server: improved server stability (#11285) and reworked triggers/playable logic (#8426):

* game: now all playable calculations done in game simulation, outside real game (no more freeze and ruined games by wrong Nyxbloom Ancient and other cards with wrong replacement dialog);
* game: fixed multiple problems with triggers (wrong order, duplicated calls or "too many mana" bugs, see #8426, #12087);
* tests: added data integrity checks for game's triggers (3 enabled and 3 disabled due current game engine logic);

Mage.Server.Plugins/Mage.Player.AI.MA/src/mage/player/ai/ComputerPlayer6.java

@@ -414,7 +414,7 @@ public class ComputerPlayer6 extends ComputerPlayer {
                 Target target = effect.getTarget();
                 if (!target.doneChoosing()) {
                     for (UUID targetId : target.possibleTargets(stackObject.getControllerId(), stackObject.getStackAbility(), game)) {
-                        Game sim = game.copy();
+                        Game sim = game.createSimulationForAI();
                         StackAbility newAbility = (StackAbility) stackObject.copy();
                         SearchEffect newEffect = getSearchEffect(newAbility);
                         newEffect.getTarget().addTarget(targetId, newAbility, sim);
@@ -514,8 +514,7 @@ public class ComputerPlayer6 extends ComputerPlayer {
                 logger.info("Sim Prio [" + depth + "] -- interrupted");
                 break;
             }
-            Game sim = game.copy();
+            Game sim = game.createSimulationForAI();
-            sim.setSimulation(true);
             if (!(action instanceof StaticAbility) //for MorphAbility, etc
                     && sim.getPlayer(currentPlayer.getId()).activateAbility((ActivatedAbility) action.copy(), sim)) {
                 sim.applyEffects();
@@ -1067,8 +1066,7 @@ public class ComputerPlayer6 extends ComputerPlayer {
      * @return a new game object with simulated players
      */
     protected Game createSimulation(Game game) {
-        Game sim = game.copy();
+        Game sim = game.createSimulationForAI();
-        sim.setSimulation(true);
         for (Player oldPlayer : sim.getState().getPlayers().values()) {
             // replace original player by simulated player and find result (execute/resolve current action)
             Player origPlayer = game.getState().getPlayers().get(oldPlayer.getId()).copy();

Mage.Server.Plugins/Mage.Player.AI.MA/src/mage/player/ai/SimulatedPlayer2.java

@@ -65,8 +65,7 @@ public final class SimulatedPlayer2 extends ComputerPlayer {
 
     public List<Ability> simulatePriority(Game game) {
         allActions = new ConcurrentLinkedQueue<>();
-        Game sim = game.copy();
+        Game sim = game.createSimulationForAI();
-        sim.setSimulation(true);
         forced = false;
         simulateOptions(sim);
 
@@ -170,17 +169,6 @@ public final class SimulatedPlayer2 extends ComputerPlayer {
 
     }
 
-//    protected void simulateAction(Game game, SimulatedAction previousActions, Ability action) {
-//        List<Ability> actions = new ArrayList<Ability>(previousActions.getAbilities());
-//        actions.add(action);
-//        Game sim = game.copy();
-//        if (sim.getPlayer(playerId).activateAbility((ActivatedAbility) action.copy(), sim)) {
-//            sim.applyEffects();
-//            sim.getPlayers().resetPassed();
-//            allActions.add(new SimulatedAction(sim, actions));
-//        }
-//    }
-
     /**
      * if suggested abilities exist, return only those from playables
      *
@@ -322,7 +310,7 @@ public final class SimulatedPlayer2 extends ComputerPlayer {
         int powerElements = (int) Math.pow(2, attackersList.size());
         StringBuilder binary = new StringBuilder();
         for (int i = powerElements - 1; i >= 0; i--) {
-            Game sim = game.copy();
+            Game sim = game.createSimulationForAI();
             binary.setLength(0);
             binary.append(Integer.toBinaryString(i));
             while (binary.length() < attackersList.size()) {
@@ -360,7 +348,7 @@ public final class SimulatedPlayer2 extends ComputerPlayer {
         }
 
         //add a node with no blockers
-        Game sim = game.copy();
+        Game sim = game.createSimulationForAI();
         engagements.put(sim.getCombat().getValue().hashCode(), sim.getCombat());
         sim.fireEvent(GameEvent.getEvent(GameEvent.EventType.DECLARED_BLOCKERS, playerId, playerId));
 
