[sgk-go] / interface / play_twoplayer.c

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *\
 * This is GNU Go, a Go program. Contact gnugo@gnu.org, or see       *
 * http://www.gnu.org/software/gnugo/ for more information.          *
 *                                                                   *
 * Copyright 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007,   *
 * 2008 and 2009 by the Free Software Foundation.                    *
 *                                                                   *
 * This program is free software; you can redistribute it and/or     *
 * modify it under the terms of the GNU General Public License as    *
 * published by the Free Software Foundation - version 3 or          *
 * (at your option) any later version.                               *
 *                                                                   *
 * This program is distributed in the hope that it will be useful,   *
 * but WITHOUT ANY WARRANTY; without even the implied warranty of    *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the     *
 * GNU General Public License in file COPYING for more details.      *
 *                                                                   *
 * You should have received a copy of the GNU General Public         *
 * License along with this program; if not, write to the Free        *
 * Software Foundation, Inc., 51 Franklin Street, Fifth Floor,       *
 * Boston, MA 02111, USA.                                            *
\* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

#include "gnugo.h"

#include <ctype.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>

#define _XOPEN_SOURCE 500

#if READLINE
#include <readline/history.h>
#include <readline/readline.h>
#endif

#include "gg_utils.h"
#include "interface.h"
#include "liberty.h"
#include "sgftree.h"

#define DEBUG_COMMANDS "\
capture <pos>    try to capture indicated group\n\
dead             Toggle display of dead stones\n\
defend <pos>     try to defend indicated group\n\
listdragons      print dragon info \n\
showarea         display area\n\
showdragons      display dragons\n\
showmoyo         display moyo\n\
showterri        display territory\n\
"

#define MASTER_FIFO_NAME "/tmp/sgkgo-fifo-master"
#define SLAVE_FIFO_NAME  "/tmp/sgkgo-fifo-slave"

/* ANSI color codes */
#define RESETCOLOR "\x1B[0m"
#define WHITECOLOR "\x1B[41m"
#define BLACKCOLOR "\x1B[44m"
#define TILE1COLOR "\x1B[47m"
#define TILE2COLOR "\x1B[107m"
#define TILE3COLOR "\x1B[43m"

/* some options for the twoplayer interface */
static int opt_showboard = 1;
static int showdead = 0;
static SGFTree sgftree;
static int resignation_allowed;

static int clock_on = 0;

/* Unreasonable score used to detect missing information. */
#define NO_SCORE 4711
/* Keep track of the score estimated before the last computer move. */
static int current_score_estimate = NO_SCORE;

static void do_play_twoplayer(Gameinfo* gameinfo);
static int twoplayer_endgame(Gameinfo* gameinfo, int reason);
static void twoplayer_count(Gameinfo* gameinfo);
static void showcapture(char* line);
static void showdefense(char* line);
static void twoplayer_goto(Gameinfo* gameinfo, char* line);
static void twoplayer_free_handicap(Gameinfo* gameinfo, char* handicap_string);

/* If sgf game info is written can't reset parameters like handicap, etc. */
static int sgf_initialized;

/*
 * Create letterbar for the top and bottom of the ANSI board.
 */

static void
make_letterbar(int boardsize, char* letterbar)
{
    int i, letteroffset;
    char spaces[64];
    char letter[64];

    if (boardsize <= 25)
        strcpy(spaces, " ");
    strcpy(letterbar, "   ");

    for (i = 0; i < boardsize; i++) {
        letteroffset = 'A';
        if (i + letteroffset >= 'I')
            letteroffset++;
        strcat(letterbar, spaces);
        sprintf(letter, "%c", i + letteroffset);
        strcat(letterbar, letter);
    }
}

/* This array contains +'s and -'s for the empty board positions.
 * hspot_size contains the board size that the grid has been
 * initialized to.
 */

static int hspot_size;
static char hspots[MAX_BOARD][MAX_BOARD];

/*
 * Mark the handicap spots on the board.
 */

static void
set_handicap_spots(int boardsize)
{
    if (hspot_size == boardsize)
        return;

    hspot_size = boardsize;

    memset(hspots, '.', sizeof(hspots));

    if (boardsize == 5) {
        /* place the outer 4 */
        hspots[1][1] = '+';
        hspots[boardsize - 2][1] = '+';
        hspots[1][boardsize - 2] = '+';
        hspots[boardsize - 2][boardsize - 2] = '+';
        /* and the middle one */
        hspots[boardsize / 2][boardsize / 2] = '+';
        return;
    }

    if (!(boardsize % 2)) {
        /* If the board size is even, no center handicap spots. */
        if (boardsize > 2 && boardsize < 12) {
            /* Place the outer 4 only. */
            hspots[2][2] = '+';
            hspots[boardsize - 3][2] = '+';
            hspots[2][boardsize - 3] = '+';
            hspots[boardsize - 3][boardsize - 3] = '+';
        } else {
            /* Place the outer 4 only. */
            hspots[3][3] = '+';
            hspots[boardsize - 4][3] = '+';
            hspots[3][boardsize - 4] = '+';
            hspots[boardsize - 4][boardsize - 4] = '+';
        }
    } else {
        /* Uneven board size */
        if (boardsize > 2 && boardsize < 12) {
            /* Place the outer 4... */
            hspots[2][2] = '+';
            hspots[boardsize - 3][2] = '+';
            hspots[2][boardsize - 3] = '+';
            hspots[boardsize - 3][boardsize - 3] = '+';

