-- | An example AI player.
module AI.Lame(lameStrategy) where

import System.Random
import AI.Utils
import Board

-- randomly selects the next valid turn
lameStrategy :: Strategy
lameStrategy = withNPieces $ 
               \n -> if n==60 then lame0 else lameNext     

-- | Starting move: capture only
lame0 :: Strategy
lame0 (GameTree _ branches) rnd = (turns !! i, rnd')
  where
  turns = [ (m1, Pass) | (m1, _) <- branches ]
  (i, rnd') = randomR (0, length turns - 1) rnd


-- | The lame strategy picks a valid turn at random. 
-- If a two-move turn is available, it picks one.  (wow, pretty smart!)
lameNext :: Strategy
lameNext (GameTree _ branches) rnd = (turns !! i, rnd')
  where
  allTurns = [ (m1,m2) | 
               (m1,GameTree _ branches')<-branches, 
               (m2, _) <- branches']
  goodTurns = [ (m1, m2) | (m1, m2) <- allTurns, m2/=Pass ]
  turns = if null goodTurns then allTurns else goodTurns
  (i, rnd') = randomR (0, length turns - 1) rnd