move to workspace mode

This commit is contained in:
cool-mist
2026-01-22 15:52:52 +05:30
parent 8cd1f86ba6
commit 86d160cab0
34 changed files with 202 additions and 195 deletions
+717
View File
@@ -0,0 +1,717 @@
pub mod cmove;
mod constants;
pub mod errors;
pub mod piece;
pub mod square;
use core::fmt;
use std::{
collections::HashSet,
fmt::{Display, Formatter},
mem,
};
use cmove::CMove;
use constants::BOARD_SIZE;
use errors::SError;
use piece::Piece;
use square::{Square, SquarePair};
use crate::generator::Puzzle;
#[derive(Clone)]
pub struct Board {
pub cells: [[Option<Piece>; BOARD_SIZE]; BOARD_SIZE],
pub legal_moves: HashSet<CMove>,
pub game_state: BoardState,
pub id: String,
pub size: usize,
pieces_remaining: u8,
}
#[derive(PartialEq, Eq, Debug, Clone)]
pub enum BoardState {
NotStarted,
InProgress,
Lost,
Won,
}
impl Board {
pub fn new() -> Self {
let cells = [[None; BOARD_SIZE]; BOARD_SIZE];
let id = Board::encode(cells);
Board {
cells,
legal_moves: HashSet::new(),
id,
pieces_remaining: 0,
game_state: BoardState::NotStarted,
size: BOARD_SIZE,
}
}
pub fn from_id(board_id: &str) -> Result<Self, SError> {
// TODO: validate board_id before decode
let mut board_id_bytes = [0; 8];
board_id_bytes.copy_from_slice(board_id.as_bytes());
let mut working_bytes_slice = [0; 6];
b64_decode_exact_48(&board_id_bytes, &mut working_bytes_slice);
let mut working_bytes = [0; 8];
working_bytes[2..].copy_from_slice(&working_bytes_slice);
let mut working = u64::from_be_bytes(working_bytes);
let mut board = Board::new();
let mask = 0b111;
for i in (0..BOARD_SIZE).rev() {
for j in (0..BOARD_SIZE).rev() {
let piece = Board::get_piece_from_encoding((working & mask) as u8);
working = working >> 3;
let piece = piece?;
board.set(Square::new(i, j, piece));
}
}
Ok(board)
}
pub fn from_string(board_string: String) -> Result<Self, SError> {
if board_string.chars().count() != 16 {
return Err(SError::InvalidBoard);
}
let mut board = Board::new();
let mut chars = board_string.chars();
for r in 0..BOARD_SIZE {
for f in 0..BOARD_SIZE {
let c = chars.next().unwrap();
let piece = match c {
'K' | 'k' => Piece::King,
'Q' | 'q' => Piece::Queen,
'B' | 'b' => Piece::Bishop,
'N' | 'n' => Piece::Knight,
'R' | 'r' => Piece::Rook,
'P' | 'p' => Piece::Pawn,
'.' => continue,
_ => return Err(SError::InvalidBoard),
};
let square = Square::new(f, r, Some(piece));
board.set(square);
}
}
Ok(board)
}
pub fn set(&mut self, square: Square) -> Option<Piece> {
let new_is_occuppied = square.piece.is_some();
let existing = mem::replace(&mut self.cells[square.file][square.rank], square.piece);
// If placing a piece on a blank, increment piece count
if existing.is_none() && new_is_occuppied {
self.pieces_remaining += 1;
}
// If placing a blank on a piece, decrement piece count
if existing.is_some() && !new_is_occuppied {
self.pieces_remaining -= 1;
}
self.board_state_changed();
existing
}
pub fn make_move(&mut self, mv: CMove) -> Option<CMove> {
if !self.legal_moves.contains(&mv) {
println!("Invalid move - {}", mv.notation());
println!("Legal moves - ");
for m in &self.legal_moves {
println!("{}", m.notation());
}
return None;
}
let from_piece = mem::replace(&mut self.cells[mv.from.file][mv.from.rank], None);