            /* ...and the middle one. */
            hspots[boardsize / 2][boardsize / 2] = '+';
        } else if (boardsize > 12) {
            /* Place the outer 4... */
            hspots[3][3] = '+';
            hspots[boardsize - 4][3] = '+';
            hspots[3][boardsize - 4] = '+';
            hspots[boardsize - 4][boardsize - 4] = '+';

            /* ...and the inner 4... */
            hspots[3][boardsize / 2] = '+';
            hspots[boardsize / 2][3] = '+';
            hspots[boardsize / 2][boardsize - 4] = '+';
            hspots[boardsize - 4][boardsize / 2] = '+';

            /* ...and the middle one. */
            hspots[boardsize / 2][boardsize / 2] = '+';
        }
    }

    return;
}

/*
 * Display the board position when playing in ANSI.
 */

static void
twoplayer_showboard(void)
{
    int i, j;
    char letterbar[64];
    int last_pos_was_move;
    int pos_is_move;
    int dead;
    int last_move = get_last_move();

    make_letterbar(board_size, letterbar);
    set_handicap_spots(board_size);

    printf("\n");
    printf("    White (" WHITECOLOR " " RESETCOLOR ") has captured %d pieces\n", black_captured);
    printf("    Black (" BLACKCOLOR " " RESETCOLOR ") has captured %d pieces\n", white_captured);
    if (showscore) {
        if (current_score_estimate == NO_SCORE)
            printf("    No score estimate is available yet.\n");
        else if (current_score_estimate < 0)
            printf("    Estimated score: Black is ahead by %d\n",
                -current_score_estimate);
        else if (current_score_estimate > 0)
            printf("    Estimated score: White is ahead by %d\n",
                current_score_estimate);
        else
            printf("    Estimated score: Even!\n");
    }

    printf("\n");

    fflush(stdout);
    printf("%s", letterbar);

    if (get_last_player() != EMPTY) {
        gfprintf(stdout, "        Last move: %s %1m",
            get_last_player() == WHITE ? "White" : "Black",
            last_move);
    }

    printf("\n");
    fflush(stdout);

    for (i = 0; i < board_size; i++) {
        printf(" %2d", board_size - i);
        last_pos_was_move = 0;
        for (j = 0; j < board_size; j++) {
            if (POS(i, j) == last_move)
                pos_is_move = 128;
            else
                pos_is_move = 0;
            dead = (dragon_status(POS(i, j)) == DEAD) && showdead;
            switch (BOARD(i, j) + pos_is_move + last_pos_was_move) {
            case BLACK:
            case BLACK + 256:
                printf(BLACKCOLOR "  " RESETCOLOR);
                last_pos_was_move = 0;
                break;
            case WHITE:
            case WHITE + 256:
                printf(WHITECOLOR "  " RESETCOLOR);
                last_pos_was_move = 0;
                break;
            case BLACK + 128:
                printf(BLACKCOLOR "()" RESETCOLOR);
                last_pos_was_move = 0;
                break;
            case WHITE + 128:
                printf(WHITECOLOR "()" RESETCOLOR);
                last_pos_was_move = 0;
                break;
            case EMPTY:
            case EMPTY + 128:
            case EMPTY + 256:
                if (i % 2 == 0) {
                    if (j % 2 == 0) {
                        printf(TILE1COLOR "  " RESETCOLOR);
                    } else {
                        printf(TILE2COLOR "  " RESETCOLOR);
                    }
                } else {
                    if (j % 2 == 0) {
                        printf(TILE2COLOR "  " RESETCOLOR);
                    } else {
                        printf(TILE1COLOR "  " RESETCOLOR);
                    }
                }
                last_pos_was_move = 0;
                break;
            default:
                fprintf(stderr, "Illegal board value %d\n", (int)BOARD(i, j));
                exit(EXIT_FAILURE);
                break;
            }
        }

        if (last_pos_was_move == 0) {
            if (board_size > 10)
                printf(" %2d", board_size - i);
            else
                printf(" %1d", board_size - i);
        } else {
            if (board_size > 10)
                printf("%2d", board_size - i);
            else
                printf("%1d", board_size - i);
        }
        printf("\n");
    }

    fflush(stdout);
    printf("%s\n\n", letterbar);
    fflush(stdout);

    if (clock_on) {
        clock_print(WHITE);
        clock_print(BLACK);
    }

} /* end twoplayer_showboard */

/*
 * command help
 */

static void
show_commands(void)
{
    printf("\nCommands:\n");
    printf(" back                Take back your last move\n");
    printf(" boardsize           Set boardsize (on move 1 only)\n");
    printf(" comment             Write a comment to outputfile\n");
    printf(" depth <num>         Set depth for reading\n");
    printf(" display             Display game board\n");
    printf(" exit                Exit GNU Go\n");
    printf(" force <move>        Force a move for current color\n");
    printf(" forward             Go to next node in game tree\n");
    printf(" goto <movenum>      Go to movenum in game tree\n");
    printf(" level <amount>      Playing level (default = 10)\n");
    printf(" handicap <num>      Set fixed handicap (on move 1 only)\n");
    printf(" freehandicap <num>  Place free handicap (on move 1 only)\n");
    printf("                     Omit <num> to place handicap yourself\n");
    printf(" help                Display this help menu\n");
    printf(" helpdebug           Display debug help menu\n");
    printf(" info                Display program settings\n");
    printf(" komi                Set komi (on move 1 only)\n");
    printf(" last                Goto last node in game tree\n");
    printf(" pass                Pass on your move\n");
    printf(" play <num>          Play <num> moves\n");
    printf(" playblack           Play as Black (switch if White)\n");
    printf(" playwhite           Play as White (switch if Black)\n");
    printf(" quit                Exit GNU Go\n");
    printf(" resign              Resign the current game\n");
    printf(" save <file>         Save the current game\n");
    printf(" load <file>         Load a game from file\n");
    printf(" score               Toggle display of score On/Off\n");
    printf(" showboard           Toggle display of board On/Off\n");
    printf(" switch              Switch the color you are playing\n");
    printf(" undo                Take the last move back (same as back)\n");
    printf(" <move>              A move of the format <letter><number>");
    printf("\n");
}

