/*
 *  Empire - A multi-player, client/server Internet based war game.
 *  Copyright (C) 1986-2000, Dave Pare, Jeff Bailey, Thomas Ruschak,
 *                           Ken Stevens, Steve McClure
 *
 *  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; either version 2 of the License, 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 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 *  ---
 *
 *  See the "LEGAL", "LICENSE", "CREDITS" and "README" files for all the
 *  related information and legal notices. It is expected that any future
 *  projects/authors will amend these files as needed.
 *
 *  ---
 *
 *  aircombat.c: Deal with air to air combat
 * 
 *  Known contributors to this file:
 *     Dave Pare, 1986
 *     Thomas Ruschak, 1992
 *     Steve McClure, 1996
 */

#include <string.h>

#include "misc.h"
#include "player.h"
#include "var.h"
#include "news.h"
#include "land.h"
#include "sect.h"
#include "nuke.h"
#include "plane.h"
#include "ship.h"
#include "nat.h"
#include "file.h"
#include "xy.h"
#include "nsc.h"
#include "path.h"
#include "prototypes.h"
#include "optlist.h"

extern int update_pending;

#ifndef MIN
#define MIN(x,y) ((x) < (y) ? (x) : (y))
#endif
#ifndef MAX
#define MAX(x,y) ((x) < (y) ? (y) : (x))
#endif

static void getilist(struct emp_qelem *list, natid own,
		     struct emp_qelem *a, struct emp_qelem *b,
		     struct emp_qelem *c, struct emp_qelem *d);
static void ac_dog(register struct plist *ap, register struct plist *dp);

#define DOG_MAX         15
#define FLAK_MAX        15

		/*       -7    -6    -5    -4    -3    -2    -1    0 */
float flaktable[16] = { 0.20, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50,
    0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85,
};

void
ac_encounter(struct emp_qelem *bomb_list, struct emp_qelem *esc_list,
	     coord x, coord y, s_char *path, int mission_flags,
	     int no_air_defense, struct emp_qelem *obomb,
	     struct emp_qelem *oesc)
{
    int val, non_missiles;
    int rel;
    int dir;
    int nats[MAXNOC];
    int lnats[MAXNOC];
    int gotilist[MAXNOC];
    int unfriendly[MAXNOC];
    int overfly[MAXNOC];
    struct emp_qelem ilist[MAXNOC], *qp;
    s_char mypath[1024];
    int myp;
    int civ, mil;
    natid plane_owner;
    struct sctstr sect;
    struct shpstr ship;
    struct lndstr land;
    struct nstr_item ni;
    natid cn;
    struct natstr *over, *mynatp;
    struct plist *plp;
    int evaded;
    struct shiplook head;
    struct shiplook *s, *s2;
    int changed = 0;
    int intx, inty;		/* Last sector planes intercepted over */
    int intown = 0;		/* Last owner to intercept */
/* We want to only intercept once per sector per owner.  So, if we overfly
   a sector, and then overfly some land units or ships, we don't want to
   potentially intercept 3 times. */

    memset(&head, 0, sizeof(struct shiplook));
    head.uid = -1;

    plp = (struct plist *)bomb_list->q_forw;
    plane_owner = plp->plane.pln_own;

    strncpy(mypath, path, sizeof(mypath));
    myp = 0;

    memset(overfly, 0, sizeof(overfly));
    memset(gotilist, 0, sizeof(gotilist));
    memset(unfriendly, 0, sizeof(unfriendly));
    for (cn = 1; cn < MAXNOC; cn++) {
	if ((mynatp = getnatp(cn)) == 0)
	    continue;
	rel = getrel(mynatp, plane_owner);
	if (rel > HOSTILE)
	    continue;
	if (plane_owner == cn)
	    continue;
	unfriendly[cn]++;
    }
    if (mission_flags & PM_R) {
	if (mission_flags & P_S) {
	    PR(plane_owner, "\nSPY Plane report\n");
	    PRdate(plane_owner);
	    sathead();
	} else if (mission_flags & P_A) {
	    PR(plane_owner, "\nAnti-Sub Patrol report\n");
	} else {
	    PR(plane_owner, "\nReconnaissance report\n");
	    PRdate(plane_owner);
	}
    }

    pln_removedupes(bomb_list, esc_list);
    while ((dir = mypath[myp++]) && !QEMPTY(bomb_list)) {
	if ((val = chkdir(dir, DIR_STOP, DIR_LAST)) == 0)
	    break;
	/* XXX using xnorm is probably bad */
	x = xnorm(x + diroff[val][0]);
	y = ynorm(y + diroff[val][1]);
	getsect(x, y, &sect);
	over = getnatp(sect.sct_own);
	if (opt_HIDDEN) {
	    setcont(plane_owner, sect.sct_own, FOUND_FLY);
	}

