/*      $OpenBSD: bs.c,v 1.42 2021/10/23 11:22:48 mestre Exp $  */
/*
 * Copyright (c) 1986, Bruce Holloway
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 * 
 * - Redistributions of source code must retain the above copyright
 *  notice, this list of conditions and the following disclaimer.
 * - 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.
 * - Neither the name of the <ORGANIZATION> nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 * 
 * 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
 * OWNER 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.
 */
/*
 * bs.c - original author: Bruce Holloway
 *              salvo option by: Chuck A DeGaul
 * with improved user interface, autoconfiguration and code cleanup
 *              by Eric S. Raymond <esr@snark.thyrsus.com>
 * v1.2 with color support and minor portability fixes, November 1990
 * v2.0 featuring strict ANSI/POSIX conformance, November 1993.
 * v2.1 with ncurses mouse support, September 1995
 * v2.2 with bugfixes and strategical improvements, March 1998.
 */

#include <ctype.h>
#include <curses.h>
#include <err.h>
#include <limits.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

typedef struct {
        char *name;             /* name of the ship type */
        char hits;              /* how many times has this ship been hit? */
        char symbol;            /* symbol for game purposes */
        char length;            /* length of ship */
        signed char x, y;       /* coordinates of ship start point */
        unsigned char dir;      /* direction of `bow' */
        bool placed;            /* has it been placed on the board? */
} ship_t;

static void      announceopts(void);
static int       awinna(void);
static bool      checkplace(int, ship_t *, int);
static int       collidecheck(int, int, int);
static int       cpufire(int, int);
static bool      cpushipcanfit(int, int, int, int);
static int       cputurn(void);
static void      do_options(int, char *[]);
static void      error(char *);
static int       getcoord(int);
static ship_t   *hitship(int, int);
static void      initgame(void);
static void      intro(void);
static void      placeship(int, ship_t *, int);
static int       playagain(void);
static int       plyturn(void);
static void      prompt(int, const char *, ...)
    __attribute__((__format__ (printf, 2, 3)));
static void      randomfire(int *, int *);
static void      randomplace(int, ship_t *);
static int       rnd(int);
static int       scount(int);
static int       sgetc(char *);
__dead static void       uninitgame(int);
__dead void      usage(void);

/*
 * Constants for tuning the random-fire algorithm. It prefers moves that
 * diagonal-stripe the board with a stripe separation of srchstep. If
 * no such preferred moves are found, srchstep is decremented.
 */
#define BEGINSTEP       3       /* initial value of srchstep */

/* miscellaneous constants */
#define SHIPTYPES       5
#define OTHER           (1-turn)
#define PLAYER          0
#define COMPUTER        1
#define MARK_HIT        'H'
#define MARK_MISS       'o'
#define CTRLC           '\003'  /* used as terminate command */
#define FF              '\014'  /* used as redraw command */

/* coordinate handling */
#define BWIDTH          10
#define BDEPTH          10

/* display symbols */
#define SHOWHIT         '*'
#define SHOWSPLASH      ' '
#define IS_SHIP(c)      isupper(c)

/* how to position us on player board */
#define PYBASE  3
#define PXBASE  3
#define PY(y)   (PYBASE + (y))
#define PX(x)   (PXBASE + (x)*3)
#define pgoto(y, x)     (void)move(PY(y), PX(x))

/* how to position us on cpu board */
#define CYBASE  3
#define CXBASE  48
#define CY(y)   (CYBASE + (y))
#define CX(x)   (CXBASE + (x)*3)
#define CYINV(y)        ((y) - CYBASE)
#define CXINV(x)        (((x) - CXBASE) / 3)
#define cgoto(y, x)     (void)move(CY(y), CX(x))

#define ONBOARD(x, y)   (x >= 0 && x < BWIDTH && y >= 0 && y < BDEPTH)

/* other board locations */
#define COLWIDTH        80
#define PROMPTLINE      21                      /* prompt line */
#define SYBASE          CYBASE + BDEPTH + 3     /* move key diagram */
#define SXBASE          63
#define MYBASE          SYBASE - 1              /* diagram caption */
#define MXBASE          64
#define HYBASE          SYBASE - 1              /* help area */
#define HXBASE          0

/* this will need to be changed if BWIDTH changes */
static char numbers[] = "   0  1  2  3  4  5  6  7  8  9";

static char carrier[] = "Aircraft Carrier";
static char battle[] = "Battleship";
static char sub[] = "Submarine";
static char destroy[] = "Destroyer";
static char ptboat[] = "PT Boat";

static char name[LOGIN_NAME_MAX];
static char dftname[] = "stranger";

/* direction constants */
#define E       0
#define SE      1
#define S       2
#define SW      3
#define W       4
#define NW      5
#define N       6
#define NE      7
static int xincr[8] = { 1,  1,  0, -1, -1, -1,  0,  1 };
static int yincr[8] = { 0,  1,  1,  1,  0, -1, -1, -1 };