enum commands { INVALID = -1,
    END,
    EXIT,
    QUIT,
    RESIGN,
    PASS,
    MOVE,
    FORCE,
    SWITCH,
    PLAY,
    PLAYBLACK,
    PLAYWHITE,
    SETHANDICAP,
    FREEHANDICAP,
    SETBOARDSIZE,
    SETKOMI,
    SETDEPTH,
    INFO,
    DISPLAY,
    SHOWBOARD,
    HELP,
    UNDO,
    COMMENT,
    SCORE,
    CMD_DEAD,
    CMD_BACK,
    CMD_FORWARD,
    CMD_LAST,
    CMD_CAPTURE,
    CMD_DEFEND,
    CMD_HELPDEBUG,
    CMD_SHOWAREA,
    CMD_SHOWMOYO,
    CMD_SHOWTERRI,
    CMD_GOTO,
    CMD_SAVE,
    CMD_LOAD,
    CMD_SHOWDRAGONS,
    CMD_LISTDRAGONS,
    SETLEVEL,
    NEW,
    COUNT,
    CONTINUE
};

/*
 * Check if we have a valid command.
 */

static int
get_command(char* command)
{
    char c;
    int d;

    /* Check to see if a move was input. */
    if (!((sscanf(command, "%c%d", &c, &d) != 2)
            || ((c = toupper((int)c)) < 'A')
            || ((c = toupper((int)c)) > 'Z')
            || (c == 'I')))
        return MOVE;

    /* help shortcut */
    if (command[0] == '?')
        return HELP;

    /* Kill leading spaces. */
    while (command[0] == ' ')
        command++;

    if (!strncmp(command, "playblack", 9))
        return PLAYBLACK;
    if (!strncmp(command, "playwhite", 9))
        return PLAYWHITE;
    if (!strncmp(command, "showboard", 9))
        return SHOWBOARD;
    if (!strncmp(command, "showdragons", 9))
        return CMD_SHOWDRAGONS;
    if (!strncmp(command, "listdragons", 9))
        return CMD_LISTDRAGONS;
    if (!strncmp(command, "boardsize", 9))
        return SETBOARDSIZE;
    if (!strncmp(command, "freehandicap", 9))
        return FREEHANDICAP;
    if (!strncmp(command, "handicap", 5))
        return SETHANDICAP;
    if (!strncmp(command, "display", 7))
        return DISPLAY;
    if (!strncmp(command, "helpdebug", 7))
        return CMD_HELPDEBUG;
    if (!strncmp(command, "resign", 6))
        return RESIGN;
    if (!strncmp(command, "showmoyo", 6))
        return CMD_SHOWMOYO;
    if (!strncmp(command, "showterri", 6))
        return CMD_SHOWTERRI;
    if (!strncmp(command, "showarea", 6))
        return CMD_SHOWAREA;
    if (!strncmp(command, "depth", 5))
        return SETDEPTH;
    if (!strncmp(command, "switch", 5))
        return SWITCH;
    if (!strncmp(command, "komi", 4))
        return SETKOMI;
    if (!strncmp(command, "play", 4))
        return PLAY;
    if (!strncmp(command, "info", 4))
        return INFO;
    if (!strncmp(command, "force", 4))
        return FORCE;
    if (!strncmp(command, "level", 5))
        return SETLEVEL;
    if (!strncmp(command, "pass", 4))
        return PASS;
    if (!strncmp(command, "save", 3))
        return CMD_SAVE;
    if (!strncmp(command, "load", 3))
        return CMD_LOAD;
    if (!strncmp(command, "end", 3))
        return END;
    if (!strncmp(command, "move", 3))
        return MOVE;
    if (!strncmp(command, "undo", 3))
        return UNDO;
    if (!strncmp(command, "comment", 3))
        return COMMENT;
    if (!strncmp(command, "score", 3))
        return SCORE;
    if (!strncmp(command, "dead", 3))
        return CMD_DEAD;
    if (!strncmp(command, "capture", 3))
        return CMD_CAPTURE;
    if (!strncmp(command, "defend", 3))
        return CMD_DEFEND;
    if (!strncmp(command, "exit", 4))
        return EXIT;
    if (!strncmp(command, "quit", 4))
        return QUIT;
    if (!strncmp(command, "help", 1))
        return HELP;
    if (!strncmp(command, "back", 2))
        return CMD_BACK;
    if (!strncmp(command, "forward", 2))
        return CMD_FORWARD;
    if (!strncmp(command, "last", 2))
        return CMD_LAST;
    if (!strncmp(command, "goto", 2))
        return CMD_GOTO;
    if (!strncmp(command, "game", 2))
        return NEW;
    if (!strncmp(command, "count", 3))
        return COUNT;
    if (!strncmp(command, "continue", 4))
        return CONTINUE;

