Add depth limit on quiescence, add node/timer measurements

src/search/quiescence.rs

@@ -1,12 +1,20 @@
-use crate::{
-    board::game::Game,
-    evaluation::evaluation::evaluate_position,
-    movegen::r#move::{Move, MoveType},
-};
+use crate::{board::game::Game, evaluation::evaluation::evaluate_position, movegen::r#move::Move};
 
 use super::move_ordering::score_by_mvv_lva;
 
-pub fn quiescence(game: &mut Game, mut alpha: i32, beta: i32) -> (Option<Move>, i32) {
+pub fn quiescence(
+    game: &mut Game,
+    mut alpha: i32,
+    beta: i32,
+    nodes: &mut u64,
+    depth: u8,
+) -> (Option<Move>, i32) {
+    *nodes += 1;
+
+    if depth == 0 {
+        return (None, evaluate_position(&game.board));
+    }
+
     let color = game.current_player();
     let stand_pat = evaluate_position(&game.board);
 
@@ -18,18 +26,7 @@ pub fn quiescence(game: &mut Game, mut alpha: i32, beta: i32) -> (Option<Move>,
         alpha = stand_pat;
     }
 
-    let mut captures: Vec<_> = game
-        .board
-        .pseudo_moves_all()
-        .into_iter()
-        .filter(|m| {
-            matches!(
-                m.move_type,
-                MoveType::Capture | MoveType::PromotionCapture(_)
-            )
-        })
-        .collect();
-
+    let mut captures: Vec<_> = game.board.pseudo_moves_all_captures();
     captures.sort_unstable_by_key(|mv| score_by_mvv_lva(&game.mailbox, *mv));
 
     for mv in captures {
@@ -40,7 +37,7 @@ pub fn quiescence(game: &mut Game, mut alpha: i32, beta: i32) -> (Option<Move>,
             continue;
         }
 
-        let move_score = -quiescence(game, -beta, -alpha).1;
+        let move_score = -quiescence(game, -beta, -alpha, nodes, depth - 1).1;
         game.unmake_move();
 
         if move_score >= beta {