src/lib/subs/mission.c

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/*
 *  Empire - A multi-player, client/server Internet based war game.
 *  Copyright (C) 1986-2007, 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 files README, COPYING and CREDITS in the root of the source
 *  tree for related information and legal notices.  It is expected
 *  that future projects/authors will amend these files as needed.
 *
 *  ---
 *
 *  mission.c: Mission subroutines for planes/ships/units
 * 
 *  Known contributors to this file:
 *     Ken Stevens, 1995
 *     Steve McClure, 1996-2000
 */

#include <config.h>

#include <stdlib.h>
#include "damage.h"
#include "empobj.h"
#include "file.h"
#include "item.h"
#include "misc.h"
#include "mission.h"
#include "nsc.h"
#include "optlist.h"
#include "path.h"
#include "player.h"
#include "prototypes.h"
#include "queue.h"
#include "xy.h"

struct genlist {
    struct emp_qelem queue;     /* list of units */
    void *cp;                   /* pointer to desc of thing */
    struct empobj *thing;       /* thing's struct */
};

struct airport {
    struct emp_qelem queue;
    coord x, y;
    natid own;
};

static void add_airport(struct emp_qelem *, coord, coord);
static int air_damage(struct emp_qelem *, coord, coord, int, natid,
                      char *, int);
static void build_mission_list(struct genlist *, coord, coord, int, natid);
static void build_mission_list_type(struct genlist *, coord, coord, int,
                                    int, natid);
static void divide(struct emp_qelem *, struct emp_qelem *, coord, coord);
static int dosupport(struct genlist *, coord, coord, natid, natid);
static int find_airport(struct emp_qelem *, coord, coord);
static int mission_pln_arm(struct emp_qelem *, coord, coord, int,
                           int, struct ichrstr *, int, int, int *);
static void mission_pln_sel(struct emp_qelem *, int, int, int);
static int perform_mission(coord, coord, natid, struct emp_qelem *, int,
                           char *, int);

/*
 * Interdict commodities & transported planes
 */
int
ground_interdict(coord x, coord y, natid victim, char *s)
{
    int cn;
    int dam = 0, newdam, rel;
    struct genlist mi[MAXNOC];
    int z;

    memset(mi, 0, sizeof(mi));
    for (z = 1; z < MAXNOC; z++)
        emp_initque((struct emp_qelem *)&mi[z]);

    build_mission_list(mi, x, y, MI_INTERDICT, victim);

    for (cn = 1; cn < MAXNOC; cn++) {
        rel = getrel(getnatp(cn), victim);
        if (rel > HOSTILE)
            continue;

        if (QEMPTY(&mi[cn].queue))
            continue;

        newdam = perform_mission(x, y, victim, &mi[cn].queue,
                                 MI_INTERDICT, s, SECT_HARDTARGET);
        dam += newdam;
        if (newdam)
            mpr(victim, "%s interdiction mission does %d damage!\n",
                cname(cn), newdam);
    }
    if (dam) {
        collateral_damage(x, y, dam, 0);
    }
    return dam;
}

int
collateral_damage(coord x, coord y, int dam, struct emp_qelem *list)
{
    int coll;
    struct sctstr sect;

    if (!dam)
        return 0;

    getsect(x, y, &sect);
    if (sect.sct_own) {
        coll = ldround((double)dam * collateral_dam, 1);
        if (coll == 0)
            return 0;
        mpr(sect.sct_own, "%s takes %d%% collateral damage\n",
            xyas(x, y, sect.sct_own), coll);
        sectdamage(&sect, coll, list);
        putsect(&sect);
        return coll;
    }
    return 0;
}

static int
only_subs(struct emp_qelem *list)
{
    struct emp_qelem *qp;
    struct genlist *glp;
    struct mchrstr *mcp;

    for (qp = list->q_forw; qp != list; qp = qp->q_forw) {
        glp = (struct genlist *)qp;

        if (glp->thing->ef_type != EF_SHIP)
            return 0;
        mcp = glp->cp;
        if (!(mcp->m_flags & M_SUB))
            return 0;
        /* It's a sub! */
    }
    /* They were all subs! */
    return 1;
}


/*
 *  Interdict ships & land units
 */
int
unit_interdict(coord x, coord y, natid victim, char *s, int hardtarget,
               int mission)
{
    int cn;
    int dam = 0, newdam;
    struct genlist mi[MAXNOC];
    int z;
    int osubs;

    memset(mi, 0, sizeof(mi));
    for (z = 1; z < MAXNOC; z++)
        emp_initque((struct emp_qelem *)&mi[z]);

    build_mission_list(mi, x, y, mission, victim);

    for (cn = 1; cn < MAXNOC; cn++) {
        if (cn == victim)
            continue;
        if (mission == MI_SINTERDICT) {
            if (getrel(getnatp(cn), victim) >= FRIENDLY)
                continue;
        } else if (getrel(getnatp(cn), victim) > HOSTILE)
            continue;

        if (QEMPTY(&mi[cn].queue))
            continue;

        osubs = only_subs(&mi[cn].queue);
        newdam = perform_mission(x, y, victim, &mi[cn].queue,
                                 mission, s, hardtarget);
        dam += newdam;
        if (newdam) {
            /* If only subs responded, then we don't know who's
               subs they are */
            mpr(victim, "%s interdiction mission does %d damage!\n",
                osubs ? "Enemy" : cname(cn), newdam);
        }
    }
    if (dam) {
        collateral_damage(x, y, dam, 0);
    }
    return dam;
}

