Change squadrons to operate out of a single base.

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

Currently this is fixed at the start of the campaign. The squadron
locations are defined by the campaign file.

Follow up work:

* Track aircraft ownership per-squadron rather than per-airbase.
* UI for relocating squadrons.
* Ferry missions for squadrons that are relocating.
* Auto-relocation (probably only for retreat handling).

Fixes https://github.com/dcs-liberation/dcs_liberation/issues/1138

game/squadrons/squadron.py

@@ -0,0 +1,262 @@
+from __future__ import annotations
+
+import logging
+from collections import Iterable
+from dataclasses import dataclass, field
+from typing import (
+    TYPE_CHECKING,
+    Optional,
+    Sequence,
+)
+
+from faker import Faker
+
+from game.dcs.aircrafttype import AircraftType
+from game.settings import AutoAtoBehavior, Settings
+from game.squadrons.operatingbases import OperatingBases
+from game.squadrons.pilot import Pilot, PilotStatus
+from game.squadrons.squadrondef import SquadronDef
+
+if TYPE_CHECKING:
+    from game import Game
+    from game.coalition import Coalition
+    from gen.flights.flight import FlightType
+    from game.theater import ControlPoint
+
+
+@dataclass
+class Squadron:
+    name: str
+    nickname: Optional[str]
+    country: str
+    role: str
+    aircraft: AircraftType
+    livery: Optional[str]
+    mission_types: tuple[FlightType, ...]
+    operating_bases: OperatingBases
+
+    #: The pool of pilots that have not yet been assigned to the squadron. This only
+    #: happens when a preset squadron defines more preset pilots than the squadron limit
+    #: allows. This pool will be consumed before random pilots are generated.
+    pilot_pool: list[Pilot]
+
+    current_roster: list[Pilot] = field(default_factory=list, init=False, hash=False)
+    available_pilots: list[Pilot] = field(
+        default_factory=list, init=False, hash=False, compare=False
+    )
+
+    auto_assignable_mission_types: set[FlightType] = field(
+        init=False, hash=False, compare=False
+    )
+
+    coalition: Coalition = field(hash=False, compare=False)
+    settings: Settings = field(hash=False, compare=False)
+
+    location: ControlPoint
+
+    def __post_init__(self) -> None:
+        self.auto_assignable_mission_types = set(self.mission_types)
+
+    def __str__(self) -> str:
+        if self.nickname is None:
+            return self.name
+        return f'{self.name} "{self.nickname}"'
+
+    @property
+    def player(self) -> bool:
+        return self.coalition.player
+
+    def assign_to_base(self, base: ControlPoint) -> None:
+        self.location.squadrons.remove(self)
+        self.location = base
+        self.location.squadrons.append(self)
+        logging.debug(f"Assigned {self} to {base}")
+
+    @property
+    def pilot_limits_enabled(self) -> bool:
+        return self.settings.enable_squadron_pilot_limits
+
+    def set_allowed_mission_types(self, mission_types: Iterable[FlightType]) -> None:
+        self.mission_types = tuple(mission_types)
+        self.auto_assignable_mission_types.intersection_update(self.mission_types)
+
+    def set_auto_assignable_mission_types(
+        self, mission_types: Iterable[FlightType]
+    ) -> None:
+        self.auto_assignable_mission_types = set(self.mission_types).intersection(
+            mission_types
+        )
+
+    def claim_new_pilot_if_allowed(self) -> Optional[Pilot]:
+        if self.pilot_limits_enabled:
+            return None
+        self._recruit_pilots(1)
+        return self.available_pilots.pop()
+
+    def claim_available_pilot(self) -> Optional[Pilot]:
+        if not self.available_pilots:
+            return self.claim_new_pilot_if_allowed()
+
+        # For opfor, so player/AI option is irrelevant.
+        if not self.player:
+            return self.available_pilots.pop()
+
+        preference = self.settings.auto_ato_behavior
+
+        # No preference, so the first pilot is fine.
+        if preference is AutoAtoBehavior.Default:
+            return self.available_pilots.pop()
+
+        prefer_players = preference is AutoAtoBehavior.Prefer
+        for pilot in self.available_pilots:
+            if pilot.player == prefer_players:
+                self.available_pilots.remove(pilot)
+                return pilot
+
+        # No pilot was found that matched the user's preference.
+        #
+        # If they chose to *never* assign players and only players remain in the pool,
+        # we cannot fill the slot with the available pilots.
+        #
+        # If they only *prefer* players and we're out of players, just return an AI
+        # pilot.
+        if not prefer_players:
+            return self.claim_new_pilot_if_allowed()
+        return self.available_pilots.pop()
+
+    def claim_pilot(self, pilot: Pilot) -> None:
