update the IAF distance estimation to provide better results

src/PlugIn.cpp

@@ -376,6 +376,7 @@ void PlugIn::generateAircraftReportMessage(EuroScopePlugIn::CRadarTarget& radarT
         break;
     }
 
+    int iafRouteIndex = flightPlan.GetExtractedRoute().GetPointsNumber();
     auto currentPosition = radarTarget.GetPosition().GetPosition();
     EuroScopePlugIn::CPosition iafPosition;
     std::string iafName;
@@ -397,6 +398,7 @@ void PlugIn::generateAircraftReportMessage(EuroScopePlugIn::CRadarTarget& radarT
                         iafPosition = flightPlan.GetExtractedRoute().GetPointPosition(i);
                         iafName = flightPlan.GetExtractedRoute().GetPointName(i);
                         report->set_initialapproachfix(iafName);
+                        iafRouteIndex = i;
                         break;
                     }
                 }
@@ -408,27 +410,35 @@ void PlugIn::generateAircraftReportMessage(EuroScopePlugIn::CRadarTarget& radarT
     }
 
     if (0 != iafName.length()) {
-        const auto iafDistance = currentPosition.DistanceTo(iafPosition);
-
-        /* calculate the distance to the IAF */
-        double distanceToIaf = 0.0f;
-        for (int i = 1; i < flightPlan.GetPositionPredictions().GetPointsNumber(); ++i) {
-            const double distance = flightPlan.GetPositionPredictions().GetPosition(i).DistanceTo(currentPosition);
-            const double headingDelta = std::abs(radarTarget.GetPosition().GetReportedHeading() - flightPlan.GetPositionPredictions().GetPosition(i).DirectionTo(iafPosition));
-
-            /*
-             * 1. no direct way to IAF -> some direct given -> stop after lateral passing
-             * 2. passed the IAF on a way to a direct
-             */
-            if ((90.0 < headingDelta && 270.0 > headingDelta) || iafDistance < distance)
-                break;
+        const std::string_view direct(flightPlan.GetControllerAssignedData().GetDirectToPointName());
+        bool directBehindIAF = false;
+
+        if (0 != direct.length()) {
+            for (int i = 0; i < flightPlan.GetExtractedRoute().GetPointsNumber(); ++i) {
+                if (direct == flightPlan.GetExtractedRoute().GetPointName(i)) {
+                    directBehindIAF = iafRouteIndex < i;
+                    break;
+                }
+            }
+        }
 
-            distanceToIaf += distance;
-            currentPosition = flightPlan.GetPositionPredictions().GetPosition(i);
+        if (true == directBehindIAF) {
+            PlugIn::distanceToPredictedIaf(radarTarget, flightPlan, iafPosition, report);
         }
-        if (0.01f >= std::abs(distanceToIaf))
-            distanceToIaf = iafDistance;
-        report->set_distancetoiaf(static_cast<int>(std::round(distanceToIaf)));
+        else {
+            const GeoCoordinate iaf(static_cast<float>(iafPosition.m_Longitude) * degree, static_cast<float>(iafPosition.m_Latitude) * degree);
+            const Velocity groundspeed = static_cast<float>(radarTarget.GetGS()) * knot;
+            Length distanceToIaf;
+            const auto idx = Inbound::matchToPredictedPath(flightPlan.GetPositionPredictions(), iaf, groundspeed, distanceToIaf);
+
+            /* not inbound the IAF -> check if we passed it */
+            if (flightPlan.GetPositionPredictions().GetPointsNumber() <= idx)
+                PlugIn::distanceToPredictedIaf(radarTarget, flightPlan, iafPosition, report);
+            else
+                report->set_distancetoiaf(static_cast<int>(std::round(distanceToIaf.convert(nauticmile))));
+        }
+
+        this->DisplayUserMessage("TEST", "TEST", (radarTarget.GetCallsign() + std::string(": ") + std::to_string(report->distancetoiaf())).c_str(), true, true, false, false, false);
     }
     report->set_destination(std::string(destination));