/*
 *  Perform a mission against victim, on behalf of actee
 */
int
off_support(coord x, coord y, natid victim, natid actee)
{
    int dam = 0;
    struct genlist mi[MAXNOC];
    int z;

    memset(mi, 0, sizeof(mi));
    for (z = 1; z < MAXNOC; z++)
        emp_initque((struct emp_qelem *)&mi[z]);

    build_mission_list(mi, x, y, MI_SUPPORT, victim);
    build_mission_list(mi, x, y, MI_OSUPPORT, victim);

    dam = dosupport(mi, x, y, victim, actee);
    return dam;
}

/*
 *  Perform a mission against victim, on behalf of actee
 */
int
def_support(coord x, coord y, natid victim, natid actee)
{
    int dam = 0;
    struct genlist mi[MAXNOC];
    int z;

    memset(mi, 0, sizeof(mi));
    for (z = 1; z < MAXNOC; z++)
        emp_initque((struct emp_qelem *)&mi[z]);

    build_mission_list(mi, x, y, MI_SUPPORT, victim);
    build_mission_list(mi, x, y, MI_DSUPPORT, victim);

    dam = dosupport(mi, x, y, victim, actee);
    return dam;
}

static int
dosupport(struct genlist *mi, coord x, coord y, natid victim, natid actee)
{
    int cn;
    int rel;
    int dam = 0;

    for (cn = 1; cn < MAXNOC; cn++) {
        rel = getrel(getnatp(cn), actee);
        if ((cn != actee) && (rel != ALLIED))
            continue;
        rel = getrel(getnatp(cn), victim);
        if ((cn != actee) && (rel != AT_WAR))
            continue;

        if (QEMPTY(&mi[cn].queue))
            continue;

        dam += perform_mission(x, y, victim, &mi[cn].queue, MI_SUPPORT,
                               "", SECT_HARDTARGET);
    }
    return dam;
}

static void
build_mission_list(struct genlist *mi, coord x, coord y, int mission,
                   natid victim)
{
    build_mission_list_type(mi, x, y, mission, EF_LAND, victim);
    build_mission_list_type(mi, x, y, mission, EF_SHIP, victim);
    build_mission_list_type(mi, x, y, mission, EF_PLANE, victim);
}

static void
build_mission_list_type(struct genlist *mi, coord x, coord y, int mission,
                        int type, natid victim)
{
    struct nstr_item ni;
    struct genlist *glp;
    struct empobj *gp;
    union empobj_storage item;
    int dist;
    int radius;
    int relat;
    struct sctstr sect;

    snxtitem_all(&ni, type);
    while (nxtitem(&ni, &item)) {
        gp = (struct empobj *)&item;

        if (gp->own == 0)
            continue;

        if (gp->mobil < 1)
            continue;

        if ((gp->mission != mission) && (mission != MI_SINTERDICT))
            continue;

        if ((gp->mission != mission) && (mission == MI_SINTERDICT) &&
            (gp->mission != MI_INTERDICT))
            continue;

        relat = getrel(getnatp(gp->own), victim);
        if (mission == MI_SINTERDICT) {
            if (relat >= FRIENDLY)
                continue;
            else if (type != EF_PLANE && relat > HOSTILE)
                continue;
        } else if (relat > HOSTILE)
            continue;

        dist = mapdist(x, y, gp->opx, gp->opy);

        radius = gp->radius;
        if (mission != MI_RESERVE)      /* XXX */
            oprange(gp, &radius);

        if (dist > radius)
            continue;

        /* Ok, it is within the operations range. */
        /* Now check from where the object actually is */
        dist = mapdist(x, y, gp->x, gp->y);
        radius = 999;
        oprange(gp, &radius);
        if (dist > radius)
            continue;
        /* Ok, the object can get to where the x,y is */

        if (opt_SLOW_WAR) {
            if (mission != MI_AIR_DEFENSE) {
                getsect(x, y, &sect);
                if (getrel(getnatp(gp->own), sect.sct_own) > AT_WAR) {

                    /*
                     * If the player->owner of the unit isn't at war
                     * with the victim, and doesn't own the
                     * sect being acted upon, and isn't the
                     * old player->owner of that sect, bounce them.
                     */
                    if (sect.sct_type != SCT_WATER &&
                        sect.sct_own != gp->own &&
                        sect.sct_oldown != gp->own)
                        continue;
                }
            }
        }

        glp = malloc(sizeof(struct genlist));
        memset(glp, 0, sizeof(struct genlist));
        glp->cp = get_empobj_chr(gp);
        glp->thing = malloc(sizeof(item));
        memcpy(glp->thing, &item, sizeof(item));
        emp_insque(&glp->queue, &mi[gp->own].queue);
    }
}

static void
find_escorts(coord x, coord y, natid cn, struct emp_qelem *escorts)
{
    struct nstr_item ni;
    struct plist *plp;
    struct plnstr plane;
    int dist;

    snxtitem_all(&ni, EF_PLANE);
    while (nxtitem(&ni, &plane)) {
        if (plane.pln_own != cn)
            continue;

        if (plane.pln_mission != MI_ESCORT)
            continue;

        dist = mapdist(x, y, plane.pln_x, plane.pln_y);
        if (dist > plane.pln_range / 2)
            continue;

        plp = malloc(sizeof(struct plist));
        memset(plp, 0, sizeof(struct plist));
        plp->pcp = &plchr[(int)plane.pln_type];
        plp->plane = plane;
        emp_insque(&plp->queue, escorts);
    }
}

static int
perform_mission(coord x, coord y, natid victim, struct emp_qelem *list,
                int mission, char *s, int hardtarget)
{
    struct emp_qelem *qp, missiles, bombers, escorts, airp, b, e;
    struct emp_qelem *newqp;
    struct genlist *glp;
    struct plist *plp;
    struct empobj *gp;
    struct lndstr *lp;
    struct shpstr *sp;
    struct sctstr sect;
    struct mchrstr *mcp;
    struct plchrstr *pcp;
    int dam = 0, dam2, mission_flags, tech;
    natid plane_owner = 0;
    int gun, shell, md, range, air_dam = 0;
    double prb, hitchance, vrange;

