src/lib/subs/attsub.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.
 *
 *  ---
 *
 *  attsub.c: Attack subroutines
 * 
 *  Known contributors to this file:
 *     Ken Stevens, 1995
 *     Steve McClure, 1996-2000
 *     Markus Armbruster, 2006
 */

#include <config.h>

#include <ctype.h>
#include <math.h>
#include "combat.h"
#include "file.h"
#include "map.h"
#include "misc.h"
#include "mission.h"
#include "nsc.h"
#include "optlist.h"
#include "path.h"
#include "plague.h"
#include "player.h"
#include "prototypes.h"
#include "xy.h"
#include "empobj.h"
#include "unit.h"

#define CASUALTY_LUMP   1       /* How big casualty chunks should be */

static void ask_olist(int combat_mode, struct combat *off,
                      struct combat *def, struct emp_qelem *olist,
                      char *land_answer, int *a_spyp, int *a_engineerp);
static void take_move_in_mob(int combat_mode, struct ulist *llp,
                             struct combat *off, struct combat *def);
static void move_in_land(int combat_mode, struct combat *off,
                         struct emp_qelem *olist, struct combat *def);
static void ask_move_in(struct combat *off, struct emp_qelem *olist,
                        struct combat *def);
static void ask_move_in_off(struct combat *off, struct combat *def);

static int board_abort(struct combat *off, struct combat *def);
static int land_board_abort(struct combat *off, struct combat *def);
static int ask_off(int combat_mode, struct combat *off,
                   struct combat *def);
static void get_dlist(struct combat *def, struct emp_qelem *list, int a_spy,
                      int *d_spyp);
static int get_ototal(int combat_mode, struct combat *off,
                      struct emp_qelem *olist, double osupport, int check);
static int get_dtotal(struct combat *def, struct emp_qelem *list,
                      double dsupport, int check);
static double att_calcodds(int, int);
static int take_casualty(int combat_mode, struct combat *off,
                         struct emp_qelem *olist);

static void send_reacting_units_home(struct emp_qelem *list);
static int take_def(int combat_mode, struct emp_qelem *list,
                    struct combat *off, struct combat *def);

static int get_land(int combat_mode, struct combat *def, int uid,
                    struct ulist *llp, int victim_land);

char *att_mode[] = {
    /* must match combat types in combat.h */
    "defend", "attack", "assault", "paradrop", "board", "lboard"
};


/*
 * The principal object in this code is the "combat" object.  A combat object
 * is either a sector or ship.  There are
 * usually two instances of this, the "def" or defense combat object, and
 * the array of "off" or offense objects.  The number of offense objects is
 * determined by the value of off->last (e.g. more than one attacking sector).
 * the type of the object is determined by combat->type which can take the
 * values EF_SECTOR, EF_SHIP, EF_PLANE, or EF_BAD.  Another important parameter
 * which is often passed to these functions is combat_mode.  This can take
 * the value A_DEFEND, A_ATTACK, A_ASSAULT, A_PARA, A_BOARD and A_LBOARD.
 * As these six modes of being in combat affect things like mobcost and combat
 * value, there are often switches made on combat_mode.  Note that in all cases
 * no mobility is taken from sectors, ships, or land units until the player
 * has committed to a fight.  Instead, the cost is temporarily placed in
 * combat->mobcost, or llp->mobil as the case may be, and then when the object
 * is "put" back onto disk, then the amounts in these variables are subtracted
 * from the object's mobility.  It needs to be done this way as the objects
 * are constantly being re-read from disk, and we don't want to take any mob
 * unless a fight actually occurrs.
 * -Ken Stevens
 */

/* initialize combat object */

int
att_combat_init(struct combat *com, int type)
{
    memset(com, 0, sizeof(*com));
    com->type = type;
    return type;
}

/* print a combat object with optional preposition */

static char *
pr_com(int inon, struct combat *com, natid who)
{
    if (com->type == EF_SECTOR) {
        return prbuf("%s%s",
                     inon ? inon == 1 ? "in " : "into " : "",
                     xyas(com->x, com->y, who));
    } else if (com->type == EF_SHIP) {
        return prbuf("%s%s %s(#%d)",
                     inon ? inon == 1 ? "on " : "onto " : "",
                     com->shp_mcp->m_name, com->shp_name,
                     com->shp_uid);
    } else if (com->type == EF_LAND) {
        return prbuf("%s%s #%d",
                     inon ? inon == 1 ? "on " : "onto " : "",
                     com->lnd_lcp->l_name, com->lnd_uid);
    } else {
        return "your forces";
    }
}

static char *
prcom(int inon, struct combat *com)
{
    return pr_com(inon, com, player->cnum);
}

/*
 * This is the combat object "type" based integrity check.  It basically
 * splits along three divisions: ship/sector, attacker/defender, 
 * first time/not first time.
 */

int
att_get_combat(struct combat *com, int isdef)
{
    struct sctstr sect;
    struct shpstr ship;
    struct lndstr land;
    int pstage;
    natid owner;
    int mil;
    int eff;
    int mob;
    coord x, y;

    switch (com->type) {
    case EF_SECTOR:
        if (!getsect(com->x, com->y, &sect)) {
            pr("Bad sector: %s\n", xyas(com->x, com->y, player->cnum));
            return att_combat_init(com, EF_BAD);
        }
        com->sct_type = sect.sct_type;
        com->sct_dcp = &dchr[sect.sct_type];
        mil = sect.sct_item[I_MILIT];
        pstage = sect.sct_pstage;
        owner = sect.sct_own;
        eff = sect.sct_effic;
        mob = sect.sct_mobil;
        x = com->x;
        y = com->y;
        break;
    case EF_LAND:
        if (!getland(com->lnd_uid, &land) || !land.lnd_own) {
            if (isdef)
                pr("Land unit #%d is not in the same sector!\n",
                   com->lnd_uid);
            return att_combat_init(com, EF_BAD);
        }
        if (isdef && player->owner) {
            pr("Boarding yourself?  Try using the 'load' command.\n");
            return att_combat_init(com, EF_BAD);
        }
        com->lnd_lcp = &lchr[(int)land.lnd_type];
        mil = land.lnd_item[I_MILIT];
        pstage = land.lnd_pstage;
        owner = land.lnd_own;
        eff = land.lnd_effic;
        mob = land.lnd_mobil;
        x = land.lnd_x;
        y = land.lnd_y;
        break;
    case EF_SHIP:
        if (!getship(com->shp_uid, &ship) || !ship.shp_own) {
            if (isdef)
                pr("Ship #%d is not in the same sector!\n", com->shp_uid);
            else
                pr("Ship #%d is not your ship!\n", com->shp_uid);
            return att_combat_init(com, EF_BAD);
        }
        if (opt_MARKET) {
            if (isdef && player->owner &&
                ontradingblock(EF_SHIP, &ship)) {
                pr("%s is on the trading block.\n", prcom(0, com));
                return att_combat_init(com, EF_BAD);
            }
        }
        if (isdef && player->owner) {
            pr("Boarding yourself?  Try using the 'tend' command.\n");
            return att_combat_init(com, EF_BAD);
        }
        com->shp_mcp = &mchr[(int)ship.shp_type];
        strncpy(com->shp_name, ship.shp_name, MAXSHPNAMLEN);
        if (!isdef && !player->owner) {
            if (com->set)
                pr("%s was just sunk!\n", prcom(0, com));
            else
                pr("Ship #%d is not your ship!\n", com->shp_uid);
            return att_combat_init(com, EF_BAD);
        }
        mil = ship.shp_item[I_MILIT];
        pstage = ship.shp_pstage;
        owner = ship.shp_own;
        eff = ship.shp_effic;
        mob = ship.shp_mobil;
        x = ship.shp_x;
        y = ship.shp_y;
        break;
    case EF_PLANE:
        return com->mil;
    case EF_BAD:
        return EF_BAD;
    default:
        return att_combat_init(com, EF_BAD);
    }

    if (!com->set) {            /* first time */
        if (isdef) {            /* defender */
            com->troops = mil;
        } else {                /* attacker */
            if (!mil)
                pr("No mil %s\n", prcom(1, com));
            else if (mil == 1)
                pr("Only 1 mil %s\n", prcom(1, com));
            /* don't abandon attacking sectors or ships */
            com->troops = MAX(0, mil - 1);
        }
        com->plague = pstage == PLG_INFECT;
    } else {                    /* not first time */
        if (isdef) {            /* defender */
            if (com->x != x || com->y != y) {
                pr("%s has moved!\n", prcom(0, com));
                return att_combat_init(com, EF_BAD);
            }
            if (owner != com->own) {
                if (owner) {
                    pr("WARNING: The ownership of %s just changed from %s to %s!\n",
                       prcom(0, com), cname(com->own), cname(owner));
                } else if (com->type == EF_SECTOR) {
                    pr("WARNING: %s just abandoned sector %s!\n",
                       cname(com->own),
                       xyas(com->x, com->y, player->cnum));
                }
            }
            if (com->mil != mil)
                pr("WARNING: The enemy mil %s just %s from %d to %d!\n",
                   prcom(1, com),
                   com->mil < mil ? "increased" : "decreased", com->mil,
                   mil);
            com->troops = mil;
        } else {                /* attacker */
            if (owner != player->cnum && getrel(getnatp(owner), player->cnum) != ALLIED) {
                /* must be EF_SECTOR */
                if (com->mil)
                    pr("WARNING: Your %d mil in %s were destroyed because %s just took the sector!\n",
                       com->mil, xyas(com->x, com->y, player->cnum),
                       cname(owner));
                else
                    pr("You no longer own %s\n",
                       xyas(com->x, com->y, player->cnum));
                return att_combat_init(com, EF_BAD);
            }
            if (com->troops && com->troops + 1 > mil) {
                if (com->own == owner && player->cnum == owner)
                    /* not a takeover */
                    pr("WARNING: Your mil %s has been reduced from %d to %d!\n",
                       prcom(1, com), com->troops, MAX(0, mil - 1));
                com->troops = MAX(0, mil - 1);
            }
        }
    }
    com->set = 1;
    com->mil = mil;
    com->own = owner;
    com->x = x;
    com->y = y;
    com->eff = eff;
    com->mob = mob;
    return com->troops;
}

