Initial commit

src/Lib.hs

@@ -0,0 +1,66 @@
+module Lib
+  ( flagTile
+  , printBoard
+  , Board(..)
+  , Tile(..)
+  , TileState(..)
+  ) where
+
+newtype Board =
+  Board
+    { unBoard :: [[Tile]]
+    }
+  deriving (Eq, Show)
+
+data Tile
+  = Value Int TileState
+  | Bomb TileState
+  deriving (Eq, Show)
+
+data TileState
+  = Revealed
+  | Flagged
+  | Hidden
+  deriving (Eq, Show)
+
+type Coordinates = (Int, Int)
+
+flagTile :: Board -> Coordinates -> Board
+flagTile (Board board) (x, y) =
+  case findTile (Board board) (x, y) of
+    (Just tile) -> flagHiddenTile tile
+    Nothing     -> Board board
+  where
+    flagHiddenTile (Value value Hidden) = replaceTile (Board board) (x, y) (Value value Flagged)
+    flagHiddenTile (Bomb Hidden) = replaceTile (Board board) (x, y) (Bomb Flagged)
+    flagHiddenTile _ = Board board
+
+replaceTile :: Board -> Coordinates -> Tile -> Board
+replaceTile (Board board) (x, y) tile =
+  let (firstRows, line:lastRows) = splitAt y board
+      (firstTiles, _:lastTiles) = splitAt x line
+   in Board $ firstRows ++ (firstTiles ++ tile : lastTiles) : lastRows
+
+findTile :: Board -> Coordinates -> Maybe Tile
+findTile (Board board) (x, y) =
+  if not (coordinatesExists (Board board) (x, y))
+    then Nothing
+    else Just $ board !! y !! x
+
+coordinatesExists :: Board -> Coordinates -> Bool
+coordinatesExists (Board board) (x, y) = isPositive && isYWithinTheBoard board && isXWithinTheBoard board
+  where
+    isPositive = x >= 0 && y >= 0
+    isYWithinTheBoard = (> y) . length
+    isXWithinTheBoard = any ((> x) . length)
+
+printBoard :: Board -> String
+printBoard (Board board) = concatMap printLine board
+  where
+    printLine line = concatMap printTile line ++ "\n"
+    printTile (Bomb Hidden) = "#"
+    printTile (Bomb Revealed) = "B"
+    printTile (Value _ Hidden) = "#"
+    printTile (Value x Revealed) = show x
+    printTile (Bomb Flagged) = "F"
+    printTile (Value _ Flagged) = "F"