/*-
 * Copyright (c) 1990, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Ed James.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University 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 REGENTS 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 REGENTS 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.
 *
 * @(#)input.c  8.1 (Berkeley) 5/31/93
 * $FreeBSD: src/games/atc/input.c,v 1.7 2000/02/27 23:02:47 mph Exp $
 */

/*
 * Copyright (c) 1987 by Ed James, UC Berkeley.  All rights reserved.
 *
 * Copy permission is hereby granted provided that this notice is
 * retained on all partial or complete copies.
 *
 * For more info on this and all of my stuff, mail edjames@berkeley.edu.
 */

#include <sys/wait.h>

#include <stdlib.h>
#include <string.h>
#include "include.h"
#include "pathnames.h"

#define MAXRULES        6
#define MAXDEPTH        15

#define RETTOKEN        '\r'
#define REDRAWTOKEN     '\014'  /* CTRL(L) */
#define SHELLTOKEN      '!'
#define HELPTOKEN       '?'
#define ALPHATOKEN      256
#define NUMTOKEN        257

typedef struct {
        int             token;
        int             to_state;
        const char      *str;
        const char      *(*func)(int);
} RULE;

typedef struct {
        int     num_rules;
        RULE    *rule;
} STATE;

typedef struct {
        char    str[20];
        int     state;
        int     rule;
        int     ch;
        int     pos;
} STACK;

#define T_RULE          stack[level].rule
#define T_STATE         stack[level].state
#define T_STR           stack[level].str
#define T_POS           stack[level].pos
#define T_CH            stack[level].ch

#define NUMELS(a)       (sizeof (a) / sizeof (*(a)))

#define NUMSTATES       NUMELS(st)

static int      pop(void);
static void     rezero(void);
static void     push(int, int);
static void     noise(void);
static int      gettoken(void);
static const char       *setplane(int);
static const char       *turn(int);
static const char       *circle(int);
static const char       *left(int);
static const char       *right(int);
static const char       *Left(int);
static const char       *Right(int);
static const char       *delayb(int);
static const char       *beacon(int);
static const char       *ex_it(int);
static const char       *airport(int);
static const char       *climb(int);
static const char       *descend(int);
static const char       *setalt(int);
static const char       *setrelalt(int);
static const char       *benum(int);
static const char       *to_dir(int);
static const char       *rel_dir(int);
static const char       *mark(int);
static const char       *unmark(int);
static const char       *ignore(int);

RULE    state0[] = {    { ALPHATOKEN,   1,      "%c:",          setplane},
                        { RETTOKEN,     -1,     "",             NULL    },
                        { HELPTOKEN,    12,     " [a-z]<ret>",  NULL    }},
        state1[] = {    { 't',          2,      " turn",        turn    },
                        { 'a',          3,      " altitude:",   NULL    },
                        { 'c',          4,      " circle",      circle  },
                        { 'm',          7,      " mark",        mark    },
                        { 'u',          7,      " unmark",      unmark  },
                        { 'i',          7,      " ignore",      ignore  },
                        { HELPTOKEN,    12,     " tacmui",      NULL    }},
        state2[] = {    { 'l',          6,      " left",        left    },
                        { 'r',          6,      " right",       right   },
                        { 'L',          4,      " left 90",     Left    },
                        { 'R',          4,      " right 90",    Right   },
                        { 't',          11,     " towards",     NULL    },
                        { 'w',          4,      " to 0",        to_dir  },
                        { 'e',          4,      " to 45",       to_dir  },
                        { 'd',          4,      " to 90",       to_dir  },
                        { 'c',          4,      " to 135",      to_dir  },
                        { 'x',          4,      " to 180",      to_dir  },
                        { 'z',          4,      " to 225",      to_dir  },
                        { 'a',          4,      " to 270",      to_dir  },
                        { 'q',          4,      " to 315",      to_dir  },
                        { HELPTOKEN,    12,     " lrLRt<dir>",  NULL    }},
        state3[] = {    { '+',          10,     " climb",       climb   },
                        { 'c',          10,     " climb",       climb   },
                        { '-',          10,     " descend",     descend },
                        { 'd',          10,     " descend",     descend },
                        { NUMTOKEN,     7,      " %c000 feet",  setalt  },
                        { HELPTOKEN,    12,     " +-cd[0-9]",   NULL    }},
        state4[] = {    { '@',          9,      " at",          NULL    },
                        { 'a',          9,      " at",          NULL    },
                        { RETTOKEN,     -1,     "",             NULL    },
                        { HELPTOKEN,    12,     " @a<ret>",     NULL    }},
        state5[] = {    { NUMTOKEN,     7,      "%c",           delayb  },
                        { HELPTOKEN,    12,     " [0-9]",       NULL    }},
        state6[] = {    { '@',          9,      " at",          NULL    },
                        { 'a',          9,      " at",          NULL    },
                        { 'w',          4,      " 0",           rel_dir },
                        { 'e',          4,      " 45",          rel_dir },
                        { 'd',          4,      " 90",          rel_dir },
                        { 'c',          4,      " 135",         rel_dir },
                        { 'x',          4,      " 180",         rel_dir },
                        { 'z',          4,      " 225",         rel_dir },
                        { 'a',          4,      " 270",         rel_dir },
                        { 'q',          4,      " 315",         rel_dir },
                        { RETTOKEN,     -1,     "",             NULL    },
                        { HELPTOKEN,    12,     " @a<dir><ret>",NULL    }},
        state7[] = {    { RETTOKEN,     -1,     "",             NULL    },
                        { HELPTOKEN,    12,     " <ret>",       NULL    }},
        state8[] = {    { NUMTOKEN,     4,      "%c",           benum   },
                        { HELPTOKEN,    12,     " [0-9]",       NULL    }},
        state9[] = {    { 'b',          5,      " beacon #",    NULL    },
                        { '*',          5,      " beacon #",    NULL    },
                        { HELPTOKEN,    12,     " b*",          NULL    }},
        state10[] = {   { NUMTOKEN,     7,      " %c000 ft",    setrelalt},
                        { HELPTOKEN,    12,     " [0-9]",       NULL    }},
        state11[] = {   { 'b',          8,      " beacon #",    beacon  },
                        { '*',          8,      " beacon #",    beacon  },
                        { 'e',          8,      " exit #",      ex_it   },
                        { 'a',          8,      " airport #",   airport },
                        { HELPTOKEN,    12,     " b*ea",        NULL    }},
        state12[] = {   { -1,           -1,     "",             NULL    }};

