/*
   base/npc.cc
   This file is part of the Osirion project and is distributed under
   the terms of the GNU General Public License version 2
*/

#include "base/npc.h"
#include "base/game.h"

namespace game {
	
// NPC Wingman factory function
NPC *NPC::add_wingman(Ship *leader)
{
	if (!leader) {
		return 0;
	}
	
	if (leader->state() != Entity::Normal) {
		return 0;
	}

	NPC *npc = new NPC(ProfileWingman, leader->shipmodel());
	
	npc->set_leader(leader);
	npc->set_owner(leader->owner());
	npc->set_name("Wingman");
	npc->set_mood(MoodFormation);
	
	npc->set_color(npc->leader()->color());
	npc->set_color_second(npc->leader()->color_second());
	
	npc->set_location(leader->location() - leader->axis().forward() *  2.0f * (leader->radius() + npc->radius()));
	
	npc->set_axis(leader->axis());
	npc->set_zone(leader->zone());
	
	npc->reset();
	
	return npc;
}
	
NPC::NPC(const Profile profile, const ShipModel *shipmodel) : Ship(0, shipmodel)
{
	npc_profile = profile;
	npc_mood = MoodWander;
	npc_destroyed_timestamp = 0;
}

void NPC::set_mood(const Mood mood)
{
	npc_mood = mood;
}

void NPC::set_leader(Ship *leader)
{
	npc_leader = leader;
}

void NPC::frame(const unsigned long elapsed)
{
	if (state() == core::Entity::Destroyed) {
		
		if (!npc_destroyed_timestamp) {
			npc_destroyed_timestamp = core::game()->time();
			
		} else if (npc_destroyed_timestamp + 10.0f < core::game()->time()) {
		// stay alive for 10 more seconds while explosion particles are drawn
		
			die();
		}

	} else {
	
		// FIXME verify the leader is still alive
		
		// TODO pilot magic and mood witchcraft
		
		if (leader()) {
			
			// verify leader still exists
			if (!core::Entity::find(leader())) {
				
				set_leader(0);
				explode();
				npc_destroyed_timestamp = core::game()->time();
			
			} else if (leader()->zone() == zone()) {
				
				// rotate towards leader: direction
				math::Vector3f d(leader()->location() - location());
				float distance = d.length();
				
				d.normalize();
				
				float direction_angle = math::dotproduct(axis().forward(), d);
				float direction_sign = math::sgnf(math::dotproduct(axis().left(), d));
				
				if (direction_sign < 0 ) {
					target_direction = direction_sign;
				} else if (direction_angle + MIN_DELTA < 1.0f ) {
					target_direction = direction_sign * direction_angle;
				} else {
					target_direction = 0.0f;
				}
				
				// rotate towards leader: pitch
				direction_angle = math::dotproduct(axis().forward(), d);
				direction_sign = math::sgnf(math::dotproduct(axis().up(), d));
				
				if (direction_sign < 0 ) {
					target_pitch = direction_sign;
				} else if (direction_angle + MIN_DELTA < 1.0f ) {
					target_pitch = direction_sign * direction_angle;
				} else {
					target_pitch = 0.0f;
				}
				
				const float r =  2.0f * (radius() + leader()->radius());
				
				if (distance > 2.0f * r + 50.0f) {
					if (state() == core::Entity::Normal) {
						// enable impulse drive
						func_impulse();
					}
				} else {
					if (state() == core::Entity::Impulse) {
						
						if (leader()->state() != core::Entity::Impulse) {
							// disbable impulse drive
							func_impulse();
						}
						
					} else if (state() == core::Entity::Normal) {
						
						if ((leader()->state() == core::Entity::Impulse) || (leader()->state() == core::Entity::ImpulseInitiate)) {
							// enable impulse drive
							func_impulse();
						}
					}
					
				}
				
				if (distance > 2.0f * r) {
					target_thrust = 1.0f;
				} else if (distance > r) {
					target_thrust = (distance - r ) / r;
				} else {
					target_thrust = 0.0f;
				}
				
			} else {
				
				target_direction = 0;
				target_pitch = 0;
				target_roll = 0;
				target_strafe = 0.0f;
				target_vstrafe = 0.0f;
				
				target_afterburner = 0.0f;
				target_thrust = 0;
				
				if (state() == core::Entity::Impulse) {
					func_impulse();
				}
			}
		}
	}
	
	// run a ship game frame
	Ship::frame(elapsed);
}

} // namespace game