# SPDX-License-Identifier: GPL-2.0-or-later
#
# NOTE! This copyright does *not* cover user models that use these Nasal
# services by normal function calls - this is merely considered normal use
# of the code, and does *not* fall under the heading of "derived work."
#
# Copyright (C) 2012-202 by James Turner

# route_manager.nas -  FlightPlan delegate(s) corresponding to the built-
# in route-manager dialog and GPS. Intended to provide a sensible default behaviour,
# but can be disabled by an aircraft-specific FMS / GPS system.

# This delegate corresponds to functionality of the built-in route-manager dialog.
# if you disable it, the built-in route-manager dialog may not work as expected.
# Especially, this dialog is responsible for building departure, approach and
# arrival waypoints corresponding to the requested SID/STAR/approach,
# and replacing them when the inputs change (eg, user seelcted a different 
# destination or STAR while enroute)
#
# You can disable the default GPS behaviour *without* touching this delegate : they are
# kept seperate since this first one is less likely to need changes

var GPSPath = "/instrumentation/gps";

# this delegate corresponds to the default behaviour of the built-in GPS.
# depending on the real GPS/FMS you are modelling, you probably need to
# replace this with your own.
#
# To do that, just set /autopilot/route-manager/disable-fms to true, which
# will block creation of this delegate.
#
# Of course you are then responsible for many basic FMS functions, such as
# route sequencing and activation
#

var A320GPSDelegate = {
    new: func(fp) {
        var m = { parents: [A320GPSDelegate], flightplan:fp, landingCheck:nil };

        logprint(LOG_INFO, 'creating A320 GPS FPDelegate');

        # tell the GPS C++ code we will do sequencing ourselves, so it can disable
        # its legacy logic for this
		
        setprop(GPSPath ~ '/config/delegate-sequencing', 1);
		
        # disable turn anticipation
        setprop(GPSPath ~ '/config/enable-fly-by', 0);
		
		# flyOver maximum distance
		setprop(GPSPath ~ '/config/over-flight-arm-distance', 5);
		
        fp.followLegTrackToFix = 1;
        fp.aircraftCategory = 'C';
		
        m._modeProp = props.globals.getNode(GPSPath ~ '/mode');
        return m;
    },

    _landingCheckTimeout: func
    {
        if (pts.Gear.wow[0].getValue() and pts.Velocities.groundspeed.getValue() < 25)  {
          logprint(LOG_INFO, 'GPS saw speed < 25kts on destination runway, end of route.');
          me.landingCheck.stop();
          # record touch-down time?
          me.flightplan.finish();
        }
    },

    _captureCurrentCourse: func
    {
        setprop(GPSPath ~ "/selected-course-deg", getprop(GPSPath ~ "/desired-course-deg"));
    },

    _selectOBSMode: func
    {
        setprop(GPSPath ~ "/command", "obs");
    },

    waypointsChanged: func
    {
    },

    activated: func
    {
        if (!me.flightplan.active)
            return;

        logprint(LOG_INFO,'flightplan activated, default GPS to LEG mode');
        setprop(GPSPath ~ "/command", "leg");
    },

    deactivated: func
    {
        if (me._modeProp.getValue() == 'leg') {
            logprint(LOG_INFO, 'flightplan deactivated, default GPS to OBS mode');
            me._captureCurrentCourse();
            me._selectOBSMode();
        }
    },

    endOfFlightPlan: func
    {
        if (me._modeProp.getValue() == 'leg') {
            logprint(LOG_INFO, 'end of flight-plan, switching GPS to OBS mode');
            me._captureCurrentCourse();
            me._selectOBSMode();
        }
    },

    cleared: func
    {
        if (!me.flightplan.active)
            return;

        if (me._modeProp.getValue() == 'leg') {
            logprint(LOG_INFO, 'flight-plan cleared, switching GPS to OBS mode');
            me._captureCurrentCourse();
            me._selectOBSMode();
        }
    },

    sequence: func
    {
		if (!me.flightplan.active)
            return;
			
		if (me._modeProp.getValue() == 'leg') {
			if (me.flightplan.nextWP().wp_type == 'discontinuity') {
				logprint(LOG_INFO, "default GPS sequencing DISCONTINUITY in flightplan, switching to HDG");
				# set HDG mode
			} else {
				logprint(LOG_INFO, "default GPS sequencing to next WP");
				me.flightplan.current = me.flightplan.current + 1;
			}
        } else {
            # OBS, do nothing
        }
    },

    currentWaypointChanged: func
    {
        if (!me.flightplan.active)
            return;

        if (me.landingCheck != nil) {
            me.landingCheck.stop();
            me.landingCheck = nil; # delete timer
        }
		
        var active = me.flightplan.currentWP();
        if (active == nil) return;

        var activeRunway = active.runway();
        # this check is needed to avoid problems with circular routes; when
        # activating the FP we end up here, and without this check, immediately
        # detect that we've 'landed' and finish the FP again.

        if (!pts.Gear.wow[0].getValue() and
            (activeRunway != nil) and (me.flightplan.destination_runway != nil) and 
            (activeRunway.id == me.flightplan.destination_runway.id))
        {
            me.landingCheck = maketimer(2.0, me, A320GPSDelegate._landingCheckTimeout);
            me.landingCheck.start();
        }
    }
};

registerFlightPlanDelegate(A320GPSDelegate.new);