    getsect(x, y, &sect);

    emp_initque(&missiles);
    emp_initque(&bombers);
    emp_initque(&escorts);
    emp_initque(&airp);

    for (qp = list->q_forw; qp != list; qp = qp->q_forw) {
        glp = (struct genlist *)qp;
        gp = glp->thing;

        md = mapdist(x, y, gp->x, gp->y);

        if (glp->thing->ef_type == EF_LAND) {
            lp = (struct lndstr *)glp->thing;

            if (lp->lnd_effic < LAND_MINFIREEFF)
                continue;

            if (mission == MI_SINTERDICT)
                continue;

            if ((mission == MI_INTERDICT) &&
                (md > land_max_interdiction_range))
                continue;

            if ((lp->lnd_ship != -1) || (lp->lnd_land != -1))
                continue;

            if (lp->lnd_item[I_MILIT] < 1)
                continue;

            range = roundrange(effrange(lp->lnd_frg, lp->lnd_tech));
            if (md > range)
                continue;

            shell = lp->lnd_item[I_SHELL];
            gun = lp->lnd_item[I_GUN];
            if (shell == 0 || gun == 0)
                continue;

            if (has_supply(lp)) {
                use_supply(lp);
                putland(lp->lnd_uid, lp);
                dam2 = ldround(landunitgun(lp->lnd_effic, lp->lnd_dam, gun,
                                           lp->lnd_ammo, shell), 1);
                if (sect.sct_type == SCT_WATER) {
                    if (chance(lp->lnd_acc / 100.0))
                        dam2 = ldround(dam2 / 2.0, 1);
                }
                dam += dam2;
                if (sect.sct_type == SCT_WATER)
                    nreport(lp->lnd_own, N_SHP_SHELL, victim, 1);
                else
                    nreport(lp->lnd_own, N_SCT_SHELL, victim, 1);
                wu(0, lp->lnd_own,
                   "%s fires at %s %s at %s\n",
                   prland(lp), cname(victim), s, xyas(x, y, lp->lnd_own));

                mpr(victim, "%s %s fires at you at %s\n",
                    cname(lp->lnd_own), prland(lp), xyas(x, y, victim));
            }
        } else if (glp->thing->ef_type == EF_SHIP) {
            sp = (struct shpstr *)glp->thing;
            mcp = glp->cp;

            if (sp->shp_effic < 60)
                continue;
            if (sp->shp_frnge == 0)
                continue;
            if (((mission == MI_INTERDICT) ||
                 (mission == MI_SINTERDICT)) &&
                (md > ship_max_interdiction_range))
                continue;
            if (sp->shp_item[I_MILIT] < 1)
                continue;
/*
  if ((mcp->m_flags & M_SUB) &&
  (sect.sct_type != SCT_WATER))
  continue;
*/
            if (mission == MI_SINTERDICT) {
                if (!(mcp->m_flags & M_SONAR))
                    continue;
                if (!(mcp->m_flags & M_DCH) && !(mcp->m_flags & M_SUBT))
                    continue;
                vrange = techfact(sp->shp_tech, mcp->m_vrnge);
                vrange *= sp->shp_effic / 200.0;
                if (md > vrange)
                    continue;
                /* can't look all the time */
                if (chance(0.5))
                    continue;
            }
            if (mcp->m_flags & M_SUB) {
/* If we aren't shooting at "subs" or "ships" don't fire at all from
   a sub. */
                if (*s != 's')
                    continue;
                if (sp->shp_mobil < 0)
                    continue;
                gun = sp->shp_item[I_GUN];
                if (gun < 1)
                    continue;
                shell = sp->shp_item[I_SHELL];
                if (shell < SHP_TORP_SHELLS)
                    shell += supply_commod(sp->shp_own,
                                           sp->shp_x, sp->shp_y, I_SHELL,
                                           SHP_TORP_SHELLS - shell);
                if (shell < SHP_TORP_SHELLS)
                    continue;

                range = roundrange(torprange(sp));
                if (md > range)
                    continue;

                if (!line_of_sight(NULL, x, y, gp->x, gp->y))
                    continue;
                sp->shp_item[I_SHELL] = shell - SHP_TORP_SHELLS;
                sp->shp_mobil -= shp_mobcost(sp) / 2.0;
                putship(sp->shp_uid, sp);
                hitchance = DTORP_HITCHANCE(md, sp->shp_visib);

                wu(0, sp->shp_own,
                   "%s locking on %s %s in %s\n",
                   prship(sp), cname(victim), s, xyas(x, y, sp->shp_own));
                wu(0, sp->shp_own,
                   "\tEffective torpedo range is %d.0\n", range);
                wu(0, sp->shp_own,
                   "\tWhooosh... Hitchance = %d%%\n",
                   (int)(hitchance * 100));

                if (hitchance < 1.0 && !chance(hitchance)) {
                    wu(0, sp->shp_own, "\tMissed\n");
                    mpr(victim,
                        "Incoming torpedo sighted @ %s missed (whew)!\n",
                        xyas(x, y, victim));
                    continue;
                }
                wu(0, sp->shp_own, "\tBOOM!...\n");
                dam2 = TORP_DAMAGE();

                dam += dam2;
                nreport(victim, N_TORP_SHIP, 0, 1);
                wu(0, sp->shp_own,
                   "\tTorpedo hit %s %s for %d damage\n",
                   cname(victim), s, dam2);