/*
 * In the course of the fight, the combat object may have lost mil, eff, or
 * mobility.  This is the place where the data in the object gets flushed to
 * disk to make it "real".
 */

static void
put_combat(struct combat *com)
{
    struct sctstr sect;
    struct shpstr ship;
    struct lndstr land;
    int deff;

    switch (com->type) {
    case EF_SECTOR:
        getsect(com->x, com->y, &sect);
        sect.sct_type = com->sct_type;
        deff = sect.sct_effic - com->eff;
        if (deff > 0) {
            sect.sct_road -= sect.sct_road * deff / 100.0;
            sect.sct_rail -= sect.sct_rail * deff / 100.0;
            sect.sct_defense -= sect.sct_defense * deff / 100.0;
            if (sect.sct_road <= 0)
                sect.sct_road = 0;
            if (sect.sct_rail <= 0)
                sect.sct_rail = 0;
            if (sect.sct_defense <= 0)
                sect.sct_defense = 0;
        }
        sect.sct_effic = com->eff;
        if (com->mobcost) {
            if (opt_MOB_ACCESS) {
                if ((com->mob - com->mobcost) < -127)
                    sect.sct_mobil = -127;
                else
                    sect.sct_mobil = (short)(com->mob - com->mobcost);
            } else {
                if ((com->mob - com->mobcost) < 0)
                    sect.sct_mobil = 0;
                else
                    sect.sct_mobil = (short)(com->mob - com->mobcost);
            }
        }
        makelost(EF_SECTOR, sect.sct_own, 0, sect.sct_x, sect.sct_y);
        makenotlost(EF_SECTOR, com->own, 0, sect.sct_x, sect.sct_y);
        sect.sct_own = com->own;
        if (com->plague) {
            if (sect.sct_pstage == PLG_HEALTHY)
                sect.sct_pstage = PLG_EXPOSED;
        }
        sect.sct_item[I_MILIT] = com->mil;
        putsect(&sect);
        com->own = sect.sct_own;        /* avoid WARNING if sector reverts */
        break;
    case EF_LAND:
        getland(com->lnd_uid, &land);
        land.lnd_effic = com->eff;
        if (com->mobcost) {
            if (com->mob - com->mobcost < -127)
                land.lnd_mobil = -127;
            else
                land.lnd_mobil = (signed char)(com->mob - com->mobcost);
        }
        makelost(EF_LAND, land.lnd_own, land.lnd_uid,
                 land.lnd_x, land.lnd_y);
        land.lnd_own = com->own;
        makenotlost(EF_LAND, land.lnd_own, land.lnd_uid,
                    land.lnd_x, land.lnd_y);
        if (com->plague) {
            if (land.lnd_pstage == PLG_HEALTHY)
                land.lnd_pstage = PLG_EXPOSED;
        }
        if (!(com->lnd_lcp->l_flags & L_SPY))
            land.lnd_item[I_MILIT] = com->mil;
        lnd_count_units(&land);
        if (com->own == player->cnum) {
            land.lnd_mission = 0;
            land.lnd_rflags = 0;
            memset(land.lnd_rpath, 0, sizeof(land.lnd_rpath));
        }
        putland(com->lnd_uid, &land);
        break;
    case EF_SHIP:
        getship(com->shp_uid, &ship);
        ship.shp_effic = com->eff;
        if (com->mobcost) {
            if (com->mob - com->mobcost < -127)
                ship.shp_mobil = -127;
            else
                ship.shp_mobil = (signed char)(com->mob - com->mobcost);
        }
        makelost(EF_SHIP, ship.shp_own, ship.shp_uid,
                 ship.shp_x, ship.shp_y);
        ship.shp_own = com->own;
        makenotlost(EF_SHIP, ship.shp_own, ship.shp_uid,
                    ship.shp_x, ship.shp_y);
        if (com->plague) {
            if (ship.shp_pstage == PLG_HEALTHY)
                ship.shp_pstage = PLG_EXPOSED;
        }
        ship.shp_item[I_MILIT] = com->mil;
        count_units(&ship);
        if (com->own == player->cnum) {
            ship.shp_mission = 0;
            ship.shp_rflags = 0;
            memset(ship.shp_rpath, 0, sizeof(ship.shp_rpath));
        }
        putship(com->shp_uid, &ship);
    }
    com->mobcost = 0;
    att_get_combat(com, com->own != player->cnum);
}

/* If pre-attack, abort fight.  If post-attack, don't move anything in */

static int
abort_attack(void)
{
    return player->aborted = 1;
}

/*
 * This is the combat_mode based integrity check.  It splits among two main
 * divisions: first time/not first time, and attack/assault/para/board.
 */

int
att_abort(int combat_mode, struct combat *off, struct combat *def)
{
    struct sctstr sect;
    int rel;
    char y_or_n[512];
    struct natstr *natp;

    if (player->aborted)
        return 1;
    if (att_get_combat(def, 1) < 0)
        return abort_attack();

    if (off && combat_mode != A_ATTACK) {
        if (att_get_combat(off, 0) < 0)
            return abort_attack();
        if (off->type == EF_SHIP &&
            (!getsect(off->x, off->y, &sect) ||
             sect.sct_type != SCT_WATER)) {
            pr("%s can not %s from that far inland!\n",
               prcom(0, off), att_mode[combat_mode]);
            return abort_attack();
        }
    }
    switch (combat_mode) {
    case A_ATTACK:
        if (!neigh(def->x, def->y, player->cnum) &&
            !adj_units(def->x, def->y, player->cnum)) {
            pr("You are not adjacent to %s\n",
               xyas(def->x, def->y, player->cnum));
            return abort_attack();
        }
        if (def->own == player->cnum) {
            pr("You can't attack your own sector.\n");
            return abort_attack();
        }
        break;
    case A_ASSAULT:
        if (off && mapdist(off->x, off->y, def->x, def->y) > 1) {
            pr("You'll have to get there first...\n");
            return abort_attack();
        }
        if (off && def->sct_type == SCT_MOUNT) {
            pr("You can't assault a %s sector!\n", def->sct_dcp->d_name);
            return abort_attack();
        }
        break;
    case A_PARA:
        if (def->own == player->cnum) {
            pr("You can't air-assault your own sector.\n");
            return abort_attack();
        }
        if (off && (def->sct_type == SCT_MOUNT ||
                    def->sct_type == SCT_WATER ||
                    def->sct_type == SCT_CAPIT ||
                    def->sct_type == SCT_FORTR ||
                    def->sct_type == SCT_WASTE)) {
            pr("You can't air-assault a %s sector!\n",
               def->sct_dcp->d_name);
            return abort_attack();
        }
        break;
    case A_BOARD:
        return board_abort(off, def);
    case A_LBOARD:
        return land_board_abort(off, def);
    }

    if (off && def->sct_dcp->d_mob0 < 0) {
        pr("You can't %s a %s sector!\n",
           att_mode[combat_mode], def->sct_dcp->d_name);
        return abort_attack();
    }
    if (!off || off->relations_checked)
        return 0;
    off->relations_checked = 1;

    if (opt_HIDDEN) {
        setcont(player->cnum, def->own, FOUND_SPY);
        setcont(def->own, player->cnum, FOUND_SPY);
    }
    if (opt_SLOW_WAR && def->own != player->cnum) {
        natp = getnatp(player->cnum);
        rel = getrel(natp, def->own);

        if (rel == ALLIED) {
            sprintf(y_or_n, "Sector is owned by %s, your ally, %s [yn]? ",
                    cname(def->own), att_mode[combat_mode]);
            if (!confirm(y_or_n))
                return abort_attack();

        }
        if ((rel != AT_WAR) && (def->own) &&
            (sect.sct_oldown != player->cnum)) {
            pr("You're not at war with them!\n");
            return abort_attack();
        }
    }
    return 0;
}

/*
 * Lots of special things need to be checked for boarding, so I put it in
 * it's own function.
 */

static int
board_abort(struct combat *off, struct combat *def)
{
    struct shpstr aship, dship; /* for tech levels */
    struct sctstr sect;

    if (att_get_combat(def, 1) < 0)
        return abort_attack();

    if (!off)
        return 0;

    if (att_get_combat(off, 0) < 0)
        return abort_attack();

    if (off->x != def->x || off->y != def->y) {
        pr("Ship #%d is not in the same sector!\n", def->shp_uid);
        return abort_attack();
    }
    if (off->type == EF_SHIP) {
        if (off->mob <= 0) {
            pr("%s has no mobility!\n", prcom(0, off));
            return abort_attack();
        }
        getship(off->shp_uid, &aship);
        getship(def->shp_uid, &dship);
        if (techfact(aship.shp_tech, 1.0) * aship.shp_speed * off->eff
            <= techfact(dship.shp_tech, 1.0) * dship.shp_speed * def->eff) {
            pr("Victim ship moves faster than you do!\n");
            if (def->own)
                wu(0, def->own,
                   "%s (#%d) %s failed to catch %s\n",
                   cname(aship.shp_own), aship.shp_own,
                   pr_com(0, off, def->own), pr_com(0, def, def->own));
            return abort_attack();
        }
    } else if (off->type != EF_SECTOR) {
        pr("Please tell the deity that you got the 'banana boat' error\n");
        return abort_attack();
    }
    if (def->shp_mcp->m_flags & M_SUB) {
        getsect(def->x, def->y, &sect);
        if (sect.sct_type == SCT_WATER) {
            pr("You can't board a submarine!\n");
            return abort_attack();
        }
    }
    return 0;
}

/*
 * Lots of special things need to be checked for boarding, so I put it in
 * it's own function.
 * STM - I copied it for land unit boarding. :)
 */

static int
land_board_abort(struct combat *off, struct combat *def)
{
    if (att_get_combat(def, 1) < 0)
        return abort_attack();

    if (!off)
        return 0;

    if (att_get_combat(off, 0) < 0)
        return abort_attack();

    if (off->x != def->x || off->y != def->y) {
        pr("Land unit #%d is not in the same sector!\n", def->lnd_uid);
        return abort_attack();
    }

    return 0;
}

/* If we are boarding, then the defending ship gets a chance to fire back */
int
att_approach(struct combat *off, struct combat *def)
{
    int dam;
    struct sctstr sect;
    struct shpstr ship;

    pr("Approaching %s...\n", prcom(0, def));
    if (def->own)
        wu(0, def->own,
           "%s is being approached by %s...\n",
           pr_com(0, def, def->own), pr_com(0, off, def->own));
    if (!(dam = shipdef(player->cnum, def->own, def->x, def->y)))
        return 0;

    pr("They're firing at us sir!\n");
    if (def->own) {
        wu(0, def->own,
           "Your fleet at %s does %d damage to %s\n",
           xyas(def->x, def->y, def->own), dam, pr_com(0, off, def->own));
    }
    if (off->type == EF_SECTOR) {
        getsect(off->x, off->y, &sect);
        sectdamage(&sect, dam, 0);
        putsect(&sect);
        pr("Enemy fleet at %s does %d damage to %s\n",
           xyas(def->x, def->y, player->cnum), dam, prcom(0, off));
    } else if (off->type == EF_SHIP) {
        getship(off->shp_uid, &ship);
        shipdamage(&ship, dam);
        putship(off->shp_uid, &ship);
        if (def->own && ship.shp_effic < SHIP_MINEFF) {
            wu(0, def->own, "%s sunk!\n", pr_com(0, off, def->own));
            nreport(player->cnum, N_SHP_LOSE, def->own, 1);
        }
    }
    if (att_get_combat(off, 0) < 0)
        return abort_attack();
    return 0;
}