+        if pilot not in self.available_pilots:
+            raise ValueError(
+                f"Cannot assign {pilot} to {self} because they are not available"
+            )
+        self.available_pilots.remove(pilot)
+
+    def return_pilot(self, pilot: Pilot) -> None:
+        self.available_pilots.append(pilot)
+
+    def return_pilots(self, pilots: Sequence[Pilot]) -> None:
+        # Return in reverse so that returning two pilots and then getting two more
+        # results in the same ordering. This happens commonly when resetting rosters in
+        # the UI, when we clear the roster because the UI is updating, then end up
+        # repopulating the same size flight from the same squadron.
+        self.available_pilots.extend(reversed(pilots))
+
+    def _recruit_pilots(self, count: int) -> None:
+        new_pilots = self.pilot_pool[:count]
+        self.pilot_pool = self.pilot_pool[count:]
+        count -= len(new_pilots)
+        new_pilots.extend([Pilot(self.faker.name()) for _ in range(count)])
+        self.current_roster.extend(new_pilots)
+        self.available_pilots.extend(new_pilots)
+
+    def populate_for_turn_0(self) -> None:
+        if any(p.status is not PilotStatus.Active for p in self.pilot_pool):
+            raise ValueError("Squadrons can only be created with active pilots.")
+        self._recruit_pilots(self.settings.squadron_pilot_limit)
+
+    def replenish_lost_pilots(self) -> None:
+        if not self.pilot_limits_enabled:
+            return
+
+        replenish_count = min(
+            self.settings.squadron_replenishment_rate,
+            self._number_of_unfilled_pilot_slots,
+        )
+        if replenish_count > 0:
+            self._recruit_pilots(replenish_count)
+
+    def return_all_pilots(self) -> None:
+        self.available_pilots = list(self.active_pilots)
+
+    @staticmethod
+    def send_on_leave(pilot: Pilot) -> None:
+        pilot.send_on_leave()
+
+    def return_from_leave(self, pilot: Pilot) -> None:
+        if not self.has_unfilled_pilot_slots:
+            raise RuntimeError(
+                f"Cannot return {pilot} from leave because {self} is full"
+            )
+        pilot.return_from_leave()
+
+    @property
+    def faker(self) -> Faker:
+        return self.coalition.faker
+
+    def _pilots_with_status(self, status: PilotStatus) -> list[Pilot]:
+        return [p for p in self.current_roster if p.status == status]
+
+    def _pilots_without_status(self, status: PilotStatus) -> list[Pilot]:
+        return [p for p in self.current_roster if p.status != status]
+
+    @property
+    def max_size(self) -> int:
+        return self.settings.squadron_pilot_limit
+
+    @property
+    def active_pilots(self) -> list[Pilot]:
+        return self._pilots_with_status(PilotStatus.Active)
+
+    @property
+    def pilots_on_leave(self) -> list[Pilot]:
+        return self._pilots_with_status(PilotStatus.OnLeave)
+
+    @property
+    def number_of_pilots_including_inactive(self) -> int:
+        return len(self.current_roster)
+
+    @property
+    def _number_of_unfilled_pilot_slots(self) -> int:
+        return self.max_size - len(self.active_pilots)
+
+    @property
+    def number_of_available_pilots(self) -> int:
+        return len(self.available_pilots)
+
+    def can_provide_pilots(self, count: int) -> bool:
+        return not self.pilot_limits_enabled or self.number_of_available_pilots >= count
+
+    @property
+    def has_available_pilots(self) -> bool:
+        return not self.pilot_limits_enabled or bool(self.available_pilots)
+
+    @property
+    def has_unfilled_pilot_slots(self) -> bool:
+        return not self.pilot_limits_enabled or self._number_of_unfilled_pilot_slots > 0
+
+    def can_auto_assign(self, task: FlightType) -> bool:
+        return task in self.auto_assignable_mission_types
+
+    def operates_from(self, control_point: ControlPoint) -> bool:
+        if control_point.is_carrier:
+            return self.operating_bases.carrier
+        elif control_point.is_lha:
+            return self.operating_bases.lha
+        else:
+            return self.operating_bases.shore
+
+    def pilot_at_index(self, index: int) -> Pilot:
+        return self.current_roster[index]
+
+    @classmethod
+    def create_from(
+        cls,
+        squadron_def: SquadronDef,
+        base: ControlPoint,
+        coalition: Coalition,
+        game: Game,
+    ) -> Squadron:
+        return Squadron(
+            squadron_def.name,
+            squadron_def.nickname,
+            squadron_def.country,
+            squadron_def.role,
+            squadron_def.aircraft,
+            squadron_def.livery,
+            squadron_def.mission_types,
+            squadron_def.operating_bases,
+            squadron_def.pilot_pool,
+            coalition,
+            game.settings,
+            base,
+        )