self.cells[mv.to.file][mv.to.rank] = from_piece;
self.pieces_remaining -= 1;
self.board_state_changed();
Some(mv)
}
pub fn empty_squares(&self) -> Vec<Square> {
let mut empty_squares = Vec::new();
for file in 0..BOARD_SIZE {
for rank in 0..BOARD_SIZE {
if self.cells[file][rank].is_none() {
empty_squares.push(Square::new(file, rank, None));
}
}
}
empty_squares
}
pub fn pretty_print(&self) {
println!("{}", self.print(true));
// println!("{:^40}\n", format!("id: {:#018x}", self.id()));
println!("{:^40}\n", format!("id: {}", self.id));
}
pub fn solve(&self) -> Puzzle {
struct StackItem {
board: Board,
moves_so_far: Vec<CMove>,
next_move: CMove,
}
if let BoardState::Won = self.game_state {
return Puzzle {
board: self.clone(),
solutions: vec![vec![]],
solved: true,
};
}
let mut stack = Vec::new();
for mv in &self.legal_moves {
let item = StackItem {
board: self.clone(),
moves_so_far: vec![],
next_move: mv.clone(),
};
stack.push(item);
}
let mut solutions = Vec::new();
loop {
let top = stack.pop();
let Some(top) = top else {
let solved = solutions.len() > 0;
return Puzzle {
board: self.clone(),
solutions,
solved,
};
};
let (mut board, mut moves_so_far, next) = (top.board, top.moves_so_far, top.next_move);
board.make_move(next.clone());
match board.game_state {
BoardState::Won => {
moves_so_far.push(next);
solutions.push(moves_so_far);
}
BoardState::InProgress => {
moves_so_far.push(next);
for mv in &board.legal_moves {
let item = StackItem {
board: board.clone(),
moves_so_far: moves_so_far.clone(),
next_move: mv.clone(),
};
stack.push(item);
}
}
_ => {}
}
}
}
fn encode(cells: [[Option<Piece>; BOARD_SIZE]; BOARD_SIZE]) -> String {
let mut res: u64 = 0;
for i in 0..BOARD_SIZE {
for j in 0..BOARD_SIZE {
res = res << 3;
let byte = Board::get_piece_encoding(cells[i][j]);
res = res | byte as u64
}
}
let mut id_bytes = [0; 6];
id_bytes.copy_from_slice(&res.to_be_bytes()[2..]);
b64_encode_exact_48(&id_bytes)
}
fn print(&self, pretty: bool) -> String {
let mut board_string = String::new();
for rank in 0..BOARD_SIZE {
let mut row = String::new();
for file in 0..BOARD_SIZE {
let piece = self.cells[file][rank];
row.push_str(&get_square_for_display(&piece, pretty));
}
if pretty {
board_string.push_str(&format!("{:^40}\n", row));
} else {
board_string.push_str(&row);
}
board_string.push('\n');
}
board_string
}
fn calc_legal_moves(&mut self) {
self.legal_moves = self
.all_possible_move_pairs()
.into_iter()
.filter(SquarePair::is_different)
.filter_map(|pair| self.is_legal_move(pair))
.collect()
}
fn is_legal_move(&self, pair: SquarePair) -> Option<CMove> {
// The below block is just to make the compiler happy. Start will always
// have a piece
let Some(piece) = pair.start.piece else {
return None;
};
let legal = match piece {
Piece::King => self.is_king_legal(&pair),
Piece::Queen => self.is_queen_legal(&pair),
Piece::Bishop => self.is_bishop_legal(&pair),
Piece::Knight => self.is_knight_legal(&pair),
Piece::Rook => self.is_rook_legal(&pair),
Piece::Pawn => self.is_pawn_legal(&pair),
};
if legal {
return Some(CMove::new(pair.start, pair.end));
}
None
}
fn is_king_legal(&self, pair: &SquarePair) -> bool {
pair.dx <= 1 && pair.dy <= 1
}
fn is_queen_legal(&self, pair: &SquarePair) -> bool {