/* The attack is valid.  Tell the attacker about what they're going to hit */

int
att_show(struct combat *def)
{
    /* Note that we tell the player about the treaty BEFORE we tell them
       about the item.  If we didn't, then they gain free information */
    if (def->type == EF_SECTOR) {
        if (!trechk(player->cnum, def->own, LANATT))
            return abort_attack();
        pr("%s is a %d%% %s %s with approximately %d military.\n",
           xyas(def->x, def->y, player->cnum),
           roundintby((int)def->eff, 10),
           cname(def->own), def->sct_dcp->d_name,
           roundintby(def->troops, 10));
        if (map_set(player->cnum, def->x, def->y, def->sct_dcp->d_mnem, 0))
            writemap(player->cnum);
    } else if (def->type == EF_SHIP || def->type == EF_LAND) {
        if (def->type == EF_SHIP) {
            if (!trechk(player->cnum, def->own, SEAATT))
                return abort_attack();
        } else {
            if (!trechk(player->cnum, def->own, LNDATT))
                return abort_attack();
        }
        pr("%s is about %d%% efficient and has approximately %d mil on board.\n", prcom(0, def), roundintby((int)def->eff, 10), roundintby(def->troops, 10));
    }
    /* Ok, everything is fine */
    return 0;
}

/* Attack and assault ask the user which kind of support they want */

int
att_ask_support(int offset, int *fortp, int *shipp, int *landp,
                int *planep)
{
    char buf[1024];
    char *p;
    *fortp = *shipp = *landp = *planep = 1;

    if (player->argp[offset] != NULL) {
        if ((player->argp[offset + 1] == NULL) ||
            (player->argp[offset + 2] == NULL) ||
            (player->argp[offset + 3] == NULL)) {
            pr("If any support arguments are used, all must be!\n");
            return RET_SYN;
        }

        *fortp = *shipp = 0;
        *landp = *planep = 0;

        if (!(p = getstarg(player->argp[offset], "Use fort support? ",
                           buf)))
            return RET_SYN;

        if ((*p == 'y') || (*p == 'Y'))
            *fortp = 1;

        if (!(p = getstarg(player->argp[offset + 1], "Use ship support? ",
                           buf)))
            return RET_SYN;

        if ((*p == 'y') || (*p == 'Y'))
            *shipp = 1;

        if (!(p = getstarg(player->argp[offset + 2], "Use land support? ",
                           buf)))
            return RET_SYN;

        if ((*p == 'y') || (*p == 'Y'))
            *landp = 1;

        if (!(p = getstarg(player->argp[offset + 3], "Use plane support? ",
                           buf)))
            return RET_SYN;

        if ((*p == 'y') || (*p == 'Y'))
            *planep = 1;
    }
    return RET_OK;
}

/*
 * Attack, assault, and board ask the attacker what they'd like to attack
 * with.  This includes mil and land units from each "off" object.  Note that
 * after each sub-prompt, we check to make sure that the attack is still
 * valid, and if it's not, then we abort the attack.
 */

int
att_ask_offense(int combat_mode, struct combat *off, struct combat *def,
                struct emp_qelem *olist, int *a_spyp, int *a_engineerp)
{
    int n;
    char land_answer[256];

    emp_initque(olist);
    if (att_abort(combat_mode, off, def))
        return 0;
    memset(land_answer, 0, sizeof(land_answer));
    for (n = 0; n <= off->last; ++n) {
        off[n].troops = ask_off(combat_mode, off + n, def);
        if (att_abort(combat_mode, off, def))
            return 0;
        ask_olist(combat_mode, off + n, def, olist, land_answer,
                  a_spyp, a_engineerp);
        if (att_abort(combat_mode, off, def))
            return 0;
    }
    return 0;
}

/*
 * Return path cost for ATTACKER to enter sector given by DEF.
 * MOBTYPE is a mobility type accepted by sector_mcost().
 */
static double
att_mobcost(natid attacker, struct combat *def, int mobtype)
{
    struct sctstr sect;
    int ok;

    if (CANT_HAPPEN(def->type != EF_SECTOR))
        return -1.0;
    ok = getsect(def->x, def->y, &sect);
    if (CANT_HAPPEN(!ok))
        return -1.0;

    /*
     * We want the cost to move/march into the sector.  If we just
     * called sector_mcost(), we'd get the defender's cost.  The
     * attacker's cost is higher unless he's the old-owner.  Note: if
     * there are no civilians, a victorious attacker will become the
     * old-owner.  But he isn't now.
     */
    sect.sct_own = attacker;
    sect.sct_mobil = 0;
    return sector_mcost(&sect, mobtype);
}

/* How many mil is off allowed to attack with when it attacks def? */

static int
get_mob_support(int combat_mode, struct combat *off, struct combat *def)
{
    int mob_support;
    double mobcost;

    switch (combat_mode) {
    case A_ATTACK:
        mobcost = att_mobcost(off->own, def, MOB_MOVE);
        if (mobcost < 0 || off->mob <= 0)
            return 0;
        mob_support = off->mob / mobcost;
        if (mob_support < off->troops)
            pr("Sector %s has %d mobility which can only support %d mil,\n",
               xyas(off->x, off->y, player->cnum), off->mob, mob_support);
        else
            mob_support = off->troops;
        return mob_support;
    case A_ASSAULT:
        if (def->own != player->cnum && def->mil) {
            if (off->shp_mcp->m_flags & M_SEMILAND)
                return off->troops / 4;
            else if (!(off->shp_mcp->m_flags & M_LAND))
                return off->troops / 10;
        }
        break;
    case A_BOARD:
        if (off->type == EF_SECTOR && off->mob <= 0)
            return 0;
        mob_support = def->shp_mcp->m_item[I_MILIT];
        if (mob_support < off->troops)
            pr("The size of the ship you are trying to board limits your party to %d mil,\n", mob_support);
        else
            mob_support = off->troops;
        return mob_support;
    case A_LBOARD:
        if (off->mob <= 0)
            return 0;
        if (def->lnd_lcp->l_flags & L_SPY)
            return 1;
        mob_support = def->lnd_lcp->l_item[I_MILIT];
        if (mob_support < off->troops)
            pr("The size of the unit you are trying to board limits your party to %d mil,\n", mob_support);
        else
            mob_support = off->troops;
        return mob_support;
    }
    return off->troops;
}

/*
 * If the attacker decides to go through with the attack, then the
 * sectors/ships they are attacking with may be charged some mobility.
 * This is where that amount of mobility is calculated.  It is actually
 * subtracted "for real" from the object's mobility in put_combat().
 */

static void
calc_mobcost(int combat_mode, struct combat *off, struct combat *def,
             int attacking_mil)
{
    struct shpstr ship;

    if (!attacking_mil)
        return;
    switch (combat_mode) {
    case A_ATTACK:
        off->mobcost += MAX(1,
                            (int)(attacking_mil
                                  * att_mobcost(off->own, def, MOB_MOVE)));
        break;
    case A_LBOARD:
        off->mobcost += MAX(1, attacking_mil / 5);
        break;
    case A_BOARD:
        switch (off->type) {
        case EF_SECTOR:
            off->mobcost += MAX(1, attacking_mil / 5);
            break;
        case EF_SHIP:
            /* the 2 in the formula below is a fudge factor */
            getship(def->shp_uid, &ship);
            off->mobcost += (def->eff / 100) * (ship.shp_speed / 2);
        }
    }
}

/* How many mil to we want to attack from off against def? */

static int
ask_off(int combat_mode, struct combat *off, struct combat *def)
{
    int attacking_mil;
    int mob_support;
    char prompt[512];

    if (att_get_combat(off, 0) <= 0)
        return 0;
    if ((off->type == EF_SECTOR) && (off->own != player->cnum))
        return 0;
    if ((mob_support = get_mob_support(combat_mode, off, def)) <= 0)
        return 0;
    if (off->type == EF_SECTOR) {
        if (off->own != player->cnum)
            return 0;
        sprintf(prompt, "Number of mil from %s at %s (max %d) : ",
                off->sct_dcp->d_name,
                xyas(off->x, off->y, player->cnum), mob_support);
    } else {
        sprintf(prompt, "Number of mil from %s (max %d) : ",
                prcom(0, off), mob_support);
    }
    if ((attacking_mil = onearg(0, prompt)) < 0)
        abort_attack();
    if (att_abort(combat_mode, off, def))
        return 0;
    if (att_get_combat(off, 0) <= 0)
        return 0;
    if ((attacking_mil =
         MIN(attacking_mil, MIN(mob_support, off->troops))) <= 0)
        return 0;

    calc_mobcost(combat_mode, off, def, attacking_mil);
    return attacking_mil;
}

/*
 * Which units would you like to attack with or move in with [ynYNq?]
 */

static char
att_prompt(char *prompt, char army)
{
    char buf[1024];
    char *p;

    if (!army)
        army = '~';
    for (;;) {
        p = getstring(prompt, buf);
        if (player->aborted || (p && *p == 'q')) {
            abort_attack();
            return 'N';
        }
        if (!p || !*p)
            return 'n';
        if (tolower(*p) == 'y' || tolower(*p) == 'n')
            return *p;
        pr("y - yes this unit\n"
           "n - no this unit\n"
           "Y - yes to all units in army '%c'\n"
           "N - no to all units in army '%c'\n"
           "q - quit\n? - this help message\n\n",
           army, army);
    }
}