#define DEF_STATE(s)    { NUMELS(s),    (s)     }

STATE   st[] = {
        DEF_STATE(state0), DEF_STATE(state1), DEF_STATE(state2),
        DEF_STATE(state3), DEF_STATE(state4), DEF_STATE(state5),
        DEF_STATE(state6), DEF_STATE(state7), DEF_STATE(state8),
        DEF_STATE(state9), DEF_STATE(state10), DEF_STATE(state11),
        DEF_STATE(state12)
};

PLANE   p;
STACK   stack[MAXDEPTH];
int     level;
int     tval;
int     dest_type, dest_no, dir;

static int
pop(void)
{
        if (level == 0)
                return (-1);
        level--;

        ioclrtoeol(T_POS);

        strcpy(T_STR, "");
        T_RULE = -1;
        T_CH = -1;
        return (0);
}

static void
rezero(void)
{
        iomove(0);

        level = 0;
        T_STATE = 0;
        T_RULE = -1;
        T_CH = -1;
        T_POS = 0;
        strcpy(T_STR, "");
}

static void
push(int ruleno, int ch)
{
        int     newstate, newpos;

        sprintf(T_STR, st[T_STATE].rule[ruleno].str, tval);
        T_RULE = ruleno;
        T_CH = ch;
        newstate = st[T_STATE].rule[ruleno].to_state;
        newpos = T_POS + strlen(T_STR);

        ioaddstr(T_POS, T_STR);

        if (level == 0)
                ioclrtobot();
        level++;
        T_STATE = newstate;
        T_POS = newpos;
        T_RULE = -1;
        strcpy(T_STR, "");
}

int
getcommand(void)
{
        int             c, i, done;
        const char      *s, *(*func)(int);
        PLANE           *pp;

        rezero();

        do {
                c = gettoken();
                if (c == tty_new.c_cc[VERASE]) {
                        if (pop() < 0)
                                noise();
                } else if (c == tty_new.c_cc[VKILL]) {
                        while (pop() >= 0)
                                ;
                } else {
                        done = 0;
                        for (i = 0; i < st[T_STATE].num_rules; i++) {
                                if (st[T_STATE].rule[i].token == c ||
                                    st[T_STATE].rule[i].token == tval) {
                                        push(i, (c >= ALPHATOKEN) ? tval : c);
                                        done = 1;
                                        break;
                                }
                        }
                        if (!done)
                                noise();
                }
        } while (T_STATE != -1);

        if (level == 1)
                return (1);     /* forced update */

        dest_type = T_NODEST;

        for (i = 0; i < level; i++) {
                func = st[stack[i].state].rule[stack[i].rule].func;
                if (func != NULL)
                        if ((s = (*func)(stack[i].ch)) != NULL) {
                                ioerror(stack[i].pos, strlen(stack[i].str), s);
                                return (-1);
                        }
        }

