/*
   core/entity.h
   This file is part of the Osirion project and is distributed under
   the terms of the GNU General Public License version 2.
*/

#ifndef __INCLUDED_CORE_ENTITY_H__
#define __INCLUDED_CORE_ENTITY_H__

#include <iostream>
#include <string>
#include <map>
#include <list>

#include "core/level.h"
#include "model/model.h"
#include "math/axis.h"
#include "math/mathlib.h"

namespace core
{

class Entity;
class EntityControlable;

}

#include "core/extension.h"
#include "core/descriptions.h"
#include "core/inventory.h"
#include "core/label.h"
#include "core/physics.h"
#include "core/player.h"
#include "core/slots.h"
#include "core/zone.h"

namespace core
{

/**
 * @brief The base world entity. All gameworld entities must derive from this class.
 * */
class Entity : public Label
{
	friend class Extension;

public:
	/**
	 * @brief entity flags
	 * NonSolid will exclude the entity from the bullet physics world
	 * Bright is used by EntityGlobe, where a bright sphere is a light source
	 * Dockable means the entity can be docked by a player
	 * ShowOnMap will make the entity appear on the map
	 * KeepAlive is used by EntityDynamic and marks the entity as deletable in the keepalive run
	 * */
	enum Flags { NonSolid = 2, Bright = 4, Dockable = 8, ShowOnMap = 16, KeepAlive = 32 };

	/**
	 * @brief Entity type constants
	 * @see Entity::type()
	 * */
	enum Type { Default = 0, Dynamic = 1, Controlable = 2, Globe = 3, Projectile = 4 };

	/**
	 * @brief Entity shape constants
	 * @see Entity::shape()
	 * */
	enum Shape { Diamond = 0, Sphere = 1, Cube = 2, Axis = 3 };

	/**
	 * @brief EntityDynamic state constants
	 * @see EntityDynamic::state()
	 * */
	enum State { Normal = 0, NoPower = 1, ImpulseInitiate = 2, Impulse = 3, JumpInitiate = 4, Jump = 5, Docked = 6, Destroyed = 7 };

	/**
	 * @brief entity menu collection type definition
	 * */
	typedef std::list<MenuDescription *> Menus;
	
	/**
	 * @brief entity bullet shapes collection type definition
	 * */
	typedef std::list<btCollisionShape *> CollisionShapes;

	/**
	 * @brief server-side constructor
	 * create a new entity and add it to the registry
	 * */
	Entity();

	/**
	 * @brief client-side constructor
	 * create an entity from stream data
	 * */
	Entity(std::istream & is);

	/**
	 * @brief destructor
	 * */
	virtual ~Entity();
	
	/**
	 * @brief print information about the entity
	 * */
	virtual void print() const;
	
	/**
	 * @brief print information header
	 * */
	virtual void print_header() const;
	
	/**
	 * @brief print inventory if available
	 * */
	virtual void print_inventory() const;


	/*----- inspectors ------------------------------------------------ */

	/// entity id
	inline const unsigned int id() const
	{
		return entity_id;
	}

	/// module type id
	inline const unsigned int moduletype() const
	{
		return entity_moduletypeid;
	}

	///  core type id
	virtual inline const unsigned int type() const
	{
		return Default;
	}

	/// entity flags
	inline const unsigned int flags() const
	{
		return entity_flags;
	}

	/// returns true of a flag is set
	inline const bool has_flag(const Flags flag) const
	{
		return ((entity_flags & (unsigned int)flag) == (unsigned int)flag);
	}

	/// pointer to the model, is used client-side
	inline model::Model * model() const
	{
		return entity_model;
	}

	/// modelname
	inline const std::string & modelname() const {
		return entity_modelname;
	}

	/// pointer to the zone the entity belongs to
	inline Zone *zone() const
	{
		return entity_zone;
	}

	/// the zone the entity left in case of a zone change
	inline Zone *oldzone() const
	{
		return entity_oldzone;
	}

	/// dirty flag
	inline bool dirty() const
	{
		return entity_dirty;
	}

	/// entity location
	inline const math::Vector3f& location() const
	{
		return entity_location;
	}

	/// local coordinates system of the entity
	inline const math::Axis& axis() const
	{
		return entity_axis;
	}

	/// primary entity color
	inline const math::Color& color() const
	{
		return entity_color;
	}

	/// secondary entity color
	inline const math::Color& color_second() const
	{
		return entity_color_second;
	}

