fix othello player skip logic

src/agent.rs

@@ -17,10 +17,14 @@ impl Agent for ManualAgent {
     fn next_move(&mut self, _: &Board) -> Option<(usize, usize)> {
         let stdin = io::stdin();
         let mut input = String::new();
-        println!("Your turn!");
+        println!("Your turn! ('Skip' to skip)");
         loop {
             input.clear();
             stdin.lock().read_line(&mut input).ok()?;
+            if input.to_lowercase().trim() == "skip" {
+                // skips move
+                return None;
+            }
 
             let got = input
                 .split_whitespace()

src/board.rs

@@ -196,7 +196,10 @@ impl Board {
     }
 
     pub fn game_winner(&self, turn: Piece) -> Option<Piece> {
-        if self.possible_moves(turn).count() > 0 {
+        // 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;
         }

src/complexagent.rs

@@ -226,9 +226,9 @@ impl FutureMoves {
         let mut new_arena = Vec::new();
         let mut index_map = vec![None; self.arena.len()];
 
-        for (old_idx, _) in retain.iter().enumerate().filter(|(_, a)| **a) {
+        for (old_idx, _) in retain.iter().enumerate().rev().filter(|(_, a)| **a) {
             index_map[old_idx] = Some(new_arena.len());
-            let mut node = self.arena[old_idx].clone();
+            let mut node = self.arena.remove(old_idx);
             node.parent = node.parent.and_then(|p| index_map[p]);
             node.children = node.children.iter().filter_map(|&c| index_map[c]).collect();
             new_arena.push(node);

src/game.rs

@@ -53,7 +53,11 @@ impl Game {
                 }
             } else {
                 println!("Player {} did not make a move!", player_i);
-                // TODO! break, player should not be able to skip a move
+                // players are able to skip a move if they have no valid moves to make
+                assert!(
+                    !self.board.possible_moves(player_color).any(|_| true),
+                    "Player skipped a move, but they had a possible move to make"
+                );
                 return; // No valid move available
             }
         }

src/main.rs

@@ -11,8 +11,8 @@ mod piece;
 fn main() {
     let player1 = complexagent::ComplexAgent::new(Piece::Black);
     // let player2 = complexagent::ComplexAgent::new(Piece::White);
-    // let player2 = agent::ManualAgent::new(Piece::White);
-    let player2 = agent::RandomAgent::new(Piece::White);
+    let player2 = agent::ManualAgent::new(Piece::White);
+    // let player2 = agent::RandomAgent::new(Piece::White);
     let mut game = Game::new(Box::new(player1), Box::new(player2));
     game.game_loop();
 }