src/game.c

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 2014 Mike Becker. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   1. Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *
 *   2. Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include "game.h"
#include "input.h"
#include "rules/rules.h"
#include <ncurses.h>
#include <string.h>

static const uint8_t boardx = 10, boardy = 10;

static void draw_board(Board board, uint8_t mycolor) {
    
    for (uint8_t y = 0 ; y < 8 ; y++) {
        for (uint8_t x = 0 ; x < 8 ; x++) {
            uint8_t col = board[y][x] & COLOR_MASK;
            uint8_t piece = board[y][x] & PIECE_MASK;
            char piecec = ' ';
            switch (piece) {
                case PAWN: piecec = 'P'; break;
                case ROOK: piecec = 'R'; break;
                case KNIGHT: piecec = 'N'; break;
                case BISHOP: piecec = 'B'; break;
                case QUEEN: piecec = 'Q'; break;
                case KING: piecec = 'K'; break;
            }
            
            attrset((col == WHITE ? A_BOLD : A_DIM) |
                COLOR_PAIR((y&1)==(x&1) ? COL_WB : COL_BW));
            
            int cy = mycolor == WHITE ? boardy-y : boardy-7+y;
            int cx = mycolor == WHITE ? boardx+x*3 : boardx+21-x*3;
            mvaddch(cy, cx, ' ');
            mvaddch(cy, cx+1, piecec);
            mvaddch(cy, cx+2, ' ');
        }
    }
    
    attrset(A_NORMAL);
    for (uint8_t i = 0 ; i < 8 ; i++) {
        int x = mycolor == WHITE ? boardx+i*3+1 : boardx+22-i*3;
        int y = mycolor == WHITE ? boardy-i : boardy-7+i;
        mvaddch(boardy+1, x, 'a'+i);
        mvaddch(y, boardx-2, '1'+i);
    }
}

static void apply_move(Board board, Move *move) {
    board[move->fromrow][move->fromfile] = 0;
    // TODO: care for en passant capture
    board[move->torow][move->tofile] = move->piece;
    
    /* castling */
    if ((move->piece & PIECE_MASK) == KING &&
        move->fromfile == fileidx('e')) {
        uint8_t color = move->piece & COLOR_MASK;
        
        if (move->tofile == fileidx('g')) {
            board[move->torow][fileidx('h')] = 0;
            board[move->torow][fileidx('f')] = color|ROOK;
        } else if (move->tofile == fileidx('c')) {
            board[move->torow][fileidx('a')] = 0;
            board[move->torow][fileidx('d')] = color|ROOK;
        }
    }
}

static _Bool validate_move(Board board, Move *move) {
    _Bool result;
    
    /* does piece exist */
    result = board[move->fromrow][move->fromfile] == move->piece;
    
    switch (move->piece & PIECE_MASK) {
    case PAWN:
        result = result && pawn_chkrules(board, move);
        result = result && !pawn_isblocked(board, move);
        break;
    case ROOK:
        result = result && rook_chkrules(board, move);
        result = result && !rook_isblocked(board, move);
        break;
    case KNIGHT:
        result = result && knight_chkrules(board, move);
        result = result && !knight_isblocked(board, move);
        break;
    case BISHOP:
        result = result && bishop_chkrules(board, move);
        result = result && !bishop_isblocked(board, move);
        break;
    case QUEEN:
        result = result && queen_chkrules(board, move);
        result = result && !queen_isblocked(board, move);
        break;
    case KING:
        result = result && king_chkrules(board, move);
        result = result && !king_isblocked(board, move);
        break;
    default:
        result = FALSE;
    }
    
    /* is piece pinned */
    // TODO: make it so
    
    /* correct check and checkmate flags */
    // TODO: make it so
    
    return result;
}

static _Bool eval_move(Board board, uint8_t mycolor, char *mstr, Move *move) {
    memset(move, 0, sizeof(Move));
    
    size_t len = strlen(mstr);
    
    /* evaluate check/checkmate flags */
    if (mstr[len-1] == '+') {
        len--; mstr[len] = '\0';
        move->check = TRUE;
    } else if (mstr[len-1] == '#') {
        len--; mstr[len] = '\0';
        move->checkmate = TRUE;
    }
    
    if (len == 2) {
        /* pawn move (e.g. "e4") */
        if (isfile(mstr[0]) && isrow(mstr[1])) {
            move->piece = PAWN|mycolor;
            move->tofile = fileidx(mstr[0]);
            move->torow = rowidx(mstr[1]);
            if (!pawn_getlocation(board, move)) {
                move->piece = 0;
            }
        }
    } else if (len == 3) {
        if (strcmp(mstr, "O-O") == 0) {
            /* king side castling */
            move->piece = KING|mycolor;
            move->fromfile = fileidx('e');
            move->tofile = fileidx('g');
            move->fromrow = move->torow = mycolor == WHITE ? 0 : 7;
        } else {
            /* unambiguous move (e.g. "Nf3") */
        }
        
    } else if (len == 4) {
        /* ambiguous move (e.g. "Ndf3") */
        
        /* unambiguous capture (e.g. "Nxf3", "dxe5") */
        
    } else if (len == 5) {
        if (strcmp(mstr, "O-O-O") == 0) {
            /* queen side castling "O-O-O" */
            move->piece = KING|mycolor;
            move->fromfile = fileidx('e');
            move->tofile = fileidx('c');
            move->fromrow = move->torow = mycolor == WHITE ? 0 : 7;
        } else {
            /* ambiguous capture (e.g. "Ndxf3") */