	/// base shape of the entity
	inline const Shape shape() const
	{
		return entity_shape;
	}

	/// base radius of the entity
	inline const float radius() const
	{
		return entity_radius;
	}

	/**
	 * @brief current entity level
	 * */
	inline const Level level() const
	{
		return entity_level;
	}
	
	/**
	 * @brief current speed of the entity in game units per second
	 * For a normal entity, speed is always 0. Use the EntityDynamic 
	 * and EntityControlable classes to create moving entities
	 */
	inline const float speed() const {
		return entity_speed;
	}

	/// physics body
	inline btRigidBody *body() {
		return entity_body;
	}
	
	/// physics collision shape
	inline btCollisionShape *collision_shape() {
		return entity_collision_shape;
	}
	
	/**
	 * @brief physics collision child shapes
	 * if the collision_shape is not a btcompoundShape, 
	 * this set will be empty
	 **/
	inline CollisionShapes & collision_child_shapes() {
		return entity_collision_child_shapes;
	}
	
	/// indicates a server-side entity
	inline const bool serverside() const {
		return entity_serverside;
	}

	/// general visibility
	inline const bool visible() const {
		return entity_visible;
	}

	/// entity inventory
	inline Inventory *inventory() const {
		return entity_inventory;
	}

	/// entity weapon slots
	inline Slots *slots() const {
		return entity_slots;
	}
	
	/// entity information record
	inline const Info *info() const {
		return entity_info;
	}
	
	/// entity menus
	inline Menus &menus() {
		return entity_menus;
	}
	
	/// extensions
	inline Extension *extension(size_t type) const {
		return entity_extension[type];
	}

	/// find a menu
	MenuDescription *find_menu(const std::string &label);
	
	/// true if the entity is to be deleted
	inline const bool died() const {
		return entity_died;
	}

	/// time when the entity was last alive
	inline const unsigned long keepalive() const {
		return entity_keepalive;
	}
	
		
	inline const Info *faction() const 
	{
		return entity_faction;
	}
	
	/* ---- mutators -------------------------------------------------- */

	/// assign shape
	inline void set_shape(Shape shape) {
		entity_shape = shape;
	}
	
	/// assign entity color
	inline void set_color(const math::Color &color) {
		entity_color.assign(color);
	}

	/// assign entity secondary color
	inline void set_color_second(const math::Color &color) {
		entity_color_second.assign(color);
	}

	/**
	 * @brief set dirty flag
	 * setting the dirty flag will cause the server to broadcast changes
	 * to the clients.
	 */
	inline void set_dirty(const bool dirty = true) {
		entity_dirty = dirty;
	}

	/**
	 * @brief mark the entity as dead
	 * die() should be called by the game module when it needs to destroy an entity,
	 * the game server will broadcast the delete event to the clients.
	 * The game module should not delete entities directly.
	 */
	virtual void die();

	/**
	 * @brief runs one game frame for the entity
	 * The default implementation does nothing
	 * @param elapsed elepased time since previous frame, in milliseconds
	 */
	virtual void frame(const unsigned long elapsed);

	/**
	 * @brief runs one upkeep frame for the entity
	 * The upkeep frame will be executed by the engine if the entity has the KeepAlive flag set
	 * and the keepalive timeout has been elapsed.
	 * The default implementation does nothing
	 * @param timestamp game timestamp for the current upkeep frame
	 */
	virtual void upkeep(const unsigned long timestamp);
	
	/**
	 * @brief set the zone the entity is currently in
	 * this fuction removes the entity from its previous zone
	 * and removes it to the new one, if it is not 0
	 */
	virtual void set_zone(Zone *zone);
	
	/**
	 * @brief set the entity level
	 * */
	inline void set_level(const Level level)
	{
		entity_level = level;
	}

	/// set visibility
	inline void set_visible(const bool visible = true)
	{
		entity_visible = visible;
	}

	/// set as server-side entity
	inline void set_serverside(const bool serverside = true)
	{
		entity_serverside = serverside;
	}

	/// set the model name and load the model
	void set_modelname(const std:: string &model);

	/// set the model
	void set_model(model::Model *model);

	/// set entity radius
	inline void set_radius(const float radius) {
		entity_radius = radius;
	}
	
		
	/// set location
	inline void set_location(const math::Vector3f &location) {
		entity_location.assign(location);
	}
	
	/// set location
	inline void set_axis(const math::Axis &axis) {
		entity_axis.assign(axis);
	}

	/**
	 * @brief set flag
	 * */
	inline void set_flag(Flags flag) {
		entity_flags |= (unsigned int) flag;
	}

	/**
	 * @brief unset flag
	 * */
	inline void unset_flag(Flags flag)
	{
		entity_flags &= ~((unsigned int) flag);
	}

	/**
	 * @brief set flags
	 * */
	 inline  void set_flags(unsigned int flags)
	 {
		 entity_flags = flags;
	 }
	 
	/**
	 * @brief add an inventory to this entity
	 * If this entity already has an inventory,
	 * the current inventory will be return
	 * */
	Inventory *add_inventory();
	
	/**
	 * @brief add equipment slots to this entity
	 * If this entity already has slots,
	 * the current slots will be returned.
	 * */
	Slots *add_slots();

	/**
	 * @brief set the information record for this entity
	 * */
	void set_info(const Info *info);
	 
	/**
	 * @brief set the timestamp when the entity was last alive
	 * */
	inline void set_keepalive(unsigned long timestamp)
	{
		entity_keepalive = timestamp;
	}
	
	/**
	 * @brief set the faction this entity belongs to.
	 * */
	inline void set_faction(const Info *faction)
	{
		entity_faction = faction;
	}

	/* ---- actors ---------------------------------------------------- */

	/**
	 * @brief reset the physics state
	 */
	virtual void reset();
	
	/// add an entity menu
	void add_menu(MenuDescription *menu);

	/// remove an entity menu
	void remove_menu(std::string const &label);

	/// clear all update flags
	virtual void clear_updates();

	/**
	 * @brief mutable reference to the location
	 */
	inline math::Vector3f& get_location() {
		return entity_location;
	}

	/**
	 * @brief mutable reference to the axis
	 */
	inline math::Axis& get_axis() {
		return entity_axis;
	}

	/**
	 * @brief mutable reference to the primary color
	 */
	inline math::Color& get_color() {
		return entity_color;
	}

	/**
	 * @brief mutable reference to the secondary color
	 */
	inline math::Color& get_color_second() {
		return entity_color_second;
	}
 
	/* ---- deserializers -------------------------------------- */

	/// receive a client-to-server update from a stream
	virtual void receive_client_update(std::istream &is);

	/// receive a server-to-client create from a stream
	virtual void receive_server_create(std::istream &is);

	/// receive a server-to-client update from a stream
	virtual void receive_server_update(std::istream &is);

	/* ---- serializers ---------------------------------------- */

	/// serialize the entity to a stream
	virtual void serialize_server_create(std::ostream & os) const;

	/// serialize a client-to-server update on a stream
	virtual void serialize_client_update(std::ostream & os) const;

	/// serialize a server-to-client update on a stream
	virtual void serialize_server_update(std::ostream & os) const;

	/* ---- static --------------------------------------------- */
	
	/// default infotype for entities
	static inline const InfoType *infotype() {
		return entity_infotype;
	}
	
	/// set the default infotype for entities
	static inline void set_infotype(const InfoType *infotype) {
		entity_infotype = infotype;
	}

	/// type definition for the entity registry
	typedef std::map<unsigned int, Entity*> Registry;

	/// find an entity in the registry
	static Entity *find(unsigned int id);
	
	/// find an entity in the registry
	static Entity *find(Entity * entity);

	/// add an entity to the registry
	static void add(Entity *ent, unsigned int it);

	/// erase an entity from the registry and delete it
	static void erase(unsigned int entity_id);

	/// print the list header
	static void list_header();

	/// list the entity registry
	static void list(const Entity *entity);
	
	/// list the entity registry
	static void list();

	/// clear the entity registry
	static void clear();

	/// the entity registry
	static inline Registry & registry() {
		return entity_registry;
	}

	/**
	 * @brief game module type id
	 * this id can be assigned by the game module
	 * */
	unsigned int		entity_moduletypeid;

	bool 			entity_created;
	
	bool			entity_died;

	/// timestamp when entity data was received from the server
	float			entity_servertimestamp;

protected:
	btRigidBody					*entity_body;
	btRigidBody::btRigidBodyConstructionInfo	*entity_body_info;
	
	// the main bullet collision shape for this entity
	btCollisionShape				*entity_collision_shape;
	
	// bullet collision child shapes for this entity, 
	CollisionShapes					entity_collision_child_shapes;