	if (mission_flags & PM_R) {
	    if (sect.sct_type == SCT_WATER) {
		PR(plane_owner, "flying over %s at %s\n",
		   dchr[sect.sct_type].d_name, xyas(x, y, plane_owner));
		if (mission_flags & PM_S)
		    plane_sweep(bomb_list, x, y);
		if (mission_flags & P_A) {
		    plane_sona(bomb_list, x, y, &head);
		}
		changed += map_set(plane_owner,
				   sect.sct_x, sect.sct_y,
				   dchr[sect.sct_type].d_mnem, 0);
	    } else if (mission_flags & P_S) {
		satdisp(&sect, (mission_flags & P_I) ? 10 : 50, 1);
	    } else {
		/* This is borrowed from lookout */
		if (sect.sct_own == plane_owner)
		    PR(plane_owner, "Your ");
		else
		    PR(plane_owner,
		       "%s (#%d) ", cname(sect.sct_own), sect.sct_own);
		PR(plane_owner, dchr[sect.sct_type].d_name);
		changed += map_set(plane_owner,
				   sect.sct_x, sect.sct_y,
				   dchr[sect.sct_type].d_mnem, 0);
		PR(plane_owner, " %d%% efficient ",
		   (sect.sct_own == plane_owner) ?
		   sect.sct_effic : roundintby((int)sect.sct_effic, 25));
		civ = getvar(V_CIVIL, (s_char *)&sect, EF_SECTOR);
		mil = getvar(V_MILIT, (s_char *)&sect, EF_SECTOR);
		if (civ)
		    PR(plane_owner, "with %s%d civ ",
		       (sect.sct_own == plane_owner) ?
		       "" : "approx ",
		       (sect.sct_own == plane_owner) ?
		       civ : roundintby(civ, 25));
		if (mil)
		    PR(plane_owner, "with %s%d mil ",
		       (sect.sct_own == plane_owner) ?
		       "" : "approx ",
		       (sect.sct_own == plane_owner) ?
		       mil : roundintby(mil, 25));
		PR(plane_owner, "@ %s\n", xyas(x, y, plane_owner));
	    }
	} else {
	    PR(plane_owner, "flying over %s at %s\n",
	       dchr[sect.sct_type].d_name, xyas(x, y, plane_owner));
	    changed += map_set(plane_owner, sect.sct_x,
			       sect.sct_y, dchr[sect.sct_type].d_mnem, 0);
	}
	if ((rel = getrel(over, plane_owner)) == ALLIED)
	    continue;

	evaded = do_evade(bomb_list, esc_list);

	if (sect.sct_own != 0 && sect.sct_own != plane_owner && (!evaded)) {
	    /* We only show planes overhead if they didn't
	     * evade radar */
	    overfly[sect.sct_own]++;
	    PR(sect.sct_own, "%s planes spotted over %s\n",
	       cname(plane_owner), xyas(x, y, sect.sct_own));
	}

	if (!evaded) {
	    /* Fire flak */
	    if (unfriendly[sect.sct_own])
		ac_doflak(bomb_list, &sect);
	    /* If bombers left, fire flak from units and ships */
	    if (!QEMPTY(bomb_list))
		ac_landflak(bomb_list, x, y);
	    if (!QEMPTY(bomb_list))
		ac_shipflak(bomb_list, x, y);
	}
	/* mission planes aborted due to flak -- don't send escorts */
	if (QEMPTY(bomb_list))
	    break;
	if ((!no_air_defense) && (!evaded))
	    air_defense(x, y, plane_owner, bomb_list, esc_list);

	if (sect.sct_own == 0 || sect.sct_own == plane_owner)
	    continue;

	if (evaded)
	    continue;

	non_missiles = 0;
	for (qp = bomb_list->q_forw; qp != bomb_list; qp = qp->q_forw) {
	    struct plist *ip = (struct plist *)qp;
	    if (!(plchr[(int)ip->plane.pln_type].pl_flags & P_M))
		non_missiles = 1;
	}

	if (!non_missiles)
	    continue;

	if (unfriendly[sect.sct_own] && !gotilist[sect.sct_own]) {
	    getilist(&ilist[sect.sct_own], sect.sct_own,
		     bomb_list, esc_list, obomb, oesc);
	    gotilist[sect.sct_own]++;
	}
	if (rel > HOSTILE)
	    continue;
	ac_intercept(bomb_list, esc_list, &ilist[sect.sct_own],
		     sect.sct_own, x, y);
	intx = x;
	inty = y;
	intown = sect.sct_own;
    }

    /* Let's report all of the overflights even if aborted */
    for (cn = 1; cn < MAXNOC; cn++) {
	if (plane_owner == cn)
	    continue;
	if (overfly[cn] > 0)
	    nreport(plane_owner, N_OVFLY_SECT, cn, overfly[cn]);
    }
    /* If the map changed, update it */
    if (changed)
	if (!update_pending && plane_owner == player->cnum)
	    writemap(player->cnum);
    /* Now, if the bomber and escort lists are empty, we are done */
    if (QEMPTY(bomb_list) && QEMPTY(esc_list)) {
	if (mission_flags & P_A) {
	    s = head.next;
	    while (s != (struct shiplook *)0) {
		s2 = s;
		s = s->next;
		free(s2);
	    }
	}
	return;
    }

