/*
 *  Empire - A multi-player, client/server Internet based war game.
 *  Copyright (C) 1986-2000, Dave Pare, Jeff Bailey, Thomas Ruschak,
 *                           Ken Stevens, Steve McClure
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 *  ---
 *
 *  See the "LEGAL", "LICENSE", "CREDITS" and "README" files for all the
 *  related information and legal notices. It is expected that any future
 *  projects/authors will amend these files as needed.
 *
 *  ---
 *
 *  lten.c: Transfer commodity from a ship to a land unit the ship is
 *          carrying
 * 
 *  Known contributors to this file:
 *     Dave Pare, 1986
 *     Thomas Ruschak
 *     Ken Stevens, 1995
 *     Steve McClure, 1998
 */

#include "misc.h"
#include "player.h"
#include "var.h"
#include "xy.h"
#include "file.h"
#include "ship.h"
#include "item.h"
#include "nsc.h"
#include "nat.h"
#include "plane.h"
#include "nuke.h"
#include "land.h"
#include "genitem.h"
#include "commands.h"

static void expose_land(struct shpstr *s1, struct lndstr *l1);

int
ltend(void)
{
	struct	nstr_item	targets;
	struct	nstr_item	tenders;
	struct	shpstr	tender;
	struct	lndstr	target;
	struct	ichrstr	*ip;
	struct	mchrstr	*vbase;
	struct	lchrstr	*lbase;
	int     amt;
	int     ontender;
	int     ontarget;
	int     maxtender;
	int     maxtarget;
	int     transfer;
	int     total;
	s_char	*p;
	s_char	buf[1024];

	if (!(ip = whatitem(player->argp[1], "Transfer what commodity? ")))
		return RET_SYN;
	
	if (!snxtitem(&tenders, EF_SHIP, getstarg(player->argp[2], "Tender(s)? ", buf)))
		return RET_SYN;
	while (nxtitem(&tenders, (s_char *)&tender)) {
		if (!player->owner)
			continue;
		if ((p = getstarg(player->argp[3], "Amount to transfer? ", buf)) == 0)
			break;
		if (!check_ship_ok(&tender))
		    return RET_FAIL;
		if ((amt = atoi(p)) == 0)
			break;
		ontender = getvar(ip->i_vtype, (s_char *)&tender, EF_SHIP);
		if (ontender == 0 && amt > 0) {
			pr("No %s on %s\n", ip->i_name, prship(&tender));
			return RET_FAIL;
		}
		vbase = &mchr[(int)tender.shp_type];
		maxtender = vl_find(ip->i_vtype, vbase->m_vtype,
			vbase->m_vamt, (int)vbase->m_nv);
		if (maxtender == 0) {
			pr("A %s cannot hold any %s\n",
			       mchr[(int)tender.shp_type].m_name,
			       ip->i_name);
			break;
		}
		if (!snxtitem(&targets, EF_LAND,
		    getstarg(player->argp[4], "Units to be tended? ", buf)))
			break;
		if (!check_ship_ok(&tender))
		    return RET_FAIL;
		total = 0;
		while (tend_nxtitem(&targets, (s_char *)&target)) {
			if (!player->owner)
				continue;

			if (target.lnd_ship != tender.shp_uid)
				continue;
			ontarget = getvar(ip->i_vtype,(s_char *)&target, EF_LAND);
			if (ontarget == 0 && amt < 0) {
				pr("No %s on %s\n",
					ip->i_name, prship((struct shpstr *)&target));
				continue;
			}
			lbase = &lchr[(int)target.lnd_type];
			maxtarget = vl_find(ip->i_vtype, lbase->l_vtype,
				lbase->l_vamt, (int)lbase->l_nv);
			if (amt < 0) {
				if (!player->owner)
					amt=0;

				/* take from target and give to tender */
				transfer = min(ontarget, -amt);
				transfer = min(maxtender - ontender, transfer);
				if (transfer == 0)
					continue;
				putvar(ip->i_vtype, ontarget - transfer,
					(s_char *)&target, EF_LAND);
				ontender += transfer;
				total += transfer;
			} else {
				/* give to target from tender */
				transfer = min(ontender, amt);
				transfer = min(transfer, maxtarget - ontarget);
				if (transfer == 0)
					continue;
				putvar(ip->i_vtype, ontarget + transfer,
					(s_char *)&target, EF_LAND);
				ontender -= transfer;
				total += transfer;
			}
			expose_land(&tender, &target);
			putland(target.lnd_uid, &target);
			if (amt > 0 && ontender == 0) {
				pr("%s out of %s\n", prship(&tender),
				   ip->i_name);
				break;
			}
		}
		pr("%d total %s transferred %s %s\n",
		   total, ip->i_name, (amt > 0) ? "off of" : "to",
		   prship(&tender));
		putvar(ip->i_vtype, ontender, (s_char *)&tender, EF_SHIP);
		tender.shp_mission = 0;
		putship(tender.shp_uid, &tender);
	}
	return RET_OK;
}

static void
expose_land(struct shpstr *s1, struct lndstr *l1)
{
	if (getvar(V_PSTAGE, (s_char *)s1, EF_SHIP) == PLG_INFECT &&
	    getvar(V_PSTAGE, (s_char *)l1, EF_LAND) == PLG_HEALTHY)
		putvar(V_PSTAGE, PLG_EXPOSED, (s_char *)l1, EF_LAND);
	if (getvar(V_PSTAGE, (s_char *)l1, EF_LAND) == PLG_INFECT &&
	    getvar(V_PSTAGE, (s_char *)s1, EF_SHIP) == PLG_HEALTHY)
		putvar(V_PSTAGE, PLG_EXPOSED, (s_char *)s1, EF_SHIP);
}