/*
 * Copyright (C) Volition, Inc. 1999.  All rights reserved.
 *
 * All source code herein is the property of Volition, Inc. You may not sell 
 * or otherwise commercially exploit the source or things you created based on the 
 * source.
 *
*/ 



#include "object/objcollide.h"
#include "ship/ship.h"
#include "debris/debris.h"
#include "playerman/player.h"
#include "ship/shiphit.h"
#include "io/timer.h"
#include "asteroid/asteroid.h"
#include "hud/hud.h"
#include "object/object.h"
#include "parse/scripting.h"


void calculate_ship_ship_collision_physics(collision_info_struct *ship_ship_hit_info);

/**
 * Checks debris-ship collisions.  
 * @param pair obj_pair pointer to the two objects. pair->a is debris and pair->b is ship.
 * @return 1 if all future collisions between these can be ignored
 */
int collide_debris_ship( obj_pair * pair )
{
	float dist;
	object *pdebris = 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;
	}

	Assert( pdebris->type == OBJ_DEBRIS );
	Assert( pship->type == OBJ_SHIP );

	// don't check collision if it's our own debris and we are dying
	if ( (pdebris->parent == OBJ_INDEX(pship)) && (Ships[pship->instance].flags & SF_DYING) )
		return 0;

	dist = vm_vec_dist( &pdebris->pos, &pship->pos );
	if ( dist < pdebris->radius + pship->radius )	{
		int hit;
		vec3d	hitpos;
		// create and initialize ship_ship_hit_info struct
		collision_info_struct debris_hit_info;
		init_collision_info_struct(&debris_hit_info);

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

		hit = debris_check_collision(pdebris, pship, &hitpos, &debris_hit_info );
		if ( hit )
		{
			Script_system.SetHookObjects(2, "Ship", pship, "Debris", pdebris);

			Script_system.SetHookObjects(2, "Self",pship, "Object", pdebris);
			bool ship_override = Script_system.IsConditionOverride(CHA_COLLIDEDEBRIS, pship);

			Script_system.SetHookObjects(2, "Self",pdebris, "Object", pship);
			bool debris_override = Script_system.IsConditionOverride(CHA_COLLIDESHIP, pdebris);
			if(!ship_override && !debris_override)
			{
				float		ship_damage;	
				float		debris_damage;

				// do collision physics
				calculate_ship_ship_collision_physics( &debris_hit_info );

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

				// calculate ship damage
				ship_damage = 0.005f * debris_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;

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

				// modify ship damage by debris damage multiplier
				ship_damage *= Debris[pdebris->instance].damage_mult;

				// supercaps cap damage at 10-20% max hull ship damage
				if (Ship_info[Ships[pship->instance].ship_info_index].flags & SIF_SUPERCAP) {
					float cap_percent_damage = frand_range(0.1f, 0.2f);
					ship_damage = MIN(ship_damage, cap_percent_damage * Ships[pship->instance].ship_max_hull_strength);
				}

				// apply damage to debris
				debris_hit( pdebris, pship, &hitpos, debris_damage);		// speed => damage
				int quadrant_num, apply_ship_damage;

				// apply damage to ship unless 1) debris is from ship
				apply_ship_damage = !(pship->signature == pdebris->parent_sig);

				if ( debris_hit_info.heavy == pship ) {
					quadrant_num = get_ship_quadrant_from_global(&hitpos, pship);
					if ((pship->flags & OF_NO_SHIELDS) || !ship_is_shield_up(pship, quadrant_num) ) {
						quadrant_num = -1;
					}
					if (apply_ship_damage) {
						ship_apply_local_damage(debris_hit_info.heavy, debris_hit_info.light, &hitpos, ship_damage, quadrant_num, CREATE_SPARKS, debris_hit_info.submodel_num);
					}
				} else {
					// don't draw sparks using sphere hit position
					if (apply_ship_damage) {
						ship_apply_local_damage(debris_hit_info.light, debris_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, pdebris, pship==Player_obj);
			}

			Script_system.SetHookObjects(2, "Self",pship, "Object", pdebris);
			if(!(debris_override && !ship_override))
				Script_system.RunCondition(CHA_COLLIDEDEBRIS, '\0', NULL, pship);

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

			Script_system.RemHookVars(4, "Ship", "Debris", "Self","ObjectB");

			return 0;
		}
	} else {	//	Bounding spheres don't intersect, set timestamp for next collision check.
		float	ship_max_speed, debris_speed;
		float	time;
		ship *shipp;

		shipp = &Ships[pship->instance];

		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);

		debris_speed = pdebris->phys_info.speed;

		time = 1000.0f * (dist - pship->radius - pdebris->radius - 10.0f) / (ship_max_speed + debris_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;
}

/**
 * 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 & OF_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","ObjectB");

			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;
	}
}