    /* Something made it through */
    /* Go figure out if there are ships in this sector, and who's they are */
    memset(nats, 0, sizeof(nats));
    snxtitem_xy(&ni, EF_SHIP, x, y);
    while (nxtitem(&ni, (s_char *)&ship)) {
	if (mchr[(int)ship.shp_type].m_flags & M_SUB)
	    continue;
	nats[ship.shp_own]++;
    }
    /* Go figure out if there are units in this sector, and who's they are */
    memset(lnats, 0, sizeof(lnats));
    snxtitem_xy(&ni, EF_LAND, x, y);
    while (nxtitem(&ni, (s_char *)&land)) {
	lnats[land.lnd_own]++;
    }

    /* Now, let's make life a little rougher. */
    for (cn = 1; cn < MAXNOC && !QEMPTY(bomb_list); cn++) {
	if (plane_owner == cn)
	    continue;
	intown = -1;
	/* Are there ships owned by this country? */
	if (nats[cn] != 0) {
	    /* Yes. */
	    if (cn != 0)
		PR(cn, "%s planes spotted over ships in %s\n",
		   cname(plane_owner), xyas(x, y, cn));
	    if (unfriendly[cn]) {
		/* They are unfriendly too */
		if (!gotilist[cn]) {
		    getilist(&ilist[cn], cn, bomb_list, esc_list, obomb,
			     oesc);
		    gotilist[cn]++;
		}
		PR(plane_owner, "Flying over %s ships in %s\n", cname(cn),
		   xyas(x, y, plane_owner));
		/* This makes going for ships in harbors tough */
		if (!evaded) {
		    /* We already fired flak up above.  Now we intercept again if we haven't already */
		    /* Flag that we intercepted */
		    intown = 1;
		    /* And now intercept again */
		    ac_intercept(bomb_list, esc_list, &ilist[cn], cn, x,
				 y);
		}
	    }
	}
	/* Are there units owned by this country? */
	if (lnats[cn] != 0) {
	    /* Yes. */
	    if (cn != 0)
		PR(cn, "%s planes spotted over land units in %s\n",
		   cname(plane_owner), xyas(x, y, cn));
	    if (unfriendly[cn]) {
		/* They are unfriendly too */
		if (!gotilist[cn]) {
		    getilist(&ilist[cn], cn, bomb_list, esc_list, obomb,
			     oesc);
		    gotilist[cn]++;
		}
		PR(plane_owner, "Flying over %s land units in %s\n",
		   cname(cn), xyas(x, y, plane_owner));
		if (!evaded) {
		    if (intown == -1) {
			/* We haven't intercepted yet, so intercept */
			ac_intercept(bomb_list, esc_list, &ilist[cn], cn,
				     x, y);
		    }
		}
	    }
	}
    }

    if ((mission_flags & P_A) && (head.uid != -1)) {
	s = head.next;
	while (s != (struct shiplook *)0) {
	    s2 = s;
	    s = s->next;
	    free(s2);
	}
    }
}

static int
count_non_missiles(struct emp_qelem *list)
{
    struct emp_qelem *qp;
    struct plist *plp;
    int att_count = 0;

    /* don't intercept missiles */
    for (qp = list->q_forw; qp != list; qp = qp->q_forw) {
	plp = (struct plist *)qp;
	if (!(plp->pcp->pl_flags & P_M))
	    att_count++;
    }
    return att_count;
}

void
sam_intercept(struct emp_qelem *att_list, struct emp_qelem *def_list,
	      natid def_own, natid plane_owner, coord x, coord y,
	      int delete_missiles)
{
    struct emp_qelem *aqp;
    struct emp_qelem *anext;
    struct emp_qelem *dqp;
    struct emp_qelem *dnext;
    struct plist *aplp;
    struct plist *dplp;
    int first = 1;

    for (aqp = att_list->q_forw,
	 dqp = def_list->q_forw;
	 aqp != att_list && dqp != def_list; aqp = anext) {
	anext = aqp->q_forw;
	aplp = (struct plist *)aqp;
	if (aplp->pcp->pl_flags & P_M)
	    continue;
	if (aplp->pcp->pl_cost < 1000)
	    continue;
	for (; dqp != def_list; dqp = dnext) {
	    dnext = dqp->q_forw;
	    dplp = (struct plist *)dqp;
	    if (!(dplp->pcp->pl_flags & P_M))
		continue;

