src/game.c

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 2016 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 "network.h"
#include "input.h"
#include "colors.h"
#include "chess/rules.h"
#include "chess/pgn.h"
#include <ncurses.h>
#include <string.h>
#include <sys/select.h>
#include <stdio.h>
#include <errno.h>

static const uint8_t boardx = 4, boardy = 10;
static int inputy = 21; /* should be overridden on game startup */

static int timecontrol(GameState *gamestate, GameInfo *gameinfo) {
    if (gameinfo->timecontrol) {
        uint16_t white = remaining_movetime(gameinfo, gamestate, WHITE);
        uint16_t black = remaining_movetime(gameinfo, gamestate, BLACK);
        char clkstr[16];
        bool always_hours = gameinfo->time >= 3600;
        print_clk(white, clkstr, always_hours);
        mvprintw(boardy+4, boardx-1, "White time: %s", clkstr);
        print_clk(black, clkstr, always_hours);
        mvprintw(boardy+5, boardx-1, "Black time: %s", clkstr);
    
        if (white == 0) {
            move(inputy, 0);
            printw("Time is over - Black wins!");
            clrtobot();
            refresh();
            return 1;
        }
        if (black == 0) {
            move(inputy, 0);
            printw("Time is over - White wins!");
            clrtobot();
            refresh();
            return 1;
        }
    }
    
    return 0;
}

static void draw_board(GameState *gamestate,
		       uint8_t perspective,
		       bool unicode) {
    char fen[90];
    compute_fen(fen, gamestate);
    mvaddstr(0, 0, fen);
    
    for (uint8_t y = 0 ; y < 8 ; y++) {
        for (uint8_t x = 0 ; x < 8 ; x++) {
            uint8_t col = gamestate->board[y][x] & COLOR_MASK;
            uint8_t piece = gamestate->board[y][x];
            char piecestr[5];
            if (piece) {
                if (unicode) {
                    char* uc = getpieceunicode(piece);
                    strncpy(piecestr, uc, 5);
                } else {
                    piecestr[0] = (piece & PIECE_MASK) == PAWN
                                      ? 'P' : getpiecechr(piece);
                    piecestr[1] = '\0';
                }
            } else {
                piecestr[0] = ' ';
                piecestr[1] = '\0';
            }
            
            bool boardblack = (y&1)==(x&1);
            attrset((col==WHITE ? A_BOLD : A_DIM)|
                COLOR_PAIR(col == WHITE ?
                    (boardblack ? COL_WB : COL_WW) :
                    (boardblack ? COL_BB : COL_BW)
                )
            );
            
            int cy = perspective == WHITE ? boardy-y : boardy-7+y;
            int cx = perspective == WHITE ? boardx+x*3 : boardx+21-x*3;
            mvprintw(cy, cx, " %s ", piecestr);
        }
    }
    
    attrset(A_NORMAL);
    for (uint8_t i = 0 ; i < 8 ; i++) {
        int x = perspective == WHITE ? boardx+i*3+1 : boardx+22-i*3;
        int y = perspective == WHITE ? boardy-i : boardy-7+i;
        mvaddch(boardy+1, x, 'a'+i);
        mvaddch(y, boardx-2, '1'+i);
    }
    
    /* move log */
    uint8_t logy = 2;
    const uint8_t logx = boardx + 28;
    move(logy, logx);

    /* count full moves */
    unsigned int logi = 0;

    /* wrap log after 45 moves */
    while (gamestate->movecount/6-logi/3 >= 15) {
        logi++;
    }
    
    for (unsigned mi = logi*2 ; mi < gamestate->movecount ; mi++) {
        bool iswhite = mi % 2 == 0;
        if (iswhite) {
            logi++;
            printw("%d. ", logi);
        }

        addstr(gamestate->moves[mi].string);
        if (!iswhite && logi%3 == 0) {
            move(++logy, logx);
        } else {
            addch(' ');
        }
    }
}