    /* No valid command was found. */
    return INVALID;
}

/*
 * Write sgf root node. 
 */

static void
init_sgf(Gameinfo* ginfo)
{
    if (sgf_initialized)
        return;
    sgf_initialized = 1;

    sgf_write_header(sgftree.root, 1, get_random_seed(), komi,
        ginfo->handicap, get_level(), chinese_rules);
    if (ginfo->handicap > 0)
        sgffile_recordboard(sgftree.root);
}

/*
 * Generate the computer move. 
 */

static int
computer_move(Gameinfo* gameinfo, int* passes)
{
    int move;
    float move_value;
    int resign;
    int resignation_declined = 0;
    float upper_bound, lower_bound;

    init_sgf(gameinfo);

    /* Generate computer move. */
    if (autolevel_on)
        adjust_level_offset(gameinfo->to_move);
    move = genmove(gameinfo->to_move, &move_value, &resign);
    if (resignation_allowed && resign) {
        int state = twoplayer_endgame(gameinfo, 2);
        if (state != -1)
            return state;

        /* The opponent declined resignation. Remember not to resign again. */
        resignation_allowed = 0;
        resignation_declined = 1;
    }

    if (showscore) {
        gnugo_estimate_score(&upper_bound, &lower_bound);
        current_score_estimate = (int)((lower_bound + upper_bound) / 2.0);
    }

    mprintf("%s(%d): %1m\n", color_to_string(gameinfo->to_move),
        movenum + 1, move);
    if (is_pass(move))
        (*passes)++;
    else
        *passes = 0;

    gnugo_play_move(move, gameinfo->to_move);
    sgffile_add_debuginfo(sgftree.lastnode, move_value);
    sgftreeAddPlay(&sgftree, gameinfo->to_move, I(move), J(move));
    if (resignation_declined)
        sgftreeAddComment(&sgftree, "GNU Go resignation was declined");
    sgffile_output(&sgftree);

    gameinfo->to_move = OTHER_COLOR(gameinfo->to_move);
    return 0;
}

/*
 * Make a move.
 */

static int
do_move(Gameinfo* gameinfo, char* command, int* passes, int force)
{
    int move = string_to_location(board_size, command);

    if (move == NO_MOVE) {
        printf("\nInvalid move: %s\n", command);
        return 0;
    }

    if (!is_allowed_move(move, gameinfo->to_move)) {
        printf("\nIllegal move: %s", command);
        return 0;
    }

    *passes = 0;
    TRACE("\nyour move: %1m\n\n", move);
    init_sgf(gameinfo);
    gnugo_play_move(move, gameinfo->to_move);
    sgffile_add_debuginfo(sgftree.lastnode, 0.0);
    sgftreeAddPlay(&sgftree, gameinfo->to_move, I(move), J(move));
    sgffile_output(&sgftree);

    if (opt_showboard) {
        twoplayer_showboard();
        printf("GNU Go is thinking...\n");
    }

    if (force) {
        gameinfo->computer_player = OTHER_COLOR(gameinfo->computer_player);
        gameinfo->to_move = OTHER_COLOR(gameinfo->to_move);
        sgftreeAddComment(&sgftree, "forced");
        return 0;
    }

    gameinfo->to_move = OTHER_COLOR(gameinfo->to_move);
    return computer_move(gameinfo, passes);
}

/*
 * Make a pass.
 */

static int
do_pass(Gameinfo* gameinfo, int* passes, int force)
{
    (*passes)++;
    init_sgf(gameinfo);
    gnugo_play_move(PASS_MOVE, gameinfo->to_move);
    sgffile_add_debuginfo(sgftree.lastnode, 0.0);
    sgftreeAddPlay(&sgftree, gameinfo->to_move, -1, -1);
    sgffile_output(&sgftree);

    gameinfo->to_move = OTHER_COLOR(gameinfo->to_move);
    if (force) {
        gameinfo->computer_player = OTHER_COLOR(gameinfo->computer_player);
        sgftreeAddComment(&sgftree, "forced");
        return 0;
    }

    return computer_move(gameinfo, passes);
}

/*
 * Play a game using ANSI client.
 */

void play_twoplayer(SGFTree* tree, Gameinfo* gameinfo, char* filename, char* until)
{
    int sz;

    int transmit_fifo_fd, receive_fifo_fd;
    printf("DEBUG: Attempting to setup connection with other player.\n");
    if (mknod(MASTER_FIFO_NAME, S_IFIFO | 0666, 0) == 0) {
        printf("DEBUG: We are the master. Created %s.\n", MASTER_FIFO_NAME);
        // TODO: Choose black for the master.
        printf("DEBUG: Waiting for other player to connect.\n");
        transmit_fifo_fd = open(MASTER_FIFO_NAME, O_WRONLY);
        printf("DEBUG: Slave connected to our FIFO. Now we connect to the slave's FIFO.\n");
        receive_fifo_fd = open(SLAVE_FIFO_NAME, O_RDONLY);
        printf("DEBUG: Bidirectional communication established.\n");
    } else {
        printf("DEBUG: Failed to create master FIFO. Perhaps we are the slave?\n");
        // TODO: Choose white for the slave.
        if (mknod(SLAVE_FIFO_NAME, S_IFIFO | 0666, 0) == 0) {
            printf("DEBUG: We are the slave. Created %s.\n", SLAVE_FIFO_NAME);
            receive_fifo_fd = open(MASTER_FIFO_NAME, O_RDONLY);
            printf("DEBUG: We connected to master's FIFO. Now we wait for master's connection to our FIFO.\n");
            transmit_fifo_fd = open(SLAVE_FIFO_NAME, O_WRONLY);
            printf("DEBUG: Bidirectional communication established.\n");
        } else {
            printf("DEBUG: Failed to create slave FIFO. This is an unrecoverable error.\n");
            exit(EXIT_FAILURE);
        }
    }
    // Allow both master and slave to attempt removal. Ignore error code since
    // this is a best-effort situation for now.
    unlink(MASTER_FIFO_NAME);
    unlink(SLAVE_FIFO_NAME);
while(1){sleep(1);}
exit(EXIT_SUCCESS);

