/*
 *  Copyright (C) 1999 Brad Stephens
 *
 *  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 
 */

#include <stdlib.h>
#include <math.h>
#include "../log.h"
#include "../ballistics.h"
#include "../terrain.h"
#include "napalm.h"

Shellstat_bal
wepNapalmGuidance(void *info, struct Projectilepos_bal *prjpos,
		  Shellstat_bal(*initexplosion) (struct Projectilepos_bal *
						 prjpos,
						 void **explosioninfo),
		  void **explosioninfo)
{
    int ix, iy;
    int i;
    Player_pl *plhit = NULL;
    unsigned char lets_blow = 0;
    Weapon_wep *bs;
    struct Projectilelist_bal *prj;
    double v, angle, vx1, vy1, vx2, vy2;
    IsectTypes_bal isect;

    prjpos->rox = prjpos->ox = prjpos->x;
    prjpos->roy = prjpos->oy = prjpos->y;
    prjpos->x += prjpos->vx + (bal_wind / bal_lerp_tweak);
    prjpos->y += prjpos->vy;
    prjpos->vy -= (bal_grav / bal_lerp_tweak);

    switch (balEnvironmentAdjustProjPos(prjpos))
    {
	case HOLDING:
	    /* wtf ??? */
	    break;
	case FLYING:
	    break;
	case EXPLODING:
	    lets_blow = 1;
	    break;
	case FREEING:
	    return FREEING;
	    break;
    }

    /* Need to check five spots for terrain.
     **
     **      <---o--->
     **         /|\
     **        / | \
     **       /  |  \
     */

    /* Left side */
    isect=balCheckIntersect(prjpos->x, prjpos->y, prjpos->x-NAPALM_HEIGHT, prjpos->y, &plhit, &ix, &iy);
    if(isect==TERRAIN_ISECT || isect==TANK_ISECT)
    {
	lets_blow = 1;
    }
    /* lower left */
    isect=balCheckIntersect(prjpos->x, prjpos->y, prjpos->x-NAPALM_HEIGHT, prjpos->y-NAPALM_HEIGHT, &plhit, &ix, &iy);
    if(isect==TERRAIN_ISECT || isect==TANK_ISECT)
    {
	lets_blow = 1;
    }
    /* below */
    isect=balCheckIntersect(prjpos->x, prjpos->y, prjpos->x, prjpos->y-NAPALM_HEIGHT, &plhit, &ix, &iy);
    if(isect==TERRAIN_ISECT || isect==TANK_ISECT)
    {
	lets_blow = 1;
    }
    /* lower right */
    isect=balCheckIntersect(prjpos->x, prjpos->y, prjpos->x+NAPALM_HEIGHT, prjpos->y-NAPALM_HEIGHT, &plhit, &ix, &iy);
    if(isect==TERRAIN_ISECT || isect==TANK_ISECT)
    {
	lets_blow = 1;
    }
    /* right side */
    isect=balCheckIntersect(prjpos->x, prjpos->y, prjpos->x+NAPALM_HEIGHT, prjpos->y, &plhit, &ix, &iy);
   if(isect==TERRAIN_ISECT || isect==TANK_ISECT)
    {
	lets_blow = 1;
    }
    if(lets_blow == 1)
    {
	/* Only blow if vy is less than 10 or so */
	if(prjpos->vy < 10)
	{
	    /* Put in the napalm projectiles */
	    bs = wepLookupWeapon("Burning Napalm");

	    logPrintf(DEBUG, "Exploding Napalm with vx=%f, vy=%f\n",
		      prjpos->vx, prjpos->vy);
	    /* Calculate some data for determining velocities */
	    angle = atan(prjpos->vy / prjpos->vx);
	    if(prjpos->vx < 0)
	    {
		angle += M_PI;	/* Need to get correct angle since atan goes from -90 to 90 degrees */
	    }
	    v = sqrt(pow(prjpos->vx, 2) + pow(prjpos->vy, 2));

	    logPrintf(DEBUG, "Angle=%f, Velocity=%f\n", (angle * 180 / M_PI),
		      v);

	    /* Launce a projectile following the path of the original */
	    prj =
		balNewShotXY(prjpos->id, 0, prjpos->x, prjpos->y, prjpos->vx,
			     prjpos->vy, bs);
	    prj->stat = INITSHOT(prj);

	    for(i = 1; i <= NAPALM_FRAGMENTS; i++)
	    {
		vx1 = v * cos(angle + (NAPALM_SPREAD * i));
		vy1 = v * sin(angle + (NAPALM_SPREAD * i));
		vx2 = v * cos(angle - (NAPALM_SPREAD * i));
		vy2 = v * sin(angle - (NAPALM_SPREAD * i));

		logPrintf(DEBUG, "Shot 1: (%f,%f), Shot 2: (%f,%f)\n", vx1,
			  vy1, vx2, vy2);

		prj =
		    balNewShotXY(prjpos->id, 0, prjpos->x, prjpos->y, vx1,
				 vy1, bs);
		prj->stat = INITSHOT(prj);

		prj =
		    balNewShotXY(prjpos->id, 0, prjpos->x, prjpos->y, vx2,
				 vy2, bs);
		prj->stat = INITSHOT(prj);
	    }

	    return initexplosion(prjpos, explosioninfo);
	}
    }

    return FLYING;
}

Shellstat_bal
wepBurningNapalmExplosionInit(struct Projectilepos_bal * prjpos,
			      void **explosioninfo)
{
    struct DurationExplosion_wep *e = (struct DurationExplosion_wep*)malloc(sizeof(struct DurationExplosion_wep));

    e->x = prjpos->x;
    e->y = prjpos->y;
    e->width = NAPALM_EXPL_WIDTH;
    e->id = prjpos->id;
    e->duration = NAPALM_EXPL_DURATION;
    e->wid = prjpos->wid;

    *((struct DurationExplosion_wep**)explosioninfo)=e;
    return EXPLODING;
}

Shellstat_bal wepBurningNapalmExplosion(void *info)
{
    struct DurationExplosion_wep *prj = (struct DurationExplosion_wep *)info;
    Player_pl *pcur;

    prj->duration--;
    if(prj->duration < 0)
    {
	return FREEING;
    }
    else
    {
	for(pcur = pl_begin; pcur; pcur = pcur->next)
	{
	    if(pcur->ready==READY && plPlayerInCircleArea(pcur, prj->x, prj->y, (prj->width/2)))	
	    {
		pcur->last_hit = prj->id;
		plDamageTank(pcur, EXPLOSIVE,
			     prj->id, prj->wid, 1);
	    }
	}
	return EXPLODING;
    }
}