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  /**
  * @file tailsitter.h
  *
  * @author Roman Bapst 		<bapstroman@gmail.com>
  * @author David Vorsin     <davidvorsin@gmail.com>
  *
  */
  
  #ifndef TAILSITTER_H
  #define TAILSITTER_H
  
  #include "vtol_type.h"
  #include <systemlib/perf_counter.h>  /** is it necsacery? **/
  #include <systemlib/param/param.h>
  #include <drivers/drv_hrt.h>
  
  class Tailsitter : public VtolType
  {
  
  public:
  	Tailsitter(VtolAttitudeControl *_att_controller);
  	~Tailsitter();
  
  	virtual void update_vtol_state();
  	virtual void update_transition_state();
  	virtual void update_mc_state();
  	virtual void update_fw_state();
  	virtual void fill_actuator_outputs();
  	virtual void waiting_on_tecs();
  
  private:
  
  	struct {
  		float front_trans_dur;			/**< duration of first part of front transition */
  		float front_trans_dur_p2;
  		float back_trans_dur;			/**< duration of back transition */
  		float airspeed_trans;			/**< airspeed at which we switch to fw mode after transition */
  		float airspeed_blend_start;		/**< airspeed at which we start blending mc/fw controls */
  	} _params_tailsitter;
  
  	struct {
  		param_t front_trans_dur;
  		param_t front_trans_dur_p2;
  		param_t back_trans_dur;
  		param_t airspeed_trans;
  		param_t airspeed_blend_start;
  
  	} _params_handles_tailsitter;
  
  	enum vtol_mode {
  		MC_MODE = 0,			/**< vtol is in multicopter mode */
  		TRANSITION_FRONT_P1,	/**< vtol is in front transition part 1 mode */
  		TRANSITION_FRONT_P2,	/**< vtol is in front transition part 2 mode */
  		TRANSITION_BACK,		/**< vtol is in back transition mode */
  		FW_MODE					/**< vtol is in fixed wing mode */
  	};
  
  	struct {
  		vtol_mode flight_mode;			/**< vtol flight mode, defined by enum vtol_mode */
  		hrt_abstime transition_start;	/**< absoulte time at which front transition started */
  	} _vtol_schedule;
  
  	/** not sure about it yet ?! **/
  	float _min_front_trans_dur;	/**< min possible time in which rotors are rotated into the first position */
  
  	float _thrust_transition_start; // throttle value when we start the front transition
  	float _yaw_transition;	// yaw angle in which transition will take place
  	float _pitch_transition_start;  // pitch angle at the start of transition (tailsitter)
  
  	/**
  	 * Update parameters.
  	 */
  	virtual void parameters_update();
  
  };
  #endif
  