// gps.hxx - distance-measuring equipment.
// Written by David Megginson, started 2003.
//
// This file is in the Public Domain and comes with no warranty.


#ifndef __INSTRUMENTS_GPS_HXX
#define __INSTRUMENTS_GPS_HXX 1

#include <cassert>

#include <simgear/props/props.hxx>
#include <simgear/structure/subsystem_mgr.hxx>
#include <simgear/math/SGMath.hxx>

#include "Navaids/positioned.hxx"

// forward decls
class SGRoute;
class FGRouteMgr;
class FGAirport;
class GPSListener;

class SGGeodProperty
{
public:
    SGGeodProperty()
    {
    }
        
    void init(SGPropertyNode* base, const char* lonStr, const char* latStr, const char* altStr = NULL);    
    void init(const char* lonStr, const char* latStr, const char* altStr = NULL);    
    void clear();    
    void operator=(const SGGeod& geod);    
    SGGeod get() const;
private:
    SGPropertyNode_ptr _lon, _lat, _alt;
};

/**
 * Model a GPS radio.
 *
 * Input properties:
 *
 * /position/longitude-deg
 * /position/latitude-deg
 * /position/altitude-ft
 * /environment/magnetic-variation-deg
 * /systems/electrical/outputs/gps
 * /instrumentation/gps/serviceable
 * 
 *
 * Output properties:
 *
 * /instrumentation/gps/indicated-longitude-deg
 * /instrumentation/gps/indicated-latitude-deg
 * /instrumentation/gps/indicated-altitude-ft
 * /instrumentation/gps/indicated-vertical-speed-fpm
 * /instrumentation/gps/indicated-track-true-deg
 * /instrumentation/gps/indicated-track-magnetic-deg
 * /instrumentation/gps/indicated-ground-speed-kt
 *
 * /instrumentation/gps/wp-distance-nm
 * /instrumentation/gps/wp-bearing-deg
 * /instrumentation/gps/wp-bearing-mag-deg
 * /instrumentation/gps/TTW
 * /instrumentation/gps/course-deviation-deg
 * /instrumentation/gps/course-error-nm
 * /instrumentation/gps/to-flag
 * /instrumentation/gps/odometer
 * /instrumentation/gps/trip-odometer
 * /instrumentation/gps/true-bug-error-deg
 * /instrumentation/gps/magnetic-bug-error-deg

 */
class GPS : public SGSubsystem
{

public:

    GPS (SGPropertyNode *node);
    GPS ();
    virtual ~GPS ();

    virtual void init ();
    virtual void update (double delta_time_sec);
    
    virtual void bind();
    virtual void unbind();
private:
    friend class GPSListener;
    friend class SearchFilter;
    
    /**
     * Configuration manager, track data relating to aircraft installation
     */
    class Config
    {
    public:
      Config();
            
      void bind(GPS* aOwner, SGPropertyNode* aCfg);
      
      bool turnAnticipationEnabled() const
      { return _enableTurnAnticipation; }
      
      /**
       * Desired turn rate in degrees/second. From this we derive the turn
       * radius and hence how early we need to anticipate it.
       */
      double turnRateDegSec() const
      { return _turnRate; }
      
      /**
       * Distance at which we arm overflight sequencing. Once inside this
       * distance, a change of the wp1 'TO' flag to false will be considered
       * overlight of the wp.
       */
      double overflightArmDistanceNm() const
      { return _overflightArmDistance; }
      
      /**
       * Time before the next WP to activate an external annunciator
       */
      double waypointAlertTime() const
      { return _waypointAlertTime; }
            
      bool requireHardSurface() const
      { return _requireHardSurface; }
      
      double minRunwayLengthFt() const
      { return _minRunwayLengthFt; }
      
      bool cdiDeflectionIsAngular() const
      { return (_cdiMaxDeflectionNm <= 0.0); }
      
      double cdiDeflectionLinearPeg() const
      {
        assert(_cdiMaxDeflectionNm > 0.0);
        return _cdiMaxDeflectionNm;
      }
      
      bool driveAutopilot() const
      { return _driveAutopilot; }
      
      bool courseSelectable() const
      { return _courseSelectable; }
    private:
      bool _enableTurnAnticipation;
      
      // desired turn rate in degrees per second
      double _turnRate;
      
      // distance from waypoint to arm overflight sequencing (in nm)
      double _overflightArmDistance;
      
      // time before reaching a waypoint to trigger annunicator light/sound 
      // (in seconds)
      double _waypointAlertTime;
      