/* current ship position and direction */
static int curx = (BWIDTH / 2);
static int cury = (BDEPTH / 2);

ship_t plyship[SHIPTYPES] =
{
        { carrier,      0, 'A', 5, 0, 0, 0, FALSE },
        { battle,       0, 'B', 4, 0, 0, 0, FALSE },
        { destroy,      0, 'D', 3, 0, 0, 0, FALSE },
        { sub,          0, 'S', 3, 0, 0, 0, FALSE },
        { ptboat,       0, 'P', 2, 0, 0, 0, FALSE }
};

ship_t cpuship[SHIPTYPES] =
{
        { carrier,      0, 'A', 5, 0, 0, 0, FALSE },
        { battle,       0, 'B', 4, 0, 0, 0, FALSE },
        { destroy,      0, 'D', 3, 0, 0, 0, FALSE },
        { sub,          0, 'S', 3, 0, 0, 0, FALSE },
        { ptboat,       0, 'P', 2, 0, 0, 0, FALSE }
};

/* The following variables (and associated defines), used for computer 
 * targetting, must be global so that they can be reset for each new game 
 * played without restarting the program.
 */
#define POSSIBLE(x, y)  (ONBOARD(x, y) && !hits[COMPUTER][x][y])
#define RANDOM_FIRE     0
#define RANDOM_HIT      1
#define HUNT_DIRECT     2
#define FIRST_PASS      3
#define REVERSE_JUMP    4
#define SECOND_PASS     5
    static int next = RANDOM_FIRE;
    static int turncount = 0;
    static int srchstep = BEGINSTEP;
/* Computer needs to keep track of longest and shortest player ships still
 * not sunk, for better targetting. 
 */
static int cpushortest;
static int cpulongest;

/* "Hits" board, and main board. */
static char hits[2][BWIDTH][BDEPTH], board[2][BWIDTH][BDEPTH];

static int turn;                        /* 0=player, 1=computer */
static int plywon=0, cpuwon=0;          /* How many games has each won? */

static int salvo, blitz, closepack;

/* end the game, either normally or due to signal */
static void
uninitgame(int sig)
{
    clear();
    (void)refresh();
    (void)resetterm();
    (void)echo();
    (void)endwin();
    exit(sig);
}

/* announce which game options are enabled */
static void
announceopts(void)
{
    if (salvo || blitz || closepack)
    {
        (void) printw("Playing optional game (");
        if (salvo)
            (void) printw("salvo, ");
        else
            (void) printw("nosalvo, ");
        if (blitz)
            (void) printw("blitz ");
        else
            (void) printw("noblitz, ");
        if (closepack)
            (void) printw("closepack)");
        else
            (void) printw("noclosepack)");
    }
    else
        (void) printw(
        "Playing standard game (noblitz, nosalvo, noclosepack)");
}

static void
intro(void)
{
    char *tmpname;

    (void) signal(SIGINT,uninitgame);
    if(signal(SIGQUIT,SIG_IGN) != SIG_IGN)
        (void)signal(SIGQUIT,uninitgame);

    if ((tmpname = getlogin()) != NULL)
    {
        (void)strlcpy(name, tmpname, sizeof(name));
        name[0] = toupper((unsigned char)name[0]);
    }
    else
        (void)strlcpy(name, dftname, sizeof(name));

    (void)initscr();
    keypad(stdscr, TRUE);
    (void)saveterm();
    (void)nonl();
    (void)cbreak();
    (void)noecho();

    if ((LINES < PROMPTLINE + 3) || (COLS < COLWIDTH)) {
        endwin();
        errx(1, "screen must be at least %dx%d.", PROMPTLINE + 3, COLWIDTH);
    }

#define PR      (void)addstr
    (void)clear();
    (void)mvaddstr(4,29,"Welcome to Battleship!");
    (void)move(8,0);
    PR("                                                  \\\n");
    PR("                           \\                     \\ \\\n");
    PR("                          \\ \\                   \\ \\ \\_____________\n");
    PR("                         \\ \\ \\_____________      \\ \\/            |\n");
    PR("                          \\ \\/     \\__/    \\      \\/             |\n");
    PR("                           \\/     \\/  \\/    \\_____/              |__\n");
    PR("           ________________/    /\\/  ..\\/                         |\n");
    PR("           \\  S.S. Puffy        \\/\\___o/                          |\n");
    PR("            \\                     / /\\ \\                          /\n");
    PR("             \\___________________________________________________/\n");

    (void) mvaddstr(22,27,"Hit any key to continue..."); (void)refresh();
    (void) getch();

    start_color();

    init_pair(COLOR_BLACK, COLOR_BLACK, COLOR_BLACK);
    init_pair(COLOR_GREEN, COLOR_GREEN, COLOR_BLACK);
    init_pair(COLOR_RED, COLOR_RED, COLOR_BLACK);
    init_pair(COLOR_CYAN, COLOR_CYAN, COLOR_BLACK);
    init_pair(COLOR_WHITE, COLOR_WHITE, COLOR_BLACK);
    init_pair(COLOR_MAGENTA, COLOR_MAGENTA, COLOR_BLACK);
    init_pair(COLOR_BLUE, COLOR_BLUE, COLOR_BLACK);
    init_pair(COLOR_YELLOW, COLOR_YELLOW, COLOR_BLACK);

    (void) mousemask(BUTTON1_CLICKED, (mmask_t *)NULL);
}

/* print a message at the prompt line */
static void
prompt(int n, const char *f, ...)
{
    va_list va;

