refactor: common logic for "at..." triggered abilities (#13045)

* add new common framework for at step triggered abilities

* move postcombat main and second main triggers to it

* update draw step triggers

* refactor BeginningOfCombatTriggeredAbility

* refactor BeginningOfFirstMainTriggeredAbility

* move Pronoun to constants package

* cleanup some cards to use simpler constructors

* package reorganization

Mage/src/main/java/mage/abilities/triggers/BeginningOfSecondMainTriggeredAbility.java

@@ -0,0 +1,101 @@
+package mage.abilities.triggers;
+
+import mage.abilities.effects.Effect;
+import mage.constants.TargetController;
+import mage.constants.WatcherScope;
+import mage.constants.Zone;
+import mage.game.Game;
+import mage.game.events.GameEvent;
+import mage.watchers.Watcher;
+
+/**
+ * @author TheElk801
+ */
+public class BeginningOfSecondMainTriggeredAbility extends AtStepTriggeredAbility {
+
+    /**
+     * At the beginning of your second main phase
+     */
+    public BeginningOfSecondMainTriggeredAbility(Effect effect, boolean optional) {
+        this(Zone.BATTLEFIELD, TargetController.YOU, effect, optional);
+    }
+
+    public BeginningOfSecondMainTriggeredAbility(Zone zone, TargetController targetController, Effect effect, boolean optional) {
+        super(zone, targetController, effect, optional);
+        setTriggerPhrase(generateTriggerPhrase());
+        this.addWatcher(new MainPhaseWatcher());
+    }
+
+    protected BeginningOfSecondMainTriggeredAbility(final BeginningOfSecondMainTriggeredAbility ability) {
+        super(ability);
+    }
+
+    @Override
+    public BeginningOfSecondMainTriggeredAbility copy() {
+        return new BeginningOfSecondMainTriggeredAbility(this);
+    }
+
+    @Override
+    public boolean checkEventType(GameEvent event, Game game) {
+        switch (event.getType()) {
+            case PRECOMBAT_MAIN_PHASE_PRE:
+            case POSTCOMBAT_MAIN_PHASE_PRE:
+                return true;
+            default:
+                return false;
+        }
+    }
+
+    @Override
+    public boolean checkTrigger(GameEvent event, Game game) {
+        return MainPhaseWatcher.checkCount(game) && super.checkTrigger(event, game);
+    }
+
+    @Override
+    protected String generateTriggerPhrase() {
+        switch (targetController) {
+            case YOU:
+                return "At the beginning of your second main phase, ";
+            case OPPONENT:
+                return "At the beginning of each opponent's second main phase, ";
+            case ANY:
+                return "At the beginning of each player's second main phase, ";
+            case ENCHANTED:
+                return "At the beginning of enchanted player's second main phase, ";
+            default:
+                throw new UnsupportedOperationException("Unsupported TargetController in BeginningOfSecondMainTriggeredAbility: " + targetController);
+        }
+    }
+
+}
+
+class MainPhaseWatcher extends Watcher {
+
+    private int mainPhaseCount = 0;
+
+    MainPhaseWatcher() {
+        super(WatcherScope.GAME);
+    }
+
+    @Override
+    public void watch(GameEvent event, Game game) {
+        switch (event.getType()) {
+            case PRECOMBAT_MAIN_PHASE_PRE:
+            case POSTCOMBAT_MAIN_PHASE_PRE:
+                mainPhaseCount++;
+        }
+    }
+
+    @Override
+    public void reset() {
+        super.reset();
+        this.mainPhaseCount = 0;
+    }
+
+    static boolean checkCount(Game game) {
+        return game
+                .getState()
+                .getWatcher(MainPhaseWatcher.class)
+                .mainPhaseCount == 2;
+    }
+}