- Added Forcefield.

.gitattributes

@@ -3913,6 +3913,7 @@ res/cardsfolder/f/forced_fruition.txt svneol=native#text/plain
 res/cardsfolder/f/forced_march.txt svneol=native#text/plain
 res/cardsfolder/f/forced_retreat.txt svneol=native#text/plain
 res/cardsfolder/f/forced_worship.txt svneol=native#text/plain
+res/cardsfolder/f/forcefield.txt -text
 res/cardsfolder/f/forcemage_advocate.txt svneol=native#text/plain
 res/cardsfolder/f/foresee.txt svneol=native#text/plain
 res/cardsfolder/f/foreshadow.txt -text

res/cardsfolder/f/forcefield.txt

@@ -0,0 +1,15 @@
+Name:Forcefield
+ManaCost:3
+Types:Artifact
+A:AB$ ChooseCard | Cost$ 1 | Choices$ Creature.unblocked | RememberChosen$ True | AILogic$ NeedsPrevention | SubAbility$ DBEffect | SVars$ DBEffect,RPreventNextFromCreature,CombatDmg,ExileEffect | SpellDescription$ The next time an unblocked creature of your choice would deal combat damage to you this turn, prevent all but 1 of that damage.
+SVar:DBEffect:DB$ Effect | ReplacementEffects$ RPreventNextFromCreature | RememberObjects$ Remembered | SVars$ RPreventNextFromCreature,CombatDmg,ExileEffect | SubAbility$ DBCleanup | ConditionDefined$ Remembered | ConditionPresent$ Card | ConditionCompare$ GE1
+SVar:RPreventNextFromCreature:Event$ DamageDone | ValidSource$ Card.IsRemembered | ValidTarget$ You | ReplaceWith$ CombatDmg | PreventionEffect$ True | CombatDamage$ True | Description$ The next time an unblocked creature of your choice would deal combat damage to you this turn, prevent all but 1 of that damage.
+SVar:CombatDmg:AB$ DealDamage | Cost$ 0 | Defined$ ReplacedTarget | DamageSource$ ReplacedSource | CombatDamage$ True | NumDmg$ 1 | SubAbility$ ExileEffect
+SVar:ExileEffect:DB$ ChangeZone | Defined$ Self | Origin$ Command | Destination$ Exile
+SVar:DBCleanup:DB$ Cleanup | ClearRemembered$ True
+SVar:NonStackingEffect:True
+SVar:Picture:http://www.wizards.com/global/images/magic/general/forcefield.jpg
+Oracle:{1}: The next time an unblocked creature of your choice would deal combat damage to you this turn, prevent all but 1 of that damage.
+SetInfo:LEB Rare
+SetInfo:LEA Rare
+SetInfo:2ED Rare

src/main/java/forge/card/ability/ai/ChooseCardAi.java

@@ -2,11 +2,16 @@ package forge.card.ability.ai;
 
 import java.util.List;
 
+import com.google.common.base.Predicate;
+
 import forge.Card;
 import forge.CardLists;
 import forge.card.ability.SpellAbilityAi;
 import forge.card.spellability.SpellAbility;
 import forge.card.spellability.Target;
+import forge.game.GameState;
+import forge.game.ai.ComputerUtilCombat;
+import forge.game.phase.PhaseType;
 import forge.game.player.Player;
 import forge.game.zone.ZoneType;
 
@@ -16,8 +21,9 @@ public class ChooseCardAi extends SpellAbilityAi {
      * @see forge.card.abilityfactory.SpellAiLogic#canPlayAI(forge.game.player.Player, java.util.Map, forge.card.spellability.SpellAbility)
      */
     @Override
-    protected boolean canPlayAI(Player ai, SpellAbility sa) {
+    protected boolean canPlayAI(final Player ai, SpellAbility sa) {
         final Card host = sa.getSourceCard();
+        final GameState game = ai.getGame();
 
         final Target tgt = sa.getTarget();
         if (tgt != null) {
@@ -55,6 +61,25 @@ public class ChooseCardAi extends SpellAbilityAi {
                 }
             } else if (sa.getParam("AILogic").equals("Never")) {
                 return false;
+            } else if (sa.getParam("AILogic").equals("NeedsPrevention")) {
+                if (!game.getPhaseHandler().getPhase() .equals(PhaseType.COMBAT_DECLARE_BLOCKERS_INSTANT_ABILITY)) {
+                    return false;
+                }
+                choices = CardLists.filter(choices, new Predicate<Card>() {
+                    @Override
+                    public boolean apply(final Card c) {
+                        if (!c.isAttacking(ai) || !game.getCombat().isUnblocked(c)) {
+                            return false;
+                        }
+                        if (host.getName().equals("Forcefield")) {
+                            return ComputerUtilCombat.damageIfUnblocked(c, ai, game.getCombat()) > 1;
+                        }
+                        return ComputerUtilCombat.damageIfUnblocked(c, ai, game.getCombat()) > 0;
+                    }
+                });
+                if (choices.isEmpty()) {
+                    return false;
+                }
             }
         }
 

src/main/java/forge/game/ai/AiController.java

@@ -620,8 +620,8 @@ public class AiController {
         }
 
         Card choice = null;
-        Card host = sa.getSourceCard();
+        final Card host = sa.getSourceCard();
-        String logic = sa.getParam("AILogic");
+        final String logic = sa.getParam("AILogic");
 
         switch(api) {
             case Bond: 
@@ -648,6 +648,25 @@ public class AiController {
                         options = CardLists.getValidCards(options, "Permanent.YouCtrl,Permanent.tapped", host.getController(), host);
                     }
                     choice = ComputerUtilCard.getBestAI(options);
+                } else if (logic.equals("NeedsPrevention")) {
+                    final Player ai = this.getPlayer();
+                    List<Card> better =  CardLists.filter(options, new Predicate<Card>() {
+                        @Override
+                        public boolean apply(final Card c) {
+                            if (!c.isAttacking(ai) || !game.getCombat().isUnblocked(c)) {
+                                return false;
+                            }
+                            if (host.getName().equals("Forcefield")) {
+                                return ComputerUtilCombat.damageIfUnblocked(c, ai, game.getCombat()) > 1;
+                            }
+                            return ComputerUtilCombat.damageIfUnblocked(c, ai, game.getCombat()) > 0;
+                        }
+                    });
+                    if (!better.isEmpty()) {
+                        choice = ComputerUtilCard.getBestAI(better);
+                    } else {
+                        choice = ComputerUtilCard.getBestAI(options);
+                    }
                 } else {
                     choice = ComputerUtilCard.getBestAI(options);
                 }