/* Ask the attacker which units they want to attack/assault/board with */

static void
ask_olist(int combat_mode, struct combat *off, struct combat *def,
          struct emp_qelem *olist, char *land_answer, int *a_spyp,
          int *a_engineerp)
{
    struct nstr_item ni;
    struct lndstr land;
    double mobcost;
    struct ulist *llp;
    struct lchrstr *lcp;
    double att_val;
    int count = 0;
    int maxland = 0;
    int first_time = 1;
    char prompt[512];

    if (def->type == EF_LAND)
        return;
    if (def->type == EF_SHIP)
        maxland = def->shp_mcp->m_nland;

    snxtitem_xy(&ni, EF_LAND, off->x, off->y);
    while (nxtitem(&ni, &land)) {
        if (land.lnd_own != player->cnum)
            continue;
        if (land.lnd_effic < LAND_MINEFF)
            continue;
        if (land_answer[(int)land.lnd_army] == 'N')
            continue;
        if (!lnd_can_attack(&land))
            continue;
        lcp = &lchr[(int)land.lnd_type];

        if (def->type == EF_SHIP && !maxland) {
            pr("Land units are not able to board this kind of ship\n");
            return;
        }
        if (land.lnd_mobil <= 0) {
            pr("%s is out of mobility, and cannot %s\n",
               prland(&land), att_mode[combat_mode]);
            continue;
        }

        if (opt_MARKET) {
            if (ontradingblock(EF_LAND, &land)) {
                pr("%s is on the trading block, and cannot %s\n",
                   prland(&land), att_mode[combat_mode]);
                continue;
            }
        }

        if (off->type == EF_SECTOR && land.lnd_ship >= 0) {
            pr("%s is on ship #%d, and cannot %s\n",
               prland(&land), land.lnd_ship, att_mode[combat_mode]);
            continue;
        } else if (off->type == EF_SHIP) {
            if (land.lnd_ship != off->shp_uid)
                continue;
        } else if (land.lnd_land >= 0) {
            pr("%s is on unit #%d, and cannot %s\n",
               prland(&land), land.lnd_land, att_mode[combat_mode]);
            continue;
        }
        switch (combat_mode) {
        case A_ATTACK:
            /*
             * We used to let land units attack only if they have the
             * mobility consumed by the attack, not counting combat
             * and moving in to occupy.  Making sure your land units
             * reach attack positions with enough mobility left is a
             * pain in the neck.  We now require positive mobility,
             * just like for marching.  Except we don't allow rushing
             * of high-mobility sectors (mountains): for those we
             * still require attack mobility.
             */
            mobcost = att_mobcost(off->own, def, lnd_mobtype(&land));
            if (mobcost < 1.0) {
                if (land.lnd_mobil <= 0) {
                    pr("%s is out of mobility\n", prland(&land));
                    continue;
                }
            } else {
                mobcost = lnd_pathcost(&land, mobcost);
                if (land.lnd_mobil < mobcost) {
                    pr("%s does not have enough mobility (%d needed)\n",
                       prland(&land), (int)ceil(mobcost));
                    continue;
                }
            }
            break;
        case A_ASSAULT:
        case A_BOARD:
            mobcost = 0;
            if (!(lcp->l_flags & L_ASSAULT))
                continue;
            break;
        default:
            CANT_REACH();
            return;
        }
        att_val = attack_val(combat_mode, &land);
        if (att_val < 1.0) {
            pr("%s has no offensive strength\n", prland(&land));
            continue;
        }
        resupply_all(&land);
        putland(land.lnd_uid, &land);
        if (!has_supply(&land)) {
            pr("%s is out of supply, and cannot %s\n",
               prland(&land), att_mode[combat_mode]);
            continue;
        }
        if (def->type == EF_SHIP && first_time) {
            first_time = 0;
            pr("You may board with a maximum of %d land units\n", maxland);
        }
        pr("%s has a base %s value of %.0f\n",
           prland(&land), att_mode[combat_mode], att_val);
        if (land_answer[(int)land.lnd_army] != 'Y') {
            sprintf(prompt,
                    "%s with %s %s (%c %d%%) [ynYNq?] ",
                    att_mode[combat_mode],
                    prland(&land),
                    prcom(1, off),
                    land.lnd_army ? land.lnd_army : '~',
                    land.lnd_effic);
            land_answer[(int)land.lnd_army] =
                att_prompt(prompt, land.lnd_army);
            if (att_abort(combat_mode, off, def))
                return;
            if (land_answer[(int)land.lnd_army] != 'y' &&
                land_answer[(int)land.lnd_army] != 'Y')
                continue;
        }
        if (!(llp = malloc(sizeof(struct ulist)))) {
            logerror("Malloc failed in attack!\n");
            abort_attack();
            return;
        }
        memset(llp, 0, sizeof(struct ulist));
        emp_insque(&llp->queue, olist);
        llp->mobil = mobcost;
        if (!get_land(combat_mode, def, land.lnd_uid, llp, 0))
            continue;
        if (lnd_spyval(&land) > *a_spyp)
            *a_spyp = lnd_spyval(&land);
        if (((struct lchrstr *)llp->chrp)->l_flags & L_ENGINEER)
            ++*a_engineerp;
        if (def->type == EF_SHIP && ++count >= maxland)
            break;
    }
}

/* What's the offense or defense multiplier? */

double
att_combat_eff(struct combat *com)
{
    double eff = 1.0;
    double str;
    struct shpstr ship;

    if (com->type == EF_SECTOR) {
        eff = com->eff / 100.0;
        if (com->own == player->cnum) {
            str = com->sct_dcp->d_ostr;
            eff = 1.0 + (str - 1.0) * eff;
        } else
            eff = sector_strength(getsectp(com->x, com->y));
    } else if (com->type == EF_SHIP && com->own != player->cnum) {
        getship(com->shp_uid, &ship);
        eff = 1.0 + ship.shp_armor / 100.0;
    }
    return eff;
}

int
att_get_offense(int combat_mode, struct combat *off,
                struct emp_qelem *olist, struct combat *def)
{
    int ototal;

    /*
     * Get the attacker units & mil again in case they changed while the
     * attacker was answering sub-prompts.
     */

    ototal = get_ototal(combat_mode, off, olist, 1.0, 1);
    if (att_empty_attack(combat_mode, ototal, def))
        return abort_attack();
    if (combat_mode == A_PARA)
        return ototal;
    pr("\n             Initial attack strength: %8d\n", ototal);
    return ototal;
}

/* Get the defensive units and reacting units */
int
att_get_defense(struct emp_qelem *olist, struct combat *def,
                struct emp_qelem *dlist, int a_spy, int ototal)
{
    int d_spy = 0;
    struct emp_qelem *qp;
    struct ulist *llp;
    int dtotal;
    int old_dtotal;

    emp_initque(dlist);
    get_dlist(def, dlist, 0, &d_spy);
    dtotal = get_dtotal(def, dlist, 1.0, 0);

    /*
     * Call in reacting units
     */

    if (def->type == EF_SECTOR && def->sct_type != SCT_MOUNT)
        att_reacting_units(def, dlist, a_spy, &d_spy, ototal);

    for (qp = olist->q_forw; qp != olist; qp = qp->q_forw) {
        llp = (struct ulist *)qp;
        intelligence_report(def->own, &llp->unit.land, d_spy,
                            "Scouts report attacking unit:");
    }

    old_dtotal = dtotal;
    dtotal = get_dtotal(def, dlist, 1.0, 0);
    if (dtotal != old_dtotal)
        pr("Defense strength with reacting units: %8d\n", dtotal);

    return dtotal;
}

/* Get the defensive land units in the sector or on the ship */

static void
get_dlist(struct combat *def, struct emp_qelem *list, int a_spy,
          int *d_spyp)
{
    struct nstr_item ni;
    struct ulist *llp;
    struct lndstr land;

/* In here is where you need to take out spies and trains from the defending
   lists.  Spies try to hide, trains get trapped and can be boarded. */

    snxtitem_xy(&ni, EF_LAND, def->x, def->y);
    while (nxtitem(&ni, &land)) {
        if (!land.lnd_own)
            continue;
        if (land.lnd_own != def->own)
            continue;
        if (def->type == EF_SECTOR && land.lnd_ship >= 0)
            continue;
        if (def->type == EF_SECTOR && land.lnd_land >= 0)
            continue;
        if (def->type == EF_SHIP && land.lnd_ship != def->shp_uid)
            continue;
        if (def->type == EF_LAND && land.lnd_land != def->lnd_uid)
            continue;
        if (!list) {            /* Just estimating the enemy strength */
            intelligence_report(player->cnum, &land, a_spy,
                                "Scouts report defending unit:");
            continue;
        }
        if (!(llp = malloc(sizeof(struct ulist)))) {
            logerror("Malloc failed in attack!\n");
            abort_attack();
            return;
        }
        memset(llp, 0, sizeof(struct ulist));
        emp_insque(&llp->queue, list);
        llp->supplied = has_supply(&land);
        if (!get_land(A_DEFEND, def, land.lnd_uid, llp, 1))
            continue;
        if (lnd_spyval(&land) > *d_spyp)
            *d_spyp = lnd_spyval(&land);
    }
}

/* Calculate the total offensive strength */

static int
get_ototal(int combat_mode, struct combat *off, struct emp_qelem *olist,
           double osupport, int check)
{
    double ototal = 0.0;
    struct emp_qelem *qp, *next;
    struct ulist *llp;
    int n, w;

    /*
     * first, total the attacking mil
     */

    for (n = 0; n <= off->last; ++n) {
        if (off[n].type == EF_BAD || (check &&
                                      att_get_combat(&off[n], 0) <= 0))
            continue;
        ototal += off[n].troops * att_combat_eff(off + n);
    }

    /*
     * next, add in the attack_values of all
     * the attacking units
     */

    for (qp = olist->q_forw; qp != olist; qp = next) {
        next = qp->q_forw;
        llp = (struct ulist *)qp;
        if (check && !get_land(combat_mode, 0, llp->unit.land.lnd_uid, llp, 0))
            continue;
        if (combat_mode == A_ATTACK) {
            w = -1;
            for (n = 0; n <= off->last; ++n) {
                if (off[n].type == EF_BAD)
                    continue;
                if ((off[n].x == llp->unit.land.lnd_x) &&
                    (off[n].y == llp->unit.land.lnd_y))
                    w = n;
            }
            if (w < 0) {
                lnd_delete(llp, "is in a sector not owned by you");
                continue;
            }
            ototal += attack_val(combat_mode, &llp->unit.land) *
                att_combat_eff(off + w);
        } else {
            ototal += attack_val(combat_mode, &llp->unit.land);
        }
    }
    ototal *= osupport;

    return ldround(ototal, 1);
}

/* Calculate the total defensive strength */

static int
get_dtotal(struct combat *def, struct emp_qelem *list, double dsupport,
           int check)
{
    double dtotal = 0.0, eff = 1.0, d_unit;
    struct emp_qelem *qp, *next;
    struct ulist *llp;

    if (check && att_get_combat(def, 1) < 0)
        return 0;
    eff = att_combat_eff(def);
    dtotal = def->troops * eff;