self.is_path_free(pair)
}
fn is_bishop_legal(&self, pair: &SquarePair) -> bool {
pair.dx == pair.dy && self.is_path_free(pair)
}
fn is_knight_legal(&self, pair: &SquarePair) -> bool {
(pair.dx == 2 && pair.dy == 1) || (pair.dx == 1 && pair.dy == 2)
}
fn is_rook_legal(&self, pair: &SquarePair) -> bool {
if pair.dx != 0 && pair.dy != 0 {
return false;
}
self.is_path_free(pair)
}
fn is_pawn_legal(&self, pair: &SquarePair) -> bool {
pair.dx == 1 && pair.dy == 1 && pair.y_dir == -1
}
fn is_path_free(&self, pair: &SquarePair) -> bool {
// There is no straight line or diagonal to get through
if pair.dx != pair.dy && pair.dx != 0 && pair.dy != 0 {
return false;
}
let x_inc = pair.x_dir;
let y_inc = pair.y_dir;
let mut x: i8 = pair.start.file.try_into().unwrap();
let mut y: i8 = pair.start.rank.try_into().unwrap();
loop {
x = x + x_inc;
y = y + y_inc;
let file: usize = x.try_into().unwrap();
let rank: usize = y.try_into().unwrap();
if rank == pair.end.rank && file == pair.end.file {
return true;
}
if self.cells[file][rank].is_some() {
return false;
}
}
}
fn calc_game_state(&mut self) {
self.game_state = if self.pieces_remaining == 0 {
BoardState::NotStarted
} else if self.pieces_remaining == 1 {
BoardState::Won
} else if self.legal_moves.is_empty() {
BoardState::Lost
} else {
BoardState::InProgress
}
}
/// This is just a cartesian product of {occupied_squares} x {occupied_squares}
fn all_possible_move_pairs(&self) -> impl IntoIterator<Item = SquarePair> {
let ret = self
.all_occupied_squares()
.into_iter()
.map(|start| {
self.all_occupied_squares()
.into_iter()
.map(move |end| SquarePair::new(start.clone(), end))
})
.flatten()
.collect::<Vec<SquarePair>>();
return ret;
}
fn all_occupied_squares(&self) -> impl IntoIterator<Item = Square> {
let mut ret = Vec::new();
for i in 0..BOARD_SIZE {
for j in 0..BOARD_SIZE {
let p = &self.cells[i][j];
if p.is_some() {
ret.push(Square::new(i, j, *p))
}
}
}
ret
}
fn board_state_changed(&mut self) {
self.calc_legal_moves();
self.calc_game_state();
self.calc_id();
}
fn get_piece_encoding(piece: Option<Piece>) -> u8 {
match piece {
Some(p) => match p {
Piece::King => 0b001,
Piece::Queen => 0b010,
Piece::Rook => 0b011,
Piece::Bishop => 0b100,
Piece::Knight => 0b101,
Piece::Pawn => 0b110,
},
None => 0b000,
}
}
fn get_piece_from_encoding(encoding: u8) -> Result<Option<Piece>, SError> {
match encoding {
0b001 => Ok(Some(Piece::King)),
0b010 => Ok(Some(Piece::Queen)),
0b011 => Ok(Some(Piece::Rook)),
0b100 => Ok(Some(Piece::Bishop)),
0b101 => Ok(Some(Piece::Knight)),
0b110 => Ok(Some(Piece::Pawn)),
0b000 => Ok(None),
_ => Err(SError::InvalidBoard),
}
}
fn calc_id(&mut self) {
self.id = Board::encode(self.cells);
}
}
fn get_square_for_display(piece: &Option<Piece>, pretty: bool) -> String {
let contents = if let Some(piece) = piece {
if pretty {
piece.pretty()
} else {
piece.notation()
}
} else {
".".to_string()
};
if pretty {
format!(" {} ", contents)
} else {
contents
}
}
impl Display for BoardState {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
let display = match self {
BoardState::NotStarted => "Not Started",
BoardState::InProgress => "In Progress",
BoardState::Lost => "Lost",
BoardState::Won => "Won",
};
write!(f, "{}", display)
}
}
