From 1cad8f1308e4af86027f9ae25523b8a8b3f6592c Mon Sep 17 00:00:00 2001 From: "info@mode42.com" Date: Sun, 9 Aug 2026 05:27:00 +0000 Subject: Next development steps --- src/core/chess.c | 668 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 668 insertions(+) create mode 100644 src/core/chess.c (limited to 'src/core/chess.c') diff --git a/src/core/chess.c b/src/core/chess.c new file mode 100644 index 0000000..94d35a6 --- /dev/null +++ b/src/core/chess.c @@ -0,0 +1,668 @@ +#if defined(__linux__) +#define _DEFAULT_SOURCE +#endif + +#include "hybbx/chess.h" +#include "hybbx/session.h" +#include "hybbx/service.h" +#include "hybbx/log.h" +#include "hybbx/util.h" +#include "hybbx/config.h" + +#include +#include +#include +#include + +static chess_game_t g_games[CHESS_GAME_MAX]; +static unsigned g_max_games = CHESS_DEFAULT_MAX; + +/* ── Board init ────────────────────────────────────────────── */ + +static void board_init(chess_board_t *b) +{ + static const char back[] = "RNBQKBNR"; + unsigned f; + + memset(b, 0, sizeof(*b)); + for (f = 0; f < 8; f++) { + b->sq[0][f] = back[f]; + b->sq[1][f] = 'P'; + b->sq[6][f] = 'p'; + b->sq[7][f] = (char)tolower((unsigned char)back[f]); + } + for (unsigned r = 2; r < 6; r++) + for (f = 0; f < 8; f++) + b->sq[r][f] = CHESS_EMPTY; +} + +void hybbx_chess_init(void) +{ + memset(g_games, 0, sizeof(g_games)); + g_max_games = CHESS_DEFAULT_MAX; +} + +void hybbx_chess_shutdown(void) +{ + unsigned i; + for (i = 0; i < g_max_games; i++) + g_games[i].active = 0; +} + +void hybbx_chess_config_apply(const struct hybbx_config *config) +{ + unsigned val; + + if (config != NULL) { + val = hybbx_config_get_uint(config, "chess", "max_games", + CHESS_DEFAULT_MAX, 1, CHESS_GAME_MAX); + } else { + val = CHESS_DEFAULT_MAX; + } + g_max_games = val; + hybbx_log_info("[chess] max_games=%u", g_max_games); +} + +unsigned hybbx_chess_max_games(void) +{ + return g_max_games; +} + +/* ── Helpers ───────────────────────────────────────────────── */ + +static int parse_square(const char *s, unsigned *rank, unsigned *file) +{ + if (s == NULL || strlen(s) < 2) + return 0; + if (s[0] < 'a' || s[0] > 'h' || s[1] < '1' || s[1] > '8') + return 0; + *file = (unsigned)(s[0] - 'a'); + *rank = (unsigned)(s[1] - '1'); + return 1; +} + +static chess_color_t piece_color(char p) +{ + if (p == CHESS_EMPTY) return CHESS_COLOR_NONE; + return (p >= 'A' && p <= 'Z') ? CHESS_WHITE : CHESS_BLACK; +} + +static char piece_upper(char p) +{ + return (char)toupper((unsigned char)p); +} + +static int in_bounds(unsigned r, unsigned f) +{ + return r < 8 && f < 8; +} + +/* ── Check detection ───────────────────────────────────────── */ + +static int square_attacked_by(const chess_board_t *b, unsigned rank, + unsigned file, chess_color_t by) +{ + unsigned r, f; + int dr, df; + char pawn, knight, bishop, rook, queen, king; + + if (by == CHESS_WHITE) { + pawn = 'P'; knight = 'N'; bishop = 'B'; + rook = 'R'; queen = 'Q'; king = 'K'; + } else { + pawn = 'p'; knight = 'n'; bishop = 'b'; + rook = 'r'; queen = 'q'; king = 'k'; + } + + /* Pawn attacks */ + if (by == CHESS_WHITE) { + if (rank > 0 && file > 0 && b->sq[rank - 1][file - 1] == pawn) return 1; + if (rank > 0 && file < 7 && b->sq[rank - 1][file + 1] == pawn) return 1; + } else { + if (rank < 7 && file > 0 && b->sq[rank + 1][file - 1] == pawn) return 1; + if (rank < 7 && file < 7 && b->sq[rank + 1][file + 1] == pawn) return 1; + } + + /* Knight */ + { + static const int kr[] = {2,2,-2,-2,1,1,-1,-1}; + static const int kf[] = {1,-1,1,-1,2,-2,2,-2}; + for (unsigned i = 0; i < 8; i++) { + int nr = (int)rank + kr[i], nf = (int)file + kf[i]; + if (nr >= 0 && nr < 8 && nf >= 0 && nf < 8) + if (b->sq[nr][nf] == knight) return 1; + } + } + + /* Sliding: bishop/queen diagonals */ + { + static const int drs[] = {1,1,-1,-1}; + static const int dfs[] = {1,-1,1,-1}; + for (unsigned d = 0; d < 4; d++) { + dr = drs[d]; df = dfs[d]; + r = rank; f = file; + while (1) { + r = (unsigned)((int)r + dr); + f = (unsigned)((int)f + df); + if (!in_bounds(r, f)) break; + if (b->sq[r][f] != CHESS_EMPTY) { + if (b->sq[r][f] == bishop || b->sq[r][f] == queen) return 1; + break; + } + } + } + } + + /* Sliding: rook/queen straights */ + { + static const int drs[] = {1,-1,0,0}; + static const int dfs[] = {0,0,1,-1}; + for (unsigned d = 0; d < 4; d++) { + dr = drs[d]; df = dfs[d]; + r = rank; f = file; + while (1) { + r = (unsigned)((int)r + dr); + f = (unsigned)((int)f + df); + if (!in_bounds(r, f)) break; + if (b->sq[r][f] != CHESS_EMPTY) { + if (b->sq[r][f] == rook || b->sq[r][f] == queen) return 1; + break; + } + } + } + } + + /* King */ + { + static const int drs[] = {1,1,1,0,0,-1,-1,-1}; + static const int dfs[] = {1,0,-1,1,-1,1,0,-1}; + for (unsigned d = 0; d < 8; d++) { + int nr = (int)rank + drs[d], nf = (int)file + dfs[d]; + if (nr >= 0 && nr < 8 && nf >= 0 && nf < 8) + if (b->sq[nr][nf] == king) return 1; + } + } + + return 0; +} + +static int find_king(const chess_board_t *b, chess_color_t color, + unsigned *kr, unsigned *kf) +{ + char king = (color == CHESS_WHITE) ? 'K' : 'k'; + for (unsigned r = 0; r < 8; r++) + for (unsigned f = 0; f < 8; f++) + if (b->sq[r][f] == king) { *kr = r; *kf = f; return 1; } + return 0; +} + +static int is_in_check(const chess_board_t *b, chess_color_t side) +{ + unsigned kr, kf; + chess_color_t opp = (side == CHESS_WHITE) ? CHESS_BLACK : CHESS_WHITE; + if (!find_king(b, side, &kr, &kf)) return 0; + return square_attacked_by(b, kr, kf, opp); +} + +/* ── Move legality ─────────────────────────────────────────── */ + +static int pseudo_legal_pawn(const chess_board_t *b, unsigned fr, + unsigned ff, unsigned tr, unsigned tf, + chess_color_t side) +{ + int dir = (side == CHESS_WHITE) ? 1 : -1; + int start_rank = (side == CHESS_WHITE) ? 