static void eval_move_failed_msg(int code) {
    switch (code) {
    case AMBIGUOUS_MOVE:
        printw("Ambiguous move - please specify the piece to move.");
        break;
    case INVALID_POSITION:
        printw("No piece can be moved this way.");
        break;
    case NEED_PROMOTION:
        printw("You need to promote the pawn (append \"=Q\" e.g.)!");
        break;
    case KING_IN_CHECK:
        printw("Your king is in check!");
        break;
    case PIECE_PINNED:
        printw("This piece is pinned!");
        break;
    case INVALID_MOVE_SYNTAX:
        printw("Can't interpret move - please use algebraic notation.");
        break;
    case RULES_VIOLATED:
        printw("Move does not comply chess rules.");
        break;
    case KING_MOVES_INTO_CHECK:
        printw("Can't move the king into a check position.");
        break;
    default:
        printw("Unknown move parser error.");
    }
}

static void save_pgn(GameState *gamestate, GameInfo *gameinfo) {
    printw("Filename: ");
    clrtoeol();
    refresh();
    
    char filename[64];
    int y = getcury(stdscr);
    if (getnstr(filename, 64) == OK && filename[0] != '\0') {
        move(y, 0);
        FILE *file = fopen(filename, "w");
        if (file) {
            write_pgn(file, gamestate, gameinfo);
            fclose(file);
            printw("File saved.");
        } else {
            printw("Can't write to file (%s).", strerror(errno));
        }
        clrtoeol();
    }
}

#define MOVESTR_BUFLEN 10
static int domove_singlemachine(GameState *gamestate,
        GameInfo *gameinfo, uint8_t curcolor) {
    

    size_t bufpos = 0;
    char movestr[MOVESTR_BUFLEN];
    
    flushinp();
    while (1) {
        const char *curcolorstr = curcolor == WHITE ? "White" : "Black";
        if (timecontrol(gamestate, gameinfo)) {
            return 1;
        }
        move(inputy, 0);
        printw(
            "Use chess notation to enter your move.\n"
            "Or use a command: remis, resign, savepgn\n\n"
            "%s to move: ", curcolorstr);
        clrtoeol();
        
        if (asyncgetnstr(movestr, &bufpos, MOVESTR_BUFLEN)) {
            if (strncmp(movestr, "resign", MOVESTR_BUFLEN) == 0) {
                gamestate->resign = 1;
                printw("%s resigned!", curcolorstr);
                clrtobot();
                refresh();
                return 1;
            } else if (strncmp(movestr, "remis", MOVESTR_BUFLEN) == 0) {
                gamestate->remis = 1;
                printw("Game ends remis.");
                clrtobot();
                refresh();
                return 1;
            } else if (strncmp(movestr, "savepgn", MOVESTR_BUFLEN) == 0) {
                save_pgn(gamestate, gameinfo);
            } else {
                Move move;
                int result = eval_move(gamestate, movestr, &move, curcolor);
                if (result == VALID_MOVE_SYNTAX) {
                    result = validate_move(gamestate, &move);
                    if (result == VALID_MOVE_SEMANTICS) {
                        apply_move(gamestate, &move);
                        if (gamestate->checkmate) {
                            printw("Checkmate!");
                            clrtoeol();
                            return 1;
                        } else if (gamestate->stalemate) {
                            printw("Stalemate!");
                            clrtoeol();
                            return 1;
                        } else {
                            return 0;
                        }
                    } else {
                        eval_move_failed_msg(result);
                    }
                } else {
                    eval_move_failed_msg(result);
                }
                clrtoeol();
            }
        }
    }
}

static int sendmove(GameState *gamestate, GameInfo *gameinfo,
        int opponent, uint8_t mycolor) {
    
    size_t bufpos = 0;
    char movestr[MOVESTR_BUFLEN];
    bool remis_rejected = false;
    bool remis_suggested = false;
    bool use_premove = false;
    uint8_t code;

    if (*gamestate->premove) {
        use_premove = true;
        const unsigned mlen = sizeof(gamestate->premove);
        strncpy(movestr, gamestate->premove, mlen);
        movestr[mlen] = '\0';
        memset(gamestate->premove, 0, mlen);
    }
    
    flushinp();
    while (1) {
        if (timecontrol(gamestate, gameinfo)) {
            net_send_code(opponent, NETCODE_TIMEOVER);
            return 1;
        }
        
        move(inputy, 0);
        printw("Use chess notation to enter your move.\n");
        if (remis_suggested) {
            printw("The opponent offers remis. Also type remis to accept.\n\n");
        } else if (remis_rejected) {
            printw("Remis offer rejected.                                \n\n");
        } else {
            printw("Or use a command: remis, resign, savepgn             \n\n");
        }
        printw("Type your move: ");
        clrtoeol();

