/****************************************************************************
 * Copyright (c) 2005 Free Software Foundation, Inc.                        *
 *                                                                          *
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 * copy of this software and associated documentation files (the            *
 * "Software"), to deal in the Software without restriction, including      *
 * without limitation the rights to use, copy, modify, merge, publish,      *
 * distribute, distribute with modifications, sublicense, and/or sell       *
 * copies of the Software, and to permit persons to whom the Software is    *
 * furnished to do so, subject to the following conditions:                 *
 *                                                                          *
 * The above copyright notice and this permission notice shall be included  *
 * in all copies or substantial portions of the Software.                   *
 *                                                                          *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
 * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    *
 * THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
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 * holders shall not be used in advertising or otherwise to promote the     *
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 * authorization.                                                           *
 ****************************************************************************/

/*

         @@@        @@@    @@@@@@@@@@     @@@@@@@@@@@    @@@@@@@@@@@@
         @@@        @@@   @@@@@@@@@@@@    @@@@@@@@@@@@   @@@@@@@@@@@@@
         @@@        @@@  @@@@      @@@@   @@@@           @@@@ @@@  @@@@
         @@@   @@   @@@  @@@        @@@   @@@            @@@  @@@   @@@
         @@@  @@@@  @@@  @@@        @@@   @@@            @@@  @@@   @@@
         @@@@ @@@@ @@@@  @@@        @@@   @@@            @@@  @@@   @@@
          @@@@@@@@@@@@   @@@@      @@@@   @@@            @@@  @@@   @@@
           @@@@  @@@@     @@@@@@@@@@@@    @@@            @@@  @@@   @@@
            @@    @@       @@@@@@@@@@     @@@            @@@  @@@   @@@

                                 Eric P. Scott
                          Caltech High Energy Physics
                                 October, 1980

                           Color by Eric S. Raymond
                                  July, 1995

Options:
        -f                      fill screen with copies of 'WORM' at start.
        -l <n>                  set worm length
        -n <n>                  set number of worms
        -t                      make worms leave droppings
*/

#include <curses.h>
#include <stdlib.h>
#include <time.h>

#define FLAVORS 7

static chtype flavor[FLAVORS] =
{
    'O', '*', '#', '$', '%', '0', '@'
};

static const short xinc[] =
{
    1, 1, 1, 0, -1, -1, -1, 0
},
yinc[] =
{
    -1, 0, 1, 1, 1, 0, -1, -1
};

static struct worm
{
    int orientation, head;
    short *xpos, *ypos;
} worm[40];

static const char *field;
static int length = 16, number = 3;
static chtype trail = ' ';