	    if (dplp->plane.pln_range <
		mapdist(x, y, dplp->plane.pln_x, dplp->plane.pln_y)) {
		emp_remque(dqp);
		free((s_char *)dqp);
		continue;
	    }
	    if (mission_pln_equip(dplp, 0, P_F, 0) < 0) {
		emp_remque(dqp);
		free((s_char *)dqp);
		continue;
	    }
	    if (first) {
		first = 0;
		PR(plane_owner, "%s launches SAMs!\n", cname(def_own));
		PR(def_own, "Launching SAMs at %s planes!\n",
		   cname(plane_owner));
		ac_combat_headers(plane_owner, def_own);
	    }
	    ac_dog(aplp, dplp);
	    dqp = dnext;
	    break;
	}
    }
    if (!first) {
	PR(plane_owner, "\n");
	PR(def_own, "\n");
    }
    if (delete_missiles) {
	for (; dqp != def_list; dqp = dnext) {
	    dnext = dqp->q_forw;
	    dplp = (struct plist *)dqp;
	    if (!(dplp->pcp->pl_flags & P_M))
		continue;
	    emp_remque(dqp);
	    free((s_char *)dqp);
	    continue;
	}
    }
}

void
ac_intercept(struct emp_qelem *bomb_list, struct emp_qelem *esc_list,
	     struct emp_qelem *def_list, natid def_own, coord x, coord y)
{
    register struct plnstr *pp;
    struct plist *plp;
    int icount;
    struct emp_qelem *next;
    struct emp_qelem *qp;
    struct emp_qelem int_list;
    int att_count;
    natid plane_owner;
    int dist;

    plp = (struct plist *)bomb_list->q_forw;
    plane_owner = plp->plane.pln_own;

    icount = 0;

    sam_intercept(bomb_list, def_list, def_own, plane_owner, x, y, 0);
    sam_intercept(esc_list, def_list, def_own, plane_owner, x, y, 1);
    if (!(att_count = count_non_missiles(bomb_list) +
	  count_non_missiles(esc_list)))
	return;

    emp_initque(&int_list);
    for (qp = def_list->q_forw; qp != def_list; qp = next) {
	next = qp->q_forw;
	plp = (struct plist *)qp;
	pp = &plp->plane;
	/* SAMs interdict separately */
	if (plp->pcp->pl_flags & P_M)
	    continue;
	dist = mapdist(x, y, pp->pln_x, pp->pln_y) * 2;
	if (pp->pln_range < dist)
	    continue;
	if (mission_pln_equip(plp, 0, P_F, 0) < 0) {
	    emp_remque(qp);
	    free((s_char *)qp);
	    continue;
	}
	/* got one; delete from def_list, add to int_list */
	emp_remque(qp);
	emp_insque(qp, &int_list);
	pp->pln_mobil -= pln_mobcost(dist, pp, P_F);
	putplane(pp->pln_uid, pp);
	icount++;
	if (icount > att_count)
	    break;
    }
    if (icount == 0)
	return;
    PR(plane_owner, "%d %s fighter%s rising to intercept!\n", icount,
       cname(def_own), icount == 1 ? " is" : "s are");
    PR(def_own, "%d fighter%s intercepting %s planes!\n", icount,
       icount == 1 ? " is" : "s are", cname(plane_owner));
    ac_combat_headers(plane_owner, def_own);
    ac_airtoair(esc_list, &int_list, def_own);
    ac_airtoair(bomb_list, &int_list, def_own);
    PR(plane_owner, "\n");
    PR(def_own, "\n");
}

void
ac_combat_headers(natid plane_owner, natid def_own)
{
    PR(plane_owner,
       " %-10.10s %-10.10s  strength int odds  damage           results\n",
       cname(plane_owner), cname(def_own));
    PR(def_own,
       " %-10.10s %-10.10s  strength int odds  damage           results\n",
       cname(def_own), cname(plane_owner));
}

/*
 * air-to-air combat.
 */
void
ac_airtoair(struct emp_qelem *att_list, struct emp_qelem *int_list,
	    natid def_own)
{
    register struct plist *attacker;
    register struct plist *interceptor;
    struct emp_qelem *att;
    struct emp_qelem *in;
    int nplanes;
    int more_att;
    int more_int;
    struct emp_qelem *att_next;
    struct emp_qelem *in_next;
    natid att_own;

    att = att_list->q_forw;
    in = int_list->q_forw;
    more_att = 1;
    more_int = 1;
    if (QEMPTY(att_list) || QEMPTY(int_list)) {
	more_att = 0;
	more_int = 0;
    }
    while (more_att || more_int) {
	in_next = in->q_forw;
	att_next = att->q_forw;
	attacker = (struct plist *)att;

	/* skip missiles. If only missiles left, we're done */
	if (plchr[(int)attacker->plane.pln_type].pl_flags & P_M) {
	    att = att_next;
	    if (att == att_list) {
		more_att = 0;
		if (QEMPTY(att_list))
		    more_int = 0;
		else
		    att = att->q_forw;
	    }
	    if (all_missiles(att_list))
		more_att = 0;
	    continue;
	}
	interceptor = (struct plist *)in;
	att_own = attacker->plane.pln_own;
	def_own = interceptor->plane.pln_own;
	nplanes = attacker->plane.pln_effic;
	if (nplanes > interceptor->plane.pln_effic)
	    nplanes = interceptor->plane.pln_effic;
	ac_dog(attacker, interceptor);
	in = in_next;
	att = att_next;
	if (att == att_list) {
	    more_att = 0;
	    if (QEMPTY(att_list))
		more_int = 0;
	    else
		att = att->q_forw;
	}
	if (in == int_list) {
	    more_int = 0;
	    if (QEMPTY(int_list))
		more_att = 0;
	    else
		in = in->q_forw;
	}
    }
}

