rewrite basically done

src/board.rs

@@ -59,6 +59,13 @@ fn gen_adj_lookup() -> PosMap<ChainCollection> {
         .collect()
 }
 
+#[derive(PartialEq, Eq, Copy, Clone, Debug)]
+pub enum Winner {
+    Player(Piece),
+    Tie,
+    None,
+}
+
 lazy_static! {
     /// Precompute all possible chains for each position on the board
     pub static ref ADJ_LOOKUP: PosMap<ChainCollection> = gen_adj_lookup();
@@ -263,22 +270,20 @@ impl Board {
     }
 
     /// Returns the winner of the board (if any)
-    pub fn game_winner(&self, turn: Piece) -> Option<Piece> {
+    pub fn game_winner(&self, turn: Piece) -> Winner {
         // Wikipedia: `Players take alternate turns. If one player cannot make a valid move, play passes back to the other player. The game ends when the grid has filled up or if neither player can make a valid move.`
 
         if self.possible_moves(turn).next().is_some() || self.possible_moves(!turn).next().is_some()
         {
             // player can still make a move, there is no winner
-            return None;
+            return Winner::None;
         }
 
         let (white_score, black_score) = self.get_score();
         match white_score.cmp(&black_score) {
-            Ordering::Greater => Some(Piece::White), // White win
-            Ordering::Less => Some(Piece::Black),    // Black win
-
-            // TODO! this will end up being parsed the same as a "no winner", it should be a seperate type
-            Ordering::Equal => None, // Tie
+            Ordering::Greater => Winner::Player(Piece::White), // White win
+            Ordering::Less => Winner::Player(Piece::Black),    // Black win
+            Ordering::Equal => Winner::Tie,
         }
     }
 }