- Added a more conservative version of AILogic PayEnergy for PutCounter AI that only pays energy if the creature is in combat (attacking/blocking) or if there's more energy available than the most expensive energy cost of a permanent SA on the battlefield requires plus whatever the PutCounter SA requires.

- Set this logic for Longtusk Cub and Bristling Hydra.
- TODO: maybe somehow teach the AI to pay energy if it can save the creature from lethal damage from a spell?

forge-ai/src/main/java/forge/ai/ComputerUtilCard.java

@@ -40,6 +40,8 @@ import forge.game.card.CardUtil;
 import forge.game.card.CounterType;
 import forge.game.combat.Combat;
 import forge.game.combat.CombatUtil;
+import forge.game.cost.CostPart;
+import forge.game.cost.CostPayEnergy;
 import forge.game.keyword.Keyword;
 import forge.game.phase.PhaseHandler;
 import forge.game.phase.PhaseType;
@@ -1587,4 +1589,28 @@ public class ComputerUtilCard {
     public static boolean isPresentOnBattlefield(final Game game, final String cardName) {
         return !CardLists.filter(game.getCardsIn(ZoneType.Battlefield), CardPredicates.nameEquals(cardName)).isEmpty();
     }
+
+    public static int getMaxSAEnergyCostOnBattlefield(final Player ai) {
+        // returns the maximum energy cost of an ability that permanents on the battlefield under AI's control have
+        CardCollectionView otb = ai.getCardsIn(ZoneType.Battlefield);
+        int maxEnergyCost = 0;
+
+        for (Card c : otb) {
+            for (SpellAbility sa : c.getSpellAbilities()) {
+                if (sa.getPayCosts() == null) {
+                    continue;
+                }
+
+                CostPayEnergy energyCost = sa.getPayCosts().getCostEnergy();
+                if (energyCost != null) {
+                    int amount = energyCost.convertAmount();
+                    if (amount > maxEnergyCost) {
+                        maxEnergyCost = amount;
+                    }
+                }
+            }
+        }
+
+        return maxEnergyCost;
+    }
 }

forge-ai/src/main/java/forge/ai/ability/CountersPutAi.java

@@ -217,7 +217,18 @@ public class CountersPutAi extends SpellAbilityAi {
         }
         
         if ("PayEnergy".equals(sa.getParam("AILogic"))) {
-            return true;
+            return false;
+        }
+
+        if ("PayEnergyConservatively".equals(sa.getParam("AILogic"))) {
+            if (ai.getGame().getCombat() != null && sa.getHostCard() != null) {
+                if (ai.getGame().getCombat().isAttacking(sa.getHostCard()) || ai.getGame().getCombat().isBlocking(sa.getHostCard())) {  
+                    return true;
+                }
+            }
+            if (ai.getCounters(CounterType.ENERGY) > ComputerUtilCard.getMaxSAEnergyCostOnBattlefield(ai) + sa.getPayCosts().getCostEnergy().convertAmount()) {
+                return true;
+            }
         }
 
         if (sa.getConditions() != null && !sa.getConditions().areMet(sa) && sa.getSubAbility() == null) {

forge-game/src/main/java/forge/game/cost/Cost.java

@@ -494,6 +494,15 @@ public class Cost {
         return null;
     }
 
+    public final CostPayEnergy getCostEnergy() {
+        for (final CostPart part : this.costParts) {
+            if (part instanceof CostPayEnergy) {
+                return (CostPayEnergy) part;
+            }
+        }
+        return null;
+    }
+
     /**
      * <p>
      * refundPaidCost.

forge-gui/res/cardsfolder/b/bristling_hydra.txt

@@ -4,7 +4,7 @@ Types:Creature Hydra
 PT:4/3
 T:Mode$ ChangesZone | Origin$ Any | Destination$ Battlefield | ValidCard$ Card.Self | Execute$ TrigEnergy | TriggerDescription$ When CARDNAME enters the battlefield, you get {E}{E}{E} (three energy counters).
 SVar:TrigEnergy:DB$ PutCounter | Defined$ You | CounterType$ ENERGY | CounterNum$ 3
-A:AB$ PutCounter | Cost$ PayEnergy<3> | CounterType$ P1P1 | CounterNum$ 1 | SubAbility$ DBPump | SpellDescription$ Put a +1/+1 counter on CARDNAME. It gains hexproof until end of turn.
+A:AB$ PutCounter | Cost$ PayEnergy<3> | CounterType$ P1P1 | CounterNum$ 1 | SubAbility$ DBPump | AILogic$ PayEnergyConservatively | SpellDescription$ Put a +1/+1 counter on CARDNAME. It gains hexproof until end of turn.
 SVar:DBPump:DB$Pump | Defined$ Self | KW$ Hexproof
 SVar:Picture:http://www.wizards.com/global/images/magic/general/bristling_hydra.jpg
 Oracle:When Bristling Hydra enters the battlefield, you gain {E}{E}{E} (three energy counters).\nPay {E}{E}{E}: Put a +1/+1 counter on Bristling Hydra. It gains hexproof until end of turn.

forge-gui/res/cardsfolder/l/longtusk_cub.txt

@@ -4,7 +4,7 @@ Types:Creature Cat
 PT:2/2
 T:Mode$ DamageDone | ValidSource$ Card.Self | ValidTarget$ Player | CombatDamage$ True | Execute$ TrigEnergy | TriggerZones$ Battlefield | TriggerDescription$ Whenever CARDNAME deals combat damage to a player, you get {E}{E} (two energy counters).
 SVar:TrigEnergy:DB$PutCounter | Defined$ You | CounterType$ ENERGY | CounterNum$ 2
-A:AB$ PutCounter | Cost$ PayEnergy<2> | CounterType$ P1P1 | CounterNum$ 1 | SpellDescription$ Put a +1/+1 counter on CARDNAME.
+A:AB$ PutCounter | Cost$ PayEnergy<2> | CounterType$ P1P1 | CounterNum$ 1 | AILogic$ PayEnergyConservatively | SpellDescription$ Put a +1/+1 counter on CARDNAME.
 DeckHints:Ability$Energy
 DeckHas:Ability$Counters
 SVar:Picture:http://www.wizards.com/global/images/magic/general/longtusk_cub.jpg