int
all_missiles(struct emp_qelem *att_list)
{
    struct emp_qelem *qp;
    struct plist *p;

    qp = att_list->q_forw;
    while (qp != att_list) {
	p = (struct plist *)qp;
	if (!(plchr[(int)p->plane.pln_type].pl_flags & P_M))
	    return 0;

	qp = qp->q_forw;
    }
    return 1;
}

static void
ac_dog(register struct plist *ap, register struct plist *dp)
{
    int att, def;
    double odds;
    int intensity;
    natid att_own, def_own;
    int adam, ddam;
    s_char mesg[1024];
    s_char temp[14];

    att_own = ap->plane.pln_own;
    def_own = dp->plane.pln_own;

    PR(att_own, " %3.3s #%-4d  %3.3s #%-4d",
       ap->pcp->pl_name,
       ap->plane.pln_uid, dp->pcp->pl_name, dp->plane.pln_uid);
    if (def_own)
	PR(def_own, " %3.3s #%-4d  %3.3s #%-4d",
	   dp->pcp->pl_name,
	   dp->plane.pln_uid, ap->pcp->pl_name, ap->plane.pln_uid);
    if (ap->plane.pln_att == 0) {
	att = ap->plane.pln_def * ap->plane.pln_effic / 100;
	att = MAX(att, ap->pcp->pl_def / 2);
    } else {
	att = ap->plane.pln_att * ap->plane.pln_effic / 100;
	att = MAX(att, ap->pcp->pl_att / 2);
    }

    def = dp->plane.pln_def * dp->plane.pln_effic / 100;
    def = MAX(def, dp->pcp->pl_def / 2);

    if ((ap->pcp->pl_flags & P_F) && ap->bombs != 0)
	att -= 2;
    if ((dp->pcp->pl_flags & P_F) && dp->bombs != 0)
	def -= 2;
    att += ((float)ap->pcp->pl_stealth / 25.0);
    def += ((float)dp->pcp->pl_stealth / 25.0);
    if (att < 1) {
	def += 1 - att;
	att = 1;
    }
    if (def < 1) {
	att += 1 - def;
	def = 1;
    }
    odds = ((double)att / ((double)def + (double)att));
    if (odds <= 0.05)
	odds = 0.05;
    intensity = roll(20) + roll(20) + roll(20) + roll(20) + 1;

    PR(att_own, "   %3d/%-3d %3d  %3.2f  ", att, def, intensity, odds);
    PR(def_own, "   %3d/%-3d %3d  %3.2f  ", def, att, intensity, odds);

    adam = 0;
    ddam = 0;
    while ((intensity--) > 0) {

	if (chance(odds)) {
	    ddam += 1;
	    if ((dp->plane.pln_effic - ddam) < PLANE_MINEFF)
		intensity = 0;
	} else {
	    adam += 1;
	    if ((ap->plane.pln_effic - adam) < PLANE_MINEFF)
		intensity = 0;
	}
    }

    if (dp->pcp->pl_flags & P_M)
	ddam = 100;

    PR(att_own, "%3d/%-3d", adam, ddam);
    PR(def_own, "%3d/%-3d", ddam, adam);
    ac_planedamage(ap, dp->plane.pln_own, adam, def_own, 1, 0, mesg);
    strncpy(temp, mesg, 14);
    ac_planedamage(dp, ap->plane.pln_own, ddam, att_own, 1, 0, mesg);
    PR(att_own, "%-13.13s %-13.13s\n", temp, mesg);
    PR(def_own, "%-13.13s %-13.13s\n", mesg, temp);
}

/*
 * zap plane associated with plp.
 * Damaging country is "from", damage is "dam".
 * def_own is the country on the other side of the conflict from the plane
 * owner. The only time def_own != from is when the interceptor is getting
 * damaged.
 *
 * NOTE: This routine removes the appropriate plane element from the
 * queue if it gets destroyed.  That means that the caller must assume
 * that the current queue pointer is invalid on return from the ac_planedamage
 * call.  (this has caused bugs in the past)
 */
void
ac_planedamage(struct plist *plp, natid from, int dam, natid other,
	       int checkabort, int show, s_char *mesg)
{
    register struct plnstr *pp;
    int disp;
    s_char dmess[255];
    int eff;
    struct shpstr ship;
    struct lndstr land;
    /* s_char *sprintf();           already in misc.h [JFW] */
    natid plane_owner;

    disp = 0;
    pp = &plp->plane;
    plane_owner = pp->pln_own;
    eff = pp->pln_effic;
    sprintf(dmess, " no damage");
    if (dam <= 0) {
	strcpy(mesg, dmess);
	return;
    }
    memset(dmess, 0, sizeof(dmess));
    eff -= dam;
    if (eff < 0)
	eff = 0;
    if (eff < PLANE_MINEFF) {
	sprintf(dmess, " shot down");
	disp = 1;
    } else if (eff < 80 && chance((100 - eff) / 100.0) && checkabort) {
	sprintf(dmess, " aborted @%2d%%", eff);
	disp = 2;
    } else if (show == 0) {
	sprintf(dmess, " cleared");
    }

