--
-- |
-- Module      : RobberOneStepMoveFun
-- Authors     : Sean Seefried (http://www.cse.unsw.edu.au/~sseefried)
-- Copyright   : (c) 2005
-- License     : GPL version 2 or later
-- Created     : 26 Jun 2005
--
-- Looks ahead one move.
--
module RobberOneStepMoveFun
where

import Data.IORef
import System.IO.Unsafe
import Data.List

-- Local imports

import KnowledgeBase
import RobberHeuristic
import Syntax
import Logging
import Pretty
import CR
import Graph

--
-- 1. Applies larceny, evidence dropping and bank transferal for current world.
-- 2. Applies a dummy cop move
-- 3. Applies a predicted move
--
nextMove :: KnowledgeBase -> GNode -> GNode -> KnowledgeBase
nextMove kb src tgt =
  let copNodes = map cop_node (kb_cops kb)
      kb' = robberMove kb src src 
      kb'' = copMove kb' copNodes
  in robberMove kb'' src tgt


moveFun :: CR Move
moveFun = 
    do kb <- getKB
       case kb_ownLoc kb of
         [(name,loc)] -> moveFun' name loc
         l -> fatal ("robber cannot be at " ++ show (length l) ++ " locations: "
                     ++ show l)

moveFun' :: Name -> GNode -> CR Move
moveFun' name loc = 
    do kb <- getKB
       let graphFoot = kb_footMap kb
       let succNodes = gsucc graphFoot loc
           candidateNodes = loc : succNodes -- include current node
           candidatePairs = map (\next -> (next, nextMove kb loc next)) 
                                candidateNodes
           checkGoodness (nextLoc, kbNext) = 
               let g = goodness kbNext
                         loc
                         5     -- cop thresh dist
                         0.5    -- nearMoneyCoeff
                         1      -- haveMoneyCoeff
                         1000   -- smelledCoeff 
                         500    -- copCoeff
                         100000 -- caughtCoeff
                   in return (g, nextLoc)
           orderLoc (a, _) (b, _) 
             | a <= b      = LT -- these are floats. EQ does not happen
             | otherwise  = GT
       goodnessNodes <- mapM checkGoodness candidatePairs
       let showPprSnd (goodness, node) = (goodness, showPpr (locOfNode node))
           bestNode = snd (maximumBy orderLoc goodnessNodes)
         
       debug $ "The goodnesses of the next nodes are: " ++ 
               show (map showPprSnd goodnessNodes)
       --
       -- Move to best node
       -- 
       return $ Move (locOfNode bestNode) Robber name