# 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 A320RouteManagerDelegate = {
    new: func(fp) {
        var m = { parents: [A320RouteManagerDelegate] };
		
        logprint(LOG_INFO, 'creating A320 Route Manager FPDelegate');
		
        m.flightplan = fp;
        return m;
    },

    departureChanged: func
    {
        logprint(LOG_INFO, 'saw departure changed');
        me.flightplan.clearWPType('sid');
        if (me.flightplan.departure == nil)
            return;

        if (me.flightplan.departure_runway == nil) {
        # no runway, only an airport, use that
            var wp = createWPFrom(me.flightplan.departure);
            wp.wp_role = 'sid';
            me.flightplan.insertWP(wp, 0);
            return;
        }
    # first, insert the runway itself
        var wp = createWPFrom(me.flightplan.departure_runway);
        wp.wp_role = 'sid';
        me.flightplan.insertWP(wp, 0);
        if (me.flightplan.sid == nil)
            return;

    # and we have a SID
        var sid = me.flightplan.sid;
        logprint(LOG_INFO, 'routing via SID ' ~ sid.id);
		
		var wps = sid.route(me.flightplan.departure_runway, me.flightplan.sid_trans);
		var lastWP = wps[-1];
		var foundIdx = -999;
		
		for (var wptIdx = 0; wptIdx < me.flightplan.getPlanSize(); wptIdx = wptIdx + 1) {
			if (me.flightplan.getWP(wptIdx).id == lastWP.id) {
				foundIdx = wptIdx;
				break;
			}
		}
		
		if (foundIdx != -999) {
			while (foundIdx > 0) {
				me.flightplan.deleteWP(1);
				foundIdx -= 1;
			}
		}
		
        me.flightplan.insertWaypoints(wps, 1);
    },

    arrivalChanged: func
    {
        me.flightplan.clearWPType('star');
        me.flightplan.clearWPType('approach');
        if (me.flightplan.destination == nil)
            return;

        if (me.flightplan.destination_runway == nil) {
        # no runway, only an airport, use that
            var wp = createWPFrom(me.flightplan.destination);
            wp.wp_role = 'approach';
            me.flightplan.appendWP(wp);
            return;
        }

        var initialApproachFix = nil;
        if (me.flightplan.star != nil) {
            logprint(LOG_INFO, 'routing via STAR ' ~ me.flightplan.star.id);
            var wps = me.flightplan.star.route(me.flightplan.destination_runway, me.flightplan.star_trans);
            if (wps != nil) {
                me.flightplan.insertWaypoints(wps, -1);
                initialApproachFix = wps[-1]; # final waypoint of STAR
            }
        }

        if (me.flightplan.approach != nil) {
            var wps = nil;
            var approachIdent = me.flightplan.approach.id;

            if (me.flightplan.approach_trans != nil) {
                # if an approach transition was specified, let's use it explicitly
                wps = me.flightplan.approach.route(me.flightplan.destination_runway, me.flightplan.approach_trans);
                if (wps == nil) {
                    logprint(LOG_WARN, "couldn't route approach " ~ approachIdent ~ " based on specified transition:" ~ me.flightplan.approach_trans);
                }
            } else if (initialApproachFix != nil) {
                # no explicit approach transition, let's use the IAF to guess one
                wps = me.flightplan.approach.route(me.flightplan.destination_runway, initialApproachFix);
                if (wps == nil) {
                    logprint(LOG_INFO, "couldn't route approach " ~ approachIdent ~ " based on IAF:" ~ initialApproachFix.wp_name);
                }
            }

            # depending on the order the user selects the approach or STAR, we might get into
            # a mess here. If we failed to route so far, just try a direct to the approach
            if (wps == nil) {
                # route direct
                 wps = me.flightplan.approach.route(me.flightplan.destination_runway);
            }

            if (wps == nil) {
                logprint(LOG_WARN, 'routing via approach ' ~ approachIdent ~ ' failed entirely.');
            } else {
                me.flightplan.insertWaypoints(wps, -1);
            }
        } else {
            # no approach, just use the runway waypoint
            var wp = createWPFrom(me.flightplan.destination_runway);
            wp.wp_role = 'approach';
            me.flightplan.appendWP(wp);
        }
    },

    cleared: func
    {
        logprint(LOG_INFO, "saw active flightplan cleared, deactivating");
        # see http://https://code.google.com/p/flightgear-bugs/issues/detail?id=885
        fgcommand("activate-flightplan", props.Node.new({"activate": 0}));
    },

    endOfFlightPlan: func
    {
        logprint(LOG_INFO, "end of flight-plan, deactivating");
        fgcommand("activate-flightplan", props.Node.new({"activate": 0}));
    }
};

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.groundspeedKt.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.current + 1 >= me.flightplan.numWaypoints()) {
				logprint(LOG_INFO, "default GPS sequencing, finishing flightplan");
				me.flightplan.finish();
            } elsif (me.flightplan.nextWP().wp_type != 'discontinuity' and me.flightplan.nextWP().wp_type != 'vectors') {
				logprint(LOG_INFO, "default GPS sequencing to next WP");
				me.flightplan.current = me.flightplan.current + 1;
			} else {
				logprint(LOG_INFO, "default GPS sequencing to next WP (special)");
				if (fmgc.Output.lat.getValue() == 1) {
					fmgc.Input.lat.setValue(3);
				}
				if (me.flightplan.nextWP().wp_type == 'vectors') {
					me.flightplan.current = me.flightplan.current + 2;
				}
			}
        } 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);
registerFlightPlanDelegate(A320RouteManagerDelegate.new);