        /* check if the opponent sent us something */
        code = net_recieve_code_async(opponent);
        switch (code) {
            case NETCODE_REMIS:
                remis_suggested = true;
                break;
            case NETCODE_RESIGN:
                gamestate->resign = 1;
                printw("\rYour opponent resigned!");
                clrtoeol();
                return 1;
            case NETCODE_CONNLOST:
                printw("\rYour opponent has left the game.");
                clrtoeol();
                return 1;
            case NETCODE_ERROR:
                printw("\rCannot perform asynchronous network IO");
                cbreak(); getch();
                exit(EXIT_FAILURE);
            case NETCODE_AGAIN:
                /* try again */
                break;
            default:
                printw("\nThe opponent sent an invalid network pacakge.");
        }

        /* read move */
        if (use_premove || asyncgetnstr(movestr, &bufpos, MOVESTR_BUFLEN)) {
            use_premove = false;
            if (strncmp(movestr, "resign", MOVESTR_BUFLEN) == 0) {
                gamestate->resign = 1;
                printw("You resigned!");
                clrtoeol();
                refresh();
                net_send_code(opponent, NETCODE_RESIGN);
                return 1;
            } else if (strncmp(movestr, "savepgn", MOVESTR_BUFLEN) == 0) {
                save_pgn(gamestate, gameinfo);
            } else if (strncmp(movestr, "remis", MOVESTR_BUFLEN) == 0) {
                if (remis_suggested) {
                    net_send_code(opponent, NETCODE_REMIS);
                    gamestate->remis = 1;
                    printw("\rRemis accepted!");
                    clrtoeol();
                    refresh();
                    return 1;
                } if (!remis_rejected) {
                    net_send_code(opponent, NETCODE_REMIS);
                    printw("Remis offer sent - waiting for acceptance...");
                    refresh();
                    code = net_recieve_code(opponent);
                    if (code == NETCODE_ACCEPT) {
                        gamestate->remis = 1;
                        printw("\rRemis accepted!");
                        clrtoeol();
                        refresh();
                        return 1;
                    } else if (code == NETCODE_CONNLOST) {
                        printw("\rYour opponent left the game.");
                        clrtoeol();
                        refresh();
                        return 1;
                    } else {
                        remis_rejected = true;
                    }
                }
            } else {
                Move move;
                int eval_result = eval_move(gamestate, movestr, &move, mycolor);
                switch (eval_result) {
                case VALID_MOVE_SYNTAX:
                    net_send_data(opponent, NETCODE_MOVE, &move, sizeof(Move));
                    code = net_recieve_code(opponent);
                    move.check = code == NETCODE_CHECK ||
                        code == NETCODE_CHECKMATE;
                    gamestate->checkmate = code == NETCODE_CHECKMATE;
                    gamestate->stalemate = code == NETCODE_STALEMATE;
                    if (code == NETCODE_DECLINE) {
                        uint32_t reason;
                        net_recieve_data(opponent, &reason, sizeof(uint32_t));
                        reason = ntohl(reason);
                        eval_move_failed_msg(reason);
                    } else if (code == NETCODE_ACCEPT
                            || code == NETCODE_CHECK
                            || code == NETCODE_CHECKMATE
                            || code == NETCODE_STALEMATE) {
                        apply_move(gamestate, &move);
                        if (gamestate->checkmate) {
                            printw("Checkmate!");
                            clrtoeol();
                            return 1;
                        } else if (gamestate->stalemate) {
                            printw("Stalemate!");
                            clrtoeol();
                            return 1;
                        } else {
                            return 0;
                        }
                    } else if (code == NETCODE_CONNLOST) {
                        printw("Your opponent left the game.");
                        return 1;
                    } else {
                        printw("Invalid network response.");
                    }
                    break;
                default:
                    eval_move_failed_msg(eval_result);
                }
                clrtoeol();
            }
        }
    }
}