        pp = findplane(p.plane_no);
        if (pp->new_altitude != p.new_altitude)
                pp->new_altitude = p.new_altitude;
        else if (pp->status != p.status)
                pp->status = p.status;
        else {
                pp->new_dir = p.new_dir;
                pp->delayd = p.delayd;
                pp->delayd_no = p.delayd_no;
        }
        return (0);
}

static void
noise(void)
{
        putchar('\07');
        fflush(stdout);
}

static int
gettoken(void)
{
        while ((tval = getAChar()) == REDRAWTOKEN || tval == SHELLTOKEN)
        {
                if (tval == SHELLTOKEN)
                {
                        struct itimerval        itv;
                        itv.it_value.tv_sec = 0;
                        itv.it_value.tv_usec = 0;
                        setitimer(ITIMER_REAL, &itv, NULL);
                        if (fork() == 0)        /* child */
                        {
                                char *shell, *base;

                                /* revoke */
                                setgid(getgid());
                                done_screen();

                                                 /* run user's favorite shell */
                                if ((shell = getenv("SHELL")) != NULL)
                                {
                                        base = strrchr(shell, '/');
                                        if (base == NULL)
                                                base = shell;
                                        else
                                                base++;
                                        execl(shell, base, NULL);
                                }
                                else
                                        execl(_PATH_BSHELL, "sh", NULL);

                                exit(0);        /* oops */
                        }

                        wait(0);
                        tcsetattr(fileno(stdin), TCSANOW, &tty_new);
                        itv.it_value.tv_sec = 0;
                        itv.it_value.tv_usec = 1;
                        itv.it_interval.tv_sec = sp->update_secs;
                        itv.it_interval.tv_usec = 0;
                        setitimer(ITIMER_REAL, &itv, NULL);
                }
                redraw();
        }

        if (isdigit(tval))
                return (NUMTOKEN);
        else if (isalpha(tval))
                return (ALPHATOKEN);
        else
                return (tval);
}

static const char *
setplane(int c)
{
        PLANE   *pp;

        pp = findplane(number(c));
        if (pp == NULL)
                return ("Unknown Plane");
        bcopy(pp, &p, sizeof (p));
        p.delayd = 0;
        return (NULL);
}

static const char *
turn(int c __unused)
{
        if (p.altitude == 0)
                return ("Planes at airports may not change direction");
        return (NULL);
}

static const char *
circle(int c __unused)
{
        if (p.altitude == 0)
                return ("Planes cannot circle on the ground");
        p.new_dir = MAXDIR;
        return (NULL);
}

static const char *
left(int c __unused)
{
        dir = D_LEFT;
        p.new_dir = p.dir - 1;
        if (p.new_dir < 0)
                p.new_dir += MAXDIR;
        return (NULL);
}

static const char *
right(int c __unused)
{
        dir = D_RIGHT;
        p.new_dir = p.dir + 1;
        if (p.new_dir >= MAXDIR)
                p.new_dir -= MAXDIR;
        return (NULL);
}

static const char *
Left(int c __unused)
{
        p.new_dir = p.dir - 2;
        if (p.new_dir < 0)
                p.new_dir += MAXDIR;
        return (NULL);
}

static const char *
Right(int c __unused)
{
        p.new_dir = p.dir + 2;
        if (p.new_dir >= MAXDIR)
                p.new_dir -= MAXDIR;
        return (NULL);
}

static const char *
delayb(int c)
{
        int     xdiff, ydiff;

        c -= '0';

        if (c >= sp->num_beacons)
                return ("Unknown beacon");
        xdiff = sp->beacon[c].x - p.xpos;
        xdiff = SGN(xdiff);
        ydiff = sp->beacon[c].y - p.ypos;
        ydiff = SGN(ydiff);
        if (xdiff != displacement[p.dir].dx || ydiff != displacement[p.dir].dy)
                return ("Beacon is not in flight path");
        p.delayd = 1;
        p.delayd_no = c;

        if (dest_type != T_NODEST) {
                switch (dest_type) {
                case T_BEACON:
                        xdiff = sp->beacon[dest_no].x - sp->beacon[c].x;
                        ydiff = sp->beacon[dest_no].y - sp->beacon[c].y;
                        break;
                case T_EXIT:
                        xdiff = sp->exit[dest_no].x - sp->beacon[c].x;
                        ydiff = sp->exit[dest_no].y - sp->beacon[c].y;
                        break;
                case T_AIRPORT:
                        xdiff = sp->airport[dest_no].x - sp->beacon[c].x;
                        ydiff = sp->airport[dest_no].y - sp->beacon[c].y;
                        break;
                default:
                        return ("Bad case in delayb!  Get help!");
                        break;
                }
                if (xdiff == 0 && ydiff == 0)
                        return ("Would already be there");
                p.new_dir = DIR_FROM_DXDY(xdiff, ydiff);
                if (p.new_dir == p.dir)
                        return ("Already going in that direction");
        }
        return (NULL);
}

