check should return score or nothing if invalid

src/Game.hs

@@ -11,10 +11,9 @@ makeMove (MkPlayerIndex idx) (SelectSquare topLeft bottomRight) state@MkGameStat
     let tiles = select topLeft bottomRight board
         gMode = gameMode board
         transform =
-            if check gMode tiles
-                -- add one to player score
-                -- TODO: add the proper score here
-                then over (#players % (ix idx) % #score) (+ 1)
+            case check gMode tiles of
+                Just score ->
+                    over (#players % (ix idx) % #score) (+ score)
                 -- invalid move, do nothing
-                else id
+                Nothing -> id
      in transform state

src/Types/GameBoard.hs

@@ -27,7 +27,7 @@ clear topLeft bottomRight gBoard@MkGameBoard{cells} = gBoard{cells = newCells}
   where
     newCells = cells // map (,Nothing) (range (topLeft, bottomRight))
 
-selectCheck :: (GameMode mode) => BoardPosition -> BoardPosition -> GameBoard mode -> Bool
+selectCheck :: (GameMode mode) => BoardPosition -> BoardPosition -> GameBoard mode -> Maybe Int
 selectCheck topLeft bottomRight board@MkGameBoard{gameMode} =
     check gameMode (select topLeft bottomRight board)
 

src/Types/GameMode.hs

@@ -8,7 +8,6 @@ import Data.Bifunctor (Bifunctor (first))
 import Data.Kind (Type)
 import Display
 import System.Random.Stateful (Random (randomR), RandomGen)
-import Types.BoardPosition
 
 {- | The type of game that is being played.
 
@@ -19,7 +18,7 @@ that sums up to 'n'.
 -}
 class (Display (Tile t), Show (Tile t), Eq (Tile t), Eq t, Show t) => GameMode t where
     data Tile t :: Type
-    check :: t -> [Tile t] -> Bool
+    check :: t -> [Tile t] -> Maybe Int
     gen :: (RandomGen g) => t -> g -> (Tile t, g)
 
 data SumTo = MkSumTo Int
@@ -28,8 +27,8 @@ data SumTo = MkSumTo Int
 instance GameMode SumTo where
     data Tile SumTo = IntTile Int deriving (Eq, Show)
 
-    check (MkSumTo n) [] = n == 0
-    check (MkSumTo n) lst = n == sum (map toInt lst)
+    check (MkSumTo n) [] = if n == 0 then Just 0 else Nothing
+    check (MkSumTo n) lst = if n == sum (map toInt lst) then Just (length lst) else Nothing
       where
         toInt (IntTile a) = a
     gen (MkSumTo n) = first IntTile . randomR (1, n)

test/Spec.hs

@@ -32,8 +32,8 @@ spec = do
             displayText gameBoard `shouldBe` "1 2 \n3 4 \n"
 
         it "validates a move" do
-            selectCheck (0, 0) (1, 1) gameBoard `shouldBe` True
-            selectCheck (0, 0) (0, 1) gameBoard `shouldBe` False
+            selectCheck (0, 0) (1, 1) gameBoard `shouldBe` Just 4
+            selectCheck (0, 0) (0, 1) gameBoard `shouldBe` Nothing
 
         it "clears properly" do
             let cleared = clear (0, 0) (0, 1) gameBoard
@@ -55,7 +55,7 @@ spec = do
             let action = SelectSquare (0, 0) (0, 1)
                 newState = makeMove (MkPlayerIndex 0) action initialState
 
-            preview (#players % ix 0 % #score) newState `shouldBe` Just 1
+            preview (#players % ix 0 % #score) newState `shouldBe` Just 2
 
         it "does not increase score if sum does not equal target" do
             let invalidAction = SelectSquare (0, 0) (1, 0)