@@ -381,7 +369,7 @@ public final class SimulatedPlayer2 extends ComputerPlayer {
         List<Permanent> remaining = remove(blockers, blocker);
         for (int i = 0; i < numGroups; i++) {
             if (game.getCombat().getGroups().get(i).canBlock(blocker, game)) {
-                Game sim = game.copy();
+                Game sim = game.createSimulationForAI();
                 sim.getCombat().getGroups().get(i).addBlocker(blocker.getId(), playerId, sim);
                 if (engagements.put(sim.getCombat().getValue().hashCode(), sim.getCombat()) != null) {
                     logger.debug("simulating -- found redundant block combination");
@@ -419,7 +407,7 @@ public final class SimulatedPlayer2 extends ComputerPlayer {
     }
 
     protected void addAbilityNode(SimulationNode2 parent, Ability ability, int depth, Game game) {
-        Game sim = game.copy();
+        Game sim = game.createSimulationForAI();
         sim.getStack().push(new StackAbility(ability, playerId));
         if (ability.activate(sim, false) && ability.isUsesStack()) {
             game.fireEvent(new GameEvent(GameEvent.EventType.TRIGGERED_ABILITY, ability.getId(), ability, ability.getControllerId()));

Mage.Server.Plugins/Mage.Player.AI.MA/src/mage/player/ai/util/CombatUtil.java

@@ -202,7 +202,7 @@ public final class CombatUtil {
      * @deprecated TODO: unused, can be deleted?
      */
     public static SurviveInfo willItSurvive(Game game, UUID attackingPlayerId, UUID defendingPlayerId, Permanent attacker, Permanent blocker) {
-        Game sim = game.copy();
+        Game sim = game.createSimulationForAI();
 
         // TODO: bugged, miss combat.clear code (possible bugs - wrong blocker declare by AI on multiple options?)
         Combat combat = sim.getCombat();
@@ -307,7 +307,7 @@ public final class CombatUtil {
 
     public static SurviveInfo willItSurvive2(Game game, UUID attackingPlayerId, UUID defendingPlayerId, Permanent attacker, Permanent blocker) {
 
-        Game sim = game.copy();
+        Game sim = game.createSimulationForAI();
 
         // TODO: bugged, miss combat.clear code (possible bugs - wrong blocker declare by AI on multiple options?)
         Combat combat = sim.getCombat();

Mage.Server.Plugins/Mage.Player.AIMCTS/src/mage/player/ai/ComputerPlayerMCTS.java

@@ -274,7 +274,7 @@ public class ComputerPlayerMCTS extends ComputerPlayer {
      * @return a new game object with simulated players
      */
     protected Game createMCTSGame(Game game) {
-        Game mcts = game.copy();
+        Game mcts = game.createSimulationForAI();
 
         for (Player copyPlayer : mcts.getState().getPlayers().values()) {
             Player origPlayer = game.getState().getPlayers().get(copyPlayer.getId());
@@ -295,7 +295,6 @@ public class ComputerPlayerMCTS extends ComputerPlayer {
             }
             mcts.getState().getPlayers().put(copyPlayer.getId(), newPlayer);
         }
-        mcts.setSimulation(true);
         mcts.resume();
         return mcts;
     }

Mage.Server.Plugins/Mage.Player.AIMCTS/src/mage/player/ai/MCTSNode.java

@@ -245,7 +245,7 @@ public class MCTSNode {
      * @return a new game object with simulated players
      */
     protected Game createSimulation(Game game, UUID playerId) {
-        Game sim = game.copy();
+        Game sim = game.createSimulationForAI();
 
         for (Player oldPlayer: sim.getState().getPlayers().values()) {
             Player origPlayer = game.getState().getPlayers().get(oldPlayer.getId()).copy();
@@ -254,7 +254,6 @@ public class MCTSNode {
             sim.getState().getPlayers().put(oldPlayer.getId(), newPlayer);
         }
         randomizePlayers(sim, playerId);
-        sim.setSimulation(true);
         return sim;
     }
 

Mage.Server.Plugins/Mage.Player.AIMCTS/src/mage/player/ai/PriorityNextAction.java

