--
-- |
-- Module      : CopState
-- Authors     : Sean Seefried (http://www.cse.unsw.edu.au/~sseefried)
-- Copyright   : (c) 2005
-- License     : GPL version 2 or later
-- Created     : 27 Jun 2005
--
module CopState
where

import Control.Concurrent.MVar
import System.IO.Unsafe
import Data.List


import KnowledgeBase
import Logging
import CR
import Syntax

type Trust = Int

data CopState = 
  CopState { copTrust :: [(Name, Trust)] -- (names of cop, 0 <= trust  <= 100)
           , otherLocs :: [(Name, [ (Location, WorldNum)])]
           , yourLocs  :: [ (Location, WorldNum)]
           }

state :: MVar CopState
state = unsafePerformIO 
          (newMVar CopState { 
                        copTrust  = niceError "Not initialised",
                        otherLocs = niceError "Not initialised",
                        yourLocs  = niceError "Not initialised" })
{-# NOINLINE state #-}


initState :: CR ()
initState =
    do kb <- getKB
       let copNames = kb_copNames kb
           ownName = kb_ownName kb
           otherNames = copNames \\ [ownName]
       setState $ CopState { copTrust  = zip otherNames (repeat 0),   
                             otherLocs = [ (name, []) | name <- otherNames],
                             yourLocs  = [] }
        
getState :: CR CopState
getState = liftIO $ readMVar state

setState :: CopState -> CR ()
setState s = liftIO $ modifyMVar_ state $ (const $ return s)

addLoc :: Eq a => (a, b) -> [(a,[b])] -> [(a,[b])]
addLoc _ [] = []
addLoc p@(a,b) (p'@(a', bs'): rest)
  | a == a'   = (a, b : bs') : rest
  | otherwise = p' : addLoc p rest


addToLocs :: Eq a => (a, [b]) -> [(a,[b])] -> [(a,[b])]
addToLocs _ [] = []
addToLocs p@(a,bs) (p'@(a', bs'): rest)
  | a == a'   = (a, bs ++ bs') : rest
  | otherwise = p' : addToLocs p rest