/*
 *  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.
 *
 *  ---
 *
 *  sail.c: Sail ships during the update
 * 
 *  Known contributors to this file:
 *     Doug Hay
 *     Robert Forsman
 *     Ken Stevens, 1995
 *     Steve McClure, 1998-2000
 */

#include "misc.h"
#include "var.h"
#include "sect.h"
#include "path.h"
#include "ship.h"
#include "var.h"
#include "news.h"
#include "file.h"
#include "nat.h"
#include "xy.h"
#include "nsc.h"
#include "update.h"
#include "subs.h"
#include "common.h"
#include <stdlib.h>

static void
cost_ship(struct shpstr *sp, struct fltelemstr *ep, struct fltheadstr *fp)
{
	double	mobcost,ceil(double);
	int	howfar;

	mobcost = 0.0;
	if (sp->shp_effic > 0) {
		mobcost = sp->shp_effic * sp->shp_speed * 0.01;
		mobcost = 480.0 / ( mobcost*(1 + (50+sp->shp_tech)/
					(double)(200+sp->shp_tech)));
	}
/* the next two lines are not necessary since shp_mobquota is unsigned
and therefore cannot be less than 0. 
	if (sp->shp_mobquota<0)
		sp->shp_mobquota=0;
*/

	howfar = 0;
	if (mobcost > 0) {
		howfar = (int)sp->shp_mobil - (int)sp->shp_mobquota;
		howfar = ceil((howfar / mobcost));
	}
	if (howfar<0)
		howfar=0;
#ifdef SAILDEBUG
	wu(0,fp->own,
		"Ship #%d can move %d spaces on mobility %d (cost/sect %f)\n",
		sp->shp_uid, howfar, sp->shp_mobil, mobcost);
#endif
	if ((unsigned int)howfar < fp->maxmoves)
		fp->maxmoves = howfar;

	ep->mobil = sp->shp_mobil;
	ep->mobcost = mobcost;
}

static int
sail_find_fleet(struct fltheadstr **head, struct shpstr *sp)
{
	struct fltheadstr *fltp;
	struct shpstr	*ap;
	struct fltelemstr *this;
	int  len=0;
	int  follow = -1;
	int  stop;
	s_char *cp;

	if (sp->shp_own==0)
		return(0);



	/* If this ship is following, find the head of the follow list. */
	for (ap=sp; ap; len++, ap=getshipp(follow)) {
		follow = ap->shp_follow;
		/* Not same owner */
		if (ap->shp_own != sp->shp_own) {
			wu(0, sp->shp_own, 
				"Ship #%d, following #%d, which you don't own.\n",
				sp->shp_uid, ap->shp_uid);
			return(0);
		}
		/* Not a follower. */
		if (ap->shp_path[0] != 'f')
			break;
		/* Following itself */
		if (follow==ap->shp_uid ||
		    follow==sp->shp_uid)
			break;
	}
	if (!ap) {
		wu(0, sp->shp_own,
			"Ship #%d, following #%d, which you don't own.\n",
			sp->shp_uid, follow);
		return(0);
	}

	/* This should prevent infinite loops. */
	if (len>=10) {
		wu(0,sp->shp_own,
			"Ship #%d, too many follows (circular follow?).\n",
			sp->shp_uid);
		return(0);
	}

	for (stop=0,cp=ap->shp_path; (!stop) && (*cp); cp++) {
		switch (*cp) {
			case 'y':
			case 'u':
			case 'g':
			case 'j':
			case 'b':
			case 'n':
			case 'h':
			case 't':
				break;
			default:
				stop=1;
		}
	}

	/* we found a non-valid char in the path. */
	if (*cp) {
		wu(0,ap->shp_own, "invalid char '\\%03o' in path of ship %d\n",
			(unsigned char)*cp, ap->shp_uid);
		*cp=0;
	}

	/* if this ship is not sailing anywhere then ignore it. */
	if (!*ap->shp_path)
		return(0);

	/* Find the fleet structure we belong to. */
	for (fltp=(*head); (fltp && fltp->leader != follow); fltp = fltp->next)
		;

	if (!fltp) {
		fltp = (struct fltheadstr *) malloc(sizeof(*fltp));
		bzero((s_char *)fltp, sizeof(*fltp));

		/* Fix the links. */
		fltp->next = (*head);
		*head = fltp;

		/* Set the leader. */
		fltp->leader = ap->shp_uid;
		fltp->real_q = LEADER_REAL;
		fltp->x = ap->shp_x;
		fltp->y = ap->shp_y;
		fltp->own = ap->shp_own;
		fltp->maxmoves = 500;
	}

	/* If the fleet is not in the same sector as us, no go. */
	if ( ( fltp->x!=sp->shp_x ) || ( fltp->y!=sp->shp_y ) ) {
		wu(0,sp->shp_own,
			"Ship %d not in same sector as its sailing fleet\n",
			sp->shp_uid);
		fltp->real_q = LEADER_WRONGSECT;
		return(0);
	}

	this = (struct fltelemstr *) malloc(sizeof(*this));
	bzero((s_char *)this, sizeof(*this));
	this->num = sp->shp_uid;
	this->own = sp->shp_own;
	this->next = fltp->head;
	fltp->head = this;
	cost_ship(sp, this, fltp);

	return 1;
}

static int
sail_nav_fleet(struct fltheadstr *fltp)
{
	struct fltelemstr *fe;
	struct shpstr	*sp, ship;
	int	vec[I_MAX+1];
	struct sctstr *sectp;
	int	error=0;
	s_char	*s, *p;
	natid	own;
	struct	emp_qelem ship_list;
	int	dir;