static int recvmove(GameState *gamestate, GameInfo *gameinfo,
        int opponent, uint8_t mycolor) {
    memset(gamestate->premove, 0, sizeof(gamestate->premove));

    size_t bufpos = 0;
    char movestr[MOVESTR_BUFLEN];
    bool remis_suggested = false;
    while (1) {
        timecontrol(gamestate, gameinfo);
        
        move(inputy, 0);
        printw("Awaiting opponent move. Use chess notation to prepare a move.\n");
        if (*gamestate->premove) {
            printw("Current pre-move: %s                    \n\n",
                gamestate->premove);
        } else if (remis_suggested) {
            printw("Suggested remis.                        \n\n");
        } else {
            printw("Or use a command: remis, resign, savepgn\n\n");
        }
        printw("Prepare your next move: ");
        clrtoeol();
        refresh();

        /* allow the player to prepare a move */
        if (asyncgetnstr(movestr, &bufpos, MOVESTR_BUFLEN)) {
            if (strncmp(movestr, "resign", MOVESTR_BUFLEN) == 0) {
                gamestate->resign = 1;
                printw("You resigned!");
                clrtoeol();
                refresh();
                net_send_code(opponent, NETCODE_RESIGN);
                return 1;
            } else if (strncmp(movestr, "remis", MOVESTR_BUFLEN) == 0) {
                remis_suggested = true;
                net_send_code(opponent, NETCODE_REMIS);
            } else if (strncmp(movestr, "savepgn", MOVESTR_BUFLEN) == 0) {
                save_pgn(gamestate, gameinfo);
            } else if (movestr[0] == 0) {
                memset(gamestate->premove, 0, sizeof(gamestate->premove));
            } else {
                Move move;
                int res = eval_move(gamestate, movestr, &move, mycolor);
                if (res == VALID_MOVE_SYNTAX) {
                    strncpy(gamestate->premove, movestr, 8);
                    memset(movestr, 0, MOVESTR_BUFLEN);
                    bufpos = 0;
                    clrtobot();
                } else {
                    eval_move_failed_msg(res);
                }
            }
        }

        /* read opponent's move */
        uint8_t code = net_recieve_code_async(opponent);
        switch (code) {
        case NETCODE_TIMEOVER:
            /* redraw the time control */
            timecontrol(gamestate, gameinfo);
            return 1;
        case NETCODE_RESIGN:
            gamestate->resign = 1;
            printw("\rYour opponent resigned!");
            clrtoeol();
            return 1;
        case NETCODE_CONNLOST:
            printw("\rYour opponent has left the game.");
            clrtoeol();
            return 1;
        case NETCODE_REMIS:
            if (remis_suggested) {
                gamestate->remis = 1;
                printw("\rRemis accepted!");
                clrtoeol();
                return 1;
            } else {
                if (prompt_yesno(
                    "\rYour opponent offers remis - do you accept")) {
                    gamestate->remis = 1;
                    printw("\rRemis accepted!");
                    clrtoeol();
                    net_send_code(opponent, NETCODE_ACCEPT);
                    return 1;
                } else {
                    net_send_code(opponent, NETCODE_DECLINE);
                }
            }
            break;
        case NETCODE_MOVE: {
            Move move;
            net_recieve_data(opponent, &move, sizeof(Move));
            code = validate_move(gamestate, &move);
            if (code == VALID_MOVE_SEMANTICS) {
                apply_move(gamestate, &move);
                if (gamestate->checkmate) {
                    net_send_code(opponent, NETCODE_CHECKMATE);
                    printw("\rCheckmate!");
                    clrtoeol();
                    return 1;
                } else if (gamestate->stalemate) {
                    net_send_code(opponent, NETCODE_STALEMATE);
                    printw("\rStalemate!");
                    clrtoeol();
                    return 1;
                } else if (move.check) {
                    net_send_code(opponent, NETCODE_CHECK);
                } else {
                    net_send_code(opponent, NETCODE_ACCEPT);
                }
                return 0;
            } else {
                uint32_t reason = htonl(code);
                net_send_data(opponent, NETCODE_DECLINE,
                    &reason, sizeof(uint32_t));
            }
            break;
        }
        case NETCODE_ERROR:
            printw("\rCannot perform asynchronous network IO");
            cbreak(); getch();
            exit(EXIT_FAILURE);
        case NETCODE_AGAIN:
            /* try again */
            break;
        default:
            printw("\nInvalid network request.");
        }
    }
}

