Fix a misuse of a return value that lead to an error message being displayed

[flightgear.git] / src / ATC / tower.hxx

// FGTower - a class to provide tower control at towered airports.
//
// Written by David Luff, started March 2002.
//
// Copyright (C) 2002  David C. Luff - david.luff@nottingham.ac.uk
//
// This program 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 2 of the
// License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

#ifndef _FG_TOWER_HXX
#define _FG_TOWER_HXX

#include <simgear/compiler.h>
#include <simgear/math/point3d.hxx>
#include <simgear/misc/sgstream.hxx>
//#include <simgear/math/sg_geodesy.hxx>
#include <plib/sg.h>
//#include <Airports/runways.hxx>

#include STL_IOSTREAM
#include STL_STRING

SG_USING_STD(string);
SG_USING_STD(ios);

#include "ATC.hxx"
//#include "ATCmgr.hxx"
#include "ground.hxx"
#include "ATCProjection.hxx"
#include "AIPlane.hxx"

//DCL - a complete guess for now.
#define FG_TOWER_DEFAULT_RANGE 30

enum tower_traffic_type {
        CIRCUIT,
        INBOUND,        // CIRCUIT traffic gets changed to INBOUND when on final of the full-stop circuit.
        OUTBOUND,
        TTT_UNKNOWN,    // departure, but we don't know if for circuits or leaving properly
        STRAIGHT_IN
};

ostream& operator << (ostream& os, tower_traffic_type ttt);

enum tower_callback_type {
        USER_REQUEST_VFR_DEPARTURE = 1,
        USER_REQUEST_VFR_ARRIVAL = 2,
        USER_REQUEST_VFR_ARRIVAL_FULL_STOP = 3,
        USER_REQUEST_VFR_ARRIVAL_TOUCH_AND_GO = 4,
        USER_REPORT_3_MILE_FINAL = 5,
        USER_REPORT_DOWNWIND = 6,
        USER_REPORT_RWY_VACATED = 7,
        USER_REPORT_GOING_AROUND = 8
};

// TODO - need some differentiation of IFR and VFR traffic in order to give the former priority.

// Structure for holding details of a plane under tower control.
// Not fixed yet - may include more stuff later.
class TowerPlaneRec {
        
public:
        
        TowerPlaneRec();
        TowerPlaneRec(PlaneRec p);
        TowerPlaneRec(Point3D pt);
        TowerPlaneRec(PlaneRec p, Point3D pt);
        
        FGAIPlane* planePtr;    // This might move to the planeRec eventually
        PlaneRec plane;
        
        Point3D pos;
        double eta;             // seconds
        double dist_out;        // meters from theshold
        bool clearedToLand;
        bool clearedToLineUp;
        bool clearedToTakeOff;
        // ought to add time cleared to depart so we can nag if necessary
        bool holdShortReported;
        bool downwindReported;
        bool longFinalReported;
        bool longFinalAcknowledged;
        bool finalReported;
        bool finalAcknowledged;
        bool rwyVacatedReported;
        bool rwyVacatedAcknowledged;
        bool goAroundReported;          // set true if plane informs tower that it's going around.
        bool instructedToGoAround;      // set true if plane told by tower to go around.
        bool onRwy;             // is physically on the runway
        bool nextOnRwy;         // currently projected by tower to be the next on the runway
        
        bool vfrArrivalReported;
        bool vfrArrivalAcknowledged;

        // Type of operation the plane is doing
        tower_traffic_type opType;
        
        // Whereabouts in circuit if doing circuits
        PatternLeg leg;
        
        LandingType landingType;
        
        bool isUser;    // true if this plane is the user
};


typedef list < TowerPlaneRec* > tower_plane_rec_list_type;
typedef tower_plane_rec_list_type::iterator tower_plane_rec_list_iterator;
typedef tower_plane_rec_list_type::const_iterator tower_plane_rec_list_const_iterator;


class FGTower : public FGATC {

public:
        
        FGTower();
        ~FGTower();
        
        void Init();
        
        void Update(double dt);
        
        void ReceiveUserCallback(int code);

        // Contact tower for VFR approach
        // eg "Cessna Charlie Foxtrot Golf Foxtrot Sierra eight miles South of the airport for full stop with Bravo"
        // This function probably only called via user interaction - AI planes will have an overloaded function taking a planerec.
        void VFRArrivalContact(string ID, LandingType opt = AIP_LT_UNKNOWN);
        // For the AI planes...
        void VFRArrivalContact(PlaneRec plane, FGAIPlane* requestee, LandingType lt = AIP_LT_UNKNOWN);
        
        void RequestDepartureClearance(string ID);      
        void ReportFinal(string ID);
        void ReportLongFinal(string ID);
        void ReportOuterMarker(string ID);
        void ReportMiddleMarker(string ID);
        void ReportInnerMarker(string ID);
        void ReportRunwayVacated(string ID);
        void ReportReadyForDeparture(string ID);
        void ReportDownwind(string ID);
        void ReportGoingAround(string ID);
        