    /*
     * next, add in the defense_values of all
     * the defending non-retreating units
     */

    for (qp = list->q_forw; qp != list; qp = next) {
        next = qp->q_forw;
        llp = (struct ulist *)qp;
        if (check && !get_land(A_DEFEND, def, llp->unit.land.lnd_uid, llp, 1))
            continue;
        d_unit = defense_val(&llp->unit.land);
        if (!llp->supplied)
            d_unit /= 2.0;
        dtotal += d_unit * eff;
    }

    dtotal *= dsupport;

    return ldround(dtotal, 1);
}

/*
 * This is the land unit integrity check.  Note that we don't print
 * warnings about victim land units because the attacker may not have seen them
 */

static int
get_land(int combat_mode, struct combat *def, int uid, struct ulist *llp,
         int victim_land)
{
    struct lndstr *lp = &llp->unit.land;
    char buf[512];

    getland(uid, lp);

    if (!llp->chrp) {           /* first time */
        llp->x = llp->unit.land.lnd_x;
        llp->y = llp->unit.land.lnd_y;
        llp->chrp = (struct empobj_chr *)&lchr[(int)llp->unit.land.lnd_type];
    } else {                    /* not first time */
        if (lp->lnd_effic < LAND_MINEFF) {
            sprintf(buf, "was destroyed and is no longer a part of the %s",
                    att_mode[combat_mode]);
            lnd_delete(llp, buf);
            return 0;
        }
        if (victim_land) {
            if (lp->lnd_x != def->x || lp->lnd_y != def->y) {
                lnd_delete(llp,
                           "left to go fight another battle and is no longer a part of the defense");
                return 0;
            }
        } else {
            if (lp->lnd_own != player->cnum) {
                sprintf(buf,
                        "was destroyed and is no longer a part of the %s",
                        att_mode[combat_mode]);
                lnd_delete(llp, buf);
                return 0;
            }
            if (lp->lnd_x != llp->x || lp->lnd_y != llp->y) {
                sprintf(buf,
                        "left to fight another battle and is no longer a part of the %s",
                        att_mode[combat_mode]);
                lnd_delete(llp, buf);
                return 0;
            }
            if (lp->lnd_effic < llp->eff) {
                sprintf(buf, "damaged from %d%% to %d%%",
                        llp->eff, lp->lnd_effic);
                lnd_print(llp, buf);
            }
        }
    }
    llp->eff = llp->unit.land.lnd_effic;

    return 1;
}

/*
 * Put the land unit on the disk.  If there was some mobility cost, then
 * subtract it from the units mobility.  Note that this works the same way
 * as sectors & ships in that no mobility is actually taken until the attacker
 * has committed to attacking.
 */

static void
kill_land(struct emp_qelem *list)
{
    struct emp_qelem *qp, *next;
    struct ulist *llp;

    for (qp = list->q_forw; qp != list; qp = next) {
        next = qp->q_forw;
        llp = (struct ulist *)qp;
        if (llp->unit.land.lnd_ship >= 0) {
            llp->unit.land.lnd_effic = 0;
            lnd_delete(llp, "cannot return to the ship, and dies!");
        }
    }
}

static void
att_infect_units(struct emp_qelem *list, int plague)
{
    struct emp_qelem *qp, *next;
    struct ulist *llp;

    if (!plague)
        return;
    for (qp = list->q_forw; qp != list; qp = next) {
        next = qp->q_forw;
        llp = (struct ulist *)qp;
        if (llp->unit.land.lnd_pstage == PLG_HEALTHY)
            llp->unit.land.lnd_pstage = PLG_EXPOSED;
    }
}

static void
put_land(struct emp_qelem *list)
{
    struct emp_qelem *qp, *next;
    struct ulist *llp;

    for (qp = list->q_forw; qp != list; qp = next) {
        next = qp->q_forw;
        llp = (struct ulist *)qp;
        llp->unit.land.lnd_mission = 0;
        llp->unit.land.lnd_harden = 0;
        llp->unit.land.lnd_mobil -= (int)llp->mobil;
        llp->mobil = 0.0;
        putland(llp->unit.land.lnd_uid, &llp->unit.land);
        if (llp->unit.land.lnd_own != player->cnum) {
            emp_remque((struct emp_qelem *)llp);
            free(llp);
        } else
            get_land(A_ATTACK, 0, llp->unit.land.lnd_uid, llp, 0);
    }
}

/*
 * Keep sending in reinforcements until it looks like we're going to win.
 * Note that the "strength" command also calls this routine.
 */

double
att_reacting_units(struct combat *def, struct emp_qelem *list, int a_spy,
                   int *d_spyp, int ototal)
{
    struct nstr_item ni;
    struct lndstr land;
    struct sctstr sect, dsect;
    struct ulist *llp;
    int dtotal;
    double new_land = 0;
    double mobcost;
    double pathcost;
    int dist;
    int radius;
    int origx, origy;
    double eff = att_combat_eff(def);
    char buf[1024];

    if (list)
        dtotal = get_dtotal(def, list, 1.0, 1);
    else
        dtotal = 0;
    snxtitem_all(&ni, EF_LAND);
    while (nxtitem(&ni, &land) && dtotal + new_land * eff < 1.2 * ototal) {
        if (!land.lnd_own)
            continue;
        if (!land.lnd_rad_max)
            continue;
        if ((land.lnd_x == def->x) && (land.lnd_y == def->y))
            continue;
        if (land.lnd_own != def->own)
            continue;
        if (land.lnd_ship >= 0)
            continue;
        if (land.lnd_land >= 0)
            continue;
        if (defense_val(&land) < 1.0)
            continue;
        if (!lnd_can_attack(&land))
            continue;

        /* Only supplied units can react */
        if (!has_supply(&land))
            continue;

        dist = mapdist(land.lnd_x, land.lnd_y, def->x, def->y);

        getsect(land.lnd_x, land.lnd_y, &sect);
        /* Units on efficient headquarters can react 1 farther */
        if ((sect.sct_type == SCT_HEADQ) && (sect.sct_effic >= 60))
            radius = land.lnd_rad_max + 1;
        else
            radius = land.lnd_rad_max;

        if (land.lnd_mission == MI_RESERVE)
            radius += 2;

        if (dist > radius)
            continue;

        getsect(def->x, def->y, &dsect);
        if (!BestLandPath(buf, &sect, &dsect, &pathcost,
                          lnd_mobtype(&land)))
            continue;

        mobcost = lnd_pathcost(&land, pathcost);
        if (land.lnd_mobil < mobcost)
            continue;

        new_land += defense_val(&land);

        if (!list)              /* we are in the "strength" command */
            continue;

        /* move to defending sector */
        land.lnd_mobil -= ldround(mobcost, 1);
        origx = land.lnd_x;
        origy = land.lnd_y;
        land.lnd_x = def->x;
        land.lnd_y = def->y;
        putland(land.lnd_uid, &land);
        wu(0, land.lnd_own, "%s reacts to %s.\n",
           prland(&land), xyas(land.lnd_x, land.lnd_y, land.lnd_own));

        llp = malloc(sizeof(struct ulist));

        memset(llp, 0, sizeof(struct ulist));
        llp->supplied = 1;
        llp->x = origx;
        llp->y = origy;
        llp->chrp = (struct empobj_chr *)&lchr[(int)land.lnd_type];
        llp->unit.land = land;
        emp_insque(&llp->queue, list);
        if (lnd_spyval(&land) > *d_spyp)
            *d_spyp = lnd_spyval(&land);

        intelligence_report(player->cnum, &land, a_spy,
                            "Scouts sight reacting enemy unit:");
    }
    return new_land;
}

/* Pop off shells and fly bombing missions to get your attack multiplier up */

static double
get_osupport(char *outs, struct combat *def, int fort_sup, int ship_sup,
             int land_sup, int plane_sup)
{
    double osupport = 1.0;
    int dam;
    double af, as, au, ap;

    af = as = au = ap = 0.0;
    if (fort_sup) {
        dam = dd(def->own, player->cnum, def->x, def->y, 0, 0);
        af = dam / 100.0;
        osupport += af;
    }
    if (ship_sup) {
        dam = sd(def->own, player->cnum, def->x, def->y, 0, 0, 0);

        as = dam / 100.0;
        osupport += as;
    }

    if (land_sup) {
        dam = lnd_support(def->own, player->cnum, def->x, def->y, 0);
        au = dam / 100.0;
        osupport += au;
    }

    if (plane_sup) {
        dam = off_support(def->x, def->y, def->own, player->cnum);
        ap = dam / 100.0;
        osupport += ap;
    }
    sprintf(outs, "attacker\t%1.2f\t%1.2f\t%1.2f\t%1.2f\n", af, as, au,
            ap);
    return osupport;
}

/* Pop off shells and fly bombing missions to get your defense multiplier up */

static double
get_dsupport(char *outs, struct emp_qelem *list, struct combat *def,
             int ototal, int dtotal)
{
    double dsupport = 1.0;
    int dam;
    double df, ds, du, dp;
    int good = 0;

    df = ds = du = dp = 0.0;
    if (dtotal < 0.1 * ototal) {
        good = -1;
    } else if (dtotal >= 1.2 * ototal) {
        good = 1;
    } else {
        dam = dd(player->cnum, def->own, def->x, def->y, 0, 1);
        df = dam / 100.0;
        dsupport += df;

        dtotal = get_dtotal(def, list, dsupport, 0);
        if (dtotal < 1.2 * ototal) {
            dam = sd(player->cnum, def->own, def->x, def->y, 0, 1, 0);
            ds = dam / 100.0;
            dsupport += ds;
            dtotal = get_dtotal(def, list, dsupport, 0);
        }
        if (dtotal < 1.2 * ototal) {
            dam = lnd_support(player->cnum, def->own, def->x, def->y, 1);
            du = dam / 100.0;
            dsupport += du;
            dtotal = get_dtotal(def, list, dsupport, 1);
        }
        if (dtotal < 1.2 * ototal) {
            dam = def_support(def->x, def->y, player->cnum, def->own);
            dp = dam / 100.0;
            dsupport += dp;
        }
    }
    if (good)
        *outs = '\0';
    else
        sprintf(outs, "defender\t%1.2f\t%1.2f\t%1.2f\t%1.2f\n\n", df, ds,
                du, dp);
    if (def->own) {
        if (good < 0)
            wu(0, def->own,
               "\nOdds are bad for us...support cancelled.\n\n");
        else if (good > 0)
            wu(0, def->own,
               "\nOdds are good for us...support cancelled.\n\n");
    }
    return dsupport;
}

