iterator fixes

src/agent.rs

@@ -1,5 +1,5 @@
 use crate::{
-    board::{Board, BOARD_SIZE},
+    board::Board,
     piece::Piece,
 };
 use rand::prelude::*;
@@ -59,14 +59,7 @@ pub struct RandomAgent {
 
 impl Agent for RandomAgent {
     fn next_move(&mut self, board: &Board) -> Option<(usize, usize)> {
-        (0..BOARD_SIZE)
-            .flat_map(|i| {
-                (0..BOARD_SIZE)
-                    .map(|j| (i, j))
-                    .collect::<Vec<(usize, usize)>>()
-            })
-            .flat_map(|(i, j)| board.what_if(i, j, self.color).map(|_| (i, j)))
-            .choose(&mut rand::rng())
+        board.possible_moves(self.color).choose(&mut rand::rng())
     }
 
     fn name(&self) -> &'static str {