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Implemented threefold repetition
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TomaDumitrescu committed Nov 13, 2024
1 parent 11178a9 commit a8284d8
Showing 1 changed file with 94 additions and 54 deletions.
148 changes: 94 additions & 54 deletions src/board.rs
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Original file line number Diff line number Diff line change
@@ -1,3 +1,5 @@
use std::sync::{LazyLock, Mutex};

use crate::{
constants::{DisplayMode, BLACK, UNDEFINED_POSITION, WHITE},
pieces::{PieceColor, PieceMove, PieceType},
Expand Down Expand Up @@ -120,55 +122,71 @@ pub struct Board {
pub black_taken_pieces: Vec<PieceType>,
}

fn init_board() -> GameBoard {
[
[
Some((PieceType::Rook, PieceColor::Black)),
Some((PieceType::Knight, PieceColor::Black)),
Some((PieceType::Bishop, PieceColor::Black)),
Some((PieceType::Queen, PieceColor::Black)),
Some((PieceType::King, PieceColor::Black)),
Some((PieceType::Bishop, PieceColor::Black)),
Some((PieceType::Knight, PieceColor::Black)),
Some((PieceType::Rook, PieceColor::Black)),
],
[
Some((PieceType::Pawn, PieceColor::Black)),
Some((PieceType::Pawn, PieceColor::Black)),
Some((PieceType::Pawn, PieceColor::Black)),
Some((PieceType::Pawn, PieceColor::Black)),
Some((PieceType::Pawn, PieceColor::Black)),
Some((PieceType::Pawn, PieceColor::Black)),
Some((PieceType::Pawn, PieceColor::Black)),
Some((PieceType::Pawn, PieceColor::Black)),
],
[None, None, None, None, None, None, None, None],
[None, None, None, None, None, None, None, None],
[None, None, None, None, None, None, None, None],
[None, None, None, None, None, None, None, None],
[
Some((PieceType::Pawn, PieceColor::White)),
Some((PieceType::Pawn, PieceColor::White)),
Some((PieceType::Pawn, PieceColor::White)),
Some((PieceType::Pawn, PieceColor::White)),
Some((PieceType::Pawn, PieceColor::White)),
Some((PieceType::Pawn, PieceColor::White)),
Some((PieceType::Pawn, PieceColor::White)),
Some((PieceType::Pawn, PieceColor::White)),
],
[
Some((PieceType::Rook, PieceColor::White)),
Some((PieceType::Knight, PieceColor::White)),
Some((PieceType::Bishop, PieceColor::White)),
Some((PieceType::Queen, PieceColor::White)),
Some((PieceType::King, PieceColor::White)),
Some((PieceType::Bishop, PieceColor::White)),
Some((PieceType::Knight, PieceColor::White)),
Some((PieceType::Rook, PieceColor::White)),
],
]
}

fn equal_boards(o: GameBoard, oth: GameBoard) -> bool {
for i in 0..8 {
for j in 0..8 {
if o[i][j] != oth[i][j] {
return false;
}
}
}

true
}

impl Default for Board {
fn default() -> Self {
Self {
board: [
[
Some((PieceType::Rook, PieceColor::Black)),
Some((PieceType::Knight, PieceColor::Black)),
Some((PieceType::Bishop, PieceColor::Black)),
Some((PieceType::Queen, PieceColor::Black)),
Some((PieceType::King, PieceColor::Black)),
Some((PieceType::Bishop, PieceColor::Black)),
Some((PieceType::Knight, PieceColor::Black)),
Some((PieceType::Rook, PieceColor::Black)),
],
[
Some((PieceType::Pawn, PieceColor::Black)),
Some((PieceType::Pawn, PieceColor::Black)),
Some((PieceType::Pawn, PieceColor::Black)),
Some((PieceType::Pawn, PieceColor::Black)),
Some((PieceType::Pawn, PieceColor::Black)),
Some((PieceType::Pawn, PieceColor::Black)),
Some((PieceType::Pawn, PieceColor::Black)),
Some((PieceType::Pawn, PieceColor::Black)),
],
[None, None, None, None, None, None, None, None],
[None, None, None, None, None, None, None, None],
[None, None, None, None, None, None, None, None],
[None, None, None, None, None, None, None, None],
[
Some((PieceType::Pawn, PieceColor::White)),
Some((PieceType::Pawn, PieceColor::White)),
Some((PieceType::Pawn, PieceColor::White)),
Some((PieceType::Pawn, PieceColor::White)),
Some((PieceType::Pawn, PieceColor::White)),
Some((PieceType::Pawn, PieceColor::White)),
Some((PieceType::Pawn, PieceColor::White)),
Some((PieceType::Pawn, PieceColor::White)),
],
[
Some((PieceType::Rook, PieceColor::White)),
Some((PieceType::Knight, PieceColor::White)),
Some((PieceType::Bishop, PieceColor::White)),
Some((PieceType::Queen, PieceColor::White)),
Some((PieceType::King, PieceColor::White)),
Some((PieceType::Bishop, PieceColor::White)),
Some((PieceType::Knight, PieceColor::White)),
Some((PieceType::Rook, PieceColor::White)),
],
],
board: init_board(),
cursor_coordinates: Coord::new(4, 4),
selected_coordinates: Coord::undefined(),
selected_piece_cursor: 0,
Expand Down Expand Up @@ -778,17 +796,39 @@ impl Board {

// Check if the game is a draw
pub fn draw_by_repetition(&self) -> bool {
if self.move_history.len() >= 9 {
let last_ten: Vec<PieceMove> =
self.move_history.iter().rev().take(9).copied().collect();
static mut BOARD_HISTORY: Vec<GameBoard> = Vec::new();
static mut ABSTRACT_BOARD: LazyLock<Mutex<Board>> = std::sync::LazyLock::new(|| Mutex::new(Board::default()));

let copied_moves: Vec<PieceMove> =
self.move_history.iter().copied().collect();

unsafe {
let mut abstract_board = ABSTRACT_BOARD.lock().unwrap();
// Add the new move
let from = copied_moves[self.move_history.len() - 1].from;
let to = copied_moves[self.move_history.len() - 1].to;
abstract_board.move_piece_on_the_board(&from.clone(), &to.clone());
BOARD_HISTORY.push(abstract_board.board.clone());

// Index mapping
let num_positions: usize = BOARD_HISTORY.len();
let mut count_equal = vec![0; num_positions];
for i in 0..(num_positions - 1) {
for j in (i + 1)..num_positions {
if equal_boards(BOARD_HISTORY[i], BOARD_HISTORY[j]) {
count_equal[i] += 1;
}
}
}

if (last_ten[0], last_ten[1]) == (last_ten[4], last_ten[5])
&& last_ten[4] == last_ten[8]
&& (last_ten[2], last_ten[3]) == (last_ten[6], last_ten[7])
{
return true;
// Checking for unclaimed draw by threefold repetition
for i in 0..num_positions {
if count_equal[i] >= 3 {
return true;
}
}
}

false
}

Expand Down

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