    if ((plp->pcp->pl_flags & P_M) == 0) {
	if (show) {
	    PR(plane_owner, "    %s %s takes %d%s.\n",
	       cname(pp->pln_own), prplane(pp), dam, dmess);
	    if (other)
		PR(other, "    %s %s takes %d%s.\n",
		   cname(pp->pln_own), prplane(pp), dam, dmess);
	}
    }
    if (show && checkabort == 1) {
	PR(plane_owner, "\n");
	if (other)
	    PR(other, "\n");
    }

    pp->pln_effic = eff;
    pp->pln_mobil -= min(32 + pp->pln_mobil, dam / 2);
    if (disp == 1) {
	if (from != 0 && (plp->pcp->pl_flags & P_M) == 0)
	    nreport(from, N_DOWN_PLANE, pp->pln_own, 1);
	if (pp->pln_ship >= 0) {
	    getship(pp->pln_ship, &ship);
	    take_plane_off_ship(pp, &ship);
	}
	if (pp->pln_land >= 0) {
	    getland(pp->pln_land, &land);
	    take_plane_off_land(pp, &land);
	}
	makelost(EF_PLANE, pp->pln_own, pp->pln_uid, pp->pln_x, pp->pln_y);
	pp->pln_own = 0;
	putplane(pp->pln_uid, pp);
	emp_remque(&plp->queue);
	free((s_char *)plp);
    } else if (disp == 2) {
	putplane(pp->pln_uid, pp);
	emp_remque(&plp->queue);
	free((s_char *)plp);
    } else
	putplane(pp->pln_uid, pp);
    strcpy(mesg, dmess);
}

void
ac_doflak(struct emp_qelem *list, struct sctstr *from)
{
    int shell, add;
    int gun;
    natid plane_owner;
    struct plist *plp;

    plp = (struct plist *)list->q_forw;
    plane_owner = plp->plane.pln_own;

    gun = getvar(V_GUN, (s_char *)from, EF_SECTOR);
    shell = getvar(V_SHELL, (s_char *)from, EF_SECTOR);
    add = 0;
    if (shell < (gun / 2))
	add = supply_commod(from->sct_own, from->sct_x, from->sct_y,
			    I_SHELL, ldround(((double)gun / 2.0),
					     1) - shell);
    shell += add;
    if (gun == 0 || shell == 0)
	return;
    if (gun > shell * 2)
	gun = shell * 2;
    if (gun > 14)
	gun = 14;

    putvar(V_SHELL, shell, (s_char *)from, EF_SECTOR);
    putsect(from);
    gun = 2.0 * tfact(from->sct_own, (double)gun);
    if (gun > 0) {
	PR(plane_owner, "firing %d flak guns in %s...\n",
	   gun, xyas(from->sct_x, from->sct_y, plane_owner));
	if (from->sct_own != 0)
	    PR(from->sct_own, "firing %d flak guns in %s...\n",
	       gun, xyas(from->sct_x, from->sct_y, from->sct_own));
	ac_fireflak(list, from->sct_own, 0, gun);
    }
}

void
ac_shipflak(struct emp_qelem *list, coord x, coord y)
{
    struct nstr_item ni;
    struct shpstr ship;
    struct mchrstr *mcp;
    int firing;
    int guns;
    int gun;
    int shell;
    int rel;
    struct plist *plp;
    natid plane_owner;
    natid from;
    int nats[MAXNOC];

    plp = (struct plist *)list->q_forw;
    plane_owner = plp->plane.pln_own;

    memset(nats, 0, sizeof(nats));
    guns = 0;
    snxtitem_xy(&ni, EF_SHIP, x, y);
    while (!QEMPTY(list) && nxtitem(&ni, (s_char *)&ship)) {
	if (ship.shp_own == 0 || ship.shp_own == plane_owner)
	    continue;
	if (guns >= 14)
	    break;
	mcp = &mchr[(int)ship.shp_type];
	if (mcp->m_flags & M_SUB)
	    continue;
	rel = getrel(getnatp(ship.shp_own), plane_owner);
	if (rel > HOSTILE)
	    continue;
	shell = gun = 0;
	gun = min(getvar(V_GUN, (s_char *)&ship, EF_SHIP), ship.shp_glim);
	if (gun) {
	    shell = getvar(V_SHELL, (s_char *)&ship, EF_SHIP);
	    if (shell <= 0)
		shell = supply_commod(ship.shp_own, ship.shp_x,
				      ship.shp_y, I_SHELL, 1);
	}
	if (gun == 0 || shell == 0)
	    continue;
	firing = (int)(techfact(ship.shp_tech, (double)gun) * 2.0);
	guns += firing;