void game_review(Settings* settings, GameState *gamestate) {
    GameInfo *gameinfo = &(settings->gameinfo);

    move(0,0);
    draw_board(gamestate, WHITE, settings->unicode);
    
    mvaddstr(getmaxy(stdscr)-1, 0,
        "Press 'q' to quit or 's' to save a PGN file...");
    refresh();
    flushinp();
    
    noecho();
    int c;
    do {
        c = getch();
        if (c == 's') {
            addch('\r');
            echo();
            save_pgn(gamestate, gameinfo);
            addstr(" Press 'q' to quit...");
            noecho();
        }
    } while (c != 'q');
    echo();
    
    gamestate_cleanup(gamestate);
}

void game_play_singlemachine(Settings *settings) {
    inputy = getmaxy(stdscr) - 6;
    
    GameState gamestate;
    gamestate_init(&gamestate);
    uint8_t curcol = WHITE;
    
    if (settings->continuepgn) {
        FILE *pgnfile = fopen(settings->continuepgn, "r");
        if (pgnfile) {
            int result = read_pgn(pgnfile, &gamestate, &(settings->gameinfo));
            long position = ftell(pgnfile);
            fclose(pgnfile);
            if (result) {
                printw("Invalid PGN file content at position %ld:\n%s\n",
                        position, pgn_error_str(result));
                return;
            }
            if (!is_game_running(&gamestate)) {
                addstr("Game has ended. Use -S to analyze it.\n");
                return;
            }
            curcol = opponent_color(last_move(&gamestate).piece&COLOR_MASK);
        } else {
            printw("Can't read PGN file (%s)\n", strerror(errno));
            return;
        }
    }

    bool running;
    do {
        clear();
        uint8_t perspective = settings->disableflip ? WHITE : curcol;
        draw_board(&gamestate, perspective, settings->unicode);
        running = !domove_singlemachine(&gamestate,
            &(settings->gameinfo), curcol);
        curcol = opponent_color(curcol);
    }  while (running);
    
    game_review(settings, &gamestate);
}

void game_play(Settings *settings, GameState *gamestate, int opponent) {
    inputy = getmaxy(stdscr) - 6;
    
    uint8_t mycolor = settings->gameinfo.servercolor;
    if (!settings->ishost) {
        mycolor = opponent_color(mycolor);
    }
    
    bool myturn = (gamestate->movecount > 0 ?
        (last_move(gamestate).piece & COLOR_MASK) : BLACK) != mycolor;
    
    bool running;
    do {
        clear();
        draw_board(gamestate, mycolor, settings->unicode);
        if (myturn) {
            running = !sendmove(gamestate, &(settings->gameinfo),
                opponent, mycolor);
        } else {
            running = !recvmove(gamestate, &(settings->gameinfo),
                opponent, mycolor);
        }
        myturn ^= true;
    }  while (running);
}

void dump_gameinfo(GameInfo *gameinfo) {
    int serverwhite = gameinfo->servercolor == WHITE;
    attron(A_UNDERLINE);
    printw("Game details\n");
    attroff(A_UNDERLINE);
    printw("  Server:     %s\n  Client:     %s\n",
        serverwhite?"White":"Black", serverwhite?"Black":"White"
    );
    if (gameinfo->timecontrol) {
        if (gameinfo->time % 60) {
            printw("  Time limit: %ds + %ds\n",
                gameinfo->time, gameinfo->addtime);
        } else {
            printw("  Time limit: %dm + %ds\n",
                gameinfo->time/60, gameinfo->addtime);
        }
    } else {
        printw("  No time limit\n");
    }
    refresh();
}

void dump_moveinfo(GameState *gamestate) {
    for (unsigned i = 0 ; i < gamestate->movecount ; i++) {
        if (i % 2 == 0) {
            printw("%d. %s", 1+i/2, gamestate->moves[i].string);
        } else {
            printw("%s", gamestate->moves[i].string);
        }
        // only five moves reliably fit into one screen row
        if ((i+1) % 10)  {
            addch(' ');
        } else {
            addch('\n');
        }
    }
    refresh();
}