// Checks debris-weapon collisions.  pair->a is debris and pair->b is weapon.
// Returns 1 if all future collisions between these can be ignored
int collide_asteroid_weapon( obj_pair * pair )
{
#if !(defined(FS2_DEMO) || defined(FS1_DEMO))

	if (!Asteroids_enabled)
		return 0;

	vector	hitpos;
	int		hit;
	object	*pasteroid = pair->a;
	object	*weapon = pair->b;

	Assert( pasteroid->type == OBJ_ASTEROID);
	Assert( weapon->type == OBJ_WEAPON );

	// first check the bounding spheres of the two objects.
	hit = fvi_segment_sphere(&hitpos, &weapon->last_pos, &weapon->pos, &pasteroid->pos, pasteroid->radius);
	if (hit) {
		hit = asteroid_check_collision(pasteroid, weapon, &hitpos );
		if ( !hit )
			return 0;

		weapon_hit( weapon, pasteroid, &hitpos );
		asteroid_hit( pasteroid, weapon, &hitpos, Weapon_info[Weapons[weapon->instance].weapon_info_index].damage );
		return 0;

	} else {
		return weapon_will_never_hit( weapon, pasteroid, pair );
	}

#else
	return 0;
#endif
}				
/**
 * Checks debris-weapon collisions.  
 * @param pair obj_pair pointer to the two objects. pair->a is debris and pair->b is weapon.
 * @return 1 if all future collisions between these can be ignored
 */
int collide_asteroid_weapon( obj_pair * pair )
{
	if (!Asteroids_enabled)
		return 0;

	vec3d	hitpos, hitnormal;
	int		hit;
	object	*pasteroid = pair->a;
	object	*weapon_obj = pair->b;

	Assert( pasteroid->type == OBJ_ASTEROID);
	Assert( weapon_obj->type == OBJ_WEAPON );

	// first check the bounding spheres of the two objects.
	hit = fvi_segment_sphere(&hitpos, &weapon_obj->last_pos, &weapon_obj->pos, &pasteroid->pos, pasteroid->radius);
	if (hit) {
		hit = asteroid_check_collision(pasteroid, weapon_obj, &hitpos, NULL, &hitnormal);
		if ( !hit )
			return 0;

		Script_system.SetHookObjects(4, "Weapon", weapon_obj, "Asteroid", pasteroid, "Self", weapon_obj, "Object", pasteroid);

		bool weapon_override = Script_system.IsConditionOverride(CHA_COLLIDEASTEROID, weapon_obj);
		Script_system.SetHookObjects(2, "Self",pasteroid, "Object", weapon_obj);
		bool asteroid_override = Script_system.IsConditionOverride(CHA_COLLIDEWEAPON, pasteroid);

		if(!weapon_override && !asteroid_override)
		{
			weapon_hit( weapon_obj, pasteroid, &hitpos, -1, &hitnormal);
			asteroid_hit( pasteroid, weapon_obj, &hitpos, Weapon_info[Weapons[weapon_obj->instance].weapon_info_index].damage );
		}

		Script_system.SetHookObjects(2, "Self", weapon_obj, "Object", pasteroid);
		if(!(asteroid_override && !weapon_override))
			Script_system.RunCondition(CHA_COLLIDEASTEROID, '\0', NULL, weapon_obj);

		Script_system.SetHookObjects(2, "Self", pasteroid, "Object", weapon_obj);
		if((asteroid_override && !weapon_override) || (!asteroid_override && !weapon_override))
			Script_system.RunCondition(CHA_COLLIDEWEAPON, '\0', NULL, pasteroid, Weapons[weapon_obj->instance].weapon_info_index);

		Script_system.RemHookVars(4, "Weapon", "Asteroid", "Self", "Object");
		return 0;

	} else {
		return weapon_will_never_hit( weapon_obj, pasteroid, pair );
	}
}				
/**
 * Checks asteroid-ship collisions.  
 * @param pair obj_pair pointer to the two objects. pair->a is asteroid and pair->b is ship.
 * @return 1 if all future collisions between these can be ignored
 */
int collide_asteroid_ship( obj_pair * pair )
{
	if (!Asteroids_enabled)
		return 0;

	float		dist;
	object	*pasteroid = pair->a;
	object	*pship = pair->b;

	// Don't check collisions for warping out player
	if ( Player->control_mode != PCM_NORMAL )	{
		if ( pship == Player_obj ) return 0;
	}

	if (pasteroid->hull_strength < 0.0f)
		return 0;

	Assert( pasteroid->type == OBJ_ASTEROID );
	Assert( pship->type == OBJ_SHIP );

	dist = vm_vec_dist( &pasteroid->pos, &pship->pos );

	if ( dist < pasteroid->radius + pship->radius )	{
		int hit;
		vec3d	hitpos;
		// create and initialize ship_ship_hit_info struct
		collision_info_struct asteroid_hit_info;
		init_collision_info_struct(&asteroid_hit_info);

		if ( pasteroid->phys_info.mass > pship->phys_info.mass ) {
			asteroid_hit_info.heavy = pasteroid;
			asteroid_hit_info.light = pship;
		} else {
			asteroid_hit_info.heavy = pship;
			asteroid_hit_info.light = pasteroid;
		}

		hit = asteroid_check_collision(pasteroid, pship, &hitpos, &asteroid_hit_info );
		if ( hit )
		{
			//Scripting support (WMC)
			Script_system.SetHookObjects(4, "Ship", pship, "Asteroid", pasteroid, "Self",pship, "Object", pasteroid);
			bool ship_override = Script_system.IsConditionOverride(CHA_COLLIDEASTEROID, pship);

