AiAttackController: add check for GlobalAttackRestrictions used for getting MaxAttack,

when it can only attack with one creature, it should pick the strongest one. 
also moved MustAttack parts a bit.
that fixes AI using the Attack Rule of Silent Arbiter correctly

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

@@ -35,6 +35,7 @@ import forge.game.card.CardLists;
 import forge.game.card.CounterType;
 import forge.game.combat.Combat;
 import forge.game.combat.CombatUtil;
+import forge.game.combat.GlobalAttackRestrictions;
 import forge.game.player.Player;
 import forge.game.spellability.SpellAbility;
 import forge.game.trigger.Trigger;
@@ -524,12 +525,29 @@ public class AiAttackController {
         // Determine who will be attacked
         GameEntity defender = this.chooseDefender(combat, bAssault);
         List<Card> attackersLeft = new ArrayList<Card>(this.attackers);
+
+        // TODO probably use AttackConstraints instead of only GlobalAttackRestrictions?
+        GlobalAttackRestrictions restrict = GlobalAttackRestrictions.getGlobalRestrictions(ai, combat.getDefenders());
+        final int attackMax = restrict.getMax();
+
+        if (attackMax == 0) {
+            //  can't attack anymore
+            return;
+        }
+
         // Attackers that don't really have a choice
         for (final Card attacker : this.attackers) {
             if (!CombatUtil.canAttack(attacker, defender)) {
+                attackersLeft.remove(attacker);
                 continue;
             }
             boolean mustAttack = false;
+            if (attacker.getSVar("MustAttack").equals("True")) {
+                mustAttack = true;
+            } else if (attacker.getSVar("EndOfTurnLeavePlay").equals("True")
+                    && isEffectiveAttacker(ai, attacker, combat)) {
+                mustAttack = true;
+            } else {
                 for (String s : attacker.getKeywords()) {
                     if (s.equals("CARDNAME attacks each turn if able.")
                             || s.startsWith("CARDNAME attacks specific player each combat if able")
@@ -537,14 +555,9 @@ public class AiAttackController {
                         mustAttack = true;
                         break;
                     }
-                if (attacker.getSVar("EndOfTurnLeavePlay").equals("True")
-                        && isEffectiveAttacker(ai, attacker, combat)) {
-                    mustAttack = true;
-                    break;
                 }
             }
-            if (mustAttack || attacker.getController().getMustAttackEntity() != null
+            if (mustAttack || attacker.getController().getMustAttackEntity() != null) {
-                    || attacker.getSVar("MustAttack").equals("True")) {
                 combat.addAttacker(attacker, defender);
                 attackersLeft.remove(attacker);
             }
@@ -557,10 +570,15 @@ public class AiAttackController {
                 System.out.println("Assault");
             CardLists.sortByPowerDesc(attackersLeft);
             for (Card attacker : attackersLeft) {
+                // reached max, breakup
+                if (attackMax != -1 && combat.getAttackers().size() >= attackMax)
+                    return;
+
                 if (CombatUtil.canAttack(attacker, defender) && this.isEffectiveAttacker(ai, attacker, combat)) {
                     combat.addAttacker(attacker, defender);
                 }
             }
+            // no more creatures to attack
             return;
         }
 
@@ -611,6 +629,23 @@ public class AiAttackController {
             }
         }
 
+        if (attackMax != -1) {
+            // should attack with only max if able.
+            CardLists.sortByPowerDesc(this.attackers);
+            this.aiAggression = 6;
+            for (Card attacker : this.attackers) {
+                // reached max, breakup
+                if (attackMax != -1 && combat.getAttackers().size() >= attackMax)
+                    break;
+                if (CombatUtil.canAttack(attacker, defender) && this.shouldAttack(ai, attacker, this.blockers, combat)) {
+                    combat.addAttacker(attacker, defender);
+                }
+            }
+            // no more creatures to attack
+            return;
+        }
+        
+
         // *******************
         // Evaluate the creature forces
         // *******************