Halt sim on A2A contact.

https://github.com/dcs-liberation/dcs_liberation/issues/1681

game/ato/flightstate/racetrack.py

@@ -0,0 +1,49 @@
+from __future__ import annotations
+
+from datetime import timedelta
+from typing import Optional, TYPE_CHECKING
+
+from dcs import Point
+from shapely.geometry import LineString, Point as ShapelyPoint
+
+from game.ato import FlightType
+from game.ato.flightstate import InFlight
+from game.threatzones import ThreatPoly
+from game.utils import Distance, Speed
+from gen.flights.flightplan import PatrollingFlightPlan
+
+if TYPE_CHECKING:
+    from game.ato.flight import Flight
+    from game.settings import Settings
+
+
+class RaceTrack(InFlight):
+    def __init__(self, flight: Flight, settings: Settings, waypoint_index: int) -> None:
+        assert isinstance(flight.flight_plan, PatrollingFlightPlan)
+        self.patrol_duration = flight.flight_plan.patrol_duration
+        super().__init__(flight, settings, waypoint_index)
+        self.commit_region = LineString(
+            [
+                ShapelyPoint(self.current_waypoint.x, self.current_waypoint.y),
+                ShapelyPoint(self.next_waypoint.x, self.next_waypoint.y),
+            ]
+        ).buffer(flight.flight_plan.engagement_distance.meters)
+
+    def estimate_position(self) -> Point:
+        # Prevent spawning racetracks in the middle of a leg. For simplicity we
+        # always start the aircraft at the beginning of the racetrack.
+        return self.current_waypoint.position
+
+    def estimate_altitude(self) -> tuple[Distance, str]:
+        return self.current_waypoint.alt, self.current_waypoint.alt_type
+
+    def estimate_speed(self) -> Speed:
+        return self.flight.unit_type.preferred_patrol_speed(self.estimate_altitude()[0])
+
+    def travel_time_between_waypoints(self) -> timedelta:
+        return self.patrol_duration
+
+    def a2a_commit_region(self) -> Optional[ThreatPoly]:
+        if self.flight.flight_type in {FlightType.BARCAP, FlightType.TARCAP}:
+            return self.commit_region
+        return None