      // minimum runway length to require when filtering
      double _minRunwayLengthFt;
      
      // should we require a hard-surfaced runway when filtering?
      bool _requireHardSurface;
      
      double _cdiMaxDeflectionNm;
      
      // should we drive the autopilot directly or not?
      bool _driveAutopilot;
      
      // is selected-course-deg read to set desired-course or not?
      bool _courseSelectable;
    };
    
    class SearchFilter : public FGPositioned::Filter
    {
    public:      
      virtual bool pass(FGPositioned* aPos) const;
          
      virtual FGPositioned::Type minType() const;
      virtual FGPositioned::Type maxType() const;
    };
    
    /**
     * reset all output properties to default / non-service values
     */
    void clearOutput();

    void updateBasicData(double dt);
    void updateWaypoints();

    void updateTrackingBug();
    void updateReferenceNavaid(double dt);
    void referenceNavaidSet(const std::string& aNavaid);
    void updateRouteData();
    void driveAutopilot();
    
    void routeActivated();
    void routeManagerSequenced();
    void routeEdited();
    void routeFinished();
    
    void updateTurn();  
    void updateOverflight();    
    void beginTurn();
    void endTurn();
    
    double computeTurnProgress(double aBearing) const;
    void computeTurnData();
    void updateTurnData();
    double computeTurnRadiusNm(double aGroundSpeedKts) const;
  
  /**
   * Update one-shot things when WP1 / leg data change
   */
  void wp1Changed();
  
// scratch maintenence utilities
  void setScratchFromPositioned(FGPositioned* aPos, int aIndex);
  void setScratchFromCachedSearchResult();
  void setScratchFromRouteWaypoint(int aIndex);
  
  /**
   * Add airport-specific information to a scratch result
   */
  void addAirportToScratch(FGAirport* aAirport);
  
  void clearScratch();
  
  /**
   * Predicate, determine if the lon/lat position in the scratch is 
   * valid or not.
   */
  bool isScratchPositionValid() const;
  
  FGPositioned::Filter* createFilter(FGPositioned::Type aTy);
  
  /**
   * Search kernel - called each time we step through a result
   */
  void performSearch();
  
// command handlers
  void selectLegMode();
  void selectOBSMode();
  void directTo();
  void loadRouteWaypoint();
  void loadNearest();
  void search();
  void nextResult();
  void previousResult();
  void defineWaypoint();
  void insertWaypointAtIndex(int aIndex);
  void removeWaypointAtIndex(int aIndex);
  
// tied-property getter/setters
  void setCommand(const char* aCmd);
  const char* getCommand() const { return ""; }
  
  const char* getMode() const { return _mode.c_str(); }
  
  bool getScratchValid() const { return _scratchValid; }
  double getScratchDistance() const;
  double getScratchMagBearing() const;
  double getScratchTrueBearing() const;
  bool getScratchHasNext() const;
  
  double getSelectedCourse() const { return _selectedCourse; }
  void setSelectedCourse(double crs);
  double getDesiredCourse() const { return _desiredCourse; }
  
  double getCDIDeflection() const;
  
  double getLegDistance() const;
  double getLegCourse() const;
  double getLegMagCourse() const;
  double getAltDistanceRatio() const;
  
  double getTrueTrack() const { return _last_true_track; }
  double getMagTrack() const;
  double getGroundspeedKts() const { return _last_speed_kts; }
  double getVerticalSpeed() const { return _last_vertical_speed; }
  
  //bool getLegMode() const { return _mode == "leg"; }
  //bool getObsMode() const { return _mode == "obs"; }
  
  const char* getWP0Ident() const;
  const char* getWP0Name() const;
  
  const char* getWP1Ident() const;
  const char* getWP1Name() const;
  
  double getWP1Distance() const;
  double getWP1TTW() const;
  const char* getWP1TTWString() const;
  double getWP1Bearing() const;
  double getWP1MagBearing() const;
  double getWP1CourseDeviation() const;
  double getWP1CourseErrorNm() const;
  bool getWP1ToFlag() const;
  bool getWP1FromFlag() const;
  
  // true-bearing-error and mag-bearing-error
  

  /**
   * Tied-properties helper, record nodes which are tied for easy un-tie-ing
   */
  template <typename T>
  void tie(SGPropertyNode* aNode, const char* aRelPath, const SGRawValue<T>& aRawValue)
  {
    SGPropertyNode* nd = aNode->getNode(aRelPath, true);
    _tiedNodes.push_back(nd);
    nd->tie(aRawValue);
  }