    (void) move(PROMPTLINE + n, 0);
    (void) clrtoeol();
    va_start(va, f);
    (void) vw_printw(stdscr, f, va);
    va_end(va);
    (void) refresh();
}

static void
error(char *s)
{
    (void) move(PROMPTLINE + 2, 0);
    (void) clrtoeol();
    if (s)
    {
        (void) addstr(s);
        (void) beep();
    }
}

static void
placeship(int b, ship_t *ss, int vis)
{
    int l;

    for(l = 0; l < ss->length; ++l)
    {
        int newx = ss->x + l * xincr[ss->dir];
        int newy = ss->y + l * yincr[ss->dir];

        board[b][newx][newy] = ss->symbol;
        if (vis)
        {
            pgoto(newy, newx);
            (void) addch((chtype)ss->symbol);
        }
    }
    ss->hits = 0;
}

static int
rnd(int n)
{
    return(arc4random_uniform(n));
}

/* generate a valid random ship placement into px,py */
static void
randomplace(int b, ship_t *ss)
{
    do {
        ss->dir = rnd(2) ? E : S;
        ss->x = rnd(BWIDTH - (ss->dir == E ? ss->length : 0));
        ss->y = rnd(BDEPTH - (ss->dir == S ? ss->length : 0));
    } while
        (!checkplace(b, ss, FALSE));
}

static void
initgame(void)
{
    int i, j, unplaced;
    ship_t *ss;

    (void) clear();
    (void) mvaddstr(0,35,"BATTLESHIPS");
    (void) move(PROMPTLINE + 2, 0);
    announceopts();

    /* Set up global CPU algorithm variables. */
    next = RANDOM_FIRE;
    turncount = 0;
    srchstep = BEGINSTEP;
    /* set up cpulongest and cpushortest (computer targetting variables) */
    cpushortest = cpulongest = cpuship->length;

    memset(board, 0, sizeof(char) * BWIDTH * BDEPTH * 2);
    memset(hits,  0, sizeof(char) * BWIDTH * BDEPTH * 2);
    for (i = 0; i < SHIPTYPES; i++)
    {
        ss = cpuship + i;
        ss->x = ss->y = ss->dir = ss->hits = 0;
        ss->placed = FALSE;
        ss = plyship + i;
        ss->x = ss->y = ss->dir = ss->hits = 0;
        ss->placed = FALSE;

     if (ss->length > cpulongest)
                cpulongest  = ss->length;
     if (ss->length < cpushortest)
                cpushortest = ss->length;
    }

    /* draw empty boards */
    (void) mvaddstr(PYBASE - 2, PXBASE + 5, "Main Board");
    (void) mvaddstr(PYBASE - 1, PXBASE - 3,numbers);
    for(i=0; i < BDEPTH; ++i)
    {
        (void) mvaddch(PYBASE + i, PXBASE - 3, (chtype)(i + 'A'));
        if (has_colors())
            attron(COLOR_PAIR(COLOR_BLUE));
        (void) addch(' ');
        for (j = 0; j < BWIDTH; j++)
            (void) addstr(" . ");
        attrset(0);
        (void) addch(' ');
        (void) addch((chtype)(i + 'A'));
    }
    (void) mvaddstr(PYBASE + BDEPTH, PXBASE - 3,numbers);
    (void) mvaddstr(CYBASE - 2, CXBASE + 7,"Hit/Miss Board");
    (void) mvaddstr(CYBASE - 1, CXBASE - 3, numbers);
    for(i=0; i < BDEPTH; ++i)
    {
        (void) mvaddch(CYBASE + i, CXBASE - 3, (chtype)(i + 'A'));
        if (has_colors())
            attron(COLOR_PAIR(COLOR_BLUE));
        (void) addch(' ');
        for (j = 0; j < BWIDTH; j++)
            (void) addstr(" . ");
        attrset(0);
        (void) addch(' ');
        (void) addch((chtype)(i + 'A'));
    }

    (void) mvaddstr(CYBASE + BDEPTH,CXBASE - 3,numbers);

    (void) mvprintw(HYBASE,  HXBASE,
                    "To position your ships: move the cursor to a spot, then");
    (void) mvprintw(HYBASE+1,HXBASE,
                    "type the first letter of a ship type to select it, then");
    (void) mvprintw(HYBASE+2,HXBASE,
                    "type a direction ([hjkl] or [4862]), indicating how the");
    (void) mvprintw(HYBASE+3,HXBASE,
                    "ship should be pointed. You may also type a ship letter");
    (void) mvprintw(HYBASE+4,HXBASE,
                    "followed by `r' to position it randomly, or type `R' to");
    (void) mvprintw(HYBASE+5,HXBASE,
                    "place all remaining ships randomly.");

    (void) mvaddstr(MYBASE,   MXBASE, "Aiming keys:");
    (void) mvaddstr(SYBASE,   SXBASE, "y k u    7 8 9");
    (void) mvaddstr(SYBASE+1, SXBASE, " \\|/      \\|/ ");
    (void) mvaddstr(SYBASE+2, SXBASE, "h-+-l    4-+-6");
    (void) mvaddstr(SYBASE+3, SXBASE, " /|\\      /|\\ ");
    (void) mvaddstr(SYBASE+4, SXBASE, "b j n    1 2 3");