@@ -18,7 +18,7 @@ public class PriorityNextAction implements MCTSNodeNextAction{
         else
             abilities = MCTSNode.getPlayables(player, fullStateValue, game);
         for (Ability ability: abilities) {
-            Game sim = game.copy();
+            Game sim = game.createSimulationForAI();
             MCTSPlayer simPlayer = (MCTSPlayer) sim.getPlayer(player.getId());
             simPlayer.activateAbility((ActivatedAbility)ability, sim);
             sim.resume();

Mage.Server.Plugins/Mage.Player.AIMCTS/src/mage/player/ai/SelectAttackersNextAction.java

@@ -19,7 +19,7 @@ public class SelectAttackersNextAction implements MCTSNodeNextAction{
             attacks = getAttacks(player, fullStateValue, game);
         UUID defenderId = game.getOpponents(player.getId()).iterator().next();
         for (List<UUID> attack: attacks) {
-            Game sim = game.copy();
+            Game sim = game.createSimulationForAI();
             MCTSPlayer simPlayer = (MCTSPlayer) sim.getPlayer(player.getId());
             for (UUID attackerId: attack) {
                 simPlayer.declareAttacker(attackerId, defenderId, sim, false);

Mage.Server.Plugins/Mage.Player.AIMCTS/src/mage/player/ai/SelectBlockersNextAction.java

@@ -19,7 +19,7 @@ public class SelectBlockersNextAction implements MCTSNodeNextAction{
         else
             blocks = getBlocks(player, fullStateValue, game);
         for (List<List<UUID>> block : blocks) {
-            Game sim = game.copy();
+            Game sim = game.createSimulationForAI();
             MCTSPlayer simPlayer = (MCTSPlayer) sim.getPlayer(player.getId());
             List<CombatGroup> groups = sim.getCombat().getGroups();
             for (int i = 0; i < groups.size(); i++) {

Mage.Server/src/main/java/mage/server/game/GameSessionWatcher.java

@@ -97,7 +97,8 @@ public class GameSessionWatcher {
     }
 
     public GameView getGameView() {
-        // game view calculation can take some time, so use copy for thread save (protection from ConcurrentModificationException)
+        // game view calculation can take some time and can be called from non-game thread,
+        // so use copy for thread save (protection from ConcurrentModificationException)
         Game sourceGame = game.copy();
 
         GameView gameView = new GameView(sourceGame.getState(), sourceGame, null, userId);

Mage.Tests/src/test/java/org/mage/test/cards/continuous/TappedForManaFromMultipleEffects.java

@@ -53,9 +53,10 @@ public class TappedForManaFromMultipleEffects extends CardTestPlayerBase {
         // cast nyx 2
         castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, "Nyxbloom Ancient");
         // TODO: TAPPED_FOR_MANA replace event called from checkTappedForManaReplacement and start to choose replace events (is that problem?)
+        // TODO: yes, it's a problem, cause playable calc must not use dialogs!!!
         // use case (that test): comment one 1-2 choices to fail in 1-2 calls
-        setChoice(playerA, "Nyxbloom Ancient"); // getPlayable... checkTappedForManaReplacement... chooseReplacementEffect
+        setChoice(playerA, "Nyxbloom Ancient"); // x2 replacement effects from x2 nyx
-        setChoice(playerA, "Nyxbloom Ancient"); // playManaAbility... resolve... checkToFirePossibleEvents... chooseReplacementEffect
+        //setChoice(playerA, "Nyxbloom Ancient"); // wrongly choice from playable calc - no need after bug fix
 
         // cast chloro
         castSpell(1, PhaseStep.POSTCOMBAT_MAIN, playerA, "Chlorophant");

Mage.Tests/src/test/java/org/mage/test/cards/flip/SasayaOrochiAscendantTest.java

@@ -11,15 +11,48 @@ import org.mage.test.serverside.base.CardTestPlayerBase;
 import static org.mage.test.utils.ManaOptionsTestUtils.assertManaOptions;
 
 /**
- *
  * @author LevelX2
  */
 public class SasayaOrochiAscendantTest extends CardTestPlayerBase {
 