	// the zone the entity belongs to
	Zone*			entity_zone;
	// the previous zone the entity belonged too
	Zone*			entity_oldzone;

	float			entity_speed;

private:
	
	unsigned int		entity_id;
	unsigned int 		entity_flags;

	bool			entity_dirty;
	bool			entity_visible;
	bool			entity_serverside;

	math::Vector3f 		entity_location;
	math::Axis		entity_axis;

	float 			entity_radius;

	Shape 			entity_shape;

	math::Color 		entity_color;
	math::Color 		entity_color_second;
	
	Level			entity_level;

	std::string		entity_modelname;
	model::Model*		entity_model;

	Menus			entity_menus;
	
	Inventory*		entity_inventory;
	Slots*			entity_slots;
	const Info*		entity_info;

	Extension*		entity_extension[4];
	
	unsigned long		entity_keepalive;
	
	const Info		*entity_faction;
	
	static Registry 	entity_registry;
	static size_t		entity_nextid;

	static void add(Entity *ent);
	
	static const InfoType 	*entity_infotype;

};


/// an entity that can move around in the game world
class EntityDynamic : public Entity
{
public:
	/// create a dynamic entity
	EntityDynamic();

	/// create a dynamic entity from stream data
	EntityDynamic(std::istream & is);

	virtual ~EntityDynamic();

	/*----- inspectors ------------------------------------------------ */
	
	/**
	 * @brief print information about the entity
	 * */
	virtual void print() const;
	
	/// core type id
	virtual inline const unsigned int type() const {
		return Entity::Dynamic;
	}

	/// event state
	inline const int state() const {
		return entity_state;
	}

	/// mass of the entity
	inline const float mass() const {
		return entity_mass;
	}
	
	/// event state timer
	inline const float timer() const {
		return entity_timer;
	}

	/// physics motion info
	inline btMotionState *motionstate() {
		return entity_motionstate;
	}
		
	/*----- mutators -------------------------------------------------- */

	/// mass of the entity
	inline void set_mass(const float mass) {
		entity_mass = mass;
	}

	/// current speed of the entity in game units per second
	inline void set_speed(const float speed) {
		entity_speed = speed;
	}

	/*----- serializers ----------------------------------------------- */

	/// serialize the entity to a stream
	virtual void serialize_server_create(std::ostream & os) const;

	/// serialize a client-to-server update on a stream
	virtual void serialize_client_update(std::ostream & os) const ;

	/// serialize a server-to-client update on a stream
	virtual void serialize_server_update(std::ostream & os) const;

	/*----- mutators -------------------------------------------------- */

	/// receive a client-to-server update from a stream
	virtual void receive_client_update(std::istream &is);

	/// receive a server-to-client create from a stream
	virtual void receive_server_create(std::istream &is);

	/// receive a server-to-client update from a stream
	virtual void receive_server_update(std::istream &is);

	/// set event state
	virtual void set_state(int state);

	/**
	 * @brief runs one game frame for the entity
	 * The default implementation will update the position() of the entity,
	 * determined by its speed() and axis()
	 * @param elapsed elepased time since previous frame, in milliseconds
	 */
	virtual void frame(const unsigned long elapsed);

	/**
	 * @brief reset the physics state
	 */
	virtual void reset();
	
	/**
	 * @brief nudge the entity out of the radius of other entities in its current zune
	 * @param randomize if false, nudge according to axus.forward(), if false, nudge along a random axis
	 */
	void nudge(const bool randomize = true);
	
	/**
	 * @brief physics collision callback
	 * This funcion is called by the physics engine if the entity collides with another entity.
	 * It can be implemented by game child classes to provide collision effects and feedback.
	 * If the collision happens between two EntityDynamic instances (or subclasses thereof)
	 * the method will be called on each collision partner.
	 * Warning: this can be called multiple times for a single collision
	 * */
	virtual void collision(Entity *other);
	
	/**
	 * @brief weapon hit callback
	 * This method is called by the core-engine if the entity is hit by a weapon.
	 * */
	virtual void hit(Entity *other);

protected:
	float			entity_mass;
	float			entity_timer;
	int			entity_state;
	btMotionState		*entity_motionstate;
	
};

/// an entity that can be controlled by a player
class EntityControlable : public EntityDynamic
{
	friend class Player;
public:
	
	/// control flags
	enum ControlFlags {ControlFlagNone = 0, ControlFlagFire = 1, ControlFlagOverride = 2};
	