/*
 * Land mines add to the defense multiplier.  If the attacker has engineers
 * then this multiplier is cut in half.
 */

static double
get_mine_dsupport(struct combat *def, int a_engineer)
{
    int mines;
    struct sctstr sect;

    getsect(def->x, def->y, &sect);

    if (sect.sct_oldown != player->cnum) {
        mines = MIN(sect.sct_mines, 20);
        if (a_engineer)
            mines = ldround(mines / 2.0, 1);
        if (mines > 0) {
            if (def->own)
                wu(0, def->own, "Defending mines add %1.2f\n",
                   mines * 0.02);
            pr("Defending mines add %1.2f\n", mines * 0.02);
            return mines * 0.02;
        }
    }
    return 0.0;
}

/* Get the offensive and defensive support */
int
att_get_support(int combat_mode, int ofort, int oship, int oland,
                int oplane, struct emp_qelem *olist, struct combat *off,
                struct emp_qelem *dlist, struct combat *def,
                double *osupportp, double *dsupportp, int a_engineer)
{
    int ototal, dtotal;
    char osupports[512];
    char dsupports[512];

    if (combat_mode == A_PARA)
        *osupports = '\0';
    else
        *osupportp = get_osupport(osupports, def,
                                  ofort, oship, oland, oplane);

    /*
     * I need to put a 1 at the end of the next four total_stren calls
     * because units & mil may have been damaged by collateral damage or
     * nuclear warheads from the offensive & defensive support.
     */

    ototal = get_ototal(combat_mode, off, olist, *osupportp, 1);
    if (att_empty_attack(combat_mode, ototal, def))
        return abort_attack();
    dtotal = get_dtotal(def, dlist, *dsupportp, 1);

    /*
     * Calculate defensive support.  If odds are too good or too bad
     * then don't call in support.
     */

    *dsupportp = get_dsupport(dsupports, dlist, def, ototal, dtotal);
    ototal = get_ototal(combat_mode, off, olist, *osupportp, 1);
    if (att_empty_attack(combat_mode, ototal, def))
        return abort_attack();

    if ((*osupports || *dsupports) &&
        (*osupportp != 1.0 || *dsupportp != 1.0)) {
        pr("\n\t\tsupport values\n");
        pr("\t\tforts\tships\tunits\tplanes\n");
        if (*osupportp != 1.0)
            pr("%s", osupports);
        if (*dsupportp != 1.0)
            pr("%s", dsupports);
        if (def->own) {
            wu(0, def->own, "\n\t\tsupport values\n");
            wu(0, def->own, "\t\tforts\tships\tunits\tplanes\n");
            if (*osupportp != 1.0)
                wu(0, def->own, "%s", osupports);
            if (*dsupportp != 1.0)
                wu(0, def->own, "%s", dsupports);
        }
    }

    dtotal = get_dtotal(def, dlist, *dsupportp, 1);
    if (dtotal && def->type == EF_SECTOR)
        *dsupportp += get_mine_dsupport(def, a_engineer);
    return 0;
}

/* How many two-legged bipeds are in this combat force? */

static int
count_bodies(struct combat *off, struct emp_qelem *list)
{
    int n;
    int bodies = 0;
    struct emp_qelem *qp;
    struct ulist *llp;

    for (n = 0; n <= off->last; ++n)
        bodies += off[n].troops;
    for (qp = list->q_forw; qp != list; qp = qp->q_forw) {
        llp = (struct ulist *)qp;
        bodies += llp->unit.land.lnd_item[I_MILIT];
    }
    return bodies;
}

/* This is where the fighting actually occurs. */

int
att_fight(int combat_mode, struct combat *off, struct emp_qelem *olist,
          double osupport, struct combat *def, struct emp_qelem *dlist,
          double dsupport)
{
    int success = 0;
    int a_cas = 0;              /* Casualty counts */
    int d_cas = 0;
    int ototal;                 /* total attacking strength */
    int dtotal;                 /* total defending strength */
    int a_bodies;               /* total attacking mil (incl. mil in units) */
    int d_bodies;               /* total defending mil (incl. mil in units) */
    int d_mil;
    int a_troops[6];
    int n;
    int news_item;
    int recalctime;
    double odds;
    int newmob;
    char *action;

    ototal = get_ototal(combat_mode, off, olist, osupport,
                        combat_mode != A_PARA);
    dtotal = get_dtotal(def, dlist, dsupport, 0);
    if (!dtotal)
        success = 1;

    a_bodies = count_bodies(off, olist);
    d_bodies = count_bodies(def, dlist);
    d_mil = def->troops;
    for (n = 0; n <= off->last; ++n)
        if (off[n].type == EF_BAD)
            a_troops[n] = 0;
        else
            a_troops[n] = off[n].troops;

    /* This switch is required to get the spacing right */
    switch (combat_mode) {
    case A_ATTACK:
        pr("               Final attack strength: %8d\n", ototal);
        break;
    case A_ASSAULT:
        pr("              Final assault strength: %8d\n", ototal);
        break;
    case A_PARA:
        if (def->sct_type == SCT_MOUNT ||
            def->sct_type == SCT_WATER ||
            def->sct_type == SCT_CAPIT ||
            def->sct_type == SCT_FORTR || def->sct_type == SCT_WASTE) {
            pr("You can't air-assault a %s sector!\n",
               def->sct_dcp->d_name);
            a_cas = a_bodies;
            off[0].troops = 0;
            ototal = get_ototal(A_PARA, off, olist, osupport, 0);
        }
        pr("          Final air-assault strength: %8d\n", ototal);
        break;
    case A_BOARD:
    case A_LBOARD:
        pr("                Final board strength: %8d\n", ototal);
    }


    pr("              Final defense strength: %8d\n", dtotal);
    odds = att_calcodds(ototal, dtotal);
    pr("                          Final odds: %8d%%\n", (int)(odds * 100));

    /* spread the plague */
    if (combat_mode != A_PARA) {
        if (!def->plague)
            for (n = 0; n <= off->last; ++n)
                if (off[n].type != EF_BAD)
                    def->plague |= off[n].plague;
        for (n = 0; n <= off->last; ++n)
            if (off[n].type != EF_BAD)
                off[n].plague |= def->plague;
    }
    att_infect_units(olist, off->plague);
    att_infect_units(dlist, def->plague);

    /*
     * Fighting is slightly random.  There is always that last little 
     * effort you see people put in.  Or the stray bullet that takes out
     * an officer and the rest go into chaos.  Things like that.
     * Thus, we have added a very slight random factor that will sometimes
     * allow the little guy to win. We modify the odds a little
     * (either +- 5%) to account for this randomness.  We also only
     * recalculate the odds every 8-50 casualties, not every cacsualty,
     * since a single dead guy normally wouldn't cause a commander to
     * rethink his strategies, but 50 dead guys might.
     */
    odds += (random() % 11 - 5) / 100.0;
    if (odds < 0.0)
        odds = 0.1;
    if (odds > 1.0)
        odds = 1.0;
    recalctime = 8 + (random() % 43);
    while (!success && ototal) {
        if (chance(odds)) {
            pr("!");
            d_cas += take_casualty(A_DEFEND, def, dlist);
            dtotal = get_dtotal(def, dlist, dsupport, 0);
            if (!dtotal)
                ++success;
        } else {
            pr("@");
            a_cas += take_casualty(combat_mode, off, olist);
            ototal = get_ototal(combat_mode, off, olist, osupport, 0);
        }
        if (((a_cas + d_cas) % 70) == 69)
            pr("\n");
        if (recalctime-- <= 0) {
            recalctime = 8 + (random() % 43);
            odds = att_calcodds(ototal, dtotal);
            odds += (random() % 11 - 5) / 100.0;
            if (odds < 0.0)
                odds = 0.1;
            if (odds > 1.0)
                odds = 1.0;
        }
    }
    pr("\n");
    /* update defense mobility & mil */
    if (success)
        def->mil = 0;
    else {
        if (def->type == EF_SECTOR && d_mil && d_cas) {
            if (def->mob < 0)
                def->mobcost = 0;
            else {
                newmob = damage(def->mob, 100 * d_cas / d_mil);
                def->mobcost = MIN(20, def->mob - newmob);
            }
        }
        def->mil = def->troops;
    }

    /* update attack mobility & mil */
    for (n = 0; n <= off->last; ++n)
        if (off[n].type != EF_BAD && off[n].troops < a_troops[n]) {
            if (off[n].type == EF_SECTOR && off[n].mil) {
                if (!CANT_HAPPEN(off[n].mob < 0)) {
                    newmob = damage(off[n].mob,
                                    100 * (a_troops[n] - off[n].troops)
                                    / off[n].mil);
                    off[n].mobcost += MIN(20, off[n].mob - newmob);
                }
            }
            off[n].mil -= a_troops[n] - off[n].troops;
        }

    /* update land unit mobility */
    if (d_bodies && d_cas)
        lnd_takemob(dlist, (double)d_cas / d_bodies);
    if (a_bodies && a_cas)
        lnd_takemob(olist, (double)a_cas / a_bodies);