			Script_system.SetHookObjects(2, "Self",pasteroid, "Object", pship);
			bool asteroid_override = Script_system.IsConditionOverride(CHA_COLLIDESHIP, pasteroid);

			if(!ship_override && !asteroid_override)
			{
				float		ship_damage;	
				float		asteroid_damage;

				vec3d asteroid_vel = pasteroid->phys_info.vel;

				// do collision physics
				calculate_ship_ship_collision_physics( &asteroid_hit_info );

				if ( asteroid_hit_info.impulse < 0.5f )
					return 0;

				// limit damage from impulse by making max impulse (for damage) 2*m*v_max_relative
				float max_ship_impulse = (2.0f*pship->phys_info.max_vel.xyz.z+vm_vec_mag_quick(&asteroid_vel)) * 
					(pship->phys_info.mass*pasteroid->phys_info.mass) / (pship->phys_info.mass + pasteroid->phys_info.mass);

				if (asteroid_hit_info.impulse > max_ship_impulse) {
					ship_damage = 0.001f * max_ship_impulse;
				} else {
					ship_damage = 0.001f * asteroid_hit_info.impulse;	//	Cut collision-based damage in half.
				}

				//	Decrease heavy damage by 2x.
				if (ship_damage > 5.0f)
					ship_damage = 5.0f + (ship_damage - 5.0f)/2.0f;

				if ((ship_damage > 500.0f) && (ship_damage > Ships[pship->instance].ship_max_hull_strength/8.0f)) {
					ship_damage = Ships[pship->instance].ship_max_hull_strength/8.0f;
					nprintf(("AI", "Pinning damage to %s from asteroid at %7.3f (%7.3f percent)\n", Ships[pship->instance].ship_name, ship_damage, 100.0f * ship_damage/Ships[pship->instance].ship_max_hull_strength));
				}

				//	Decrease damage during warp out because it's annoying when your escoree dies during warp out.
				if (Ai_info[Ships[pship->instance].ai_index].mode == AIM_WARP_OUT)
					ship_damage /= 3.0f;

				// calculate asteroid damage and set asteroid damage to greater or asteroid and ship
				// asteroid damage is needed since we can really whack some small asteroid with afterburner and not do
				// significant damage to ship but the asteroid goes off faster than afterburner speed.
				asteroid_damage = asteroid_hit_info.impulse/pasteroid->phys_info.mass;	// ie, delta velocity of asteroid
				asteroid_damage = (asteroid_damage > ship_damage) ? asteroid_damage : ship_damage;

				// apply damage to asteroid
				asteroid_hit( pasteroid, pship, &hitpos, asteroid_damage);		// speed => damage

				//extern fix Missiontime;

				int quadrant_num;
				if ( asteroid_hit_info.heavy == pship ) {
					quadrant_num = get_ship_quadrant_from_global(&hitpos, pship);
					if ((pship->flags[Object::Object_Flags::No_shields]) || !ship_is_shield_up(pship, quadrant_num) ) {
						quadrant_num = -1;
					}
					ship_apply_local_damage(asteroid_hit_info.heavy, asteroid_hit_info.light, &hitpos, ship_damage, quadrant_num, CREATE_SPARKS, asteroid_hit_info.submodel_num);
				} else {
					// don't draw sparks (using sphere hitpos)
					ship_apply_local_damage(asteroid_hit_info.light, asteroid_hit_info.heavy, &hitpos, ship_damage, MISS_SHIELDS, NO_SPARKS);
				}

				// maybe print Collision on HUD
				if ( pship == Player_obj ) {					
					hud_start_text_flash(XSTR("Collision", 1431), 2000);
				}

				collide_ship_ship_do_sound(&hitpos, pship, pasteroid, pship==Player_obj);
			}

			Script_system.SetHookObjects(2, "Self",pship, "Object", pasteroid);
			if(!(asteroid_override && !ship_override))
				Script_system.RunCondition(CHA_COLLIDEASTEROID, '\0', NULL, pship);

			Script_system.SetHookObjects(2, "Self",pasteroid, "Object", pship);
			if((asteroid_override && !ship_override) || (!asteroid_override && !ship_override))
				Script_system.RunCondition(CHA_COLLIDESHIP, '\0', NULL, pasteroid);

			Script_system.RemHookVars(4, "Ship", "Asteroid", "Self", "Object");

			return 0;
		}

		return 0;
	} else {
		// estimate earliest time at which pair can hit
		float asteroid_max_speed, ship_max_speed, time;
		ship *shipp = &Ships[pship->instance];

		asteroid_max_speed = vm_vec_mag(&pasteroid->phys_info.vel);		// Asteroid... vel gets reset, not max vel.z
		asteroid_max_speed = MAX(asteroid_max_speed, 10.0f);

		if (ship_is_beginning_warpout_speedup(pship)) {
			ship_max_speed = MAX(ship_get_max_speed(shipp), ship_get_warpout_speed(pship));
		} else {
			ship_max_speed = ship_get_max_speed(shipp);
		}
		ship_max_speed = MAX(ship_max_speed, 10.0f);
		ship_max_speed = MAX(ship_max_speed, pship->phys_info.vel.xyz.z);


		time = 1000.0f * (dist - pship->radius - pasteroid->radius - 10.0f) / (asteroid_max_speed + ship_max_speed);		// 10.0f is a safety factor
		time -= 200.0f;		// allow one frame slow frame at ~5 fps

		if (time > 100) {
			pair->next_check_time = timestamp( fl2i(time) );
		} else {
			pair->next_check_time = timestamp(0);	// check next time
		}
		return 0;
	}
}