    /* have the computer place ships */
    for(ss = cpuship; ss < cpuship + SHIPTYPES; ss++)
    {
        randomplace(COMPUTER, ss);
        placeship(COMPUTER, ss, FALSE);
    }

    ss = (ship_t *)NULL;
    do {
        char docked[SHIPTYPES + 2], *cp = docked;
        int c;

        /* figure which ships still wait to be placed */
        *cp++ = 'R';
        for (i = 0; i < SHIPTYPES; i++)
            if (!plyship[i].placed)
                *cp++ = plyship[i].symbol;
        *cp = '\0';

        /* get a command letter */
        prompt(1, "Type one of [%s] to pick a ship.", docked+1);
        do {
            c = getcoord(PLAYER);
        } while
            (!strchr(docked, c));

        if (c == 'R')
            (void) ungetch('R');
        else
        {
            /* map that into the corresponding symbol */
            for (ss = plyship; ss < plyship + SHIPTYPES; ss++)
                if (ss->symbol == c)
                    break;

            prompt(1, "Type one of [hjklrR] to place your %s.", ss->name);
            pgoto(cury, curx);
        }
regetchar:
        c = getch();
        switch (c) {
        case FF:
            (void)clearok(stdscr, TRUE);
            (void)refresh();
            break;
        case 'r':
            prompt(1, "Random-placing your %s", ss->name);
            randomplace(PLAYER, ss);
            placeship(PLAYER, ss, TRUE);
                error(NULL);
            ss->placed = TRUE;
            break;
        case 'R':
            prompt(1, "Placing the rest of your fleet at random...");
            for (ss = plyship; ss < plyship + SHIPTYPES; ss++)
                if (!ss->placed)
                {
                    randomplace(PLAYER, ss);
                    placeship(PLAYER, ss, TRUE);
                    ss->placed = TRUE;
                }
            error(NULL);
            break;

        case 'k': case 'j': case 'h': case 'l':
        case '8': case '2': case '4': case '6':
        case KEY_LEFT: case KEY_RIGHT: case KEY_UP: case KEY_DOWN:
            ss->x = curx;
            ss->y = cury;

            switch(c)
            {
            case 'k': case '8': case KEY_UP: ss->dir = N; break;
            case 'j': case '2': case KEY_DOWN: ss->dir = S; break;
            case 'h': case '4': case KEY_LEFT: ss->dir = W; break;
            case 'l': case '6': case KEY_RIGHT: ss->dir = E; break;
            }

            if (checkplace(PLAYER, ss, TRUE))
            {
                placeship(PLAYER, ss, TRUE);
                error(NULL);
                ss->placed = TRUE;
            }
            break;
        default:
            goto regetchar;
        }

        for (unplaced = i = 0; i < SHIPTYPES; i++)
            unplaced += !plyship[i].placed;
    } while
        (unplaced);

    turn = rnd(2);

    (void) mvprintw(HYBASE,  HXBASE,
                    "To fire, move the cursor to your chosen aiming point   ");
    (void) mvprintw(HYBASE+1,  HXBASE,
                    "and strike any key other than a motion key.            ");
    (void) mvprintw(HYBASE+2,  HXBASE,
                    "                                                       ");
    (void) mvprintw(HYBASE+3,  HXBASE,
                    "                                                       ");
    (void) mvprintw(HYBASE+4,  HXBASE,
                    "                                                       ");
    (void) mvprintw(HYBASE+5,  HXBASE,
                    "                                                       ");

    (void) prompt(0, "Press any key to start...");
    (void) getch();
}

static int
getcoord(int atcpu)
{
    int ny, nx, c;

    if (atcpu)
        cgoto(cury,curx);
    else
        pgoto(cury, curx);
    (void)refresh();
    for (;;)
    {
        if (atcpu)
        {
            (void) mvprintw(CYBASE + BDEPTH+1, CXBASE+11, "(%d, %c)", curx, 'A'+cury);
            cgoto(cury, curx);
        }
        else
        {
            (void) mvprintw(PYBASE + BDEPTH+1, PXBASE+11, "(%d, %c)", curx, 'A'+cury);
            pgoto(cury, curx);
        }

        switch(c = getch())
        {
        case 'k': case '8':
        case KEY_UP:
            ny = cury+BDEPTH-1; nx = curx;
            break;
        case 'j': case '2':
        case KEY_DOWN:
            ny = cury+1;        nx = curx;
            break;
        case 'h': case '4':
        case KEY_LEFT:
            ny = cury;          nx = curx+BWIDTH-1;
            break;
        case 'l': case '6':
        case KEY_RIGHT:
            ny = cury;          nx = curx+1;
            break;
        case 'y': case '7':
        case KEY_A1:
            ny = cury+BDEPTH-1; nx = curx+BWIDTH-1;
            break;
        case 'b': case '1':
        case KEY_C1:
            ny = cury+1;        nx = curx+BWIDTH-1;
            break;
        case 'u': case '9':
        case KEY_A3:
            ny = cury+BDEPTH-1; nx = curx+1;
            break;
        case 'n': case '3':
        case KEY_C3:
            ny = cury+1;        nx = curx+1;
            break;
        case FF:
            nx = curx; ny = cury;
            (void)clearok(stdscr, TRUE);
            (void)refresh();
            break;
        case KEY_MOUSE:
            {
                MEVENT  myevent;