                mpr(victim,
                    "Incoming torpedo sighted @ %s hits and does %d damage!\n",
                    xyas(x, y, victim), dam2);
            } else {
                range = roundrange(effrange(sp->shp_frnge, sp->shp_tech));
                if (md > range)
                    continue;
                gun = sp->shp_item[I_GUN];
                gun = MIN(gun, sp->shp_glim);
                shell = sp->shp_item[I_SHELL];
                if (shell < gun)
                    shell += supply_commod(sp->shp_own,
                                           sp->shp_x, sp->shp_y, I_SHELL,
                                           gun - shell);
                gun = MIN(gun, shell);
                gun = MIN(gun, sp->shp_item[I_MILIT] / 2.0);
                if (gun == 0)
                    continue;
                gun = MAX(gun, 1);
                dam2 = seagun(sp->shp_effic, gun);
                if (range == 0.0)
                    prb = 1.0;
                else
                    prb = (double)md / range;
                prb *= prb;
                if (chance(prb))
                    dam2 /= 2;
                dam += dam2;
                if (sect.sct_type == SCT_WATER)
                    nreport(sp->shp_own, N_SHP_SHELL, victim, 1);
                else
                    nreport(sp->shp_own, N_SCT_SHELL, victim, 1);
                wu(0, sp->shp_own,
                   "%s fires at %s %s at %s\n",
                   prship(sp), cname(victim), s, xyas(x, y, sp->shp_own));

                mpr(victim, "%s %s fires at you at %s\n",
                    cname(sp->shp_own), prship(sp), xyas(x, y, victim));

                sp->shp_item[I_SHELL] = shell - gun;
                putship(sp->shp_uid, sp);
            }
        } else if (glp->thing->ef_type == EF_PLANE) {
            pcp = glp->cp;
            if (pcp->pl_flags & P_M)
                /* units have their own missile interdiction */
                if (hardtarget != SECT_HARDTARGET || pcp->pl_flags & P_MAR)
                    continue;

            /* save planes for later */
            plp = malloc(sizeof(struct plist));

            memset(plp, 0, sizeof(struct plist));
            plp->pcp = pcp;
            memcpy(&plp->plane, glp->thing, sizeof(struct plnstr));
            if (plp->pcp->pl_flags & P_M)
                emp_insque(&plp->queue, &missiles);
            else
                emp_insque(&plp->queue, &bombers);
            plane_owner = plp->plane.pln_own;
        }
    }
    if (!QEMPTY(&missiles)) {
        /* I arbitrarily chose 100 mindam -KHS */
        dam +=
            msl_launch_mindam(&missiles, x, y, hardtarget, EF_SECTOR, 100,
                              "sector", victim, mission);
        qp = missiles.q_forw;
        while (qp != (&missiles)) {
            newqp = qp->q_forw;
            emp_remque(qp);
            free(qp);
            qp = newqp;
        }
    }

    if (QEMPTY(&bombers)) {
        qp = list->q_forw;
        while (qp != list) {
            glp = (struct genlist *)qp;
            qp = qp->q_forw;

            free(glp->thing);
            free(glp);
        }
        return dam;
    }
    /*
     * If there are planes performing an
     * interdict or support mission, find
     * some escorts for them, if possible.
     * Up to 2 per bomber, if possible.
     */
    find_escorts(x, y, plane_owner, &escorts);

    if (mission == MI_SINTERDICT)
        mission_pln_sel(&bombers, P_T | P_A, 0, hardtarget);
    else
        mission_pln_sel(&bombers, P_T, P_A, SECT_HARDTARGET);

    mission_pln_sel(&escorts, P_ESC | P_F, 0, SECT_HARDTARGET);

    for (qp = bombers.q_forw; qp != (&bombers); qp = qp->q_forw) {
        plp = (struct plist *)qp;
        if (!find_airport(&airp, plp->plane.pln_x, plp->plane.pln_y))
            add_airport(&airp, plp->plane.pln_x, plp->plane.pln_y);
    }

    for (qp = airp.q_forw; qp != (&airp); qp = qp->q_forw) {
        struct airport *air;
        char buf[512];
        char *pp;

        air = (struct airport *)qp;
        md = mapdist(x, y, air->x, air->y);

        emp_initque(&b);
        emp_initque(&e);

        /* Split off the bombers at this base into b */
        divide(&bombers, &b, air->x, air->y);

        /* Split off the escorts at this base into e */
        divide(&escorts, &e, air->x, air->y);

        tech = 0;
        mission_flags = 0;
        mission_flags |= P_X;   /* stealth (shhh) */
        mission_flags |= P_H;   /* gets turned off if not all choppers */

        mission_flags = mission_pln_arm(&b, air->x, air->y, 2 * md, 'p', 0,
                                        0, mission_flags, &tech);

        if (QEMPTY(&b))
            continue;

        mission_flags = mission_pln_arm(&e, air->x, air->y, 2 * md, 'p', 0,
                                        P_F | P_ESC, mission_flags, &tech);

        pp = BestAirPath(buf, air->x, air->y, x, y);
        if (CANT_HAPPEN(!pp))
            continue;
        wu(0, plane_owner, "Flying %s mission from %s\n",
           mission_name(mission), xyas(air->x, air->y, plane_owner));
        if (air->own && (air->own != plane_owner)) {
            wu(0, air->own, "%s is flying %s mission from %s\n",
               cname(plane_owner), mission_name(mission),
               xyas(air->x, air->y, air->own));
        }

        ac_encounter(&b, &e, air->x, air->y, pp, mission_flags, 0, 0, 0);

        if (!QEMPTY(&b))
            air_dam +=
                air_damage(&b, x, y, mission, victim, s, hardtarget);

        pln_put(&b);
        pln_put(&e);
    }

    if (air_dam > 0) {
        dam += air_dam;
        if (sect.sct_type == SCT_WATER)
            nreport(plane_owner, N_SHP_BOMB, victim, 1);
        else
            nreport(plane_owner, N_SCT_BOMB, victim, 1);
    }