#ifdef SAILDEBUG
	switch (fltp->real_q) {
	case LEADER_VIRTUAL:
		s = "leaderless";
		break;
	case LEADER_REAL:
		s = "real";
		break;
	case LEADER_WRONGSECT:
		s = "scattered";
		break;
	default:
		s = "inconsistent";
	}
	wu(0,fltp->own,
		"Fleet lead by %d is %s, can go %d spaces\n  contains ships:",
		fltp->leader, s, fltp->maxmoves);
	for (fe=fltp->head; fe; fe = fe->next)
		wu(0, fltp->own, " %d", fe->num);
	wu(0, fltp->own, "\n");
#endif
	sectp = getsectp(fltp->x, fltp->y);
	switch (check_nav(sectp)) {
	case CN_NAVIGABLE:
		break;
	case CN_CONSTRUCTION:
	case CN_LANDLOCKED:
	default:
		wu(0,fltp->own, "Your fleet lead by %d is trapped by land.\n",
			fltp->leader);
		return(0);
	}
	for (fe=fltp->head; fe; fe = fe->next) {
		sp = getshipp(fe->num);
		getvec(VT_ITEM, vec, (s_char *)sp, EF_SHIP);
		if (vec[I_MILIT]==0 && vec[I_CIVIL]==0) {
			wu(0,fltp->own,
			"   ship #%d (%s) is crewless and can't go on\n",
				fe->num, cname(fe->own));
			error = 1;
		}
	}
	if (error)
		return(0);
	sp = getshipp(fltp->leader);
	own = sp->shp_own;
	fltp_to_list(fltp, &ship_list); /* hack -KHS 1995 */
	for (s=sp->shp_path; (*s) && (fltp->maxmoves>0); s++) {
		dir = chkdir(*s, DIR_STOP, DIR_LAST);
		if (0 != (error = shp_nav_one_sector(&ship_list, dir, own, 0)))
			fltp->maxmoves = 1;
		--(fltp->maxmoves);
	}
	shp_put(&ship_list, own);
	getship(sp->shp_uid, &ship);
	fltp->x = ship.shp_x;
	fltp->y = ship.shp_y;
	for (p=&ship.shp_path[0]; *s; p++,s++)
		*p = *s;
	*p = 0;
	putship(ship.shp_uid, &ship);
#ifdef SAILDEBUG
	if (sp->shp_path[0]) {
		wu(0,fltp->own,
			"Fleet lead by #%d nav'd to %s, path left = %s\n",
			fltp->leader, xyas(fltp->x,fltp->y,fltp->own),
			&sp->shp_path);
	} else
		wu(0,fltp->own,
			"Fleet lead by #%d nav'd to %s, finished.\n",
			fltp->leader, xyas(fltp->x,fltp->y,fltp->own));
		wu(0,sp->shp_own, "Ship #%d has %d mobility now.\n",
			fe->num, (int)fe->mobil);
#endif
	return 1;
}

void
sail_ship(natid cn)
{  
	struct shpstr	*sp;
	struct fltheadstr *head=0;
	struct fltheadstr *fltp;
	int	n;


	for (n=0; NULL != (sp = getshipp(n)); n++) if (sp->shp_own==cn) {
		sail_find_fleet(&head, sp);
	}

	/* see what the fleets fall out into */
	for (fltp=head; fltp; fltp = fltp->next) {
		sail_nav_fleet(fltp);
		wu(0,fltp->own, "Your fleet lead by ship #%d has reached %s.\n",
		       fltp->leader,xyas(fltp->x,fltp->y,fltp->own));
	}

	/* Free up the memory, 'cause I want to. */
	for (fltp=head; fltp!=0; ) {
		struct fltelemstr *fe;
		struct fltheadstr	*saveh;
		saveh = fltp->next;
		for (fe=fltp->head; fe!=0; ) {
			struct fltelemstr *saveel;
			saveel = fe->next;
			free(fe);
			fe = saveel;
		}
		free(fltp);
		fltp = saveh;
	}
}

/* The following is a total hack by Ken Stevens to cut down dramatically on repeated code 1995 */

void
fltp_to_list(struct fltheadstr *fltp, struct emp_qelem *list)
{
	struct fltelemstr *fe;
	struct mlist *mlp;
	struct shpstr *sp;

	emp_initque(list);
	for (fe=fltp->head; fe; fe = fe->next) {
		mlp = (struct mlist *) malloc(sizeof(struct mlist));
		sp = getshipp(fe->num);
		mlp->mcp = mchr + sp->shp_type;
		bcopy((s_char *)sp, (s_char *)&mlp->ship,
			sizeof(struct shpstr));
		mlp->mobil = fe->mobil;
		emp_insque(&mlp->queue, list);
	}
}