                getmouse(&myevent);
                if (atcpu
                        && myevent.y >= CY(0) && myevent.y < CY(BDEPTH)
                        && myevent.x >= CX(0) && myevent.x < CX(BWIDTH))
                {
                    curx = CXINV(myevent.x);
                    cury = CYINV(myevent.y);
                    return(' ');
                }
                else
                    beep();
            }
            break;
        case ERR:
            uninitgame(1);
            break;
        default:
            if (atcpu)
                (void) mvaddstr(CYBASE + BDEPTH + 1, CXBASE + 11, "      ");
            else
                (void) mvaddstr(PYBASE + BDEPTH + 1, PXBASE + 11, "      ");
            return(c);
        }

        curx = nx % BWIDTH;
        cury = ny % BDEPTH;
    }
}

/* is this location on the selected zboard adjacent to a ship? */
static int
collidecheck(int b, int y, int x)
{
    int collide;

    /* anything on the square */
    if ((collide = IS_SHIP(board[b][x][y])) != 0)
        return(collide);

    /* anything on the neighbors */
    if (!closepack)
    {
        int i;

        for (i = 0; i < 8; i++)
        {
            int xend, yend;

            yend = y + yincr[i];
            xend = x + xincr[i];
            if (ONBOARD(xend, yend))
                collide += IS_SHIP(board[b][xend][yend]);
        }
    }
    return(collide);
}

static bool
checkplace(int b, ship_t *ss, int vis)
{
    int l, xend, yend;

    /* first, check for board edges */
    xend = ss->x + (ss->length - 1) * xincr[ss->dir];
    yend = ss->y + (ss->length - 1) * yincr[ss->dir];
    if (!ONBOARD(xend, yend))
    {
        if (vis)
            switch(rnd(3))
            {
            case 0:
                error("Ship is hanging from the edge of the world");
                break;
            case 1:
                error("Try fitting it on the board");
                break;
            case 2:
                error("Figure I won't find it if you put it there?");
                break;
            }
        return(FALSE);
    }

    for(l = 0; l < ss->length; ++l)
    {
        if(collidecheck(b, ss->y+l*yincr[ss->dir], ss->x+l*xincr[ss->dir]))
        {
            if (vis)
                switch(rnd(3))
                {
                    case 0:
                        error("There's already a ship there");
                        break;
                    case 1:
                        error("Collision alert!  Aaaaaagh!");
                        break;
                    case 2:
                        error("Er, Admiral, what about the other ship?");
                        break;
                    }
            return(FALSE);
            }
        }
    return(TRUE);
}

static int
awinna(void)
{
    int i, j;
    ship_t *ss;

    for(i=0; i<2; ++i)
    {
        ss = (i) ? cpuship : plyship;
        for(j=0; j < SHIPTYPES; ++j, ++ss)
            if(ss->length > ss->hits)
                break;
        if (j == SHIPTYPES)
            return(OTHER);
    }
    return(-1);
}

/* register a hit on the targeted ship */
static ship_t *
hitship(int x, int y)
{
    ship_t *sb, *ss;
    char sym;
    int oldx, oldy;

    getyx(stdscr, oldy, oldx);
    sb = (turn) ? plyship : cpuship;
    if(!(sym = board[OTHER][x][y]))
        return((ship_t *)NULL);
    for(ss = sb; ss < sb + SHIPTYPES; ++ss)
        if(ss->symbol == sym)
        {
            if (++ss->hits < ss->length)        /* still afloat? */
                return((ship_t *)NULL);
            else                                /* sunk! */
            {
                int i, j;

                if (!closepack)
                    for (j = -1; j <= 1; j++)
                    {
                        int bx = ss->x + j * xincr[(ss->dir + 2) % 8];
                        int by = ss->y + j * yincr[(ss->dir + 2) % 8];

                        for (i = -1; i <= ss->length; ++i)
                        {
                            int x1, y1;

                            x1 = bx + i * xincr[ss->dir];
                            y1 = by + i * yincr[ss->dir];
                            if (ONBOARD(x1, y1))
                            {
                                hits[turn][x1][y1] = MARK_MISS;
                                if (turn == PLAYER)
                                {
                                    cgoto(y1, x1);
                                    if (has_colors())
                                        attron(COLOR_PAIR(COLOR_GREEN));
                                    (void)addch(MARK_MISS);
                                    attrset(0);
                                }
                            }
                        }
                    }

                for (i = 0; i < ss->length; ++i)
                {
                    int x1 = ss->x + i * xincr[ss->dir];
                    int y1 = ss->y + i * yincr[ss->dir];

                    hits[turn][x1][y1] = ss->symbol;
                    if (turn  == PLAYER)
                    {
                        cgoto(y1, x1);
                        (void) addch((chtype)(ss->symbol));
                    }
                }