fn b64_encode_exact_48(input: &[u8; 6]) -> String {
let mut output = [0 as char; 8];
for (byte_chunk, output_slice) in input.chunks_exact(3).zip(output.chunks_exact_mut(4)) {
let byte1 = byte_chunk[0];
let byte2 = byte_chunk[1];
let byte3 = byte_chunk[2];
output_slice[0] = lookup((byte1 & 0b1111_1100) >> 2);
output_slice[1] = lookup((byte1 & 0b0000_0011) << 4 | (byte2 & 0b1111_0000) >> 4);
output_slice[2] = lookup((byte2 & 0b0000_1111) << 2 | (byte3 & 0b1100_0000) >> 6);
output_slice[3] = lookup(byte3 & 0b0011_1111);
}
output.iter().collect()
}
fn b64_decode_exact_48(input: &[u8; 8], output: &mut [u8; 6]) {
for (char_chunk, output_slice) in input.chunks_exact(4).zip(output.chunks_exact_mut(3)) {
let char_1 = reverse_lookup(char_chunk[0] as char);
let char_2 = reverse_lookup(char_chunk[1] as char);
let char_3 = reverse_lookup(char_chunk[2] as char);
let char_4 = reverse_lookup(char_chunk[3] as char);
output_slice[0] = (char_1 << 2) | (char_2 >> 4);
output_slice[1] = (char_2 << 4) | (char_3 >> 2);
output_slice[2] = (char_3 << 6) | char_4;
}
}
const ALPHABET: &str = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
fn lookup(idx: u8) -> char {
ALPHABET.chars().nth(idx as usize).unwrap()
}
fn reverse_lookup(c: char) -> u8 {
ALPHABET.chars().position(|x| x == c).unwrap() as u8
}
#[cfg(test)]
mod tests {
use super::*;
macro_rules! sq {
($sq:literal) => {
Square::parse($sq)
};
}
macro_rules! mv {
($from:literal, $to:literal) => {{ CMove::new(sq!($from), sq!($to)) }};
}
macro_rules! validate_board {
($board:expr, $row1:literal, $row2:literal, $row3:literal, $row4:literal) => {
let printed = $board.print(false);
assert_eq!(
printed,
format!("{}\n{}\n{}\n{}\n", $row1, $row2, $row3, $row4)
);
};
}
macro_rules! validate_legal_moves {
($board:expr, $($move:expr,)*) => {
let mut legal_moves = $board.legal_moves.iter().map(|m| m.clone()).collect::<Vec<CMove>>();
$(
assert!(legal_moves.contains(&$move));
let position = legal_moves.iter().position(|m| m == &$move).unwrap();
legal_moves.remove(position);
)*
if (legal_moves.len() > 0) {
println!("The following moves were not matched - ");
for m in &legal_moves {
println!("{}", m.notation());
}
assert!(false);
}
};
}
#[test]
fn test_board_place() {
let mut board = Board::new();
assert!(board.set(sq!("Ka1")).is_none());
assert!(board.set(sq!("Qa2")).is_none());
assert!(board.set(sq!("Bc3")).is_none());
assert!(board.set(sq!("Nc4")).is_none());
assert!(board.set(sq!("Rd1")).is_none());
assert!(board.set(sq!("Pd4")).is_none());
assert!(board.set(sq!("Nb2")).is_none());
let existing = board.set(sq!("Pc4"));
assert!(existing.is_some());
assert_eq!(Piece::Knight, existing.unwrap());
validate_board!(board, "..PP", "..B.", "QN..", "K..R");
}
#[test]
fn test_legal_moves() {
let mut board = Board::new();
assert_eq!(0, board.pieces_remaining);
assert_eq!(0, board.legal_moves.len());
assert!(board.make_move(mv!("Rb2", "Nd1")).is_none());
board.set(sq!("Qa4"));
board.set(sq!("Ka2"));
board.set(sq!("Pa1"));
board.set(sq!("Pb3"));
board.set(sq!("Rb2"));
board.set(sq!("Pc4"));
board.set(sq!("Kc3"));
board.set(sq!("Bc1"));
board.set(sq!("Bd2"));
board.set(sq!("Nd1"));
assert_eq!(10, board.pieces_remaining);
board.pretty_print();
// Q . P .
// . P K .