	if (!nats[ship.shp_own]) {
	    /* First time here, print the message */
	    PR(ship.shp_own, "%s planes spotted over ships in %s\n",
	       cname(plane_owner), xyas(x, y, ship.shp_own));
	    PR(plane_owner, "Flying over %s ships in %s\n",
	       cname(ship.shp_own), xyas(x, y, plane_owner));
	    nats[ship.shp_own] = 1;
	}
	PR(ship.shp_own, "firing %d flak guns from %s...\n",
	   firing, prship(&ship));
	putvar(V_SHELL, shell, (s_char *)&ship, EF_SHIP);
	putship(ship.shp_uid, &ship);
	from = ship.shp_own;
    }
    if (guns > 0) {
	if (guns > 14)
	    guns = 14;
	guns = 2.0 * tfact(from, (double)guns);
	PR(plane_owner, "Flak!  Ships firing %d flak guns...\n", guns);
	ac_fireflak(list, from, 0, guns);
    }
}

void
ac_landflak(struct emp_qelem *list, coord x, coord y)
{
    struct nstr_item ni;
    struct lndstr land;
    struct lchrstr *lcp;
    int firing;
    int guns;
    int rel;
    natid from;
    struct plist *plp;
    natid plane_owner;
    int nats[MAXNOC];

    plp = (struct plist *)list->q_forw;
    plane_owner = plp->plane.pln_own;

    memset(nats, 0, sizeof(nats));
    guns = 0;
    snxtitem_xy(&ni, EF_LAND, x, y);
    while (!QEMPTY(list) && nxtitem(&ni, (s_char *)&land)) {
	if (land.lnd_own == 0 || land.lnd_own == plane_owner)
	    continue;
	if (guns >= 14)
	    break;
	lcp = &lchr[(int)land.lnd_type];

	if ((lcp->l_flags & L_FLAK) == 0)
	    continue;

	if (land.lnd_aaf == 0)
	    continue;

	rel = getrel(getnatp(land.lnd_own), plane_owner);
	if (rel > HOSTILE)
	    continue;
	firing =
	    (int)(techfact(land.lnd_tech, (double)land.lnd_aaf) * 3.0);
	guns += firing;

	if (!nats[land.lnd_own]) {
	    /* First time here, print the message */
	    PR(land.lnd_own, "%s planes spotted over land units in %s\n",
	       cname(plane_owner), xyas(x, y, land.lnd_own));
	    PR(plane_owner, "Flying over %s land units in %s\n",
	       cname(land.lnd_own), xyas(x, y, plane_owner));
	    nats[land.lnd_own] = 1;
	}
	PR(land.lnd_own, "firing flak guns from unit %s (aa rating %d)\n",
	   prland(&land), land.lnd_aaf);

	from = land.lnd_own;	/* We always use the last owner as the from */
    }
    if (guns > 0) {
	if (guns > 14)
	    guns = 14;
	guns = 2.0 * tfact(from, (double)guns);
	PR(plane_owner, "Flak!  Land units firing %d flak guns...\n",
	   guns);
	ac_fireflak(list, from, 0, guns);
    }
}

/*
 * Called from shipflak, landflak, and doflak.
 */
void
ac_fireflak(struct emp_qelem *list, natid from, natid other, int guns)
{
    register struct plnstr *pp;
    struct plist *plp;
    int n;
    float mult;
    int diff;
    struct emp_qelem *qp;
    struct emp_qelem *next;
    s_char msg[255];

    plp = (struct plist *)list->q_forw;

    for (qp = list->q_forw; qp != list; qp = next) {
	/*
	 * fighters don't get shot at by flak
	 * non-tactical bombers are harder to hit with flak.
	 * ('Cause they're not dive-bombing?)
	 */
	next = qp->q_forw;
	plp = (struct plist *)qp;
	pp = &plp->plane;
	diff = guns - pp->pln_def;
	if ((plp->pcp->pl_flags & P_T) == 0)
	    diff--;
	if (plp->pcp->pl_flags & P_X)
	    diff -= 2;
	if (plp->pcp->pl_flags & P_H)
	    diff -= 1;
	if (diff > 8)
	    mult = flaktable[FLAK_MAX] * 1.33;
	else if (diff < -7)
	    mult = flaktable[0] * 0.66;
	else {
	    diff += 7;
	    mult = flaktable[diff];
	}
	mult *= flakscale;
	n = (int)((roll(8) + 2) * mult);
	if (n > 100)
	    n = 100;
	ac_planedamage(plp, from, n, other, 2, 1, msg);
    }
}

/*
 * See if this plane is flying in this list
 */
int
ac_isflying(struct plnstr *plane, struct emp_qelem *list)
{
    struct emp_qelem *qp;
    struct emp_qelem *next;
    struct plnstr *pp;
    struct plist *plp;

    if (!list)
	return 0;
    for (qp = list->q_forw; qp != list; qp = next) {
	next = qp->q_forw;
	plp = (struct plist *)qp;
	pp = &plp->plane;
	if (plane->pln_uid == pp->pln_uid)
	    return 1;
    }
    return 0;
}