    /* damage attacked sector */
    def->eff = effdamage(def->eff, (d_cas + a_cas) / 10);

    pr("- Casualties -\n     Yours: %d\n", a_cas);
    pr("    Theirs: %d\n", d_cas);
    pr("Papershuffling ... %.1f B.T.U\n", (d_cas + a_cas) * 0.15);
    player->btused += (int)((d_cas + a_cas) * 0.015 + 0.5);

    if (success) {
        switch (combat_mode) {
        case A_ATTACK:
            news_item = def->own ? N_WON_SECT : N_TOOK_UNOCC;
            pr("We have captured %s, sir!\n", prcom(0, def));
            action = "taking";
            break;
        case A_ASSAULT:
            news_item = def->own ? N_AWON_SECT : N_START_COL;
            pr("We have secured a beachhead at %s, sir!\n", prcom(0, def));
            action = "assaulting and taking";
            break;
        case A_PARA:
            news_item = def->own ? N_PWON_SECT : N_PARA_UNOCC;
            pr("We have captured %s, sir!\n", prcom(0, def));
            action = "air-assaulting and taking";
            break;
        case A_BOARD:
            news_item = N_BOARD_SHIP;
            pr("We have boarded %s, sir!\n", prcom(0, def));
            action = "boarding";
            break;
        case A_LBOARD:
            news_item = N_BOARD_LAND;
            pr("We have boarded %s, sir!\n", prcom(0, def));
            action = "boarding";
            break;
        default:
            CANT_REACH();
            news_item = 0;
            action = "defeating";
        }
    } else {
        switch (combat_mode) {
        case A_ATTACK:
            news_item = N_SCT_LOSE;
            pr("You have been defeated!\n");
            action = "attacking";
            break;
        case A_ASSAULT:
            news_item = N_ALOSE_SCT;
            pr("You have been defeated!\n");
            kill_land(olist);
            action = "trying to assault";
            break;
        case A_PARA:
            news_item = N_PLOSE_SCT;
            pr("All of your troops were destroyed\n");
            action = "trying to air-assault";
            break;
        case A_BOARD:
            news_item = N_SHP_LOSE;
            pr("You have been repelled\n");
            kill_land(olist);
            action = "trying to board";
            break;
        case A_LBOARD:
            news_item = N_LND_LOSE;
            pr("You have been repelled\n");
            kill_land(olist);
            action = "trying to board";
            break;
        default:
            CANT_REACH();
            news_item = 0;
            action = "fighting";
        }
    }
    nreport(player->cnum, news_item, def->own, 1);
    if (def->own) {
        wu(0, def->own,
           "%s (#%d) lost %d troops %s %s\nWe lost %d troops defending\n",
           cname(player->cnum), player->cnum, a_cas,
           action, pr_com(0, def, def->own), d_cas);
    }

    send_reacting_units_home(dlist);

    /* putland the defending land */
    unit_put(dlist, 0);

    /* putland the attacking land */
    put_land(olist);

    /* put the victim sector/ship/land */
    if (!success || !take_def(combat_mode, olist, off, def))
        put_combat(def);

    /* put the attacking sectors/ship */
    for (n = 0; n <= off->last; ++n)
        if (off[n].type != EF_BAD)
            put_combat(&off[n]);

    if (!success)
        return 0;

    switch (combat_mode) {
    case A_ATTACK:
        ask_move_in(off, olist, def);

        /* put sectors again to get abandon warnings */
        for (n = 0; n <= off->last; ++n)
            if (off[n].type != EF_BAD)
                put_combat(&off[n]);
        break;
    default:
        att_move_in_off(combat_mode, off, olist, def);
    }
    if (def->mil > 0)
        pr("%d of your troops now occupy %s\n", def->mil, prcom(0, def));
    return 1;
}

/* What percentage of the combat forces going head-to-head are we? */

static double
att_calcodds(int ototal, int dtotal)
{
    double odds;

    /* calculate odds */
    if (ototal <= 0)
        odds = 0.0;
    else if (dtotal <= 0)
        odds = 1.0;
    else
        odds = (double)ototal / (dtotal + ototal);

    return odds;
}

/* Here's where the dead soldiers get dragged off the battlefield */

static int
take_casualty(int combat_mode, struct combat *off, struct emp_qelem *olist)
{
    int to_take = CASUALTY_LUMP;
    int biggest_troops = 0, index = -1;
    int n, tot_troops = 0, biggest_mil, cas;
    struct emp_qelem *qp, *biggest;
    struct ulist *llp;

    for (n = 0; n <= off->last; ++n) {
        if (off[n].type != EF_BAD) {
            tot_troops += off[n].troops;
            if (off[n].troops > biggest_troops) {
                biggest_troops = off[n].troops;
                index = n;
            }
        }
    }

    if (tot_troops)
        to_take -= tot_troops;

    if (to_take >= 0) {
        for (n = 0; n <= off->last; ++n)
            if (off[n].type != EF_BAD)
                off[n].troops = 0;
    } else {
        /*
         * They can all come off mil.  We rotate the casualties,
         * starting with the sector containing the most mil.
         */
        to_take = CASUALTY_LUMP;
        if (index < 0) {
            pr("ERROR: Tell the deity that you got the 'green librarian' error\n");
            index = 0;
        }
        while (to_take > 0) {
            for (n = index; n <= off->last && to_take; ++n) {
                if (off[n].type != EF_BAD && off[n].troops > 0) {
                    --to_take;
                    --off[n].troops;
                }
            }
            for (n = 0; n < index && to_take; ++n) {
                if (off[n].type != EF_BAD && off[n].troops > 0) {
                    --to_take;
                    --off[n].troops;
                }
            }
        }
        return CASUALTY_LUMP;
    }

    if (QEMPTY(olist))
        return CASUALTY_LUMP - to_take;

    /*
     *  Need to take some casualties from attacking units
     *  Procedure: find the biggest unit remaining (in
     *  terms of mil) and give it the casualties.
     */
    biggest = NULL;
    biggest_mil = -1;
    for (qp = olist->q_forw; qp != olist; qp = qp->q_forw) {
        llp = (struct ulist *)qp;

        if (llp->unit.land.lnd_item[I_MILIT] > biggest_mil) {
            biggest_mil = llp->unit.land.lnd_item[I_MILIT];
            biggest = qp;
        }
    }
    if (biggest == NULL)
        return CASUALTY_LUMP - to_take;

    llp = (struct ulist *)biggest;
    cas = lnd_take_casualty(combat_mode, llp, to_take);
    return CASUALTY_LUMP - (to_take - cas);
}

/* Send reacting defense units back to where they came from (at no mob cost) */

static void
send_reacting_units_home(struct emp_qelem *list)
{
    struct emp_qelem *qp, *next;
    struct ulist *llp;
    char buf[1024];

    for (qp = list->q_forw; qp != list; qp = next) {
        next = qp->q_forw;
        llp = (struct ulist *)qp;
        if ((llp->unit.land.lnd_x != llp->x) ||
            (llp->unit.land.lnd_y != llp->y)) {
            sprintf(buf, "returns to %s",
                    xyas(llp->x, llp->y, llp->unit.land.lnd_own));
            llp->unit.land.lnd_x = llp->x;
            llp->unit.land.lnd_y = llp->y;
            lnd_delete(llp, buf);
        }
    }
}

/* Check for 0 offense strength.  This call will always preceed an abort */

int
att_empty_attack(int combat_mode, int ototal, struct combat *def)
{
    if (ototal <= 0) {
        if (def->own && player->cnum != def->own) {
            wu(0, def->own,
               "%s (#%d) considered %sing you @%s\n",
               cname(player->cnum), player->cnum,
               att_mode[combat_mode], xyas(def->x, def->y, def->own));
        }
        pr("No troops for %s...\n", att_mode[combat_mode]);
        return 1;
    }
    return 0;
}

/*
 * Take the defending sector or ship from the defender and give it to the
 * attacker.
 */

static int
take_def(int combat_mode, struct emp_qelem *list, struct combat *off,
         struct combat *def)
{
    int n;
    int occuppied = 0;
    struct ulist *llp, *delete_me = 0;
    char buf[1024];
    struct sctstr sect;
    struct shpstr ship;
    struct lndstr land;

    for (n = 0; n <= off->last && !occuppied; ++n) {
        if (off[n].type != EF_BAD &&
            off[n].troops > 0 &&
            (off[n].type != EF_SECTOR || off[n].mob)) {
            ++occuppied;
            if (def->type == EF_LAND) {
                if (def->lnd_lcp->l_flags & L_SPY) {
                    continue;
                }
            }
            --(off[n].troops);
            --(off[n].mil);
            ++def->mil;
            pr("1 mil from %s moves %s\n",
               prcom(0, off + n), prcom(2, def));
        }
    }
    if (!occuppied) {
        if (QEMPTY(list)) {
            pr("%s left unoccupied\n", prcom(0, def));
            if (def->own)
                wu(0, def->own,
                   "No enemy troops moved %s so you still own it!\n",
                   pr_com(2, def, def->own));
            return 0;
        } else {
            llp = (struct ulist *)list->q_forw;
            llp->unit.land.lnd_x = def->x;
            llp->unit.land.lnd_y = def->y;
            take_move_in_mob(combat_mode, llp, off, def);
            if (def->type == EF_SHIP) {
                llp->unit.land.lnd_ship = def->shp_uid;
                sprintf(buf, "boards %s", prcom(0, def));
                delete_me = llp;
            } else {
                llp->unit.land.lnd_ship = -1;
                sprintf(buf, "moves in to occupy %s",
                        xyas(def->x, def->y, player->cnum));
                lnd_delete(llp, buf);
            }
        }
    }
    put_combat(def);
    if (def->type == EF_SECTOR) {
        getsect(def->x, def->y, &sect);
        takeover(&sect, player->cnum);
        if (sect.sct_type == SCT_CAPIT || sect.sct_type == SCT_MOUNT)
            caploss(&sect, def->own,
                    "* We have captured %s's capital, sir! *\n");
        putsect(&sect);
    } else if (def->type == EF_SHIP) {
        getship(def->shp_uid, &ship);
        takeover_ship(&ship, player->cnum, 1);
        putship(ship.shp_uid, &ship);
    } else if (def->type == EF_LAND) {
        getland(def->lnd_uid, &land);
        takeover_land(&land, player->cnum, 1);
        putland(land.lnd_uid, &land);
    }
    if (delete_me)
        lnd_delete(delete_me, buf);
    att_get_combat(def, 0);
    return 1;
}