            /* long notation move (e.g. "Nc5a4") */

            /* long notation capture (e.g. "e5xf6") */
        }
    } else if (len == 6) {
        /* long notation capture (e.g. "Nc5xf3") */
    }
    
    return move->piece != 0;
}

static int sendmove(Board board, uint8_t mycolor, int opponent) {
    const size_t buflen = 8;
    char movestr[buflen];
    _Bool remisrejected = FALSE;
    uint8_t code;
    
    while (1) {
        move(boardy+3, 0);
        if (remisrejected) {
            printw(
                "Use chess notation to enter your move.\n"
                "Remis offer rejected - type 'surr' to surrender.      \n\n"
                "Type your move: ");
        } else {
            printw(
                "Use chess notation to enter your move.\n"
                "Or type 'surr' to surrender or 'remis' to offer remis.\n\n"
                "Type your move: ");
        }
        clrtoeol();
        refresh();
        getnstr(movestr, buflen);

        if (strncmp(movestr, "surr", buflen) == 0) {
            printw("You surrendered!");
            refresh();
            net_send_code(opponent, NETCODE_SURRENDER);
            return 1;
        } else if (strncmp(movestr, "remis", buflen) == 0) {
            if (!remisrejected) {
                net_send_code(opponent, NETCODE_REMIS);
                printw("Remis offer sent - waiting for acceptance...");
                refresh();
                if (net_recieve_code(opponent) == NETCODE_ACCEPT) {
                    printw("\rRemis accepted!");
                    clrtoeol();
                    refresh();
                    return 1;
                } else {
                    remisrejected = TRUE;
                }
            }
        } else {
            Move move;
            if (eval_move(board, mycolor, movestr, &move)) {
                net_send_code(opponent, NETCODE_MOVE);
                net_send_data(opponent, &move, sizeof(Move));
                code = net_recieve_code(opponent);
                move.check = code == NETCODE_CHECK;
                move.checkmate = code == NETCODE_CHECKMATE;
                // TODO: record move
                if (code == NETCODE_DECLINE) {
                    printw("Invalid move.");
                    clrtoeol();
                } else {
                    apply_move(board, &move);
                    if (move.checkmate) {
                        printw("Checkmate!");
                        return 1;
                    }
                }
            } else {
                printw("Can't interpret move - please use algebraic notation.");
            }
        }
    }
}

static int recvmove(Board board, int opponent) {
    
    while (1) {
        move(boardy+3, 0);
        printw("Awaiting opponent move...");
        clrtoeol();
        refresh();

        // TODO: nonblocking
        uint32_t code = net_recieve_code(opponent);
        
        Move move;
        switch (code) {
            case NETCODE_SURRENDER:
                printw("\rYour opponent surrendered!");
                clrtoeol();
                return 1;
            case NETCODE_REMIS:
                if (prompt_yesno(
                    "\rYour opponent offers remis - do you accept")) {
                    printw("\rRemis accepted!");
                    clrtoeol();
                    net_send_code(opponent, NETCODE_ACCEPT);
                    return 1;
                } else {
                    net_send_code(opponent, NETCODE_DECLINE);
                }
                break;
            case NETCODE_MOVE:
                net_recieve_data(opponent, &move, sizeof(Move));
                if (validate_move(board, &move)) {
                    apply_move(board, &move);
                    // TODO: record move
                    if (move.check) {
                        net_send_code(opponent, NETCODE_CHECK);
                    } else if (move.checkmate) {
                        net_send_code(opponent, NETCODE_CHECKMATE);
                    } else {
                        net_send_code(opponent, NETCODE_ACCEPT);
                    }
                    return 0;
                } else {
                    net_send_code(opponent, NETCODE_DECLINE);
                }
        }
    }
}

void game_start(Settings *settings, int opponent) {
    _Bool myturn = is_server(settings) ==
        (settings->gameinfo.servercolor == WHITE);
    uint8_t mycolor = myturn ? WHITE:BLACK;
    
    _Bool running;
    
    Board board = {
        {WROOK, WKNIGHT, WBISHOP, WQUEEN, WKING, WBISHOP, WKNIGHT, WROOK},
        {WPAWN, WPAWN,   WPAWN,   WPAWN,  WPAWN, WPAWN,   WPAWN,   WPAWN},
        {0,     0,       0,       0,      0,     0,       0,       0},
        {0,     0,       0,       0,      0,     0,       0,       0},
        {0,     0,       0,       0,      0,     0,       0,       0},
        {0,     0,       0,       0,      0,     0,       0,       0},
        {BPAWN, BPAWN,   BPAWN,   BPAWN,  BPAWN, BPAWN,   BPAWN,   BPAWN},
        {BROOK, BKNIGHT, BBISHOP, BQUEEN, BKING, BBISHOP, BKNIGHT, BROOK}
    };
    
    do {
        clear();
        draw_board(board, mycolor);
        if (myturn) {
            running = !sendmove(board, mycolor, opponent);
        } else {
            running = !recvmove(board, opponent);
            flushinp(); // flush any input the user hacked in while waiting
        }
        myturn ^= TRUE;
    }  while (running);
    
    mvaddstr(getmaxy(tchess_window)-1, 0,
        "Game has ended. Press any key to leave...");
    getch();
}