Implement ferry flights for squadron transfers.

Fixes https://github.com/dcs-liberation/dcs_liberation/issues/1145

gen/aircraft.py

@@ -57,6 +57,7 @@ from dcs.task import (
     Transport,
     WeaponType,
     TargetType,
+    Nothing,
 )
 from dcs.terrain.terrain import Airport, NoParkingSlotError
 from dcs.triggers import Event, TriggerOnce, TriggerRule
@@ -1086,6 +1087,23 @@ class AircraftConflictGenerator:
             restrict_jettison=True,
         )
 
+    def configure_ferry(
+        self,
+        group: FlyingGroup[Any],
+        package: Package,
+        flight: Flight,
+        dynamic_runways: Dict[str, RunwayData],
+    ) -> None:
+        group.task = Nothing.name
+        self._setup_group(group, package, flight, dynamic_runways)
+        self.configure_behavior(
+            flight,
+            group,
+            react_on_threat=OptReactOnThreat.Values.EvadeFire,
+            roe=OptROE.Values.WeaponHold,
+            restrict_jettison=True,
+        )
+
     def configure_unknown_task(self, group: FlyingGroup[Any], flight: Flight) -> None:
         logging.error(f"Unhandled flight type: {flight.flight_type}")
         self.configure_behavior(flight, group)
@@ -1130,6 +1148,8 @@ class AircraftConflictGenerator:
             self.configure_oca_strike(group, package, flight, dynamic_runways)
         elif flight_type == FlightType.TRANSPORT:
             self.configure_transport(group, package, flight, dynamic_runways)
+        elif flight_type == FlightType.FERRY:
+            self.configure_ferry(group, package, flight, dynamic_runways)
         else:
             self.configure_unknown_task(group, flight)
 

gen/ato.py

@@ -183,6 +183,7 @@ class Package:
             FlightType.TARCAP,
             FlightType.BARCAP,
             FlightType.AEWC,
+            FlightType.FERRY,
             FlightType.REFUELING,
             FlightType.SWEEP,
             FlightType.ESCORT,

gen/flights/flight.py

@@ -70,6 +70,7 @@ class FlightType(Enum):
     TRANSPORT = "Transport"
     SEAD_ESCORT = "SEAD Escort"
     REFUELING = "Refueling"
+    FERRY = "Ferry"
 
     def __str__(self) -> str:
         return self.value

gen/flights/flightplan.py

@@ -37,10 +37,8 @@ from game.theater.theatergroundobject import (
     NavalGroundObject,
     BuildingGroundObject,
 )
-
 from game.threatzones import ThreatZones
 from game.utils import Distance, Heading, Speed, feet, meters, nautical_miles, knots
-
 from .closestairfields import ObjectiveDistanceCache
 from .flight import Flight, FlightType, FlightWaypoint, FlightWaypointType
 from .traveltime import GroundSpeed, TravelTime
@@ -836,6 +834,39 @@ class AirliftFlightPlan(FlightPlan):
         return self.package.time_over_target
 
 
+@dataclass(frozen=True)
+class FerryFlightPlan(FlightPlan):
+    takeoff: FlightWaypoint
+    nav_to_destination: list[FlightWaypoint]
+    land: FlightWaypoint
+    divert: Optional[FlightWaypoint]
+    bullseye: FlightWaypoint
+
+    def iter_waypoints(self) -> Iterator[FlightWaypoint]:
+        yield self.takeoff
+        yield from self.nav_to_destination
+        yield self.land
+        if self.divert is not None:
+            yield self.divert
+        yield self.bullseye
+
+    @property
+    def tot_waypoint(self) -> Optional[FlightWaypoint]:
+        return self.land
+
+    def tot_for_waypoint(self, waypoint: FlightWaypoint) -> Optional[timedelta]:
+        # TOT planning isn't really useful for ferries. They're behind the front
+        # lines so no need to wait for escorts or for other missions to complete.
+        return None
+
+    def depart_time_for_waypoint(self, waypoint: FlightWaypoint) -> Optional[timedelta]:
+        return None
+
+    @property
+    def mission_departure_time(self) -> timedelta:
+        return self.package.time_over_target
+
+
 @dataclass(frozen=True)
 class CustomFlightPlan(FlightPlan):
     custom_waypoints: List[FlightWaypoint]
@@ -958,6 +989,8 @@ class FlightPlanBuilder:
             return self.generate_transport(flight)
         elif task == FlightType.REFUELING:
             return self.generate_refueling_racetrack(flight)
+        elif task == FlightType.FERRY:
+            return self.generate_ferry(flight)
         raise PlanningError(f"{task} flight plan generation not implemented")
 
     def regenerate_package_waypoints(self) -> None:
@@ -1244,6 +1277,42 @@ class FlightPlanBuilder:
             bullseye=builder.bullseye(),
         )
 
+    def generate_ferry(self, flight: Flight) -> FerryFlightPlan:
+        """Generate a ferry flight at a given location.
+
+        Args:
+            flight: The flight to generate the flight plan for.
+        """
+
+        if flight.departure == flight.arrival:
+            raise PlanningError(
+                f"Cannot plan ferry flight: departure and arrival are both "
+                f"{flight.departure}"
+            )
+
+        altitude_is_agl = flight.unit_type.dcs_unit_type.helicopter
+        altitude = (
+            feet(1500)
+            if altitude_is_agl
+            else flight.unit_type.preferred_patrol_altitude
+        )
+
+        builder = WaypointBuilder(flight, self.coalition)
+        return FerryFlightPlan(
+            package=self.package,
+            flight=flight,
+            takeoff=builder.takeoff(flight.departure),
+            nav_to_destination=builder.nav_path(
+                flight.departure.position,
+                flight.arrival.position,
+                altitude,
+                altitude_is_agl,
+            ),
+            land=builder.land(flight.arrival),
+            divert=builder.divert(flight.divert),
+            bullseye=builder.bullseye(),
+        )
+
     def cap_racetrack_for_objective(
         self, location: MissionTarget, barcap: bool
     ) -> Tuple[Point, Point]: