Limit reserve ground units to 10.

Allowing these to grow infinitely leads to some really weird behaviors
when the enemy has been buying reserves long enough, where capturing a
base might result in 80 enemy vehicles suddenly at the gates.

This is just an interim fix. Ideally these units would be reinforcing
the front line as needed
(https://github.com/Khopa/dcs_liberation/issues/382), and a CP could be
lost without needing to completely destroy the defender.

game/procurement.py

@@ -225,7 +225,7 @@ class ProcurementAi:
         # Prefer to buy front line units at active front lines that are not
         # already overloaded.
         for cp in self.owned_points:
-            if cp.base.total_armor >= 30:
+            if cp.expected_ground_units_next_turn.total >= 30:
                 # Control point is already sufficiently defended.
                 continue
             for connected in cp.connected_points:
@@ -233,8 +233,23 @@ class ProcurementAi:
                     candidates.append(cp)
 
         if not candidates:
-            # Otherwise buy them anywhere valid.
-            candidates = [p for p in self.owned_points
-                          if p.can_deploy_ground_units]
+            # Otherwise buy reserves, but don't exceed 10 reserve units per CP.
+            # These units do not exist in the world until the CP becomes
+            # connected to an active front line, at which point all these units
+            # will suddenly appear at the gates of the newly captured CP.
+            #
+            # To avoid sudden overwhelming numbers of units we avoid buying
+            # many.
+            #
+            # Also, do not bother buying units at bases that will never connect
+            # to a front line.
+            for cp in self.owned_points:
+                if not cp.can_deploy_ground_units:
+                    continue
+                if cp.expected_ground_units_next_turn.total >= 10:
+                    continue
+                if cp.is_global:
+                    continue
+                candidates.append(cp)
 
         return candidates

game/theater/controlpoint.py

@@ -588,6 +588,20 @@ class ControlPoint(MissionTarget, ABC):
         else:
             return 0
 
+    @property
+    def expected_ground_units_next_turn(self) -> PendingOccupancy:
+        on_order = 0
+        for unit_bought in self.pending_unit_deliveries.units:
+            if issubclass(unit_bought, FlyingType):
+                continue
+            if unit_bought in TYPE_SHORAD:
+                continue
+            on_order += self.pending_unit_deliveries.units[unit_bought]
+
+        return PendingOccupancy(self.base.total_armor, on_order,
+                                # Ground unit transfers not yet implemented.
+                                transferring=0)
+
     @property
     def income_per_turn(self) -> int:
         return 0