    /* free up all this memory */
    qp = list->q_forw;
    while (qp != list) {
        glp = (struct genlist *)qp;
        qp = qp->q_forw;

        free(glp->thing);
        free(glp);
    }

    qp = escorts.q_forw;
    while (qp != (&escorts)) {
        newqp = qp->q_forw;
        emp_remque(qp);
        free(qp);
        qp = newqp;
    }

    qp = bombers.q_forw;
    while (qp != (&bombers)) {
        newqp = qp->q_forw;
        emp_remque(qp);
        free(qp);
        qp = newqp;
    }

    return dam;
}

int
cando(int mission, int type)
{
    switch (mission) {
    case MI_ESCORT:
        if (type == EF_PLANE)
            return 1;
        return 0;
    case MI_AIR_DEFENSE:
        if (type == EF_PLANE)
            return 1;
        return 0;
    case MI_SINTERDICT:
        if ((type == EF_PLANE) || (type == EF_SHIP))
            return 1;
        return 0;
    case MI_INTERDICT:
        return 1;
    case MI_SUPPORT:
    case MI_OSUPPORT:
    case MI_DSUPPORT:
        if (type == EF_PLANE)
            return 1;
        return 0;
    case MI_RESERVE:
        if (type == EF_LAND)
            return 1;
        return 0;
    }

    return 0;
}

char *
mission_name(short mission)
{
    switch (mission) {
    case MI_INTERDICT:
        return "an interdiction";
    case MI_SUPPORT:
        return "a support";
    case MI_OSUPPORT:
        return "a offensive support";
    case MI_DSUPPORT:
        return "a defensive support";
    case MI_RESERVE:
        return "a reserve";
    case MI_ESCORT:
        return "an escort";
    case MI_SINTERDICT:
        return "a sub interdiction";
    case MI_AIR_DEFENSE:
        return "an air defense";
    }
    return "a mysterious";
}

void
show_mission(int type, struct nstr_item *np)
{
    int first = 1, radius;
    union empobj_storage item;
    struct empobj *gp;

    while (nxtitem(np, &item)) {
        gp = (struct empobj *)&item;
        if (!player->owner || gp->own == 0)
            continue;

        if (first) {
            pr("Thing                         x,y   op-sect rad mission\n");
            first = 0;
        }
        pr("%-25s", obj_nameof(gp));
        prxy(" %3d,%-3d", gp->x, gp->y, player->cnum);
        if (gp->mission == MI_INTERDICT || gp->mission == MI_SUPPORT ||
            gp->mission == MI_OSUPPORT ||
            gp->mission == MI_DSUPPORT || gp->mission == MI_AIR_DEFENSE) {
            radius = 999;
            oprange(gp, &radius);
            prxy(" %3d,%-3d", gp->opx, gp->opy, player->cnum);
            if (radius < gp->radius)
                pr("  %4d", radius);
            else
                pr("  %4d", gp->radius);
        } else if (gp->mission == MI_RESERVE) {
            struct sctstr sect;
            int plus = 2;

            getsect(gp->x, gp->y, &sect);
            if ((sect.sct_type == SCT_HEADQ) && (sect.sct_effic >= 60))
                plus++;

            if (item.land.lnd_rad_max == 0)
                plus = 0;
            else
                plus += item.land.lnd_rad_max;
            prxy(" %3d,%-3d", gp->x, gp->y, player->cnum);
            pr("  %4d", plus);
        } else if (gp->mission == MI_ESCORT) {
            pr("        ");
            pr("  %4d", item.plane.pln_range / 2);
        } else
            pr("              ");
        if (gp->mission)
            pr(" is on %s mission\n", mission_name(gp->mission));
        else
            pr(" has no mission.\n");
    }
}

int
oprange(struct empobj *gp, int *radius)
{
    int range;

    switch (gp->ef_type) {
    case EF_SHIP:
        range = ldround(effrange(((struct shpstr *)gp)->shp_frnge,
                                 ((struct shpstr *)gp)->shp_tech), 1);
        break;
    case EF_LAND:
        range = ldround(effrange(((struct lndstr *)gp)->lnd_frg,
                                 ((struct lndstr *)gp)->lnd_tech), 1);
        break;
    case EF_PLANE:
        /* missiles go one way, so we can use all the range */
        if (plchr[(int)gp->type].pl_flags & P_M)
            range = ((struct plnstr *)gp)->pln_range;
        else
            range = ((struct plnstr *)gp)->pln_range / 2;
        break;
    default:
        CANT_HAPPEN("bad TYPE");
        range = -1;
    }

    if (*radius > range)
        *radius = range;

    return range;
}

/*
 *  Remove all planes who cannot go on
 *  the mission from the plane list.
 */
static void
mission_pln_sel(struct emp_qelem *list, int wantflags, int nowantflags,
                int hardtarget)
{
    struct emp_qelem *qp, *next;
    struct plnstr *pp;
    struct plchrstr *pcp;
    struct plist *plp;
    int y, bad, bad1;
    unsigned x;

    for (qp = list->q_forw; qp != list; qp = next) {
        next = qp->q_forw;
        plp = (struct plist *)qp;
        pp = &plp->plane;
        pcp = plp->pcp;

        if (pp->pln_effic < 40) {
            emp_remque(qp);
            free(qp);
            continue;
        }

        if (pp->pln_mobil < 1) {
            emp_remque(qp);
            free(qp);
            continue;
        }

        if (opt_MARKET) {
            if (ontradingblock(EF_PLANE, pp)) {
                emp_remque(qp);
                free(qp);
                continue;
            }
        }

        if (!pln_capable(pp, wantflags, nowantflags)) {
            emp_remque(qp);
            free(qp);
            continue;
        }