/*
 * Get a list of planes available for interception duties.
 */
static void
getilist(struct emp_qelem *list, natid own, struct emp_qelem *a,
	 struct emp_qelem *b, struct emp_qelem *c, struct emp_qelem *d)
{
    register struct plchrstr *pcp;
    struct plnstr plane;
    struct shpstr ship;
    struct lndstr land;
    struct sctstr sect;
    struct nstr_item ni;
    int type;
    s_char *ptr;
    struct plist *ip;

    emp_initque(list);
    snxtitem_all(&ni, EF_PLANE);
    while (nxtitem(&ni, (s_char *)&plane)) {
	if (plane.pln_own != own)
	    continue;
	pcp = &plchr[(int)plane.pln_type];
	if ((pcp->pl_flags & P_F) == 0)
	    continue;
	if (plane.pln_mission != 0)
	    continue;
	if (plane.pln_mobil <= 0)
	    continue;
	if (plane.pln_effic < 40)
	    continue;
	if (plane.pln_ship >= 0) {
	    if (!can_fly(plane.pln_uid))
		continue;
	    getship(plane.pln_ship, &ship);
	    ptr = (s_char *)&ship;
	    type = EF_SHIP;
	} else if (plane.pln_land >= 0) {
	    if (!can_fly(plane.pln_uid))
		continue;
	    getland(plane.pln_land, &land);
	    ptr = (s_char *)&land;
	    type = EF_LAND;
	} else {
	    getsect(plane.pln_x, plane.pln_y, &sect);
	    ptr = (s_char *)&sect;
	    type = EF_SECTOR;
#if 0
	    if (sect.sct_effic < 60 && (pcp->pl_flags & P_V) == 0)
		continue;
#else
	    if ((sect.sct_effic < 60 || sect.sct_type != SCT_AIRPT)
		&& (pcp->pl_flags & P_V) == 0)
		continue;
#endif
	}
	if (((float)getvar(V_PETROL, ptr, type)) <
	    (((float)pcp->pl_fuel) / 2.0))
	    continue;
	/* Finally, is it in the list of planes already in
	   flight? */
	if (ac_isflying(&plane, a))
	    continue;
	if (ac_isflying(&plane, b))
	    continue;
	if (ac_isflying(&plane, c))
	    continue;
	if (ac_isflying(&plane, d))
	    continue;
	/* got one! */
	ip = (struct plist *)malloc(sizeof(*ip));
	ip->state = P_OK;
	ip->bombs = 0;
	ip->misc = 0;
	ip->pcp = &plchr[(int)plane.pln_type];
	ip->plane = plane;
	emp_insque(&ip->queue, list);
    }
}



int
can_fly(int p)
{				/* Can this plane fly from the ship or land unit it is on? */
    struct plnstr plane;
    struct shpstr ship;
    struct lndstr land;
    struct plchrstr *pcp;
    struct mchrstr *scp;
    struct lchrstr *lcp;

    getplane(p, &plane);
    pcp = &plchr[(int)plane.pln_type];

    if (plane.pln_ship >= 0) {
	if (!(pcp->pl_flags & P_L) && !(pcp->pl_flags & P_M)
	    && !(pcp->pl_flags & P_K)
	    && !(pcp->pl_flags & P_E)
	    )
	    return 0;

	getship(plane.pln_ship, &ship);
	scp = &mchr[(int)ship.shp_type];

	if ((pcp->pl_flags & P_L) && (scp->m_flags & M_FLY)) {
	    return 1;
	}

	if ((pcp->pl_flags & P_M) && (scp->m_flags & M_MSL)) {
	    return 1;
	}

	if ((pcp->pl_flags & P_K) && (scp->m_flags & M_CHOPPER)) {
	    return 1;
	}

	if ((pcp->pl_flags & P_E) && (scp->m_flags & M_XLIGHT)) {
	    return 1;
	}
    }

    if (plane.pln_land >= 0) {
	if (!(pcp->pl_flags & P_E))
	    return 0;

	getland(plane.pln_land, &land);
	lcp = &lchr[(int)land.lnd_type];

	if ((pcp->pl_flags & P_E) && (lcp->l_flags & L_XLIGHT)) {
	    return 1;
	}
    }

    return 0;
}

int
do_evade(struct emp_qelem *bomb_list, struct emp_qelem *esc_list)
{
    struct emp_qelem *qp;
    double evade;
    struct plist *plp;

    evade = 100.0;
    for (qp = bomb_list->q_forw; qp != bomb_list; qp = qp->q_forw) {
	plp = (struct plist *)qp;
	if (evade > ((float)plp->pcp->pl_stealth / 100.0))
	    evade = (plp->pcp->pl_stealth / 100.0);
    }
    for (qp = esc_list->q_forw; qp != esc_list; qp = qp->q_forw) {
	plp = (struct plist *)qp;
	if (evade > plp->pcp->pl_stealth / 100.0)
	    evade = (plp->pcp->pl_stealth / 100.0);
    }

    if (chance(evade))
	return 1;

    return 0;
}