From 802bdcdb376343471ad328ef4a63a5eaff108d85 Mon Sep 17 00:00:00 2001
From: stefiosif <stef8iosif@gmail.com>
Date: Tue, 29 Oct 2024 22:55:35 +0200
Subject: [PATCH] Add basic iterative deepening implementation

---
 src/search/iterative_deepening.rs | 53 +++++++++++++++++++++++++++++++
 src/search/mod.rs                 |  1 +
 2 files changed, 54 insertions(+)
 create mode 100644 src/search/iterative_deepening.rs

diff --git a/src/search/iterative_deepening.rs b/src/search/iterative_deepening.rs
new file mode 100644
index 0000000..e624a49
--- /dev/null
+++ b/src/search/iterative_deepening.rs
@@ -0,0 +1,53 @@
+use crate::{
+    board::{game::Game, transposition_table::TranspositionTable},
+    evaluation::{MAX_SCORE, MIN_SCORE},
+    movegen::r#move::Move,
+};
+
+use super::negamax;
+
+pub fn iterative_deepening(
+    game: &mut Game,
+    max_depth: u8,
+    move_time: u128,
+    mut tt: TranspositionTable,
+) -> Result<Move, String> {
+    let mut nodes = 0;
+    let (mut mv, _): (Option<Move>, i32) = (None, 0);
+    let time_now = std::time::Instant::now();
+
+    for depth in 0..max_depth {
+        if move_time < time_now.elapsed().as_millis() {
+            return Ok(mv.expect("No move selected"));
+        }
+
+        (mv, _) = negamax::negamax(game, MIN_SCORE, MAX_SCORE, depth, 0, &mut tt, &mut nodes);
+        dbg!(depth, nodes);
+    }
+
+    Ok(mv.expect("No move selected"))
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::{
+        board::{fen::from_fen, transposition_table::TranspositionTable},
+        movegen::attack_generator::init_attacks,
+        search,
+    };
+
+    const FEN: &str = "1r2k2r/2P1pq1p/2npb3/1p3ppP/p3P3/P2B1Q2/1P1PNPP1/R3K2R w KQk g6 0 1";
+
+    #[test]
+    fn test_iterative_deepening() -> Result<(), String> {
+        init_attacks();
+        let mut game = from_fen(FEN)?;
+        let tt = TranspositionTable::new(1000000);
+        let time_now = std::time::Instant::now();
+
+        let _ = search::iterative_deepening::iterative_deepening(&mut game, 6, 100000, tt);
+        dbg!(time_now.elapsed());
+
+        Ok(())
+    }
+}
diff --git a/src/search/mod.rs b/src/search/mod.rs
index f1097fd..35eecbb 100644
--- a/src/search/mod.rs
+++ b/src/search/mod.rs
@@ -1,3 +1,4 @@
+pub mod iterative_deepening;
 pub mod move_ordering;
 pub mod negamax;
 pub mod perft;