module Senate(
    SenateCounter,
    createSenateCounter,
    doCount
    ) where




import qualified SenateTypes as Typ
import qualified CSV as CSV
import qualified Storage as Store
import qualified Text.ParserCombinators.Parsec as Parsec
import qualified Data.Either as Either
import qualified Data.Maybe as Maybe
import qualified Data.List as List




type Preferences = [(Typ.Position,Typ.Ranking)]
type FullPreferences = (Preferences,Preferences)

data SenateCounter = SenateCounter { prefData   :: Store.PrefStorage
                                   , ballotMap  :: Typ.BelowLineBallot
                                   , numBallots :: Integer }




headerLines = 2
minAboveTheLine = 1
minBelowTheLine = 6




createSenateCounter :: FilePath -> Typ.AboveLineBallot -> Typ.BelowLineBallot -> IO SenateCounter
createSenateCounter f a b = do
    --
    raw <- readFile f
    let numLines = length (lines raw)
    arrayData <- Store.createStorage numLines (length b)
    --
    raw2 <- readFile f
    let rawRecs = drop headerLines (lines raw2)
        parsedRecs = fromRights (map (CSV.parseRecord CSV.defaultSettings) rawRecs)
        rawPrefs = map last parsedRecs
        parsedPrefs = fromRights (map (parsePreferences (length a) (length b)) rawPrefs)
        normedPrefs = fromJusts (map (normalise a b) parsedPrefs)
        addToArray x (n,p) = mapM_ (uncurry (Store.pokePref x n)) p
    mapM_ (addToArray arrayData) (zip [1,2..] normedPrefs)
    --
    return (SenateCounter arrayData b (length normedPrefs))




doCount :: SenateCounter -> Typ.Criteria -> Int
doCount sen crit =
    let isValidCriteria = all ((`List.elem` (ballotMap sen)) . snd) crit
        critToPref (r,c) = (Maybe.fromJust (List.elemIndex c (ballotMap sen)) + 1, r)
        neededPrefs = map critToPref crit
        papers = map (Store.peekPref (prefData sen)) [1 .. (numBallots sen)]
        check paper = all (> 0) (map (uncurry paper) neededPrefs)
        result = filter id check papers
    in if isValidCriteria then (length result) else 0




--  converts a set of above+below-the-line preferences to just formal below-the-line
normalise :: Typ.AboveLineBallot -> Typ.BelowLineBallot -> FullPreferences -> Maybe Preferences
normalise a b f =
    let na = extractFormal (fst f)
        nb = extractFormal (snd f)
    in if (isValidFormal minBelowTheLine b nb)
            then Just nb
            else if (isValidFormal minAboveTheLine a na)
                    then Just (fromAboveToBelow a na)
                    else Nothing




extractFormal :: Preferences -> Preferences
extractFormal p =
    let funcTail n r p =
            let (matches,rest) = List.partition ((== n) . snd) p
            in if (p == [] || (length matches) /= 1)
                then r
                else funcTail (n + 1) ((head matches):r) rest
    in funcTail 1 [] p




isValidFormal :: Foldable t => Int -> t a -> Preferences -> Bool
isValidFormal minLimit ballot pref =
    (length pref >= minLimit) || (length pref == length ballot)




fromAboveToBelow :: Typ.AboveLineBallot -> Preferences -> Preferences
fromAboveToBelow a p =
    let sortedByRanking = List.sortBy (\x y -> compare (snd x) (snd y)) p
        tailFunc n bp ap =
            if (ap == [])
                then bp
                else let place = fst (head ap)
                         newPrefs = zip (a !! (place - 1)) [n, n+1 ..]
                     in tailFunc (n + length newPrefs) (bp ++ newPrefs) (tail ap)
    in tailFunc 1 [] sortedByRanking




--  the two int arguments are the number of boxes above the line and the number
--  of boxes below the line respectively
parsePreferences :: Int -> Int -> String -> Either Parsec.ParseError FullPreferences
parsePreferences aboveBoxes belowBoxes input =
    Parsec.parse (preference aboveBoxes belowBoxes) "error" input


preference a b = do
    x <- Parsec.count a rank
    y <- Parsec.count b rank
    Parsec.eof
    let xr = map (read :: String -> Typ.Ranking) x
        yr = map (read :: String -> Typ.Ranking) y
        xp = (filter ((> 0) . snd) (zip [1,2..] xr))
        yp = (filter ((> 0) . snd) (zip [1,2..] yr))
    return (xp,yp)


rank = do
    n <- Parsec.choice [normalRank, weirdRank, nullRank]
    Parsec.choice [Parsec.char ',' >> return (), Parsec.eof]
    return n


normalRank = do
    n <- Parsec.oneOf "123456789"
    ns <- Parsec.many Parsec.digit
    return (n:ns)


--  these symbols are taken to mean '1' according to AEC guidelines
weirdRank = do
    Parsec.choice [Parsec.char '/', Parsec.char '*']
    return "1"


--  these ranks are standins that will be filtered out
nullRank = return "0"




--  utility functions
fromJusts :: [Maybe a] -> [a]
fromJusts = (map Maybe.fromJust) . (filter Maybe.isJust)


fromRights :: [Either a b] -> [b]
fromRights = Either.rights . (filter Either.isRight)