                (void) move(oldy, oldx);
                return(ss);
            }
        }
    (void) move(oldy, oldx);
    return((ship_t *)NULL);
}

static int
plyturn(void)
{
    ship_t *ss;
    int hit;
    char *m = NULL;

    prompt(1, "Where do you want to shoot? ");
    for (;;)
    {
        (void) getcoord(COMPUTER);
        if (hits[PLAYER][curx][cury])
        {
            prompt(1, "You shelled this spot already! Try again.");
            beep();
        }
        else
            break;
    }
    hit = IS_SHIP(board[COMPUTER][curx][cury]);
    hits[PLAYER][curx][cury] = hit ? MARK_HIT : MARK_MISS;
    cgoto(cury, curx);
    if (has_colors()) {
        if (hit)
            attron(COLOR_PAIR(COLOR_RED));
        else
            attron(COLOR_PAIR(COLOR_GREEN));
    }
    (void) addch((chtype)hits[PLAYER][curx][cury]);
    attrset(0);

    prompt(1, "You %s.", hit ? "scored a hit" : "missed");
    if(hit && (ss = hitship(curx, cury)))
    {
        switch(rnd(5))
        {
        case 0:
            m = " You sank my %s!";
            break;
        case 1:
            m = " I have this sinking feeling about my %s....";
            break;
        case 2:
            m = " My %s has gone to Davy Jones's locker!";
            break;
        case 3:
            m = " Glub, glub -- my %s is headed for the bottom!";
            break;
        case 4:
            m = " You'll pick up survivors from my %s, I hope...!";
            break;
        }
        (void)printw(m, ss->name);
        (void)beep();
    }
    return(hit);
}

static int
sgetc(char *s)
{
    char *s1;
    int ch;

    (void)refresh();
    for(;;)
    {
        ch = getch();
        if (islower(ch))
            ch = toupper(ch);
        if (ch == CTRLC)
            uninitgame(0);
        for (s1=s; *s1 && ch != *s1; ++s1)
            continue;
        if (*s1)
        {
            (void) addch((chtype)ch);
            (void) refresh();
            return(ch);
            }
        }
}

/* Checks to see if there's room for a ship of a given length in a given
 * direction.  If direction is negative, check in all directions.  Note
 * that North and South are equivalent, as are East and West.
 */
static bool
cpushipcanfit(int x, int y, int length, int direction)
{
        int len = 1;
        int x1, y1;

        if (direction >= 0)
        {
                direction %= 4;
                while (direction < 8)
                {
                        x1 = x + xincr[direction];
                        y1 = y + yincr[direction];
                        while (POSSIBLE(x1,y1))
                        {
                            len++;
                            x1 += xincr[direction];
                            y1 += yincr[direction];
                        }
                        direction += 4;
                }
                return (len >= length);
        }
        else
        {
                return ((cpushipcanfit(x,y,length,E)) ||
                            (cpushipcanfit(x,y,length,S)));
        }
}

/* random-fire routine -- implements simple diagonal-striping strategy */
static void
randomfire(int *px, int *py)
{
    static int huntoffs;                /* Offset on search strategy */
    int ypossible[BWIDTH * BDEPTH], xpossible[BWIDTH * BDEPTH], nposs;
    int x, y, i;

    if (turncount++ == 0)
        huntoffs = rnd(srchstep);

    /* first, list all possible moves on the diagonal stripe */
    nposs = 0;
    for (x = 0; x < BWIDTH; x++)
        for (y = 0; y < BDEPTH; y++)
            if ((!hits[COMPUTER][x][y]) &&
                        (((x+huntoffs) % srchstep) == (y % srchstep)) &&
                        (cpushipcanfit(x,y,cpulongest,-1)))
            {
                    xpossible[nposs] = x;
                    ypossible[nposs] = y;
                    nposs++;
                }
    if (nposs)
    {
        i = rnd(nposs);

        *px = xpossible[i];
        *py = ypossible[i];
    }
        else if (srchstep > cpulongest)
    {
             --srchstep; 
             randomfire(px, py);
    }
        else
    {
                error("No moves possible?? Help!");
                exit(1);
    }
}

#define S_MISS  0
#define S_HIT   1
#define S_SUNK  -1

/* fire away at given location */
static int
cpufire(int x, int y)
{
    int hit;
    bool sunk;
    ship_t *ss = NULL;

    hits[COMPUTER][x][y] = (hit = (board[PLAYER][x][y])) ? MARK_HIT : MARK_MISS;
    (void) mvprintw(PROMPTLINE, 0,
        "I shoot at %c%d. I %s!", y + 'A', x, hit ? "hit" : "miss");
    if ((sunk = (hit && (ss = hitship(x, y)))))
        (void) printw(" I've sunk your %s", ss->name);
    (void)clrtoeol();

    pgoto(y, x);
    if (has_colors()) {
        if (hit)
            attron(COLOR_PAIR(COLOR_RED));
        else
            attron(COLOR_PAIR(COLOR_GREEN));
    }
    (void) addch((chtype)(hit ? SHOWHIT : SHOWSPLASH));
    attrset(0);

    return(hit ? (sunk ? S_SUNK : S_HIT) : S_MISS);
}

/*
 * This code implements a fairly irregular FSM, so please forgive the rampant
 * unstructuredness below. The five labels are states which need to be held
 * between computer turns.
 */
static int
cputurn(void)
{
    static bool used[4];
    static ship_t ts;
    int navail, x, y, d, n, hit = S_MISS;
    bool closenoshot = FALSE;