/*
 * Ask the attacker which mil & land units they'd like to move into the
 * conquered sector.
 */

static void
ask_move_in(struct combat *off, struct emp_qelem *olist,
            struct combat *def)
{
    int n;
    struct emp_qelem *qp, *next;
    struct ulist *llp;
    char buf[512];
    char prompt[512];
    char land_answer[256];
    char *answerp;

    for (n = 0; n <= off->last; ++n)
        if (off[n].type != EF_BAD && off[n].troops > 0)
            if (off[n].mob) {
                ask_move_in_off(&off[n], def);
                if (player->aborted)
                    break;
            }

    if (QEMPTY(olist))
        return;
    memset(land_answer, 0, sizeof(land_answer));
    for (qp = olist->q_forw; qp != olist; qp = next) {
        next = qp->q_forw;
        llp = (struct ulist *)qp;
        answerp = &land_answer[(int)llp->unit.land.lnd_army];
        if (player->aborted || att_get_combat(def, 0) < 0)
            *answerp = 'N';
        if (*answerp == 'Y')
            continue;
        if (*answerp != 'N') {
            if (!get_land(A_ATTACK, def, llp->unit.land.lnd_uid, llp, 0))
                continue;
            sprintf(prompt, "Move in with %s (%c %d%%) [ynYNq?] ",
                    prland(&llp->unit.land),
                    llp->unit.land.lnd_army ? llp->unit.land.lnd_army : '~',
                    llp->unit.land.lnd_effic);
            *answerp = att_prompt(prompt, llp->unit.land.lnd_army);
            if (player->aborted || att_get_combat(def, 0) < 0)
                *answerp = 'N';
            if (!get_land(A_ATTACK, def, llp->unit.land.lnd_uid, llp, 0))
                continue;
        }
        if (*answerp == 'y' || *answerp == 'Y')
            continue;
        sprintf(buf, "stays in %s",
                xyas(llp->unit.land.lnd_x, llp->unit.land.lnd_y,
                     player->cnum));
        lnd_delete(llp, buf);
    }
    if (QEMPTY(olist))
        return;
    if (att_get_combat(def, 0) < 0) {
        for (qp = olist->q_forw; qp != olist; qp = next) {
            next = qp->q_forw;
            llp = (struct ulist *)qp;
            if (!get_land(A_ATTACK, def, llp->unit.land.lnd_uid, llp, 0))
                continue;
            sprintf(buf, "stays in %s",
                    xyas(llp->unit.land.lnd_x, llp->unit.land.lnd_y,
                         player->cnum));
            lnd_delete(llp, buf);
        }
        return;
    }
    if (opt_INTERDICT_ATT)
        lnd_interdict(olist, def->x, def->y, player->cnum);
    move_in_land(A_ATTACK, off, olist, def);
}

/* Move offensive land units to the conquered sector or ship */

static void
move_in_land(int combat_mode, struct combat *off, struct emp_qelem *olist,
             struct combat *def)
{
    struct emp_qelem *qp, *next;
    struct ulist *llp;
    char buf[512];

    if (QEMPTY(olist))
        return;
    for (qp = olist->q_forw; qp != olist; qp = next) {
        next = qp->q_forw;
        llp = (struct ulist *)qp;
        if (!get_land(combat_mode, def, llp->unit.land.lnd_uid, llp, 0))
            continue;
        take_move_in_mob(combat_mode, llp, off, def);
        llp->unit.land.lnd_x = def->x;
        llp->unit.land.lnd_y = def->y;
        if (def->type == EF_SHIP)
            llp->unit.land.lnd_ship = def->shp_uid;
        else
            llp->unit.land.lnd_ship = -1;
    }
    if (QEMPTY(olist))
        return;
    if (def->type == EF_SECTOR) {
        if (opt_INTERDICT_ATT) {
            lnd_sweep(olist, 0, 0, def->own);
            lnd_check_mines(olist);
        }
        sprintf(buf, "now occupies %s", prcom(0, def));
    } else {
        sprintf(buf, "boards %s", prcom(0, def));
    }
    if (QEMPTY(olist))
        return;
    for (qp = olist->q_forw; qp != olist; qp = next) {
        next = qp->q_forw;
        llp = (struct ulist *)qp;
        lnd_print(llp, buf);
    }
    if (QEMPTY(olist))
        return;
    unit_put(olist, 0);
}

/*
 * Move assaulting, paradropping, or boarding mil & units into def
 * If the mil are coming from a ship, then pack a lunch.
 */

void
att_move_in_off(int combat_mode, struct combat *off,
                struct emp_qelem *olist, struct combat *def)
{
    struct sctstr sect;
    struct shpstr ship;
    int troops, n;
    int lunchbox = 0;

    move_in_land(combat_mode, off, olist, def);

    for (n = 0; n <= off->last; ++n) {
        if (off[n].type == EF_BAD || !off[n].troops)
            continue;
        troops = off[n].troops;
        off[n].troops = 0;
        off[n].mil -= troops;
        def->mil += troops;
        put_combat(off + n);
        if (combat_mode == A_ASSAULT) {
            if (CANT_HAPPEN(off[n].type != EF_SHIP))
                continue;
            getship(off[n].shp_uid, &ship);
            lunchbox += (int)((troops + 1) * ship.shp_item[I_FOOD]
                              / (ship.shp_item[I_MILIT] + troops
                                 + ship.shp_item[I_CIVIL] + 0.5));

            ship.shp_item[I_FOOD] -= lunchbox;
            putship(ship.shp_uid, &ship);
        }
    }

    put_combat(def);

    if (combat_mode == A_ASSAULT) {
        if (CANT_HAPPEN(def->type != EF_SECTOR))
            return;
        getsect(def->x, def->y, &sect);
        if (lunchbox > ITEM_MAX - sect.sct_item[I_FOOD])
            lunchbox = ITEM_MAX - sect.sct_item[I_FOOD];
        sect.sct_item[I_FOOD] += lunchbox;
        putsect(&sect);
    }
}


/* Ask how many mil to move in from each sector */

static void
ask_move_in_off(struct combat *off, struct combat *def)
{
    int mob_support;
    int num_mil, dam = 0, left;
    double d, weight;
    char prompt[512];
    char buf[1024];
    char *p;

    if (att_get_combat(off, 0) <= 0)
        return;
    if (att_get_combat(def, 0) < 0)
        return;
    if (off->own != player->cnum)
        return;
    d = att_mobcost(off->own, def, MOB_MOVE);
    if ((mob_support = MIN(off->troops, (int)(off->mob / d))) <= 0)
        return;
    sprintf(prompt, "How many mil to move in from %s (%d max)? ",
            xyas(off->x, off->y, player->cnum), mob_support);
    if (!(p = getstring(prompt, buf)) || !*p || (num_mil = atoi(p)) <= 0)
        return;
/* Make sure we don't move in more than we can support mobility-wise */
    if (num_mil > mob_support)
        num_mil = mob_support;
    if (att_get_combat(off, 0) <= 0)
        return;
    if (att_get_combat(def, 0) < 0)
        return;
    if ((num_mil = MIN(off->troops, num_mil)) <= 0) {
        pr("No mil moved in from %s\n",
           xyas(off->x, off->y, player->cnum));
        return;
    }
    mob_support = MAX(1, (int)(num_mil * d));
    off->mob -= MIN(off->mob, mob_support);
    off->mil -= num_mil;
    off->troops -= num_mil;
    put_combat(off);
    left = num_mil;
    weight = (double)num_mil * ichr[I_MILIT].i_lbs;
    if (opt_INTERDICT_ATT && chance(weight / 200.0)) {
        if (chance(weight / 100.0))
            dam +=
                ground_interdict(def->x, def->y, player->cnum, "military");
        dam += check_lmines(def->x, def->y, weight);
    }

    if (dam) {
        left = commdamage(num_mil, dam, I_MILIT);
        if (left < num_mil) {
            if (left) {
                pr("%d of the mil you were moving were destroyed!\nOnly %d mil made it to %s\n", num_mil - left, left, xyas(def->x, def->y, player->cnum));
            } else {
                pr("All of the mil you were moving were destroyed!\n");
            }
        }
        /* maybe got nuked */
        if (att_get_combat(def, 0) < 0)
            return;
    }
    def->mil += left;
    put_combat(def);
}


/* Charge land units for moving into a sector or onto a ship */

static void
take_move_in_mob(int combat_mode, struct ulist *llp, struct combat *off,
                 struct combat *def)
{
    int mobcost;
    int new;

    switch (combat_mode) {
    case A_ATTACK:
        mobcost = lnd_pathcost(&llp->unit.land,
                               att_mobcost(off->own, def,
                                           lnd_mobtype(&llp->unit.land)));
        new = llp->unit.land.lnd_mobil - mobcost;
        if (new < -127)
            new = -127;
        llp->unit.land.lnd_mobil = new;
        break;
    case A_ASSAULT:
        if (off->shp_mcp->m_flags & M_LAND) {
            if (((struct lchrstr *)llp->chrp)->l_flags & L_MARINE)
                llp->unit.land.lnd_mobil -=
                    (float)etu_per_update * land_mob_scale * 0.5;
            else
                llp->unit.land.lnd_mobil -= (float)etu_per_update *
                    land_mob_scale;
        } else {
            if (((struct lchrstr *)llp->chrp)->l_flags & L_MARINE)
                llp->unit.land.lnd_mobil = 0;
            else
                llp->unit.land.lnd_mobil = -(float)etu_per_update *
                    land_mob_scale;
        }
        break;
    case A_BOARD:
        /* I arbitrarily chose the numbers 10 and 40 below -KHS */
        if (((struct lchrstr *)llp->chrp)->l_flags & L_MARINE)
            llp->unit.land.lnd_mobil -= 10;
        else
            llp->unit.land.lnd_mobil -= 40;
        break;
    }
    llp->unit.land.lnd_harden = 0;
}

static void
free_list(struct emp_qelem *list)
{
    struct emp_qelem *qp, *next;

    if (!list || QEMPTY(list))
        return;

    qp = list->q_forw;
    while (qp != list) {
        next = qp->q_forw;
        emp_remque(qp);
        free(qp);
        qp = next;
    }
}

int
att_free_lists(struct emp_qelem *olist, struct emp_qelem *dlist)
{
    free_list(olist);
    free_list(dlist);
    return RET_OK;
}

/*
 * sector_strength - Everyone starts at 1.  You can get up to a max
 *                   of d_dstr, depending on how much you build up the
 *                   defenses of the sector. 
 */

double
sector_strength(struct sctstr *sp)
{
    double def = SCT_DEFENSE(sp) / 100.0;
    double base = sp->sct_type == SCT_MOUNT ? 2.0 : 1.0;
    double d = base + (dchr[sp->sct_type].d_dstr - base) * def;

    if (d > dchr[sp->sct_type].d_dstr)
        d = dchr[sp->sct_type].d_dstr;
    if (d < base)
        d = base;
    return d;
}

---