{-
	Copyright (C) 2018 Dr. Alistair Ward

	This file is part of BishBosh.

	BishBosh is free software: you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.

	BishBosh is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with BishBosh.  If not, see <http://www.gnu.org/licenses/>.
-}
{- |
 [@AUTHOR@]	Dr. Alistair Ward

 [@DESCRIPTION@]	The state which is threaded through successive calls to 'Search.Search.search'.
-}

module BishBosh.Search.SearchState(
-- * Types
-- ** Data-types
        SearchState(
--		MkSearchState,
                getPositionHashQuantifiedGameTree,
                getDynamicMoveData
        ),
-- * Functions
        euthanise,
-- ** Constructors
        mkSearchState,
        initialise
 ) where

import qualified        BishBosh.Component.Move                                 as Component.Move
import qualified        BishBosh.Evaluation.PositionHashQuantifiedGameTree      as Evaluation.PositionHashQuantifiedGameTree
import qualified        BishBosh.Input.SearchOptions                            as Input.SearchOptions
import qualified        BishBosh.Property.Empty                                 as Property.Empty
import qualified        BishBosh.Search.DynamicMoveData                         as Search.DynamicMoveData

-- | The data which is both received & returned by 'select', so that it is transported through the entire game.
data SearchState x y positionHash criterionValue weightedMean   = MkSearchState {
        getPositionHashQuantifiedGameTree       :: Evaluation.PositionHashQuantifiedGameTree.PositionHashQuantifiedGameTree x y positionHash criterionValue weightedMean,
        getDynamicMoveData                      :: Search.DynamicMoveData.DynamicMoveData x y positionHash
}

instance (
        Enum    x,
        Enum    y,
        Ord     x,
        Ord     y,
        Show    x,
        Show    y,
        Show    criterionValue,
        Show    positionHash,
        Show    weightedMean
 ) => Show (SearchState x y positionHash criterionValue weightedMean) where
        showsPrec _ _   = showString "SearchState {...}"

-- | Constructor.
mkSearchState
        :: Evaluation.PositionHashQuantifiedGameTree.PositionHashQuantifiedGameTree x y positionHash criterionValue weightedMean
        -> Search.DynamicMoveData.DynamicMoveData x y positionHash
        -> SearchState x y positionHash criterionValue weightedMean
mkSearchState   = MkSearchState

-- | Constructor.
initialise :: Evaluation.PositionHashQuantifiedGameTree.PositionHashQuantifiedGameTree x y positionHash criterionValue weightedMean -> SearchState x y positionHash criterionValue weightedMean
initialise positionHashQuantifiedGameTree = MkSearchState {
        getPositionHashQuantifiedGameTree       = positionHashQuantifiedGameTree,
        getDynamicMoveData                      = Property.Empty.empty
}

-- | Forwards request.
euthanise
        :: Component.Move.NPlies
        -> Input.SearchOptions.MaybeRetireAfterNMoves
        -> Input.SearchOptions.MaybeRetireAfterNMoves
        -> SearchState x y positionHash criterionValue weightedMean
        -> SearchState x y positionHash criterionValue weightedMean
euthanise nPlies maybeRetireKillerMovesAfter maybeRetireTranspositionsAfter searchState@MkSearchState { getDynamicMoveData = dynamicMoveData }  = searchState {
        getDynamicMoveData      = Search.DynamicMoveData.euthanise nPlies maybeRetireKillerMovesAfter maybeRetireTranspositionsAfter dynamicMoveData
}