// K R . B
// P . B N
validate_legal_moves!(
board,
mv!("Ka2", "Pa1"),
mv!("Ka2", "Rb2"),
mv!("Ka2", "Pb3"),
mv!("Kc3", "Rb2"),
mv!("Kc3", "Pb3"),
mv!("Kc3", "Pc4"),
mv!("Kc3", "Bd2"),
mv!("Pa1", "Rb2"),
mv!("Pb3", "Pc4"),
mv!("Pb3", "Qa4"),
mv!("Qa4", "Ka2"),
mv!("Qa4", "Pb3"),
mv!("Qa4", "Pc4"),
mv!("Rb2", "Ka2"),
mv!("Rb2", "Pb3"),
mv!("Rb2", "Bd2"),
mv!("Bc1", "Rb2"),
mv!("Bc1", "Bd2"),
mv!("Bd2", "Kc3"),
mv!("Bd2", "Bc1"),
mv!("Nd1", "Rb2"),
mv!("Nd1", "Kc3"),
);
assert_eq!(10, board.pieces_remaining);
// Validate some illegal moves
assert!(board.make_move(mv!("Ka2", "Pa2")).is_none());
assert!(board.make_move(mv!("Rb2", "Nd1")).is_none());
board.set(sq!(".b2"));
board.set(sq!(".c4"));
board.set(sq!("Rc1"));
// Q . . .
// . P K .
// K . . B
// P . R N
validate_legal_moves!(
board,
mv!("Ka2", "Pa1"),
mv!("Ka2", "Pb3"),
mv!("Kc3", "Pb3"),
mv!("Kc3", "Bd2"),
mv!("Pb3", "Qa4"),
mv!("Bd2", "Kc3"),
mv!("Bd2", "Rc1"),
mv!("Qa4", "Ka2"),
mv!("Qa4", "Pb3"),
mv!("Rc1", "Pa1"),
mv!("Rc1", "Kc3"),
mv!("Rc1", "Nd1"),
mv!("Nd1", "Kc3"),
);
assert_eq!(8, board.pieces_remaining);
}
#[test]
fn test_smoke_puzzle() {
let mut board = Board::new();
assert_eq!(BoardState::NotStarted, board.game_state);
assert_eq!(0, board.pieces_remaining);
// K . . .
// . P . .
// . . R .
// N . . .
board.set(sq!("Ka4"));
assert_eq!(BoardState::Won, board.game_state);
board.set(sq!("Pb3"));
board.set(sq!("Rc2"));
board.set(sq!("Na1"));
assert_eq!(BoardState::InProgress, board.game_state);
assert_eq!(4, board.pieces_remaining);
assert!(board.make_move(mv!("Na1", "Rc2")).is_some());
assert_eq!(3, board.pieces_remaining);
assert_eq!(BoardState::InProgress, board.game_state);
assert!(board.make_move(mv!("Pb3", "Ka4")).is_some());
assert_eq!(2, board.pieces_remaining);
assert_eq!(BoardState::Lost, board.game_state);
// P . . .
// . . . .
// . . N .
// . . . .
board.set(sq!("Pa1"));
board.set(sq!("Qa3"));
// P . . .
// Q . . .
// . . N .
// P . . .
assert_eq!(4, board.pieces_remaining);
assert_eq!(BoardState::InProgress, board.game_state);
board.make_move(mv!("Qa3", "Pa4"));
board.make_move(mv!("Nc2", "Pa1"));
assert_eq!(2, board.pieces_remaining);
assert_eq!(BoardState::InProgress, board.game_state);
// Q . . .
// . . . .
// . . . .
// N . . .
board.make_move(mv!("Qa4", "Na1"));
assert_eq!(1, board.pieces_remaining);
assert_eq!(BoardState::Won, board.game_state);
}
#[test]
fn test_encoding() {
let mut board = Board::new();
board.set(sq!("Pa1"));
board.set(sq!("Ra2"));
board.set(sq!("Qb2"));
board.set(sq!("Kd2"));
board.set(sq!("Bd4"));
board.set(sq!("Nc4"));
let id = board.id;
let board2 = Board::from_id(&id);
let board2 = board2.unwrap();
validate_board!(board2, "..NB", "....", "RQ.K", "P...");
}
}