static const char *
beacon(int c __unused)
{
        dest_type = T_BEACON;
        return (NULL);
}

static const char *
ex_it(int c __unused)
{
        dest_type = T_EXIT;
        return (NULL);
}

static const char *
airport(int c __unused)
{
        dest_type = T_AIRPORT;
        return (NULL);
}

static const char *
climb(int c __unused)
{
        dir = D_UP;
        return (NULL);
}

static const char *
descend(int c __unused)
{
        dir = D_DOWN;
        return (NULL);
}

static const char *
setalt(int c)
{
        if ((p.altitude == c - '0') && (p.new_altitude == p.altitude))
                return ("Already at that altitude");
        if (p.new_altitude == c - '0')
                return ("Already going to that altitude");
        p.new_altitude = c - '0';
        return (NULL);
}

static const char *
setrelalt(int c)
{
        int new_altitude;

        if (c == 0)
                return ("altitude not changed");

        switch (dir) {
        case D_UP:
                new_altitude = p.altitude + c - '0';
                break;
        case D_DOWN:
                new_altitude = p.altitude - (c - '0');
                break;
        default:
                return ("Unknown case in setrelalt!  Get help!");
                break;
        }
        if (new_altitude < 0)
                return ("Altitude would be too low");
        else if (new_altitude > 9)
                return ("Altitude would be too high");
        else if (new_altitude == p.new_altitude)
                return ("Already going to that altitude");

        p.new_altitude = new_altitude;
        return (NULL);
}

static const char *
benum(int c)
{
        dest_no = c -= '0';

        switch (dest_type) {
        case T_BEACON:
                if (c >= sp->num_beacons)
                        return ("Unknown beacon");
                p.new_dir = DIR_FROM_DXDY(sp->beacon[c].x - p.xpos,
                        sp->beacon[c].y - p.ypos);
                break;
        case T_EXIT:
                if (c >= sp->num_exits)
                        return ("Unknown exit");
                p.new_dir = DIR_FROM_DXDY(sp->exit[c].x - p.xpos,
                        sp->exit[c].y - p.ypos);
                break;
        case T_AIRPORT:
                if (c >= sp->num_airports)
                        return ("Unknown airport");
                p.new_dir = DIR_FROM_DXDY(sp->airport[c].x - p.xpos,
                        sp->airport[c].y - p.ypos);
                break;
        default:
                return ("Unknown case in benum!  Get help!");
                break;
        }
        return (NULL);
}

static const char *
to_dir(int c)
{
        p.new_dir = dir_no(c);
        return (NULL);
}

static const char *
rel_dir(int c)
{
        int     angle;

        angle = dir_no(c);
        switch (dir) {
        case D_LEFT:
                p.new_dir = p.dir - angle;
                if (p.new_dir < 0)
                        p.new_dir += MAXDIR;
                break;
        case D_RIGHT:
                p.new_dir = p.dir + angle;
                if (p.new_dir >= MAXDIR)
                        p.new_dir -= MAXDIR;
                break;
        default:
                return ("Bizarre direction in rel_dir!  Get help!");
                break;
        }
        return (NULL);
}

static const char *
mark(int c __unused)
{
        if (p.altitude == 0)
                return ("Cannot mark planes on the ground");
        if (p.status == S_MARKED)
                return ("Already marked");
        p.status = S_MARKED;
        return (NULL);
}

static const char *
unmark(int c __unused)
{
        if (p.altitude == 0)
                return ("Cannot unmark planes on the ground");
        if (p.status == S_UNMARKED)
                return ("Already unmarked");
        p.status = S_UNMARKED;
        return (NULL);
}

static const char *
ignore(int c __unused)
{
        if (p.altitude == 0)
                return ("Cannot ignore planes on the ground");
        if (p.status == S_IGNORED)
                return ("Already ignored");
        p.status = S_IGNORED;
        return (NULL);
}

int
dir_no(char ch)
{
        int     dirno;

        dirno = dir;
        switch (ch) {
        case 'w':       dirno = 0;      break;
        case 'e':       dirno = 1;      break;
        case 'd':       dirno = 2;      break;
        case 'c':       dirno = 3;      break;
        case 'x':       dirno = 4;      break;
        case 'z':       dirno = 5;      break;
        case 'a':       dirno = 6;      break;
        case 'q':       dirno = 7;      break;
        default:
                fprintf(stderr, "bad character in dir_no\n");
                break;
        }
        return (dirno);
}