Avoid cases where empty flights could be created.

Fixes dcs-liberation#373

qt_ui/widgets/combos/QOriginAirfieldSelector.py

@@ -1,9 +1,10 @@
 """Combo box for selecting a departure airfield."""
 from typing import Iterable
 
+from PySide2.QtCore import Signal
 from PySide2.QtWidgets import QComboBox
-
 from dcs.planes import PlaneType
+
 from game.inventory import GlobalAircraftInventory
 from theater.controlpoint import ControlPoint
 
@@ -15,6 +16,8 @@ class QOriginAirfieldSelector(QComboBox):
     that have unassigned inventory of the given aircraft type.
     """
 
+    availability_changed = Signal(int)
+
     def __init__(self, global_inventory: GlobalAircraftInventory,
                  origins: Iterable[ControlPoint],
                  aircraft: PlaneType) -> None:
@@ -23,6 +26,7 @@ def __init__(self, global_inventory: GlobalAircraftInventory,
         self.origins = list(origins)
         self.aircraft = aircraft
         self.rebuild_selector()
+        self.currentIndexChanged.connect(self.index_changed)
 
     def change_aircraft(self, aircraft: PlaneType) -> None:
         if self.aircraft == aircraft:
@@ -47,3 +51,10 @@ def available(self) -> int:
             return 0
         inventory = self.global_inventory.for_control_point(origin)
         return inventory.available(self.aircraft)
+
+    def index_changed(self, index: int) -> None:
+        origin = self.itemData(index)
+        if origin is None:
+            return
+        inventory = self.global_inventory.for_control_point(origin)
+        self.availability_changed.emit(inventory.available(self.aircraft))

qt_ui/windows/mission/flight/QFlightCreator.py

@@ -54,11 +54,11 @@ def __init__(self, game: Game, package: Package, parent=None) -> None:
             [cp for cp in game.theater.controlpoints if cp.captured],
             self.aircraft_selector.currentData()
         )
-        self.airfield_selector.currentIndexChanged.connect(self.update_max_size)
+        self.airfield_selector.availability_changed.connect(self.update_max_size)
         layout.addLayout(QLabeledWidget("Airfield:", self.airfield_selector))
 
         self.flight_size_spinner = QFlightSizeSpinner()
-        self.update_max_size()
+        self.update_max_size(self.airfield_selector.available)
         layout.addLayout(QLabeledWidget("Size:", self.flight_size_spinner))
 
         self.client_slots_spinner = QFlightSizeSpinner(
@@ -91,6 +91,8 @@ def verify_form(self) -> Optional[str]:
             return f"{origin.name} has no {aircraft.id} available."
         if size > available:
             return f"{origin.name} has only {available} {aircraft.id} available."
+        if size <= 0:
+            return f"Flight must have at least one aircraft."
         return None
 
     def create_flight(self) -> None:
@@ -120,7 +122,8 @@ def on_aircraft_changed(self, index: int) -> None:
         new_aircraft = self.aircraft_selector.itemData(index)
         self.airfield_selector.change_aircraft(new_aircraft)
 
-    def update_max_size(self) -> None:
-        self.flight_size_spinner.setMaximum(
-            min(self.airfield_selector.available, 4)
-        )
+    def update_max_size(self, available: int) -> None:
+        self.flight_size_spinner.setMaximum(min(available, 4))
+        if self.flight_size_spinner.maximum() >= 2:
+            if self.flight_size_spinner.value() < 2:
+                self.flight_size_spinner.setValue(2)