/*****************************************************************************
The Dark Mod GPL Source Code

This file is part of the The Dark Mod Source Code, originally based
on the Doom 3 GPL Source Code as published in 2011.

The Dark Mod Source Code 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 3 of the License,
or (at your option) any later version. For details, see LICENSE.TXT.

Project: The Dark Mod (http://www.thedarkmod.com/)

******************************************************************************/

#ifndef __PHYSICS_MONSTER_H__
#define __PHYSICS_MONSTER_H__

/*
===================================================================================

	Monster physics

	Simulates the motion of a monster through the environment. The monster motion
	is typically driven by animations.

===================================================================================
*/

typedef enum {
	MM_OK,
	MM_SLIDING,
	MM_BLOCKED,
	MM_STEPPED,
	MM_FALLING
} monsterMoveResult_t;

typedef struct monsterPState_s {
	int						atRest;
	bool					onGround;
	idVec3					origin;
	idVec3					velocity;
	idVec3					localOrigin;
	idVec3					pushVelocity;
} monsterPState_t;

class idPhysics_Monster : public idPhysics_Actor {

public:
	CLASS_PROTOTYPE( idPhysics_Monster );

							idPhysics_Monster( void );

	void					Save( idSaveGame *savefile ) const;
	void					Restore( idRestoreGame *savefile );

							// maximum step up the monster can take, default 18 units
	void					SetMaxStepHeight( const float newMaxStepHeight );
	float					GetMaxStepHeight( void ) const;
	
	// Translates the entity upwards by this amount when stepping up to fight gravity during stepping
	void					SetStepUpIncrease(float incr);

							// minimum cosine of floor angle to be able to stand on the floor
	void					SetMinFloorCosine( const float newMinFloorCosine );
							// set delta for next move
	void					SetDelta( const idVec3 &d );
							// returns true if monster is standing on the ground
	bool					OnGround( void ) const;
							// returns the movement result
	monsterMoveResult_t		GetMoveResult( void ) const;
							// overrides any velocity for pure delta movement
	void					ForceDeltaMove( bool force );
							// whether velocity should be affected by gravity
	void					UseFlyMove( bool force );
							// don't use delta movement
	void					UseVelocityMove( bool force );
							// get entity blocking the move
	idEntity *				GetSlideMoveEntity( void ) const;
							// enable/disable activation by impact
	void					EnableImpact( void );
	void					DisableImpact( void );

public:	// common physics interface
	virtual bool			Evaluate( int timeStepMSec, int endTimeMSec ) override;
	virtual void			UpdateTime( int endTimeMSec ) override;
	virtual int				GetTime( void ) const override;

	virtual void			GetImpactInfo( const int id, const idVec3 &point, impactInfo_t *info ) const override;
	virtual void			ApplyImpulse( const int id, const idVec3 &point, const idVec3 &impulse ) override;
	virtual void			Activate( void ) override;
	virtual void			PutToRest( void ) override;
	virtual bool			IsAtRest( void ) const override;
	virtual int				GetRestStartTime( void ) const override;

	virtual void			SaveState( void ) override;
	virtual void			RestoreState( void ) override;

	virtual void			SetOrigin( const idVec3 &newOrigin, int id = -1 ) override;
	virtual void			SetAxis( const idMat3 &newAxis, int id = -1 ) override;

	virtual void			Translate( const idVec3 &translation, int id = -1 ) override;
	virtual void			Rotate( const idRotation &rotation, int id = -1 ) override;

	virtual void			SetLinearVelocity( const idVec3 &newLinearVelocity, int id = 0 ) override;

	virtual const idVec3 &	GetLinearVelocity( int id = 0 ) const override;

	virtual void			SetPushed( int deltaTime ) override;
	virtual const idVec3 &	GetPushedLinearVelocity( const int id = 0 ) const override;

	virtual void			SetMaster( idEntity *master, const bool orientated = true ) override;

	virtual void			WriteToSnapshot( idBitMsgDelta &msg ) const override;
	virtual void			ReadFromSnapshot( const idBitMsgDelta &msg ) override;

private:
	// monster physics state
	monsterPState_t			current;
	monsterPState_t			saved;

	// properties
	float					maxStepHeight;		// maximum step height
	float					stepUpIncrease;		// translates origin upwards by this amount when stepping
	float					minFloorCosine;		// minimum cosine of floor angle
	idVec3					delta;				// delta for next move

	bool					forceDeltaMove;
	bool					fly;
	bool					useVelocityMove;
	bool					noImpact;			// if true do not activate when another object collides

	// results of last evaluate
	monsterMoveResult_t		moveResult;
	idEntity *				blockingEntity;

private:
	void					CheckGround( monsterPState_t &state );
	monsterMoveResult_t		SlideMove( idVec3 &start, idVec3 &velocity, const idVec3 &delta );
	monsterMoveResult_t		StepMove( idVec3 &start, idVec3 &velocity, const idVec3 &delta );
	void					Rest( void );
};

#endif /* !__PHYSICS_MONSTER_H__ */