1 : 6; + int dr = (int)tr - (int)fr; + int df = (int)tf - (int)ff; + + if (df == 0) { + if (dr == dir && b->sq[tr][tf] == CHESS_EMPTY) return 1; + if (dr == 2 * dir && (int)fr == start_rank && + b->sq[fr + (unsigned)dir][ff] == CHESS_EMPTY && + b->sq[tr][tf] == CHESS_EMPTY) return 1; + } + if ((df == 1 || df == -1) && dr == dir) { + if (b->sq[tr][tf] != CHESS_EMPTY) return 1; + } + return 0; +} + +static int pseudo_legal_knight(unsigned fr, unsigned ff, unsigned tr, + unsigned tf) +{ + int dr = abs((int)tr - (int)fr); + int df = abs((int)tf - (int)ff); + return (dr == 2 && df == 1) || (dr == 1 && df == 2); +} + +static int sliding_clear(const chess_board_t *b, unsigned fr, unsigned ff, + unsigned tr, unsigned tf) +{ + int dr = 0, df = 0; + unsigned r, f; + + if ((int)tr > (int)fr) dr = 1; + else if ((int)tr < (int)fr) dr = -1; + if ((int)tf > (int)ff) df = 1; + else if ((int)tf < (int)ff) df = -1; + + r = (unsigned)((int)fr + dr); + f = (unsigned)((int)ff + df); + while (r != tr || f != tf) { + if (!in_bounds(r, f) || b->sq[r][f] != CHESS_EMPTY) return 0; + r = (unsigned)((int)r + dr); + f = (unsigned)((int)f + df); + } + return 1; +} + +static int pseudo_legal(const chess_board_t *b, unsigned fr, unsigned ff, + unsigned tr, unsigned tf, chess_color_t side) +{ + char piece = b->sq[fr][ff]; + int dr = abs((int)tr - (int)fr); + int df = abs((int)tf - (int)ff); + chess_color_t target_color; + + if (piece == CHESS_EMPTY) return 0; + if (piece_color(piece) != side) return 0; + + target_color = piece_color(b->sq[tr][tf]); + if (target_color == side) return 0; + + switch (piece_upper(piece)) { + case 'P': return pseudo_legal_pawn(b, fr, ff, tr, tf, side); + case 'N': return pseudo_legal_knight(fr, ff, tr, tf); + case 'B': + if (dr != df || dr == 0) return 0; + return sliding_clear(b, fr, ff, tr, tf); + case 'R': + if (fr != tr && ff != tf) return 0; + return sliding_clear(b, fr, ff, tr, tf); + case 'Q': + if (fr != tr && ff != tf && dr != df) return 0; + return sliding_clear(b, fr, ff, tr, tf); + case 'K': + return dr <= 1 && df <= 1 && (dr + df > 0); + } + return 0; +} + +static int has_any_legal_move(chess_board_t *b, chess_color_t side); + +static int is_legal_move(chess_board_t *b, unsigned fr, unsigned ff, + unsigned tr, unsigned tf, chess_color_t side) +{ + chess_board_t tmp; + + if (!pseudo_legal(b, fr, ff, tr, tf, side)) return 0; + + memcpy(&tmp, b, sizeof(tmp)); + tmp.sq[tr][tf] = tmp.sq[fr][ff]; + tmp.sq[fr][ff] = CHESS_EMPTY; + + /* Auto-promote to queen */ + if (piece_upper(tmp.sq[tr][tf]) == 'P') { + if ((side == CHESS_WHITE && tr == 7) || + (side == CHESS_BLACK && tr == 0)) { + tmp.sq[tr][tf] = (side == CHESS_WHITE) ? 'Q' : 'q'; + } + } + + return !is_in_check(&tmp, side); +} + +static int has_any_legal_move(chess_board_t *b, chess_color_t side) +{ + for (unsigned fr = 0; fr < 8; fr++) + for (unsigned ff = 0; ff < 8; ff++) { + if (piece_color(b->sq[fr][ff]) != side) continue; + for (unsigned tr = 0; tr < 8; tr++) + for (unsigned tf = 0; tf < 8; tf++) + if (is_legal_move(b, fr, ff, tr, tf, side)) + return 1; + } + return 0; +} + +/* ── SAN notation (simplified) ─────────────────────────────── */ + +static void make_san(char *out, size_t outlen, char piece, + unsigned ff, unsigned tr, unsigned tf, + int capture, int check, int mate, char promote) +{ + char *p = out; + size_t room = outlen; + + if (piece_upper(piece) == 'P') { + if (capture) { + int n = snprintf(p, room, "%cx%c%d", 'a' + ff, 'a' + tf, tr + 1); + p += n; room -= (size_t)n; + } else { + int n = snprintf(p, room, "%c%d", 