Fixes #1404 - Stand assignments 'locked' after landing

app/Models/Vatsim/NetworkAircraft.php

@@ -17,6 +17,7 @@
 use Illuminate\Database\Eloquent\Relations\BelongsToMany;
 use Illuminate\Database\Eloquent\Relations\HasOne;
 use Location\Coordinate;
+use Location\Distance\Haversine;
 
 class NetworkAircraft extends Model
 {
@@ -168,4 +169,23 @@ public function aircraft(): BelongsTo
     {
         return $this->belongsTo(Aircraft::class);
     }
+
+    public function isNearDestination(float $thresholdNauticalMiles = 5.0): bool
+    {
+        if (!$this->destinationAirfield?->latitude || !$this->destinationAirfield?->longitude) {
+            return false;
+        }
+
+        $distanceToAirfieldInNm = LocationService::metersToNauticalMiles(
+            $this->latLong->getDistance($this->coordinate, new Haversine())
+        );
+
+        return $distanceToAirfieldInNm <= $thresholdNauticalMiles;
+    }
+
+    public function hasLanded(): bool
+    {
+        $isOnGround = $this->groundSpeed < 50;
+        return $isOnGround && $this->isNearDestination();
+    }
 }

app/Services/Stand/StandOccupationService.php

@@ -165,16 +165,22 @@ private function occupyStands(Collection $standsToOccupy): void
     }
 
     /**
-     * Given some stands that have been recently occupied, remove any conflicting stand assignments.
+     * Given some stands that have been recently occupied, remove any conflicting stand assignments, unless the
+     * aircraft has already landed.
      */
     private function deleteConflictingAssignmentsFollowingOccupation(Collection $newOccupations): void
     {
-        StandAssignment::whereNotIn('callsign', $newOccupations->pluck('callsign'))
+        $conflictingAssignments = StandAssignment::with('aircraft')
+            ->whereNotIn('callsign', $newOccupations->pluck('callsign'))
             ->whereIn('stand_id', $newOccupations->pluck('stand_id'))
-            ->get()
-            ->each(function (StandAssignment $assignment) {
-                $this->assignmentsService->deleteStandAssignment($assignment);
-            });
+            ->get();
+
+        foreach ($conflictingAssignments as $assignment) {
+            if ($assignment->aircraft && $assignment->aircraft->hasLanded()) {
+                continue;
+            }
+            $this->assignmentsService->deleteStandAssignment($assignment);
+        }
     }
 
     /**