Clean up custom loadout interface.

Wraps the pydcs data in a real type so we don't need to spread the
reflection all over.

game/data/weapons.py

@@ -0,0 +1,80 @@
+from __future__ import annotations
+
+import inspect
+from dataclasses import dataclass
+from typing import Dict, Iterator, Set, Tuple, Type, Union, cast
+
+from dcs.unitgroup import FlyingGroup
+from dcs.unittype import FlyingType
+
+
+PydcsWeapon = Dict[str, Union[int, str]]
+PydcsWeaponAssignment = Tuple[int, PydcsWeapon]
+
+
+@dataclass(frozen=True)
+class Weapon:
+    """Wraps a pydcs weapon dict in a hashable type."""
+
+    cls_id: str
+    name: str
+    weight: int
+
+    @property
+    def as_pydcs(self) -> PydcsWeapon:
+        return {
+            "clsid": self.cls_id,
+            "name": self.name,
+            "weight": self.weight,
+        }
+
+    @classmethod
+    def from_pydcs(cls, weapon_data: PydcsWeapon) -> Weapon:
+        return cls(
+            cast(str, weapon_data["clsid"]),
+            cast(str, weapon_data["name"]),
+            cast(int, weapon_data["weight"])
+        )
+
+
+@dataclass(frozen=True)
+class Pylon:
+    number: int
+    allowed: Set[Weapon]
+
+    def can_equip(self, weapon: Weapon) -> bool:
+        return weapon in self.allowed
+
+    def equip(self, group: FlyingGroup, weapon: Weapon) -> None:
+        if not self.can_equip(weapon):
+            raise ValueError(f"Pylon {self.number} cannot equip {weapon.name}")
+        group.load_pylon(self.make_pydcs_assignment(weapon), self.number)
+
+    def make_pydcs_assignment(self, weapon: Weapon) -> PydcsWeaponAssignment:
+        return self.number, weapon.as_pydcs
+
+    @classmethod
+    def for_aircraft(cls, aircraft: Type[FlyingType], number: int) -> Pylon:
+        # In pydcs these are all arbitrary inner classes of the aircraft type.
+        # The only way to identify them is by their name.
+        pylons = [v for v in aircraft.__dict__.values() if
+                  inspect.isclass(v) and v.__name__.startswith("Pylon")]
+
+        # And that Pylon class has members with irrelevant names that have
+        # values of (pylon number, allowed weapon).
+        allowed = set()
+        for pylon in pylons:
+            for key, value in pylon.__dict__.items():
+                if key.startswith("__"):
+                    continue
+                pylon_number, weapon = value
+                if pylon_number != number:
+                    continue
+                allowed.add(Weapon.from_pydcs(weapon))
+
+        return cls(number, allowed)
+
+    @classmethod
+    def iter_pylons(cls, aircraft: Type[FlyingType]) -> Iterator[Pylon]:
+        for pylon in sorted(list(aircraft.pylons)):
+            yield cls.for_aircraft(aircraft, pylon)