'a' + tf, tr + 1); + p += n; room -= (size_t)n; + } + } else { + int n = snprintf(p, room, "%c%c%d", piece_upper(piece), + 'a' + tf, tr + 1); + p += n; room -= (size_t)n; + } + if (promote) { + snprintf(p, room, "=%c", piece_upper(promote)); + } else if (mate) { + snprintf(p, room, "#"); + } else if (check) { + snprintf(p, room, "+"); + } +} + +/* ── Game management ───────────────────────────────────────── */ + +chess_game_t *hybbx_chess_get_game(unsigned index) +{ + if (index >= CHESS_GAME_MAX) return NULL; + return &g_games[index]; +} + +chess_game_t *hybbx_chess_create_game(struct hybbx_session *white, + const char *white_name) +{ + unsigned i; + for (i = 0; i < g_max_games; i++) { + if (!g_games[i].active) { + memset(&g_games[i], 0, sizeof(g_games[i])); + g_games[i].active = 1; + hybbx_strlcpy(g_games[i].white_name, white_name, + sizeof(g_games[i].white_name)); + g_games[i].white_session = white; + board_init(&g_games[i].board); + g_games[i].turn = CHESS_WHITE; + g_games[i].move_number = 1; + snprintf(g_games[i].game_id, sizeof(g_games[i].game_id), + "G%u", i + 1); + hybbx_log_info("[chess] game %s created by %s", + g_games[i].game_id, white_name); + return &g_games[i]; + } + } + return NULL; +} + +chess_game_t *hybbx_chess_find_open_game(void) +{ + unsigned i; + for (i = 0; i < g_max_games; i++) + if (g_games[i].active && g_games[i].black_session == NULL) + return &g_games[i]; + return NULL; +} + +chess_game_t *hybbx_chess_find_game_by_id(const char *id) +{ + unsigned i; + if (id == NULL) return NULL; + for (i = 0; i < g_max_games; i++) + if (g_games[i].active && strcasecmp(g_games[i].game_id, id) == 0) + return &g_games[i]; + return NULL; +} + +int hybbx_chess_join_game(chess_game_t *game, struct hybbx_session *black, + const char *black_name) +{ + if (game == NULL || game->black_session != NULL) return 0; + game->black_session = black; + hybbx_strlcpy(game->black_name, black_name, sizeof(game->black_name)); + hybbx_log_info("[chess] %s joined game %s as black", black_name, + game->game_id); + return 1; +} + +int hybbx_chess_add_spectator(chess_game_t *game, + struct hybbx_session *spec) +{ + unsigned i; + if (game == NULL || spec == NULL) return 0; + if (hybbx_chess_is_player(game, spec)) return 0; + for (i = 0; i < game->spectator_count; i++) + if (game->spectators[i] == spec) return 1; + if (game->spectator_count >= CHESS_SPECTATOR_MAX) return 0; + game->spectators[game->spectator_count++] = spec; + return 1; +} + +void hybbx_chess_remove_spectator(chess_game_t *game, + struct hybbx_session *spec) +{ + unsigned i; + if (game == NULL || spec == NULL) return; + for (i = 0; i < game->spectator_count; i++) { + if (game->spectators[i] == spec) { + game->spectators[i] = game->spectators[--game->spectator_count]; + return; + } + } +} + +int hybbx_chess_is_player(const chess_game_t *game, + const struct hybbx_session *session) +{ + if (game == NULL || session == NULL) return 0; + return game->white_session == session || game->black_session == session; +} + +int hybbx_chess_is_spectator(const chess_game_t *game, + const struct