        if (!pln_airbase_ok(pp, 0, 0)) {
            emp_remque(qp);
            free(qp);
            continue;
        }
            
        if (pcp->pl_flags & P_A) {
            if (roll(100) > pln_identchance(pp, hardtarget, EF_SHIP)) {
                emp_remque(qp);
                free(qp);
                continue;
            }
        }

        putplane(pp->pln_uid, pp);
    }
}

/*
 * Arm only the planes at x,y
 */
static int
mission_pln_arm(struct emp_qelem *list, coord x, coord y, int dist,
                int mission, struct ichrstr *ip, int flags,
                int mission_flags, int *tech)
{
    struct emp_qelem *qp;
    struct emp_qelem *next;
    struct plist *plp;

    if (*tech == 0)
        *tech = 9999;
    for (qp = list->q_forw; qp != list; qp = next) {
        next = qp->q_forw;
        plp = (struct plist *)qp;

        if (plp->plane.pln_x != x)
            continue;
        if (plp->plane.pln_y != y)
            continue;

        if (mission_pln_equip(plp, ip, flags, mission) < 0) {
            emp_remque(qp);
            free(qp);
            continue;
        }
        if (flags & (P_S | P_I)) {
            if (plp->pcp->pl_flags & P_S)
                mission_flags |= P_S;
            if (plp->pcp->pl_flags & P_I)
                mission_flags |= P_I;
        }
        if (*tech > plp->plane.pln_tech)
            *tech = plp->plane.pln_tech;
        if (!(plp->pcp->pl_flags & P_H))
            /* no stealth on this mission */
            mission_flags &= ~P_H;
        if (!(plp->pcp->pl_flags & P_X))
            /* no stealth on this mission */
            mission_flags &= ~P_X;
        if (!(plp->pcp->pl_flags & P_A)) {
            /* no asw on this mission */
            mission_flags &= ~P_A;
        }
        if (!(plp->pcp->pl_flags & P_MINE)) {
            /* no asw on this mission */
            mission_flags &= ~P_MINE;
        }

        /*
         *      Mob costs for missions are 1/2 normal
         *       Not anymore. :)
         */
/*      plp->plane.pln_mobil -= pln_mobcost(dist,&plp->plane,flags)/2;*/
        plp->plane.pln_mobil -= pln_mobcost(dist, &plp->plane, flags);

    }
    return mission_flags;
}

int
mission_pln_equip(struct plist *plp, struct ichrstr *ip, int flags,
                  char mission)
{
    struct plchrstr *pcp;
    struct plnstr *pp;
    int needed;
    struct lndstr land;
    struct shpstr ship;
    struct sctstr sect;
    i_type itype;
    int rval;
    short *item;

    pp = &plp->plane;
    pcp = plp->pcp;
    if (pp->pln_ship >= 0) {
        getship(pp->pln_ship, &ship);
        item = ship.shp_item;
    } else if (pp->pln_land >= 0) {
        getland(pp->pln_land, &land);
        item = land.lnd_item;
    } else {
        getsect(pp->pln_x, pp->pln_y, &sect);
        item = sect.sct_item;
    }
    if (pcp->pl_fuel > item[I_PETROL]) {
        return -1;
    }
    item[I_PETROL] -= pcp->pl_fuel;
    rval = 0;
    if (!(flags & P_F)) {
        itype = I_NONE;
        needed = 0;
        switch (mission) {
        case 's':
        case 'p':
            if (pp->pln_nuketype == -1) {
                itype = I_SHELL;
                needed = pp->pln_load;
            }
            break;
        case 't':
            if ((pcp->pl_flags & P_C) == 0 || ip == 0)
                break;
            itype = ip->i_uid;
            needed = (pp->pln_load * 2) / ip->i_lbs;
            break;
        case 'd':
            if ((pcp->pl_flags & P_C) == 0 || ip == 0)
                break;
            itype = ip->i_uid;
            needed = (pp->pln_load * 2) / ip->i_lbs;
            break;
        case 'a':
            if ((pcp->pl_flags & (P_V | P_C)) == 0)
                break;
            itype = I_MILIT;
            needed = pp->pln_load / ip->i_lbs;
            break;
        case 'n':
            if (pp->pln_nuketype == -1)
                rval = -1;
            break;
        case 'i':               /* missile interception */
            if (pp->pln_load) {
                itype = I_SHELL;
                needed = pp->pln_load;
            }
            break;
        default:
            break;
        }
        if (rval < 0 || (itype != I_NONE && needed <= 0)) {
            return -1;
        }
        if (itype != I_NONE) {
            if (itype == I_SHELL && item[itype] < needed)
                item[itype] += supply_commod(plp->plane.pln_own,
                                             plp->plane.pln_x,
                                             plp->plane.pln_y,
                                             I_SHELL, needed);
            if (item[itype] < needed)
                return -1;
            item[itype] -= needed;
        }
        if (itype == I_SHELL && (mission == 's' || mission == 'p'))
            plp->bombs = needed;
        else
            plp->misc = needed;
    }
    if (pp->pln_ship >= 0)
        putship(ship.shp_uid, &ship);
    else if (pp->pln_land >= 0)
        putland(land.lnd_uid, &land);
    else
        putsect(&sect);
    return rval;
}