    switch(next)
    {
    case RANDOM_FIRE:   /* last shot was random and missed */
    refire:
        randomfire(&x, &y);
        if (!(hit = cpufire(x, y)))
            next = RANDOM_FIRE;
        else
        {
            ts.x = x; ts.y = y;
            ts.hits = 1;
            next = (hit == S_SUNK) ? RANDOM_FIRE : RANDOM_HIT;
        }
        break;

    case RANDOM_HIT:    /* last shot was random and hit */
        used[E/2] = used[W/2] = (!(cpushipcanfit(ts.x,ts.y,cpushortest,E)));
        used[S/2] = used[N/2] = (!(cpushipcanfit(ts.x,ts.y,cpushortest,S)));
        /* FALLTHROUGH */

    case HUNT_DIRECT:   /* last shot hit, we're looking for ship's long axis */
        for (d = navail = 0; d < 4; d++)
        {
            x = ts.x + xincr[d*2]; y = ts.y + yincr[d*2];
            if (!used[d] && POSSIBLE(x, y))
                navail++;
            else
                used[d] = TRUE;
        }
        if (navail == 0)        /* no valid places for shots adjacent... */
            goto refire;        /* ...so we must random-fire */
        else
        {
            for (d = 0, n = rnd(navail) + 1; n; n--,d++)
                while (used[d])
                    d++;
            d--;

            x = ts.x + xincr[d*2];
            y = ts.y + yincr[d*2];

            if (!(hit = cpufire(x, y)))
                next = HUNT_DIRECT;
            else
            {
                ts.x = x; ts.y = y; ts.dir = d*2; ts.hits++;
                next = (hit == S_SUNK) ? RANDOM_FIRE : FIRST_PASS;
            }
        }
        break;

    case FIRST_PASS:    /* we have a start and a direction now */
        x = ts.x + xincr[ts.dir];
        y = ts.y + yincr[ts.dir];
        if (POSSIBLE(x, y))
        {
            if ((hit = cpufire(x, y)))
            {
                    ts.x = x; ts.y = y; ts.hits++;
                    next = (hit == S_SUNK) ? RANDOM_FIRE : FIRST_PASS;
            }
            else
                 next = REVERSE_JUMP;
            break;
        }
        else
            next = REVERSE_JUMP;
        /* FALL THROUGH */

    case REVERSE_JUMP:  /* nail down the ship's other end */
        ts.dir = (ts.dir + 4) % 8;
        ts.x += (ts.hits-1) * xincr[ts.dir];
        ts.y += (ts.hits-1) * yincr[ts.dir];
        /* FALL THROUGH */

    case SECOND_PASS:   /* kill squares not caught on first pass */
        x = ts.x + xincr[ts.dir];
        y = ts.y + yincr[ts.dir];
        if (POSSIBLE(x, y))
        {
            if ((hit = cpufire(x, y)))
            {
                    ts.x = x; ts.y = y; ts.hits++;
                    next = (hit == S_SUNK) ? RANDOM_FIRE : SECOND_PASS;
            }
            else
            {
            /* The only way to get here is if closepack is on; otherwise,
             * we _have_ sunk the ship.  I set hit to S_SUNK just to get
             * the additional closepack logic at the end of the switch.
             */
/*assert closepack*/
if (!closepack)  error("Assertion failed: not closepack 1");
                    hit = S_SUNK;
                    next = RANDOM_FIRE;
            }
        }
        else
        {
/*assert closepack*/
if (!closepack)  error("Assertion failed: not closepack 2");
            hit = S_SUNK;
            closenoshot = TRUE;  /* Didn't shoot yet! */
            next = RANDOM_FIRE;
        }
        break;
    }   /* switch(next) */

    if (hit == S_SUNK)
    {
           /* Update cpulongest and cpushortest.  We could increase srchstep
            * if it's smaller than cpushortest but that makes strategic sense
            * only if we've been doing continuous diagonal stripes, and that's
            * less interesting to watch.
            */
            ship_t *sp = plyship;