hybbx_session *session) +{ + unsigned i; + if (game == NULL || session == NULL) return 0; + for (i = 0; i < game->spectator_count; i++) + if (game->spectators[i] == session) return 1; + return 0; +} + +chess_color_t hybbx_chess_player_color(const chess_game_t *game, + const struct hybbx_session *session) +{ + if (game == NULL || session == NULL) return CHESS_COLOR_NONE; + if (game->white_session == session) return CHESS_WHITE; + if (game->black_session == session) return CHESS_BLACK; + return CHESS_COLOR_NONE; +} + +/* ── Move execution ────────────────────────────────────────── */ + +int hybbx_chess_make_move(chess_game_t *game, const char *from, + const char *to, char promote, char *err, + size_t errlen) +{ + unsigned fr, ff, tr, tf; + char piece, captured; + int check, mate; + chess_color_t side, opp; + + if (game == NULL || game->result != CHESS_RESULT_NONE) { + if (err) snprintf(err, errlen, "Game is over."); + return 0; + } + + side = game->turn; + + if (!parse_square(from, &fr, &ff)) { + if (err) snprintf(err, errlen, "Invalid square: %s", from); + return 0; + } + if (!parse_square(to, &tr, &tf)) { + if (err) snprintf(err, errlen, "Invalid square: %s", to); + return 0; + } + + piece = game->board.sq[fr][ff]; + if (piece_color(piece) != side) { + if (err) snprintf(err, errlen, "Not your piece."); + return 0; + } + + if (!is_legal_move(&game->board, fr, ff, tr, tf, side)) { + if (err) snprintf(err, errlen, "Illegal move."); + return 0; + } + + captured = game->board.sq[tr][tf]; + game->board.sq[tr][tf] = piece; + game->board.sq[fr][ff] = CHESS_EMPTY; + + /* Pawn promotion */ + if (piece_upper(piece) == 'P') { + if ((side == CHESS_WHITE && tr == 7) || + (side == CHESS_BLACK && tr == 0)) { + char pp = promote ? (char)toupper((unsigned char)promote) : 'Q'; + game->board.sq[tr][tf] = (side == CHESS_WHITE) ? pp : + (char)tolower((unsigned char)pp); + } + } + + opp = (side == CHESS_WHITE) ? CHESS_BLACK : CHESS_WHITE; + check = is_in_check(&game->board, opp); + mate = check && !has_any_legal_move(&game->board, opp); + + make_san(game->last_move_san, sizeof(game->last_move_san), piece, + ff, tr, tf, captured != CHESS_EMPTY, check, mate, promote); + + if (mate) { + game->result = (side == CHESS_WHITE) ? CHESS_WHITE_WINS : + CHESS_BLACK_WINS; + } else if (!has_any_legal_move(&game->board, opp)) { + game->result = CHESS_DRAW_STALEMATE; + } + + game->turn = opp; + if (opp == CHESS_WHITE) game->move_number++; + game->tick_counter = 0; + + hybbx_log_info("[chess] %s: %s %s", game->game_id, + (side == CHESS_WHITE) ? game->white_name : game->black_name, + game->last_move_san); + return 1; +} + +/* ── Resign / Draw ─────────────────────────────────────────── */ + +void hybbx_chess_resign(chess_game_t *game, struct hybbx_session *who) +{ + if (game == NULL || game->result != CHESS_RESULT_NONE) return; + if (game->white_session == who) + game->result = CHESS_BLACK_WINS; + else if (game->black_session == who) + game->result = CHESS_WHITE_WINS; +} + +void hybbx_chess_offer_draw(chess_game_t *game, struct hybbx_session *who) +{ + (void)who; + if (game == NULL || game->result != CHESS_RESULT_NONE) return; + game->result = CHESS_DRAW_AGREEMENT; +} + +/* ── Board rendering ───────────────────────────────────────── */ + +void hybbx_chess_render_board(const chess_board_t *board, + struct hybbx_session *session, + const char *label) +{ + static const char *glyph = ".KQRBNPkqrbnp"; + char line[96]; + unsigned r, f; + + if (label && label[0]) + hybbx_session_write_line(session, label); + + hybbx_session_write_line(session, + " +---+---+---+---+---+---+---+---+"); + + for (r = 0; r < 8; r++) { + unsigned rank = 7 - r; + int n = snprintf(line, sizeof(line), "%u |", rank + 1); + for (f = 0; f < 8; f++) { + char p = board->sq[rank][f]; + const char *ch; + switch (p) { + case 'K': ch = "K"; break; case 'Q': ch = "Q"; break; + case 'R': ch = "R"; break; case 'B': ch = "B"; break; + case 'N': ch = "N"; break; case 'P': ch = "P"; break; + case 'k': ch = "k"; break; case 'q': ch = "q"; break; + case 'r': ch = "r"; break; case 'b': ch = "b"; break; + case 'n': ch = "n"; break; case 'p': ch = "p"; break; + default: ch = "."; break; + } + n += snprintf(line + n, sizeof(line) - (size_t)n, " %s |", ch); + } + hybbx_session_write_line(session, line); + hybbx_session_write_line(session, + " +---+---+---+---+---+---+---+---+"); + } + hybbx_session_write_line(session, + " a b c d e f g h"); +} + +void hybbx_chess_send_board(chess_game_t *game, + struct hybbx_session *session) +{ + char label[96]; + const char *turn_name; + + if (game == NULL || session == NULL) return; + + turn_name = (game->turn == CHESS_WHITE) ? game->white_name : + game->black_name; + + if (game->result != CHESS_RESULT_NONE) { + const char *result_str; + switch (game->result) { + case CHESS_WHITE_WINS: result_str = "1-0 White wins"; break; + case CHESS_BLACK_WINS: result_str = "0-1 Black wins"; break; + case CHESS_DRAW_STALEMATE: result_str = "1/2-1/2 Stalemate"; break; + case CHESS_DRAW_AGREEMENT: result_str = "1/2-1/2 Draw"; break; + default: result_str = "Game over"; break; + } + snprintf(label, sizeof(label), "[%s] %s vs %s %s Move %u", + game->game_id, game->white_name, game->black_name, + result_str, game->move_number); + } else { + snprintf(label, sizeof(label), + "[%s] %s(W) vs %s(B) %s to move %s Move %u", + game->game_id, game->white_name, game->black_name, + turn_name, + game->last_move_san[0] ? game->last_move_san : "", + game->move_number); + } + + hybbx_chess_render_board(&game->board, session, label); +} + +/* ── 15-second broadcast tick ──────────────────────────────── */ + +void hybbx_chess_tick(struct hybbx_service *service) +{ + unsigned i, j; + + (void)service; + + for (i = 0; i < g_max_games; i++) { + chess_game_t *g = &g_games[i]; + + if (!g->active) continue; + if (g->black_session == NULL) continue; + + g->tick_counter++; + if (g->tick_counter < CHESS_REFRESH_SEC) continue; + g->tick_counter = 0; + + if (g->white_session) + hybbx_chess_send_board(g, g->white_session); + if (g->black_session) + hybbx_chess_send_board(g, g->black_session); + for (j = 0; j < g->spectator_count; j++) + hybbx_chess_send_board(g, g->spectators[j]); + } +} -- cgit v1.3.1