    setvbuf(stdout, (char*)NULL, _IONBF, 0); /* No buffering. */

    sgftree = *tree;

    if (filename) {
    /* No need to check for failure here since that was already done
     * when it was loaded in main().
     *
     * FIXME: Why do we load the game again?
     */
        gameinfo_play_sgftree(gameinfo, &sgftree, until);
        sgf_initialized = 1;
    } else {
        if (sgfGetIntProperty(sgftree.root, "SZ", &sz))
            gnugo_clear_board(sz);
        if (gameinfo->handicap == 0)
            gameinfo->to_move = BLACK;
        else {
            gameinfo->handicap = place_fixed_handicap(gameinfo->handicap);
            gameinfo->to_move = WHITE;
        }
        sgf_initialized = 0;
    }

    do_play_twoplayer(gameinfo);
    printf("\nThanks! for playing GNU Go.\n\n");

    close(transmit_fifo_fd);
    close(receive_fifo_fd);

    /* main() frees the tree and we might have changed it. */
    *tree = sgftree;
}

void do_play_twoplayer(Gameinfo* gameinfo)
{
    int m, num;
    float fnum;
    int passes = 0; /* two passes and its over */
    int tmp;
    char line[80];
    char* line_ptr = line;
    char* command;
    char* tmpstring;
    int state = 1;

    if (have_time_settings())
        clock_on = 1;

    while (state == 1) {
        state = 0;

        /* No score is estimated yet. */
        current_score_estimate = NO_SCORE;

        /* Allow resignation at interface level (the engine may still be not
     * allowed to resign.
     */
        resignation_allowed = 1;

        printf("\nBeginning two player game.\n\n");
        gameinfo_print(gameinfo);

        /* Does the computer play first?  If so, make a move. */
        if (gameinfo->computer_player == gameinfo->to_move)
            state = computer_move(gameinfo, &passes);

        /* main ANSI Play loop */
        while (state == 0) {
            /* Display game board. */
            if (opt_showboard)
                twoplayer_showboard();

#if !READLINE
            /* Print the prompt */
            mprintf("%s(%d): ", color_to_string(gameinfo->to_move), movenum + 1);

            /* Read a line of input. */
            line_ptr = line;
            if (!fgets(line, 80, stdin))
                return;
#else
            snprintf(line, 79, "%s(%d): ",
                color_to_string(gameinfo->to_move), movenum + 1);
            if (!(line_ptr = readline(line)))
                return;

            add_history(line_ptr);
#endif

            while (state == 0
                && (command = strtok(line_ptr, ";"), line_ptr = 0, command)) {
                /* Get the command or move. */
                switch (get_command(command)) {
                case RESIGN:
                    state = twoplayer_endgame(gameinfo, 1);
                    break;

                case END:
                case EXIT:
                case QUIT:
                    return;

                case HELP:
                    show_commands();
                    break;

                case CMD_HELPDEBUG:
                    printf(DEBUG_COMMANDS);
                    break;

                case SHOWBOARD:
                    opt_showboard = !opt_showboard;
                    break;

                case INFO:
                    printf("\n");
                    gameinfo_print(gameinfo);
                    break;

                case SETBOARDSIZE:
                    if (sgf_initialized) {
                        printf("Boardsize cannot be changed after record is started!\n");
                        break;
                    }
                    command += 10;
                    if (sscanf(command, "%d", &num) != 1) {
                        printf("\nInvalid command syntax!\n");
                        break;
                    }
                    if (!check_boardsize(num, stdout))
                        break;
                    /* Init board. */
                    board_size = num;
                    clear_board();
                    /* In case max handicap changes on smaller board. */
                    gameinfo->handicap = place_fixed_handicap(gameinfo->handicap);
                    sgfOverwritePropertyInt(sgftree.root, "SZ", board_size);
                    sgfOverwritePropertyInt(sgftree.root, "HA", gameinfo->handicap);
                    break;

                case SETHANDICAP:
                    if (sgf_initialized) {
                        printf("Handicap cannot be changed after game is started!\n");
                        break;
                    }
                    command += 9;
                    if (sscanf(command, "%d", &num) != 1) {
                        printf("\nInvalid command syntax!\n");
                        break;
                    }
                    if (num < 0 || num > MAX_HANDICAP) {
                        printf("\nInvalid handicap: %d\n", num);
                        break;
                    }
                    /* Init board. */
                    clear_board();
                    /* Place stones on board but don't record sgf 
	   * in case we change more info. */
                    gameinfo->handicap = place_fixed_handicap(num);
                    printf("\nSet handicap to %d\n", gameinfo->handicap);
                    gameinfo->to_move = (gameinfo->handicap ? WHITE : BLACK);
                    break;