  /// helper, tie the lat/lon/elev of a SGGeod to the named children of aNode
  void tieSGGeod(SGPropertyNode* aNode, SGGeod& aRef, 
    const char* lonStr, const char* latStr, const char* altStr);
  
  /// helper, tie a SGGeod to proeprties, but read-only
  void tieSGGeodReadOnly(SGPropertyNode* aNode, SGGeod& aRef, 
    const char* lonStr, const char* latStr, const char* altStr);

// members
  SGPropertyNode_ptr _gpsNode;
  SGPropertyNode_ptr _magvar_node;
  SGPropertyNode_ptr _serviceable_node;
  SGPropertyNode_ptr _electrical_node;
  SGPropertyNode_ptr _tracking_bug_node;
  SGPropertyNode_ptr _raim_node;

      SGPropertyNode_ptr _odometer_node;
    SGPropertyNode_ptr _trip_odometer_node;
    SGPropertyNode_ptr _true_bug_error_node;
    SGPropertyNode_ptr _magnetic_bug_error_node;
    SGPropertyNode_ptr _eastWestVelocity;
    SGPropertyNode_ptr _northSouthVelocity;
    
    SGPropertyNode_ptr _ref_navaid_id_node;
    SGPropertyNode_ptr _ref_navaid_bearing_node;
    SGPropertyNode_ptr _ref_navaid_distance_node;
    SGPropertyNode_ptr _ref_navaid_mag_bearing_node;
    SGPropertyNode_ptr _ref_navaid_frequency_node;
    SGPropertyNode_ptr _ref_navaid_name_node;
    
    SGPropertyNode_ptr _route_active_node;
    SGPropertyNode_ptr _route_current_wp_node;
    SGPropertyNode_ptr _routeDistanceNm;
    SGPropertyNode_ptr _routeETE;
  SGPropertyNode_ptr _routeEditedSignal;
  SGPropertyNode_ptr _routeFinishedSignal;
  SGPropertyNode_ptr _desiredCourseNode;
  
    double _selectedCourse;
    double _desiredCourse;
    
    bool _dataValid;
    SGGeod _last_pos;
    bool _lastPosValid;
    double _last_speed_kts;
    double _last_true_track;
    double _last_vertical_speed;
    double _lastEWVelocity;
    double _lastNSVelocity;
    
    std::string _mode;
    GPSListener* _listener;
    Config _config;
    FGRouteMgr* _routeMgr;
    
    bool _ref_navaid_set;
    double _ref_navaid_elapsed;
    FGPositionedRef _ref_navaid;
    
    std::string _name;
    int _num;
  
  SGGeodProperty _position;
  SGGeod _wp0_position;
  SGGeod _wp1_position;
  SGGeod _indicated_pos;
  std::string _wp0Ident, _wp0Name, _wp1Ident, _wp1Name;
  double _wp1DistanceM, _wp1TrueBearing;
  
// scratch data
  SGGeod _scratchPos;
  SGPropertyNode_ptr _scratchNode;
  bool _scratchValid;
  
// search data
  int _searchResultIndex;
  std::string _searchQuery;
  FGPositioned::Type _searchType;
  bool _searchExact;
  FGPositioned::List _searchResults;
  bool _searchIsRoute; ///< set if 'search' is actually the current route
  bool _searchHasNext; ///< is there a result after this one?
  bool _searchNames; ///< set if we're searching names instead of idents
  
  // turn data
    bool _computeTurnData; ///< do we need to update the turn data?
    bool _anticipateTurn; ///< are we anticipating the next turn or not?
    bool _inTurn; // is a turn in progress?
    bool _turnSequenced; // have we sequenced the new leg?
    double _turnAngle; // angle to turn through, in degrees
    double _turnStartBearing; // bearing of inbound leg
    double _turnRadius; // radius of turn in nm
    SGGeod _turnPt;
    SGGeod _turnCentre;
  
  SGPropertyNode_ptr _realismSimpleGps; ///< should the GPS be simple or realistic?
  
// autopilot drive properties
  SGPropertyNode_ptr _apDrivingFlag;
  SGPropertyNode_ptr _apTrueHeading;
  SGPropertyNode_ptr _apTargetAltitudeFt;
  SGPropertyNode_ptr _apAltitudeLock;
  
  std::vector<SGPropertyNode_ptr> _tiedNodes;
};


#endif // __INSTRUMENTS_GPS_HXX