PlacePanel: Limit max based on unit requirements. (#11887)

This change caps the max for each unit type in the place panel to the max that can be placed for that type when considering "units which require units" logic (i.e. factory types).

This partially prevents the error "Cannot place more units which require units, than production capacity of territories with the required units" after making the selection in the place panel.

Note: That error can still happen when selecting multiple units of different types that surpass the max.

game-app/game-core/src/main/java/games/strategy/triplea/delegate/AbstractPlaceDelegate.java

@@ -38,6 +38,7 @@
 import java.util.Map.Entry;
 import java.util.Objects;
 import java.util.function.Predicate;
+import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 import org.triplea.java.collections.CollectionUtils;
 import org.triplea.java.collections.IntegerMap;
@@ -974,6 +975,11 @@ protected Collection<Unit> getUnitsToBePlaced(
     } else {
       placeableUnits2 = placeableUnits;
     }
+    // Limit count of each unit type to the max that can be placed based on unit requirements.
+    for (UnitType ut : placeableUnits2.stream().map(Unit::getType).collect(Collectors.toSet())) {
+      var unitsOfType = CollectionUtils.getMatches(placeableUnits2, Matches.unitIsOfType(ut));
+      placeableUnits2.removeAll(getUnitsThatCantBePlacedThatRequireUnits(unitsOfType, to));
+    }
     // now check stacking limits
     return UnitStackingLimitFilter.filterUnits(
         placeableUnits2, PLACEMENT_LIMIT, player, to, produced.getOrDefault(to, List.of()));
@@ -1471,20 +1477,25 @@ private Predicate<Unit> unitWhichRequiresUnitsHasRequiredUnits(
 
   private boolean getCanAllUnitsWithRequiresUnitsBePlacedCorrectly(
       final Collection<Unit> units, final Territory to) {
+    return getUnitsThatCantBePlacedThatRequireUnits(units, to).isEmpty();
+  }
+
+  private Collection<Unit> getUnitsThatCantBePlacedThatRequireUnits(
+      final Collection<Unit> units, final Territory to) {
     if (!Properties.getUnitPlacementRestrictions(getData().getProperties())
         || units.stream().noneMatch(Matches.unitRequiresUnitsOnCreation())) {
-      return true;
+      return List.of();
     }
     final IntegerMap<Territory> producersMap = getMaxUnitsToBePlacedMap(units, to, player);
     final List<Territory> producers = getAllProducers(to, player, units);
     if (producers.isEmpty()) {
-      return false;
+      return units;
     }
     producers.sort(getBestProducerComparator(to, units, player));
     final Collection<Unit> unitsLeftToPlace = new ArrayList<>(units);
     for (final Territory t : producers) {
       if (unitsLeftToPlace.isEmpty()) {
-        return true;
+        return List.of();
       }
       final int productionHere = producersMap.getInt(t);
       final List<Unit> canBePlacedHere =
@@ -1499,7 +1510,7 @@ private boolean getCanAllUnitsWithRequiresUnitsBePlacedCorrectly(
           CollectionUtils.getNMatches(canBePlacedHere, productionHere, it -> true);
       unitsLeftToPlace.removeAll(placedHere);
     }
-    return unitsLeftToPlace.isEmpty();
+    return unitsLeftToPlace;
   }
 
   private Comparator<Territory> getBestProducerComparator(

game-app/game-core/src/test/java/games/strategy/triplea/delegate/PlaceDelegateTest.java

@@ -1,5 +1,8 @@
 package games.strategy.triplea.delegate;
 
+import static games.strategy.triplea.Constants.DAMAGE_FROM_BOMBING_DONE_TO_UNITS_INSTEAD_OF_TERRITORIES;
+import static games.strategy.triplea.Constants.UNIT_PLACEMENT_RESTRICTIONS;
+import static games.strategy.triplea.delegate.GameDataTestUtil.unitType;
 import static games.strategy.triplea.delegate.Matches.unitIsOfType;
 import static games.strategy.triplea.delegate.MockDelegateBridge.newDelegateBridge;
 import static games.strategy.triplea.delegate.remote.IAbstractPlaceDelegate.BidMode.NOT_BID;
@@ -145,6 +148,26 @@ void testCanNotProduceThatManyUnits() {
     assertEquals(2, response.getMaxUnits());
   }
 
+  @Test
+  void testCanNotProduceThatManyUnitsDueToRequiresUnits() {
+    gameData.getProperties().set(UNIT_PLACEMENT_RESTRICTIONS, true);
+    // Needed for canProduceXUnits to work. (!)
+    gameData.getProperties().set(DAMAGE_FROM_BOMBING_DONE_TO_UNITS_INSTEAD_OF_TERRITORIES, true);
+    final var factory2 = unitType("factory2", gameData);
+    final var infantry2 = unitType("infantry2", gameData);
+
+    final var threeInfantry2 = create(british, infantry2, 3);
+    final var fourInfantry2 = create(british, infantry2, 4);
+
+    uk.getUnitCollection().clear();
+    assertError(delegate.canUnitsBePlaced(uk, threeInfantry2, british));
+    uk.getUnitCollection().addAll(create(british, factory2, 1));
+    assertValid(delegate.canUnitsBePlaced(uk, threeInfantry2, british));
+    assertError(delegate.canUnitsBePlaced(uk, fourInfantry2, british));
+    final PlaceableUnits response = delegate.getPlaceableUnits(fourInfantry2, uk);
+    assertThat(response.getUnits(), hasSize(3));
+  }
+
   @Test
   void testAlreadyProducedUnits() {
     delegate.setProduced(Map.of(westCanada, create(british, infantry, 2)));

game-app/game-core/src/test/resources/DelegateTest.xml

@@ -459,6 +459,8 @@
         <unit name="submarine"/>
         <unit name="factory"/>
         <unit name="aaGun"/>
+        <unit name="factory2"/>
+        <unit name="infantry2"/>
     </unitList>
 <gamePlay>
         <delegate name="initDelegate" javaClass="games.strategy.triplea.delegate.InitializationDelegate"/>
@@ -718,6 +720,20 @@
             type="unitType">
             <option name="isFactory" value="true"/>
         </attachment>
+
+
+        <attachment name="unitAttachment" attachTo="factory2" javaClass="UnitAttachment" type="unitType">
+            <option name="isFactory" value="true"/>
+            <option name="canProduceXUnits" value="3"/>
+        </attachment>
+        <attachment name="unitAttachment" attachTo="infantry2" javaClass="UnitAttachment" type="unitType">
+            <option name="movement" value="1"/>
+            <option name="transportCost" value="1"/>
+            <option name="attack" value="1"/>
+            <option name="defense" value="2"/>
+            <option name="requiresUnits" value="factory2"/>
+        </attachment>
+
         <attachment name="unitAttachment"
             attachTo="aaGun"
             javaClass="UnitAttachment"