                case FREEHANDICAP:
                    if (sgf_initialized) {
                        printf("Handicap cannot be changed after game is started!\n");
                        break;
                    }
                    while (*command && *command != ' ')
                        command++;
                    twoplayer_free_handicap(gameinfo, command);
                    break;

                case SETKOMI:
                    if (sgf_initialized) {
                        printf("Komi cannot be modified after game record is started!\n");
                        break;
                    }
                    command += 5;
                    if (sscanf(command, "%f", &fnum) != 1) {
                        printf("\nInvalid command syntax!\n");
                        break;
                    }
                    komi = fnum;
                    printf("\nSet Komi to %.1f\n", komi);
                    break;

                case SETDEPTH:
                    command += 6;
                    if (sscanf(command, "%d", &num) != 1) {
                        printf("\nInvalid command syntax!\n");
                        break;
                    }
                    mandated_depth = num;
                    printf("\nSet depth to %d\n", mandated_depth);
                    break;

                case SETLEVEL:
                    command += 6;
                    if (sscanf(command, "%d", &num) != 1) {
                        printf("\nInvalid command syntax!\n");
                        break;
                    }
                    set_level(num);
                    printf("\nSet level to %d\n", num);
                    break;

                case DISPLAY:
                    if (!opt_showboard)
                        twoplayer_showboard();
                    break;

                case FORCE:
                    command += 6; /* skip the force part... */
                    switch (get_command(command)) {
                    case MOVE:
                        state = do_move(gameinfo, command, &passes, 1);
                        break;
                    case PASS:
                        state = do_pass(gameinfo, &passes, 1);
                        break;
                    default:
                        printf("Illegal forced move: %s %d\n", command,
                            get_command(command));
                        break;
                    }
                    break;

                case MOVE:
                    state = do_move(gameinfo, command, &passes, 0);
                    break;

                case PASS:
                    state = do_pass(gameinfo, &passes, 0);
                    break;

                case PLAY:
                    command += 5;
                    if (sscanf(command, "%d", &num) != 1) {
                        printf("\nInvalid command syntax!\n");
                        break;
                    }
                    if (num >= 0)
                        for (m = 0; m < num; m++) {
                            gameinfo->computer_player
                                = OTHER_COLOR(gameinfo->computer_player);
                            state = computer_move(gameinfo, &passes);
                            if (state)
                                break;
                            if (passes >= 2)
                                break;
                        }
                    else {
                        printf("\nInvalid number of moves specified: %d\n", num);
                        break;
                    }
                    break;

                case PLAYBLACK:
                    if (gameinfo->computer_player == WHITE)
                        gameinfo->computer_player = BLACK;
                    if (gameinfo->computer_player == gameinfo->to_move)
                        state = computer_move(gameinfo, &passes);
                    break;

                case PLAYWHITE:
                    if (gameinfo->computer_player == BLACK)
                        gameinfo->computer_player = WHITE;
                    if (gameinfo->computer_player == gameinfo->to_move)
                        state = computer_move(gameinfo, &passes);
                    break;

                case SWITCH:
                    gameinfo->computer_player = OTHER_COLOR(gameinfo->computer_player);
                    state = computer_move(gameinfo, &passes);
                    break;

                case UNDO:
                case CMD_BACK:
                    if (undo_move(1)) {
                        sgftreeAddComment(&sgftree, "undone");
                        sgftreeBack(&sgftree);
                        gameinfo->to_move = OTHER_COLOR(gameinfo->to_move);
                    } else
                        printf("\nCan't undo.\n");
                    break;

                case CMD_FORWARD:
                    if (sgftreeForward(&sgftree))
                        gameinfo->to_move = gnugo_play_sgfnode(sgftree.lastnode,
                            gameinfo->to_move);
                    else
                        printf("\nEnd of game tree.\n");
                    break;

                case CMD_LAST:
                    while (sgftreeForward(&sgftree))
                        gameinfo->to_move = gnugo_play_sgfnode(sgftree.lastnode,
                            gameinfo->to_move);
                    break;

                case COMMENT:
                    printf("\nEnter comment. Press ENTER when ready.\n");
                    fgets(line, 80, stdin);
                    sgftreeAddComment(&sgftree, line);
                    break;

                case SCORE:
                    showscore = !showscore;
                    if (!showscore)
                        current_score_estimate = NO_SCORE;
                    break;

                case CMD_DEAD:
                    silent_examine_position(FULL_EXAMINE_DRAGONS);
                    showdead = !showdead;
                    break;

                case CMD_CAPTURE:
                    strtok(command, " ");
                    showcapture(strtok(NULL, " "));
                    break;

                case CMD_DEFEND:
                    strtok(command, " ");
                    showdefense(strtok(NULL, " "));
                    break;

                case CMD_SHOWMOYO:
                    tmp = printmoyo;
                    printmoyo = PRINTMOYO_MOYO;
                    silent_examine_position(EXAMINE_DRAGONS);
                    printmoyo = tmp;
                    break;

                case CMD_SHOWTERRI:
                    tmp = printmoyo;
                    printmoyo = PRINTMOYO_TERRITORY;
                    silent_examine_position(EXAMINE_DRAGONS);
                    printmoyo = tmp;
                    break;