static const struct options
{
    int nopts;
    int opts[3];
} normal[8] =
{
    { 3, { 7, 0, 1 } }, { 3, { 0, 1, 2 } }, { 3, { 1, 2, 3 } },
    { 3, { 2, 3, 4 } }, { 3, { 3, 4, 5 } }, { 3, { 4, 5, 6 } },
    { 3, { 5, 6, 7 } }, { 3, { 6, 7, 0 } }
},
upper[8] =
{
    { 1, { 1, 0, 0 } }, { 2, { 1, 2, 0 } }, { 0, { 0, 0, 0 } },
    { 0, { 0, 0, 0 } }, { 0, { 0, 0, 0 } }, { 2, { 4, 5, 0 } },
    { 1, { 5, 0, 0 } }, { 2, { 1, 5, 0 } }
},
left[8] =
{
    { 0, { 0, 0, 0 } }, { 0, { 0, 0, 0 } }, { 0, { 0, 0, 0 } },
    { 2, { 2, 3, 0 } }, { 1, { 3, 0, 0 } }, { 2, { 3, 7, 0 } },
    { 1, { 7, 0, 0 } }, { 2, { 7, 0, 0 } }
},
right[8] =
{
    { 1, { 7, 0, 0 } }, { 2, { 3, 7, 0 } }, { 1, { 3, 0, 0 } },
    { 2, { 3, 4, 0 } }, { 0, { 0, 0, 0 } }, { 0, { 0, 0, 0 } },
    { 0, { 0, 0, 0 } }, { 2, { 6, 7, 0 } }
},
lower[8] =
{
    { 0, { 0, 0, 0 } }, { 2, { 0, 1, 0 } }, { 1, { 1, 0, 0 } },
    { 2, { 1, 5, 0 } }, { 1, { 5, 0, 0 } }, { 2, { 5, 6, 0 } },
    { 0, { 0, 0, 0 } }, { 0, { 0, 0, 0 } }
},
upleft[8] =
{
    { 0, { 0, 0, 0 } }, { 0, { 0, 0, 0 } }, { 0, { 0, 0, 0 } },
    { 0, { 0, 0, 0 } }, { 0, { 0, 0, 0 } }, { 1, { 3, 0, 0 } },
    { 2, { 1, 3, 0 } }, { 1, { 1, 0, 0 } }
},
upright[8] =
{
    { 2, { 3, 5, 0 } }, { 1, { 3, 0, 0 } }, { 0, { 0, 0, 0 } },
    { 0, { 0, 0, 0 } }, { 0, { 0, 0, 0 } }, { 0, { 0, 0, 0 } },
    { 0, { 0, 0, 0 } }, { 1, { 5, 0, 0 } }
},
lowleft[8] =
{
    { 3, { 7, 0, 1 } }, { 0, { 0, 0, 0 } }, { 0, { 0, 0, 0 } },
    { 1, { 1, 0, 0 } }, { 2, { 1, 7, 0 } }, { 1, { 7, 0, 0 } },
    { 0, { 0, 0, 0 } }, { 0, { 0, 0, 0 } }
},
lowright[8] =
{
    { 0, { 0, 0, 0 } }, { 1, { 7, 0, 0 } }, { 2, { 5, 7, 0 } },
    { 1, { 5, 0, 0 } }, { 0, { 0, 0, 0 } }, { 0, { 0, 0, 0 } },
    { 0, { 0, 0, 0 } }, { 0, { 0, 0, 0 } }
};

static void cleanup(void)
{
    standend();
    refresh();
    curs_set(1);
    endwin();
}

int main(int argc, char *argv[])
{
    const struct options *op;
    struct worm *w;
    short **ref, *ip;
    time_t seed;
    int x, y, n, h, last, bottom;

    for (x = 1; x < argc; x++)
    {
        char *p = argv[x];

        if (*p == '-')
            p++;

        switch (*p)
        {
        case 'f':
            field = "WORM";
            break;
        case 'l':
            if (++x == argc)
                goto usage;

            if ((length = atoi(argv[x])) < 2 || length > 1024)
            {
                fprintf(stderr, "%s: Invalid length\n", *argv);
                return EXIT_FAILURE;
            }

            break;
        case 'n':
            if (++x == argc)
                goto usage;

            if ((number = atoi(argv[x])) < 1 || number > 40)
            {
                fprintf(stderr, "%s: Invalid number of worms\n", *argv);
                return EXIT_FAILURE;
            }

            break;
        case 't':
            trail = '.';
            break;
        default:
              usage:
            fprintf(stderr, "usage: %s [-field] [-length #] "
                            "[-number #] [-trail]\n", *argv);
            return EXIT_FAILURE;
        }
    }

#ifdef XCURSES
    Xinitscr(argc, argv);
#else
    initscr();
#endif
    seed = time((time_t *)0);
    srand(seed);

    noecho();
    cbreak();
    nonl();
    keypad(stdscr, TRUE);

    curs_set(0);

    bottom = LINES - 1;
    last = COLS - 1;

#ifdef A_COLOR
    if (has_colors())
    {
        short bg = COLOR_BLACK;
        start_color();

# if defined(NCURSES_VERSION) || (defined(PDC_BUILD) && PDC_BUILD > 3000)
        if (use_default_colors() == OK)
            bg = -1;
# endif

# define SET_COLOR(num, fg) \
        init_pair(num + 1, fg, bg); \
        flavor[num] |= COLOR_PAIR(num + 1) | A_BOLD

        SET_COLOR(0, COLOR_GREEN);
        SET_COLOR(1, COLOR_RED);
        SET_COLOR(2, COLOR_CYAN);
        SET_COLOR(3, COLOR_WHITE);
        SET_COLOR(4, COLOR_MAGENTA);
        SET_COLOR(5, COLOR_BLUE);
        SET_COLOR(6, COLOR_YELLOW);
    }
#endif

    ref = malloc(sizeof(short *) * LINES);

    for (y = 0; y < LINES; y++)
    {
        ref[y] = malloc(sizeof(short) * COLS);

