import Data.Map as Map
import Data.Maybe

data Coordinates = Coordinates Int Int deriving (Eq, Show)

instance Ord Coordinates where
    compare (Coordinates a b) (Coordinates c d)
        |(b == d) = a `compare` c
        |otherwise = b `compare` d

data Color = White | Black deriving Eq

instance Show Color where
   show White = "o"
   show Black = "x"

data Board = Board (Map Coordinates Color)

instance Show Board where
    show = toString

negateColor color
    | (color==White) = Black
    | otherwise = White

toString (Board map) =
    iterate([Coordinates x y | y <- [1..19], x <- [1..19]])
        where
            iterate [element] = (mapToCharacter element) ++ (newLine element)
            iterate (element:listOfCoordinates) = (mapToCharacter element) ++ (newLine element) ++ iterate(listOfCoordinates)
            mapToCharacter coordinates
                | (member coordinates map) = show(fromJust (Map.lookup coordinates map))
                | otherwise = " "
            newLine (Coordinates x y)
                | (x == 19) = "\n"
                | otherwise = ""

rateBoard (Board innerMap) color =
    rate [x | x <- Map.keys innerMap, fromJust (Map.lookup x innerMap) == color] - rate [x | x <- Map.keys innerMap, fromJust (Map.lookup x innerMap) == negateColor color]
        where
            rate listOfCoordinates = sum (Prelude.map (\coords -> ((rateVerticalNeighbors coords listOfCoordinates) + (rateHorizontalNeighbors coords listOfCoordinates) +
                (rateRightDiagonalNeighbors coords listOfCoordinates) + (rateLeftDiagonalNeighbors coords listOfCoordinates))) listOfCoordinates)
            rateVerticalNeighbors coords listOfCoordinates = rateNeighborsSequence coords listOfCoordinates 0 (-1) 0 1
            rateHorizontalNeighbors coords listOfCoordinates = rateNeighborsSequence coords listOfCoordinates (-1) 0 1 0
            rateRightDiagonalNeighbors coords listOfCoordinates = rateNeighborsSequence coords listOfCoordinates (-1) (-1) 1 1
            rateLeftDiagonalNeighbors coords listOfCoordinates = rateNeighborsSequence coords listOfCoordinates (-1) 1 1 (-1)
            rateNeighborsSequence (Coordinates x y) listOfCoordinates x_1 y_1 x_2 y_2
                | ((Coordinates (x+x_1) (y+y_1)) `elem` listOfCoordinates) || ((Coordinates (x+x_2) (y+y_2)) `elem` listOfCoordinates) = 1
                | otherwise = 0


hasNeighbors (Coordinates x y) listOfCoordinates = ((Coordinates (x-1) (y-1)) `elem` listOfCoordinates) || ((Coordinates x (y-1)) `elem` listOfCoordinates) ||
    ((Coordinates (x+1) (y-1)) `elem` listOfCoordinates) || ((Coordinates (x-1) y) `elem` listOfCoordinates) ||
    ((Coordinates (x+1) y) `elem` listOfCoordinates) || ((Coordinates (x-1) (y+1)) `elem` listOfCoordinates) ||
    ((Coordinates x (y+1)) `elem` listOfCoordinates) || ((Coordinates (x+1) (y+1)) `elem` listOfCoordinates)

possibleMoves (Board map) = [Coordinates x y|x<-[1..19], y<-[1..19], notMember (Coordinates x y) map, hasNeighbors (Coordinates x y) (Map.keys map)]