                case CMD_SHOWAREA:
                    tmp = printmoyo;
                    printmoyo = PRINTMOYO_AREA;
                    silent_examine_position(EXAMINE_DRAGONS);
                    printmoyo = tmp;
                    break;

                case CMD_SHOWDRAGONS:
                    silent_examine_position(EXAMINE_DRAGONS);
                    showboard(1);
                    break;

                case CMD_GOTO:
                    strtok(command, " ");
                    twoplayer_goto(gameinfo, strtok(NULL, " "));
                    break;

                case CMD_SAVE:
                    strtok(command, " ");
                    tmpstring = strtok(NULL, " ");
                    if (tmpstring) {
                        /* discard newline */
                        tmpstring[strlen(tmpstring) - 1] = 0;
                        /* make sure we are saving proper handicap */
                        init_sgf(gameinfo);
                        writesgf(sgftree.root, tmpstring);
                        printf("You may resume the game");
                        printf(" with -l %s --mode twoplayer\n", tmpstring);
                        printf("or load %s\n", tmpstring);
                    } else
                        printf("Please specify filename\n");
                    break;

                case CMD_LOAD:
                    strtok(command, " ");
                    tmpstring = strtok(NULL, " ");
                    if (tmpstring) {
                        /* discard newline */
                        tmpstring[strlen(tmpstring) - 1] = 0;
                        if (!sgftree_readfile(&sgftree, tmpstring)) {
                            fprintf(stderr, "Cannot open or parse '%s'\n", tmpstring);
                            break;
                        }
                        /* to avoid changing handicap etc. */
                        if (gameinfo_play_sgftree(gameinfo, &sgftree, NULL) == EMPTY)
                            fprintf(stderr, "Cannot load '%s'\n", tmpstring);
                        else {
                            sgf_initialized = 1;
                            sgfOverwritePropertyInt(sgftree.root, "HA", gameinfo->handicap);
                        }
                    } else
                        printf("Please specify a filename\n");
                    break;

                case CMD_LISTDRAGONS:
                    silent_examine_position(EXAMINE_DRAGONS);
                    show_dragons();
                    break;

                default:
                    printf("\nInvalid command: %s", command);
                    break;
                }

                if (passes >= 2)
                    state = twoplayer_endgame(gameinfo, 0);
            }
#if READLINE
            free(line_ptr);
#endif
        }

        sgffile_output(&sgftree);
        passes = 0;

        /* Play a different game next time. */
        update_random_seed();

        /* Free the sgf tree and prepare for a new game. */
        sgfFreeNode(sgftree.root);
        sgftree_clear(&sgftree);
        sgftreeCreateHeaderNode(&sgftree, board_size, komi, gameinfo->handicap);
        sgf_initialized = 0;

        gameinfo_clear(gameinfo);
    }
}

/* Communicates with user after a game has ended. */
static int
twoplayer_endgame(Gameinfo* gameinfo, int reason)
{
    char line[80];
    char* line_ptr;
    char* command;
    char* tmpstring;
    int state = 0;

    if (reason == 0) { /* Two passes, game is over. */
        who_wins(gameinfo->computer_player, stdout);
        printf("\nIf you disagree, we may count the game together.\n");

        sgftreeWriteResult(&sgftree, (white_score + black_score) / 2.0, 1);
    } else {
        int color = OTHER_COLOR(gameinfo->to_move);

        if (reason == 1) /* Our opponent has resigned. */
            printf("GNU Go wins by resignation.\n");
        else /* We have resigned. */
            printf("You win by resignation.\n");

        printf("Result: %c+Resign\n\n", color == WHITE ? 'W' : 'B');
        sgftreeWriteResult(&sgftree, color == WHITE ? 1000.0 : -1000.0, 1);
    }

    while (state == 0) {
        printf("You may optionally save the game as an SGF file.\n\n");
        printf("Type \"save <filename>\" to save,\n");
        if (reason == 0)
            printf("     \"count\" to recount,\n");
        else if (reason == 2)
            printf("     \"continue\" to decline resignation and continue the game,\n");
        printf("     \"quit\" to quit\n");
        printf(" or  \"game\" to play again\n");

        line_ptr = line;
        if (!fgets(line, 80, stdin))
            break;

        command = strtok(line_ptr, "");
        switch (get_command(command)) {
        case CMD_SAVE:
            strtok(command, " ");
            tmpstring = strtok(NULL, " ");
            if (tmpstring) {
                /* discard newline */
                tmpstring[strlen(tmpstring) - 1] = 0;
                init_sgf(gameinfo);
                writesgf(sgftree.root, tmpstring);
            } else
                printf("Please specify filename\n");
            break;

        case COUNT:
            if (reason == 0)
                twoplayer_count(gameinfo);
            break;

        case CONTINUE:
            state = -1;
            break;

        case NEW:
            state = 1;
            break;

        case QUIT:
            state = 2;
            break;

        default:
            state = 0;
        }
    }

    return state;
}

/* twoplayer_count() scores the game.
 */
static void
twoplayer_count(Gameinfo* gameinfo)
{
    char line[12];
    int done = 0;
    int i;
    int xyzzy = 1;

    printf("\nGame over. Let's count!.\n");
    showdead = 1;
    twoplayer_showboard();
    while (!done) {
        printf("Dead stones are marked with small letters (x,o).\n");
        printf("\nIf you don't agree, enter the location of a group\n");
        printf("to toggle its state or \"done\".\n");