/*
 *  Return 1 if this x,y pair is in the list
 */
static int
find_airport(struct emp_qelem *airp, coord x, coord y)
{
    struct emp_qelem *qp;
    struct airport *a;

    for (qp = airp->q_forw; qp != airp; qp = qp->q_forw) {
        a = (struct airport *)qp;
        if ((a->x == x) && (a->y == y))
            return 1;
    }

    return 0;
}

/* #*# This needs to be changed to include acc's -KHS */
static void
add_airport(struct emp_qelem *airp, coord x, coord y)
{
    struct airport *a;
    struct sctstr sect;

    a = malloc(sizeof(struct airport));

    a->x = x;
    a->y = y;
    getsect(x, y, &sect);
    a->own = sect.sct_own;

    emp_insque((struct emp_qelem *)a, airp);
}

/*
 *  Take all the planes in list 1 that
 *  are at x,y, and put them into list 2.
 */
static void
divide(struct emp_qelem *l1, struct emp_qelem *l2, coord x, coord y)
{
    struct emp_qelem *qp, *next;
    struct plist *plp;

    for (qp = l1->q_forw; qp != l1; qp = next) {
        next = qp->q_forw;
        plp = (struct plist *)qp;

        if (plp->plane.pln_x != x)
            continue;
        if (plp->plane.pln_y != y)
            continue;

        emp_remque(qp);
        emp_insque(qp, l2);
    }
}

static int
air_damage(struct emp_qelem *bombers, coord x, coord y, int mission,
           natid victim, char *s, int hardtarget)
{
    struct emp_qelem *qp;
    struct plist *plp;
    struct plnstr *pp;
    int newdam, dam = 0;
    int hitchance;
    int nukedam;

    for (qp = bombers->q_forw; qp != bombers; qp = qp->q_forw) {
        plp = (struct plist *)qp;
        pp = &plp->plane;

        if ((mission == MI_SINTERDICT) && !(plp->pcp->pl_flags & P_A))
            continue;

        if (!plp->bombs)
            continue;

        newdam = 0;
        if (plp->pcp->pl_flags & P_A) {
            if (roll(100) > pln_identchance(pp, hardtarget, EF_SHIP)) {
                wu(0, pp->pln_own,
                   "\t%s detects sub movement in %s\n",
                   prplane(pp), xyas(x, y, pp->pln_own));
                continue;
            }
            if (getrel(getnatp(pp->pln_own), victim) > HOSTILE) {
                wu(0, pp->pln_own,
                   "\t%s tracks %s %s at %s\n",
                   prplane(pp), cname(victim), s, xyas(x, y, pp->pln_own));
                continue;
            }
            wu(0, pp->pln_own,
               "\t%s depth-charging %s %s in %s\n",
               prplane(pp), cname(victim), s, xyas(x, y, pp->pln_own));
        } else {
            wu(0, pp->pln_own,
               "\t%s pinbombing %s %s in %s\n",
               prplane(pp), cname(victim), s, xyas(x, y, pp->pln_own));
        }
        hitchance = pln_hitchance(pp, hardtarget, EF_SHIP);
        if (plp->plane.pln_nuketype != -1)
            hitchance = 100;
        else if (hardtarget != SECT_HARDTARGET)
            wu(0, pp->pln_own, "\t\t%d%% hitchance...", hitchance);
        /* Always calculate damage */
        if (roll(100) <= hitchance) {
            newdam = pln_damage(&plp->plane, x, y, 'p', &nukedam, 1);
            if (nukedam) {
                if (mission == MI_INTERDICT) {
                    wu(0, pp->pln_own,
                       "\t\tnuclear warhead on plane %s does %d damage to %s %s\n",
                       prplane(pp), nukedam, cname(victim), s);
                    dam += nukedam;
                }
            } else {
                wu(0, pp->pln_own,
                   "\t\thit %s %s for %d damage\n",
                   cname(victim), s, newdam);
                dam += newdam;
            }
        } else {
            newdam = pln_damage(&plp->plane, x, y, 'p', &nukedam, 0);
            wu(0, pp->pln_own, "missed\n");
            if (mission == MI_SINTERDICT) {
                mpr(victim,
                    "RUMBLE... your sub in %s hears a depth-charge explode nearby\n",
                    xyas(x, y, victim));
            } else if (*s == 's') {
                mpr(victim, "SPLASH!  Bombs miss your %s in %s\n",
                    s, xyas(x, y, victim));
            } else {
                mpr(victim, "SPLAT!  Bombs miss your %s in %s\n",
                    s, xyas(x, y, victim));
            }
            /* Now, even though we missed, the bombs
               land somewhere. */
            collateral_damage(x, y, newdam, bombers);
        }

        /* use up missiles */
        if (plp->pcp->pl_flags & P_M)
            pp->pln_effic = 0;
    }

    return dam;
}

/*
 * Check to see if anyone hostile to the victim
 * is running an air defense mission on this
 * sector. If so, do air combat
 */
int
air_defense(coord x, coord y, natid victim, struct emp_qelem *bomb_list,
            struct emp_qelem *esc_list)
{
    int dam = 0, cn;
    int mission_flags, tech, combat = 0, rel, dist, z;
    struct emp_qelem *qp, interceptors, airp, i, empty, *next;
    struct plist *plp;
    struct genlist *glp;
    struct empobj *gp;
    struct genlist mi[MAXNOC];
    char buf[512];
    char *path;
    int count;
    int tcount;

    count = 0;
    for (qp = bomb_list->q_forw; qp != bomb_list; qp = qp->q_forw)
        count++;
    for (qp = esc_list->q_forw; qp != esc_list; qp = qp->q_forw)
        count++;

    memset(mi, 0, sizeof(mi));
    for (z = 1; z < MAXNOC; z++)
        emp_initque((struct emp_qelem *)&mi[z]);

    build_mission_list_type(mi, x, y, MI_AIR_DEFENSE, EF_PLANE, victim);

    for (cn = 1; cn < MAXNOC; cn++) {
        /* Check our relations */
        rel = getrel(getnatp(cn), victim);

        if (rel > HOSTILE)
            continue;

        if (QEMPTY(&mi[cn].queue))
            continue;