        // Contact tower when at a hold short for departure - for now we'll assume plane - maybe vehicles might want to cross runway eventually?
        void ContactAtHoldShort(PlaneRec plane, FGAIPlane* requestee, tower_traffic_type operation);
        
        // Register the presence of an AI plane at a point where contact would already have been made in real life
        // CAUTION - currently it is assumed that this plane's callsign is unique - it is up to AIMgr to generate unique callsigns.
        void RegisterAIPlane(PlaneRec plane, FGAIPlane* ai, tower_traffic_type op, PatternLeg lg = LEG_UNKNOWN);
        
        // Deregister and remove an AI plane.
        void DeregisterAIPlane(string id);
        
        // Public interface to the active runway - this will get more complex 
        // in the future and consider multi-runway use, airplane weight etc.
        inline string GetActiveRunway() { return activeRwy; }
        inline RunwayDetails GetActiveRunwayDetails() { return rwy; }
        // Get the pattern direction of the active rwy.
        inline int GetPatternDirection() { return rwy.patternDirection; }
        
        inline string get_trans_ident() { return trans_ident; }
        
        inline FGGround* GetGroundPtr() { return ground; }
        
        // Returns true if positions of crosswind/downwind/base leg turns should be constrained by previous traffic
        // plus the constraint position as a rwy orientated orthopos (meters)
        bool GetCrosswindConstraint(double& cpos);
        bool GetDownwindConstraint(double& dpos);
        bool GetBaseConstraint(double& bpos);
        
        string GenText(const string& m, int c);

private:
        FGATCMgr* ATCmgr;       
        // This is purely for synactic convienience to avoid writing globals->get_ATC_mgr()-> all through the code!
        
        // Respond to a transmission
        void Respond();
        
        void ProcessRunwayVacatedReport(TowerPlaneRec* t);
        void ProcessDownwindReport(TowerPlaneRec* t);
        
        // Remove all options from the user dialog choice
        void RemoveAllUserDialogOptions();
        
        // Periodic checks on the various traffic.
        void CheckHoldList(double dt);
        void CheckCircuitList(double dt);
        void CheckRunwayList(double dt);
        void CheckApproachList(double dt);
        void CheckDepartureList(double dt);
        
        // Currently this assumes we *are* next on the runway and doesn't check for planes about to land - 
        // this should be done prior to calling this function.
        void ClearHoldingPlane(TowerPlaneRec* t);
        
        // Find a pointer to plane of callsign ID within the internal data structures
        TowerPlaneRec* FindPlane(string ID);
        
        // Remove and delete all instances of a plane with a given ID
        void RemovePlane(string ID);
        
        // Figure out if a given position lies on the active runway
        // Might have to change when we consider more than one active rwy.
        bool OnActiveRunway(Point3D pt);
        
        // Figure out if a given position lies on a runway or not
        bool OnAnyRunway(Point3D pt);
        
        // Calculate the eta of a plane to the threshold.
        // For ground traffic this is the fastest they can get there.
        // For air traffic this is the middle approximation.
        void CalcETA(TowerPlaneRec* tpr, bool printout = false);
        
        // Iterate through all the lists and call CalcETA for all the planes.
        void doThresholdETACalc();
        
        // Order the list of traffic as per expected threshold use and flag any conflicts
        bool doThresholdUseOrder();
        
        // Calculate the crow-flys distance of a plane to the threshold in meters
        double CalcDistOutM(TowerPlaneRec* tpr);

        // Calculate the crow-flys distance of a plane to the threshold in miles
        double CalcDistOutMiles(TowerPlaneRec* tpr);
        
        /*
        void doCommunication();
        */
        
        void IssueLandingClearance(TowerPlaneRec* tpr);
        void IssueGoAround(TowerPlaneRec* tpr);
        void IssueDepartureClearance(TowerPlaneRec* tpr);
        
        unsigned int update_count;      // Convienince counter for speading computational load over several updates
        unsigned int update_count_max;  // ditto.
        
        double timeSinceLastDeparture;  // Time in seconds since last departure from active rwy.
        bool departed;  // set true when the above needs incrementing with time, false when it doesn't.
        
