-- Mine Sweeper Lab

-- Import section

import Data.Char

import Data.Set ( Set )
import qualified Data.Set as S


-- Types

data Cell   = Covered Int Bool Bool -- number of bombs around ; has bomb ; has flag
            | Uncovered Int -- number of bombs around
            | Selected

data Grid = Grid [[Cell]]

data StdGen = SG -- TODO : replace

type Mat = [[Int]]


-- Methods

instance Show Cell where
    show ( Covered _ _ hasFlag ) = if hasFlag then "[F]" else "[ ]"
    show ( Uncovered n ) = ['(', intToDigit n, ')']
    show Selected = ">x<"

instance Show Grid where
    show (Grid a) = unlines $ map (unwords . map show) a

-- Functions

randSet::Int -> StdGen -> StdGen -> Int -> Int -> Set (Int, Int)
randSet n sg1 sg2 h w = 
    let byl = randomRs (0, h - 1) sg1 in
    let bxl = randomRs (0, w - 1) sg2 in
    let bl = zip byl bxl in
    let biggerSets = scanl (flip S.insert) S.empty bl in
    head (dropWhile (\s -> S.size s < n) biggerSets)

grid::Int -> Int -> Set (Int, Int) -> Grid
grid h w s = Grid [ [Covered 0 (S.member (y, x) s) False | x <- [0..w-1] ] | y <- [0..h-1] ]

randomRs (x, y) sg = [x + mod k (y - x) | k <- [1..y] ] -- TODO : replace

mineIndic::Cell -> Int
mineIndic c = let Covered _ b _ = c in if b then 1 else 0

mines::Grid -> Mat
mines g = let Grid m = g in map (map mineIndic) m

moveUp::Mat -> Mat
moveUp m = concat [tail m, [[0 | _ <- [1..length (m!!0)]]]]

moveDown::Mat -> Mat
moveDown m = concat [[[0 | _ <- [1..length (m!!0)]]], init m]

moveRight::Mat -> Mat
moveRight m = map (\l -> 0 : init l) m

moveLeft::Mat -> Mat
moveLeft m = map (\l -> concat [tail l, [0]]) m


-- Testing data

dtTinyGrid = Grid [
                    [Covered 2 True False, Uncovered 2, Covered 2 True False],
                    [Selected, Uncovered 0, Covered 2 True True]
                ]

dtRS = randSet 3 SG SG 4 5
dtGridCover = grid 4 5 dtRS
dtMines = mines dtGridCover