        /* Ok, make a list of all the interceptors.  Note that this *copies* the
         * list from the mission creation.  This list must be deleted later. */
        emp_initque(&interceptors);
        for (qp = mi[cn].queue.q_forw; qp != (&mi[cn].queue); qp = next) {
            next = qp->q_forw;
            glp = (struct genlist *)qp;
            gp = glp->thing;

            dist = mapdist(x, y, gp->x, gp->y);

            plp = malloc(sizeof(struct plist));
            memset(plp, 0, sizeof(struct plist));
            plp->pcp = glp->cp;
            memcpy(&plp->plane, glp->thing, sizeof(struct plnstr));

            /* missiles go one way, so we can use all the range */
            if (!(plp->pcp->pl_flags & P_M))
                dist *= 2;
            /* If it's out of range, free it and continue on */
            if (dist > plp->plane.pln_range) {
                free(plp);
                continue;
            }
            emp_insque(&plp->queue, &interceptors);
        }

        /* Remove those who cannot go */
        mission_pln_sel(&interceptors, P_F, 0, SECT_HARDTARGET);

        if (QEMPTY(&interceptors))
            continue;

        /* Now, delete all the extras, but delete the first ones, not the last ones, so
         * that the higher numbered planes go into battle (they should be the better ones
         * at fighting, if all went well.) */
        tcount = 0;
        for (qp = interceptors.q_forw; qp != (&interceptors);
             qp = qp->q_forw)
            tcount++;
        tcount -= count * 2;
        /* Just in case there are more incoming than we have */
        if (tcount < 0)
            tcount = 0;
        for (qp = interceptors.q_forw; qp != (&interceptors); qp = next) {
            next = qp->q_forw;
            if (tcount) {
                tcount--;
                /* Free it up and continue */
                emp_remque(qp);
                glp = (struct genlist *)qp;
                free(glp);
            }
        }

        /* Now, make a list of all the airports these planes are coming from */
        emp_initque(&airp);
        for (qp = interceptors.q_forw; qp != (&interceptors);
             qp = qp->q_forw) {
            plp = (struct plist *)qp;
            if (!find_airport(&airp, plp->plane.pln_x, plp->plane.pln_y))
                add_airport(&airp, plp->plane.pln_x, plp->plane.pln_y);
        }

        /* Now, fly them out one airport at a time */
        for (qp = airp.q_forw; qp != (&airp); qp = qp->q_forw) {
            struct airport *air;

            air = (struct airport *)qp;
            dist = mapdist(x, y, air->x, air->y);

            emp_initque(&i);

            /* Split off the interceptors at this base into i */
            divide(&interceptors, &i, air->x, air->y);

            tech = 0;
            mission_flags = 0;
            mission_flags |= P_X;       /* stealth (shhh) */
            /* gets turned off if not all choppers */
            mission_flags |= P_H;
            sam_intercept(bomb_list, &i, cn, victim, x, y, 0);
            sam_intercept(esc_list, &i, cn, victim, x, y, 1);

            /* Did we run out of interceptors? */
            if (QEMPTY(&i))
                continue;
            /* Did we run out of bombers? */
            if (QEMPTY(bomb_list)) {
                /* Yes, so we have to put the rest of the interceptors back, and
                   then continue, or we leak memory */
                pln_put(&i);
                continue;
            }
            mission_flags =
                mission_pln_arm(&i, air->x, air->y, 2 * dist, 'r', 0, P_F,
                                mission_flags, &tech);

            /* Did we run out of interceptors? */
            if (QEMPTY(&i))
                continue;
            /* Did we run out of bombers? */
            if (QEMPTY(bomb_list)) {
                /* Yes, so we have to put the rest of the interceptors back, and
                   then continue, or we leak memory */
                pln_put(&i);
                continue;
            }

            path = BestAirPath(buf, air->x, air->y, x, y);
            if (CANT_HAPPEN(!path))
                continue;
            wu(0, cn, "Flying %s mission from %s\n",
               mission_name(MI_AIR_DEFENSE), xyas(air->x, air->y, cn));
            if (air->own && (air->own != cn)) {
                wu(0, air->own, "%s is flying %s mission from %s\n",
                   cname(cn), mission_name(MI_AIR_DEFENSE),
                   xyas(air->x, air->y, air->own));
            }

            /* Now, fly the planes to the sector */
            emp_initque(&empty);
            ac_encounter(&i, &empty, air->x, air->y,
                         path, mission_flags, 1, bomb_list, esc_list);

            /* If none made it, continue */
            if (QEMPTY(&i))
                continue;

            /* Some made it, so now they get to try to fight. */
            /* Intercept the escorts first */
            combat = 0;
            if (!QEMPTY(esc_list)) {
                mpr(victim, "%s air defense planes intercept!\n",
                    cname(cn));
                ac_combat_headers(victim, cn);
                ac_airtoair(esc_list, &i);
                combat = 1;
            }
            /* Now intercept the bombers */
            if (!QEMPTY(bomb_list)) {
                if (!combat) {
                    mpr(victim, "%s air defense planes intercept!\n",
                        cname(cn));
                    ac_combat_headers(victim, cn);
                }
                ac_airtoair(bomb_list, &i);
                PR(cn, "\n");
                PR(victim, "\n");
            }

            pln_put(&i);
        }
    }

    /* We have to free all of these, if they are still there, otherwise they get
       lost and we leak memory all over the place. */
    for (cn = 1; cn < MAXNOC; cn++) {
        /* free up all this memory if it's still there */
        for (qp = mi[cn].queue.q_forw; qp != (&mi[cn].queue); qp = next) {
            next = qp->q_forw;
            glp = (struct genlist *)qp;
            free(glp->thing);
            free(glp);
        }
    }

    return dam;
}

---