	/// bullet action interface class
	class ActionInterface: public btActionInterface {
	public:
		ActionInterface(EntityControlable *entity);
		virtual ~ActionInterface();
 
         	virtual void updateAction( btCollisionWorld* collisionWorld, btScalar deltaTimeStep);
 
         	virtual void debugDraw(btIDebugDraw* debugDrawer);
		
	private:
		EntityControlable *actioninterface_entity;
	};
	
	/// server-side constructor, create a controlable entity
	EntityControlable();

	/// create a controlable entity from stream data
	EntityControlable(std::istream & is);

	virtual ~EntityControlable();

	/*----- inspectors ------------------------------------------------ */

	/// core type id
	virtual inline const unsigned int type() const {
		return Entity::Controlable;
	}

	/// owner of this entity
	inline Player *owner() const {
		return entity_owner;
	}

	/// thrust
	inline float thrust() const {
		return entity_thrust;
	}

	/// physics action
	inline ActionInterface *actioninterface() {
		return entity_actioninterface;
	}
	
	/**
	 * @brief current health, 0 - 100
	 * */
	inline const float health() const
	{
		return entity_health;
	}
	
	/**
	 * @brief returns true if a specified control flag is set
	 * */
	inline const bool has_target_controlflag(ControlFlags controlflag) const
	{
		return ((target_controlflags & controlflag) == controlflag);
	}
	
	inline const math::Vector3f &aim() const
	{
		return target_aim;
	}
	
	/*----- serializers ----------------------------------------------- */

	/// serialize the entity to a stream
	virtual void serialize_server_create(std::ostream & os) const;

	/// serialize a client-to-server update on a stream
	virtual void serialize_client_update(std::ostream & os) const;

	/// serialize a server-to-client update on a stream
	virtual void serialize_server_update(std::ostream & os) const;

	/*----- mutators -------------------------------------------------- */

	/// set the target thrust
	void set_target_thrust(float thrust);

	/// set the target direction
	void set_target_direction(float direction);

	/// set the target pitch
	void set_target_pitch(float pitch);

	/// set target roll
	void set_target_roll(float roll);

	/// set target strafe
	void set_target_strafe(float strafe);
	
	/// set target vertical strafe
	void set_target_vstrafe(float vstrafe);

	/// set target afterburner/reverse
	void set_target_afterburner(float afterburner);
	
	/// set target aim
	void set_target_aim(const math::Vector3f &aim);
	
	/// set target controlflags
	void set_target_controlflags(int controlflags);
	
	/// set target control flags
	void set_target_controlflag(const ControlFlags controlflag);
	
	/// unset target control flag
	void unset_target_controlflag(const ControlFlags controlflag);
	
	/**
	 * @brief set the zone the entity is currently in
	 * this fuction removes the entity from its previous zone
	 * and removes it to the new one, if it is not 0
	 * */
	virtual void set_zone(Zone *zone);
	
	/**
	 * @brief reset the physics state
	 */
	virtual void reset();
	
	/// receive a client-to-server update from a stream
	virtual void receive_client_update(std::istream &is);

	/// receive a server-to-client create from a stream
	virtual void receive_server_create(std::istream &is);

	/// receive a server-to-client update from a stream
	virtual void receive_server_update(std::istream &is);

	/**
	 * @brief set the player who owns this entity
	 * */
	void set_owner(Player *owner);
	
	/**
	 * @brief set thrust
	 * */
	void set_thrust(float thrust);
	
protected:
	
	/// physics action interface callback
	virtual void action (btScalar seconds);
	
	/// current thrust
	float			entity_thrust;
	
	/// current health
	float			entity_health;
		
	/* target_ variables can be set by the client */
	
	/**
	 * @brief target thrust as set by the client
	 */
	float			target_thrust;
	
	/** 
	 * @brief target direction as set by the client
	 * target_direction must be in the [-1, 1] range
	 */
	float			target_direction;
	
	/**
	 * @brief target pitch as set by the client
	 * target_pitch must be in the [-1, 1] range
	 */
	float 			target_pitch;
	
	/**
	 * @brief target roll as set by the client
	 * target_roll must be in the [-1, 1] range
	 */
	float 			target_roll;

	float 			target_afterburner;

	float			target_strafe;
	
	float			target_vstrafe;
	
	math::Vector3f		target_aim;

	int			target_controlflags;

	ActionInterface		*entity_actioninterface;	
	
private:
	/// owner of the entity
	Player			*entity_owner;
};

} // namespace core

#endif // __INCLUDED_CORE_ENTITY_H__