        if (!fgets(line, 12, stdin))
            return; /* EOF or some error */

        for (i = 0; i < 12; i++)
            line[i] = tolower((int)line[i]);
        if (!strncmp(line, "done", 4))
            done = 1;
        else if (!strncmp(line, "quit", 4))
            return;
        else if (!strncmp(line, "xyzzy", 5)) {
            if (xyzzy) {
                printf("\nYou are in a debris room filled with stuff washed in from the\n");
                printf("surface.  A low wide passage with cobbles becomes plugged\n");
                printf("with mud and debris here, but an awkward canyon leads\n");
                printf("upward and west.  A note on the wall says:\n");
                printf("   Magic Word \"XYZZY\"\n\n");
                xyzzy = 0;
            } else {
                printf("You are inside a building, a well house for a large spring.\n\n");
                xyzzy = 1;
            }
        } else if (!strncmp(line, "help", 4)) {
            printf("\nIf there are dead stones on the board I will remove them.\n");
            printf("You must tell me where they are. Type the coordinates of a\n");
            printf("dead group, or type \"done\"\n");
        } else if (!strncmp(line, "undo", 4)) {
            printf("UNDO not allowed anymore. The status of the stones now\n");
            printf("toggles after entering the location of it.\n");
            twoplayer_showboard();
        } else {
            int pos = string_to_location(board_size, line);
            if (pos == NO_MOVE || board[pos] == EMPTY)
                printf("\ninvalid!\n");
            else {
                enum dragon_status status = dragon_status(pos);
                status = (status == DEAD) ? ALIVE : DEAD;
                change_dragon_status(pos, status);
                twoplayer_showboard();
            }
        }
    }
    who_wins(gameinfo->computer_player, stdout);
}

static void
showcapture(char* line)
{
    int str;
    int move;

    gg_assert(line);
    str = string_to_location(board_size, line);
    if (str == NO_MOVE || board[str] == EMPTY) {
        printf("\ninvalid point!\n");
        return;
    }

    if (attack(str, &move))
        mprintf("\nSuccessful attack of %1m at %1m\n", str, move);
    else
        mprintf("\n%1m cannot be attacked\n", str);
}

static void
showdefense(char* line)
{
    int str;
    int move;

    gg_assert(line);
    str = string_to_location(board_size, line);
    if (str == NO_MOVE || board[str] == EMPTY) {
        printf("\ninvalid point!\n");
        return;
    }

    if (attack(str, NULL)) {
        if (find_defense(str, &move))
            mprintf("\nSuccessful defense of %1m at %1m\n", str, move);
        else
            mprintf("\n%1m cannot be defended\n", str);
    } else
        mprintf("\nThere is no need to defend %1m\n", str);
}

static void
twoplayer_goto(Gameinfo* gameinfo, char* line)
{
    const char* movenumber = line;

    if (!line)
        return;

    if (!strncmp(line, "last", 4))
        movenumber = "9999";
    else if (!strncmp(line, "first", 4))
        movenumber = "1";

    printf("goto %s\n", movenumber);
    gameinfo_play_sgftree(gameinfo, &sgftree, movenumber);
}

static void
twoplayer_free_handicap(Gameinfo* gameinfo, char* handicap_string)
{
    int handi;
    int i;
    char line[80];
    int stones[MAX_BOARD * MAX_BOARD];

    if (sscanf(handicap_string, "%d", &handi) == 1) {
        /* GNU Go is to place handicap */
        if (handi < 0 || handi == 1) {
            printf("\nInvalid command syntax!\n");
            return;
        }

        clear_board();
        handi = place_free_handicap(handi);
        printf("\nPlaced %d stones of free handicap.\n", handi);
    } else { /* User is to place handicap */
        clear_board();
        handi = 0;

        while (1) {
            twoplayer_showboard();
            printf("\nType in coordinates of next handicap stone, or one of the following commands:\n");
            printf("  undo        take back the last stone placed\n");
            printf("  clear       remove all the stones placed so far\n");
            printf("  done        finish placing handicap\n\n");
            printf("You have placed %d handicap stone(s) so far.\n\n", handi);

            if (!fgets(line, 80, stdin))
                return; /* EOF or some error */
            for (i = 0; i < 80; i++)
                line[i] = tolower((int)line[i]);

            if (!strncmp(line, "undo", 4)) {
                if (!handi)
                    printf("\nNothing to undo.\n");
                else {
                    remove_stone(stones[--handi]);
                    gprintf("\nRemoved the stone at %m.\n", I(stones[handi]),
                        J(stones[handi]));
                }
            } else if (!strncmp(line, "clear", 5)) {
                clear_board();
                handi = 0;
            } else if (!strncmp(line, "done", 4)) {
                if (handi == 1) /* Don't bother with checks later */
                    printf("\nHandicap cannot be one stone. Either add "
                           "some more, or delete the only stone.\n");
                else
                    break;
            } else {
                int pos = string_to_location(board_size, line);
                if (pos != NO_MOVE) {
                    if (board[pos] != EMPTY)
                        printf("\nThere's already a stone there.\n");
                    else {
                        add_stone(pos, BLACK);
                        stones[handi++] = pos;
                    }
                } else
                    printf("\nInvalid command: %s", line);
            }
        }
    }
    gameinfo->handicap = handi;
    gameinfo->to_move = (handi ? WHITE : BLACK);
}

/*
 * Local Variables:
 * tab-width: 4
 * c-basic-offset: 4
 * End:
 */