty
    )

  object BSONFields {

    val id                = "_id"
    val whitePlayer       = "p0"
    val blackPlayer       = "p1"
    val playerIds         = "is"
    val playerUids        = "us"
    val playingUids       = "pl"
    val binaryPieces      = "ps"
    val oldPgn            = "pg"
    val huffmanPgn        = "hp"
    val status            = "s"
    val turns             = "t"
    val startedAtTurn     = "st"
    val clock             = "c"
    val positionHashes    = "ph"
    val checkCount        = "cc"
    val castleLastMove    = "cl"
    val unmovedRooks      = "ur"
    val daysPerTurn       = "cd"
    val moveTimes         = "mt"
    val whiteClockHistory = "cw"
    val blackClockHistory = "cb"
    val rated             = "ra"
    val analysed          = "an"
    val variant           = "v"
    val crazyData         = "chd"
    val bookmarks         = "bm"
    val createdAt         = "ca"
    val movedAt           = "ua" // ua = updatedAt (bc)
    val source            = "so"
    val pgnImport         = "pgni"
    val tournamentId      = "tid"
    val swissId           = "iid"
    val simulId           = "sid"
    val tvAt              = "tv"
    val winnerColor       = "w"
    val winnerId          = "wid"
    val initialFen        = "if"
    val checkAt           = "ck"
    val perfType          = "pt" // only set on student games for aggregation
    val drawOffers        = "do"
  }
}

case class CastleLastMove(castles: Castles, lastMove: Option[Uci])

object CastleLastMove {

  def init = CastleLastMove(Castles.all, None)

  import reactivemongo.api.bson._
  import lila.db.ByteArray.ByteArrayBSONHandler

  implicit private[game] val castleLastMoveBSONHandler = new BSONHandler[CastleLastMove] {
    def readTry(bson: BSONValue) =
      bson match {
        case bin: BSONBinary => ByteArrayBSONHandler readTry bin map BinaryFormat.castleLastMove.read
        case b               => lila.db.BSON.handlerBadType(b)
      }
    def writeTry(clmt: CastleLastMove) =
      ByteArrayBSONHandler writeTry {
        BinaryFormat.castleLastMove write clmt
      }
  }
}

case class ClockHistory(
    white: Vector[Centis] = Vector.empty,
    black: Vector[Centis] = Vector.empty
) {

  def update(color: Color, f: Vector[Centis] => Vector[Centis]): ClockHistory =
    color.fold(copy(white = f(white)), copy(black = f(black)))

  def record(color: Color, clock: Clock): ClockHistory =
    update(color, _ :+ clock.remainingTime(color))

  def reset(color: Color) = update(color, _ => Vector.empty)

  def apply(color: Color): Vector[Centis] = color.fold(white, black)

  def last(color: Color) = apply(color).lastOption

  def size = white.size + black.size

  // first state is of the color that moved first.
  def bothClockStates(firstMoveBy: Color): Vector[Centis] =
    Sequence.interleave(
      firstMoveBy.fold(white, black),
      firstMoveBy.fold(black, white)
    )
}

sealed trait DrawReason
object DrawReason {
  case object MutualAgreement      extends DrawReason
  case object FiftyMoves           extends DrawReason
  case object ThreefoldRepetition  extends DrawReason
  case object InsufficientMaterial extends DrawReason
}