        for (x = 0; x < COLS; x++)
            ref[y][x] = 0;
    }

#ifdef BADCORNER
    /* if addressing the lower right corner doesn't work in your curses */

    ref[bottom][last] = 1;
#endif

    for (n = number, w = &worm[0]; --n >= 0; w++)
    {
        w->orientation = w->head = 0;

        if ((ip = malloc(sizeof(short) * (length + 1))) == NULL)
        {
            fprintf(stderr, "%s: out of memory\n", *argv);
            return EXIT_FAILURE;
        }

        w->xpos = ip;

        for (x = length; --x >= 0;)
            *ip++ = -1;

        if ((ip = malloc(sizeof(short) * (length + 1))) == NULL)
        {
            fprintf(stderr, "%s: out of memory\n", *argv);
            return EXIT_FAILURE;
        }

        w->ypos = ip;

        for (y = length; --y >= 0;)
            *ip++ = -1;
    }

    if (field)
    {
        const char *p = field;

        for (y = bottom; --y >= 0;)
            for (x = COLS; --x >= 0;)
            {
                addch((chtype) (*p++));

                if (!*p)
                    p = field;
            }
    }

    napms(12);
    refresh();
    nodelay(stdscr, TRUE);

    for (;;)
    {
        int ch;

        if ((ch = getch()) > 0)
        {
#ifdef KEY_RESIZE
            if (ch == KEY_RESIZE)
            {
# ifdef PDCURSES
                resize_term(0, 0);
# endif
                if (last != COLS - 1)
                {
                    for (y = 0; y <= bottom; y++)
                    {
                        ref[y] = realloc(ref[y], sizeof(short) * COLS);

                        for (x = last + 1; x < COLS; x++)
                            ref[y][x] = 0;
                    }

                    last = COLS - 1;
                }

                if (bottom != LINES - 1)
                {
                    for (y = LINES; y <= bottom; y++)
                        free(ref[y]);

                    ref = realloc(ref, sizeof(short *) * LINES);

                    for (y = bottom + 1; y < LINES; y++)
                    {
                        ref[y] = malloc(sizeof(short) * COLS);

                        for (x = 0; x < COLS; x++)
                            ref[y][x] = 0;
                    }

                    bottom = LINES - 1;
                }
            }

#endif /* KEY_RESIZE */

            /* Make it simple to put this into single-step mode,
               or resume normal operation - T. Dickey */

            if (ch == 'q')
            {
                cleanup();
                return EXIT_SUCCESS;
            }
            else if (ch == 's')
                nodelay(stdscr, FALSE);
            else if (ch == ' ')
                nodelay(stdscr, TRUE);
        }

        for (n = 0, w = &worm[0]; n < number; n++, w++)
        {
            if ((x = w->xpos[h = w->head]) < 0)
            {
                move(y = w->ypos[h] = bottom, x = w->xpos[h] = 0);
                addch(flavor[n % FLAVORS]);
                ref[y][x]++;
            }
            else
                y = w->ypos[h];

            if (x > last)
                x = last;

            if (y > bottom)
                y = bottom;

            if (++h == length)
                h = 0;

            if (w->xpos[w->head = h] >= 0)
            {
                int x1 = w->xpos[h];
                int y1 = w->ypos[h];

                if (y1 < LINES && x1 < COLS && --ref[y1][x1] == 0)
                {
                    move(y1, x1);
                    addch(trail);
                }
            }

            op = &(x == 0 ? (y == 0 ? upleft :
                  (y == bottom ? lowleft : left)) :
                  (x == last ? (y == 0 ? upright :
                  (y == bottom ? lowright : right)) :
                  (y == 0 ? upper :
                  (y == bottom ? lower : normal))))
                  [w->orientation];

            switch (op->nopts)
            {
            case 0:
                cleanup();
                return EXIT_SUCCESS;
            case 1:
                w->orientation = op->opts[0];
                break;
            default:
                w->orientation = op->opts[rand() % op->nopts];
            }

            move(y += yinc[w->orientation], x += xinc[w->orientation]);

            if (y < 0)
                y = 0;

            addch(flavor[n % FLAVORS]);
            ref[w->ypos[h] = y][w->xpos[h] = x]++;
        }
        napms(12);
        refresh();
    }
}