+    @Test
+    public void test_SasayasEssence_SimpleManaCalculation() {
+        addCard(Zone.HAND, playerA, "Plains", 7);
+        addCard(Zone.BATTLEFIELD, playerA, "Forest", 3);
+
+        // Reveal your hand: If you have seven or more land cards in your hand, flip Sasaya, Orochi Ascendant.
+        // Sasaya's Essence: Legendary Enchantment
+        // Whenever a land you control is tapped for mana, for each other land you control with the same name, add one mana of any type that land produced.
+        addCard(Zone.BATTLEFIELD, playerA, "Sasaya, Orochi Ascendant", 1);
+        //
+        // Mana pools don't empty as steps and phases end.
+        addCard(Zone.HAND, playerA, "Upwelling", 1); // Enchantment {3}{G}
+        //
+        // At the beginning of your upkeep, you gain 1 life.
+        addCard(Zone.BATTLEFIELD, playerB, "Fountain of Renewal", 1);
+
+        // prepare Sasaya's Essence
+        checkPermanentCount("before prepare", 1, PhaseStep.PRECOMBAT_MAIN, playerA, "Sasaya's Essence", 0);
+        activateAbility(1, PhaseStep.PRECOMBAT_MAIN, playerA, "Reveal your hand: If you have seven or more land cards in your hand, flip");
+        waitStackResolved(1, PhaseStep.PRECOMBAT_MAIN);
+        checkPermanentCount("after prepare", 1, PhaseStep.PRECOMBAT_MAIN, playerA, "Sasaya's Essence", 1);
+
+        setStrictChooseMode(true);
+        setStopAt(1, PhaseStep.END_TURN);
+        execute();
+
+        // possible error: additional triggers from neutral card can break mana triggers and will calc wrong mana
+        // reason: random triggers order on triggers iterator, can be fixed by linked map usage
+        // x3 forest + x2 for each other forest
+        ManaOptions manaOptions = playerA.getManaAvailable(currentGame);
+        assertManaOptions("{G}{G}{G}" + "{G}{G}" + "{G}{G}" + "{G}{G}", manaOptions);
+    }
+
     @Test
     public void testSasayasEssence() {
         addCard(Zone.HAND, playerA, "Plains", 7);
         addCard(Zone.BATTLEFIELD, playerA, "Forest", 3);
+        addCard(Zone.BATTLEFIELD, playerB, "Fountain of Renewal", 5);
 
         // Reveal your hand: If you have seven or more land cards in your hand, flip Sasaya, Orochi Ascendant.
         // Sasaya's Essence: Legendary Enchantment

Mage.Tests/src/test/java/org/mage/test/cards/single/khm/ValkiGodOfLiesTest.java

@@ -46,7 +46,7 @@ public class ValkiGodOfLiesTest extends CardTestPlayerBase {
         activateAbility(1, PhaseStep.PRECOMBAT_MAIN, playerA, "+2: Exile the top card of each player's library.");
         playLand(1, PhaseStep.POSTCOMBAT_MAIN, playerA, "Plains");
         castSpell(1, PhaseStep.POSTCOMBAT_MAIN, playerA, "Ephemerate", "Grizzly Bears");
-        setChoice(playerA, "Emblem Tibalt");
+        //setChoice(playerA, "Emblem Tibalt"); // wrongly x2 replacement effects - no need after bug fix
 
         setStrictChooseMode(true);
         setStopAt(1, PhaseStep.END_TURN);

Mage.Tests/src/test/java/org/mage/test/cards/single/soi/TheGitrogMonsterTest.java

@@ -7,12 +7,12 @@ import org.mage.test.serverside.base.CardTestPlayerBase;
 
 /**
  * 3BG Legendary Creature - Frog Horror Deathtouch
- *
+ * <p>
  * At the beginning of your upkeep, sacrifice The Gitrog Monster unless you
  * sacrifice a land.
- *
+ * <p>
  * You may play an additional land on each of your turns.
- *
+ * <p>
  * Whenever one or more land cards are put into your graveyard from anywhere,
  * draw a card.
  *
@@ -35,6 +35,7 @@ public class TheGitrogMonsterTest extends CardTestPlayerBase {
         castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, "The Gitrog Monster");
         castSpell(2, PhaseStep.PRECOMBAT_MAIN, playerB, "Armageddon");
 
+        setStrictChooseMode(true);
         setStopAt(3, PhaseStep.DRAW);
         execute();
 