        // environment - need to make sure we're getting the surface winds and not winds aloft.
        SGPropertyNode* wind_from_hdg;  //degrees
        SGPropertyNode* wind_speed_knots;               //knots
        
        double aptElev;         // Airport elevation
        string activeRwy;       // Active runway number - For now we'll disregard multiple / alternate runway operation.
        RunwayDetails rwy;      // Assumed to be the active one for now.
        bool rwyOccupied;       // Active runway occupied flag.  For now we'll disregard land-and-hold-short operations.
        FGATCAlignedProjection ortho;   // Orthogonal mapping of the local area with the active runway threshold at the origin
        
        // Figure out which runways are active.
        // For now we'll just be simple and do one active runway - eventually this will get much more complex
        // This is a private function - public interface to the results of this is through GetActiveRunway
        void DoRwyDetails();
        
        // Need a data structure to hold details of the various active planes
        // or possibly another data structure with the positions of the inactive planes.
        // Need a data structure to hold outstanding communications from aircraft.
        
        // Linked-list of planes on approach to active rwy ordered with nearest first (timewise).
        // Includes planes that have landed but not yet vacated runway.
        // Somewhat analagous to the paper strips used (used to be used?) in real life.
        // Doesn't include planes in circuit until they turn onto base/final?
        // TODO - may need to alter this for operation to more than one active rwy.
        tower_plane_rec_list_type appList;
        tower_plane_rec_list_iterator appListItr;

        // What should we do with planes approaching the airport to join the circuit somewhere
        // but not on straight-in though? - put them in here for now.   
        tower_plane_rec_list_type circuitAppList;
        tower_plane_rec_list_iterator circuitAppListItr;
        
        // List of departed planes (planes doing circuits go into circuitList not depList after departure)
        tower_plane_rec_list_type depList;
        tower_plane_rec_list_iterator depListItr;
        
        // List of planes in the circuit (ordered by nearest to landing first)
        tower_plane_rec_list_type circuitList;
        tower_plane_rec_list_iterator circuitListItr;
        
        // List of planes waiting to depart
        tower_plane_rec_list_type holdList;
        tower_plane_rec_list_iterator holdListItr;
                
        // List of planes on rwy
        tower_plane_rec_list_type rwyList;
        tower_plane_rec_list_iterator rwyListItr;

        // List of all planes due to use a given rwy arranged in projected order of rwy use
        tower_plane_rec_list_type trafficList;  // TODO - needs to be expandable to more than one rwy
        tower_plane_rec_list_iterator trafficListItr;
        
        // List of planes that have vacated the runway inbound but not yet handed off to ground
        tower_plane_rec_list_type vacatedList;
        tower_plane_rec_list_iterator vacatedListItr;
        
        // Returns true if successful
        bool RemoveFromTrafficList(string id);
        bool RemoveFromAppList(string id);
        bool RemoveFromRwyList(string id);
        
        // Return the ETA of plane no. list_pos (1-based) in the traffic list.
        // i.e. list_pos = 1 implies next to use runway.
        double GetTrafficETA(unsigned int list_pos, bool printout = false);
        
        // Add a tower plane rec with ETA to the traffic list in the correct position ETA-wise.
        // Returns true if this could cause a threshold ETA conflict with other traffic, false otherwise.
        bool AddToTrafficList(TowerPlaneRec* t, bool holding = false);
        
        bool AddToCircuitList(TowerPlaneRec* t);
        
        // Add to vacated list only if not already present
        void AddToVacatedList(TowerPlaneRec* t);

        // Ground can be separate or handled by tower in real life.
        // In the program we will always use a separate FGGround class, but we need to know
        // whether it is supposed to be separate or not to give the correct instructions.
        bool separateGround;    // true if ground control is separate
        FGGround* ground;       // The ground control associated with this airport.
        
        bool _departureControlled;      // true if we need to hand off departing traffic to departure control
        //FGDeparture* _departure;      // The relevant departure control (once we've actually written it!)
        
        // for failure modeling
        string trans_ident;             // transmitted ident
        bool tower_failed;              // tower failed?
        
        // Pointers to current users position and orientation
        SGPropertyNode* user_lon_node;
        SGPropertyNode* user_lat_node;
        SGPropertyNode* user_elev_node;
        SGPropertyNode* user_hdg_node;
        
        // Details of the general traffic flow etc in the circuit
        double crosswind_leg_pos;       // Distance from threshold crosswind leg is being turned to in meters (actual operation - *not* ideal circuit)
        double downwind_leg_pos;        // Actual offset distance in meters from the runway that planes are flying the downwind leg
        // Currently not sure whether the above should be always +ve or just take the natural orthopos sign (+ve for RH circuit, -ve for LH).
        double base_leg_pos;            // Actual offset distance from the threshold (-ve) that planes are turning to base leg.
        
        double nominal_crosswind_leg_pos;
        double nominal_downwind_leg_pos;
        double nominal_base_leg_pos;
        
        friend istream& operator>> ( istream&, FGTower& );
};

#endif  //_FG_TOWER_HXX