            cpushortest = cpulongest;
            cpulongest  = 0;
            for (d=0 ; d < SHIPTYPES; d++, sp++)
            {
                   if (sp->hits < sp->length)
                   {
                cpushortest = (cpushortest < sp->length) ? cpushortest : sp->length;
                cpulongest  = (cpulongest  > sp->length) ? cpulongest  : sp->length;
                   }
            }
            /* Now, if we're in closepack mode, we may have knocked off part of
             * another ship, in which case we shouldn't do RANDOM_FIRE.  A
                * more robust implementation would probably do this check regardless
                * of whether closepack was set or not.
                * Note that MARK_HIT is set only for ships that aren't sunk;
                * hitship() changes the marker to the ship's character when the
                * ship is sunk.
             */
            if (closepack)
            {
                  ts.hits = 0;
                  for (x = 0; x < BWIDTH; x++)
                        for (y = 0; y < BDEPTH; y++)
                        {
                                if (hits[COMPUTER][x][y] == MARK_HIT)
                                {
                                /* So we found part of another ship.  It may have more
                                 * than one hit on it.  Check to see if it does.  If no
                                 * hit does, take the last MARK_HIT and be RANDOM_HIT.
                                 */
        ts.x = x; ts.y = y; ts.hits = 1;
        for (d = 0; d < 8; d += 2)
        {
            while ((ONBOARD(ts.x, ts.y)) && 
                        (hits[COMPUTER][(int)ts.x][(int)ts.y] == MARK_HIT))
            {
                    ts.x += xincr[d]; ts.y += yincr[d]; ts.hits++;
            }
            if ((--ts.hits > 1) && (ONBOARD(ts.x, ts.y)) &&
                    (hits[COMPUTER][(int)ts.x][(int)ts.y] == 0))
            {
                    ts.dir = d;
                    ts.x -= xincr[d]; ts.y -= yincr[d];
                    d = 100;                  /* use as a flag */
                    x = BWIDTH; y = BDEPTH;   /* end the loop */
            } else {
                 ts.x = x; ts.y = y; ts.hits = 1;
            }
        
        }
                                }
                                if (ts.hits)
                                {
                                        next = (d >= 100) ? FIRST_PASS : RANDOM_HIT;
                                } else
                                        next = RANDOM_FIRE;
                                }
            }
            if (closenoshot)
            {
                   return(cputurn());
            }
    }

    /* check for continuation and/or winner */
    if (salvo)
    {
        (void)refresh();
        (void)sleep(1);
    }

    return(hit);
}

static int
playagain(void)
{
    int j;
    ship_t *ss;

    for (ss = cpuship; ss < cpuship + SHIPTYPES; ss++)
        for(j = 0; j < ss->length; j++)
        {
            cgoto(ss->y + j * yincr[ss->dir], ss->x + j * xincr[ss->dir]);
            (void) addch((chtype)ss->symbol);
        }

    if(awinna())
        ++cpuwon;
    else
        ++plywon;
    j = 18 + strlen(name);
        /* If you play a hundred games or more at a go, you deserve a badly
         * centred score output.
         */
    if(plywon >= 10)
        ++j;
    if(cpuwon >= 10)
        ++j;
    (void) mvprintw(1,(COLWIDTH-j)/2,
                    "%s: %d     Computer: %d",name,plywon,cpuwon);

    prompt(2, (awinna()) ? "Want to be humiliated again, %s [yn]? "
           : "Going to give me a chance for revenge, %s [yn]? ",name);
    return(sgetc("YN") == 'Y');
}

__dead void
usage(void)
{
        (void) fprintf(stderr, "usage: %s [-b | -s] [-c]\n", getprogname());
        (void) fprintf(stderr, "\tWhere the options are:\n");
        (void) fprintf(stderr, "\t-b : play a blitz game\n");
        (void) fprintf(stderr, "\t-s : play a salvo game\n");
        (void) fprintf(stderr, "\t-c : ships may be adjacent\n");
        exit(1);
}

static void
do_options(int c, char *op[])
{
    int ch;

    while ((ch = getopt(c, op, "bchs")) != -1) {
        switch (ch) {
        case 'b':
            blitz = 1;
            if (salvo == 1)
            {
                (void) fprintf(stderr,
                        "Bad Arg: -b and -s are mutually exclusive\n");
                exit(1);
            }
            break;
        case 's':
            salvo = 1;
            if (blitz == 1)
            {
                (void) fprintf(stderr,
                        "Bad Arg: -s and -b are mutually exclusive\n");
                exit(1);
            }
            break;
        case 'c':
            closepack = 1;
            break;
        case 'h':
        default:
            (void) usage();
            exit(1);
        }
    }
    if (op[optind] != NULL)
        (void) usage();
}

static int
scount(int who)
{
    int i, shots;
    ship_t *sp;

    if (who)
        sp = cpuship;   /* count cpu shots */
    else
        sp = plyship;   /* count player shots */

    for (i = 0, shots = 0; i < SHIPTYPES; i++, sp++)
    {
        if (sp->hits >= sp->length)
            continue;           /* dead ship */
        else
            shots++;
    }
    return(shots);
}

int
main(int argc, char *argv[])
{
    do_options(argc, argv);

    intro();

    if (pledge("stdio tty", NULL) == -1)
        err(1, "pledge");

    do {
        initgame();
        while(awinna() == -1)
        {
            if (!blitz)
            {
                if (!salvo)
                {
                    if(turn)
                        (void) cputurn();
                    else
                        (void) plyturn();
                }
                else  /* salvo */
                {
                    int i;

                    i = scount(turn);
                    while (i--)
                    {
                        if (turn)
                        {
                            if (cputurn() && awinna() != -1)
                                i = 0;
                        }
                        else
                        {
                            if (plyturn() && awinna() != -1)
                                i = 0;
                        }
                    }
                }
            }
            else  /* blitz */
                while(turn ? cputurn() : plyturn())
                {
                    if (turn)   /* Pause between successive computer shots */
                    {
                        (void)refresh();
                        (void)sleep(1);
                    }
                    if (awinna() != -1)
                     break;
                }
            turn = OTHER;
        }
    } while
        (playagain());
    uninitgame(0);
    return 0;
}