@@ -58,10 +59,10 @@ public class TheGitrogMonsterTest extends CardTestPlayerBase {
 
         castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, "The Gitrog Monster");
         // on 3rd turn during upkeep opt to sacrifice a land
-        // TODO: I don't know how to get these choices to work, let the choices go automatically
+        setChoice(playerA, true); // sac land
-//        addTarget(playerA, "Swamp");
+        setChoice(playerA, "Swamp"); // sac land
-//        setChoice(playerA, true);
 
+        setStrictChooseMode(true);
         setStopAt(3, PhaseStep.DRAW);
         execute();
 
@@ -88,6 +89,7 @@ public class TheGitrogMonsterTest extends CardTestPlayerBase {
         castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, "The Gitrog Monster");
         castSpell(2, PhaseStep.PRECOMBAT_MAIN, playerB, "Planar Outburst");
 
+        setStrictChooseMode(true);
         setStopAt(3, PhaseStep.DRAW);
         execute();
 
@@ -98,7 +100,7 @@ public class TheGitrogMonsterTest extends CardTestPlayerBase {
     /**
      * NOTE: As of 05/05/2017 this test is failing due to a bug in code. See
      * issue #3251
-     *
+     * <p>
      * I took control of a Gitrog Monster, while the Gitrog Monster's owner
      * controlled a Dryad Arbor and cast Toxic Deluge for 6.
      */
@@ -125,10 +127,13 @@ public class TheGitrogMonsterTest extends CardTestPlayerBase {
         addCard(Zone.GRAVEYARD, playerB, "Rags // Riches", 1);
         addCard(Zone.BATTLEFIELD, playerB, "Island", 7);
 
+        // first land
         playLand(1, PhaseStep.PRECOMBAT_MAIN, playerA, "Swamp");
+        // cast gitrog and second land
         castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, "The Gitrog Monster");
         playLand(1, PhaseStep.POSTCOMBAT_MAIN, playerA, "Dryad Arbor");
 
+        // change control to B, so no additional land for A
         castSpell(2, PhaseStep.PRECOMBAT_MAIN, playerB, "Riches");
         setChoice(playerA, "The Gitrog Monster");
 
@@ -137,6 +142,7 @@ public class TheGitrogMonsterTest extends CardTestPlayerBase {
         castSpell(3, PhaseStep.PRECOMBAT_MAIN, playerA, "Toxic Deluge");
         setChoice(playerA, "X=6");
 
+        setStrictChooseMode(true);
         setStopAt(3, PhaseStep.BEGIN_COMBAT);
         execute();
 

Mage.Tests/src/test/java/org/mage/test/serverside/base/impl/CardTestPlayerAPIImpl.java

@@ -27,6 +27,7 @@ import mage.player.ai.ComputerPlayerMCTS;
 import mage.players.ManaPool;
 import mage.players.Player;
 import mage.server.game.GameSessionPlayer;
+import mage.util.ThreadUtils;
 import mage.utils.SystemUtil;
 import mage.util.CardUtil;
 import mage.view.GameView;
@@ -236,6 +237,8 @@ public abstract class CardTestPlayerAPIImpl extends MageTestPlayerBase implement
             throw new IllegalStateException("Game is not initialized. Use load method to load a test case and initialize a game.");
         }
 
+        ThreadUtils.ensureRunInGameThread();
+
         // check stop command
         int maxTurn = 1;
         int maxPhase = 0;

Mage/src/main/java/mage/abilities/AbilityImpl.java

@@ -169,6 +169,7 @@ public abstract class AbilityImpl implements Ability {
         if (checkIfClause(game)) {
             // Ability has started resolving. Fire event.
             // Used for abilities counting the number of resolutions like Ashling the Pilgrim.
+            // TODO: called for mana abilities too, must be removed to safe place someday (see old place like StackAbility::resolve)
             game.fireEvent(new GameEvent(GameEvent.EventType.RESOLVING_ABILITY, this.getOriginalId(), this, this.getControllerId()));
             if (this instanceof TriggeredAbility) {
                 for (UUID modeId : this.getModes().getSelectedModes()) {

Mage/src/main/java/mage/abilities/DelayedTriggeredAbilities.java

@@ -24,23 +24,22 @@ public class DelayedTriggeredAbilities extends AbilitiesImpl<DelayedTriggeredAbi
     }
 
     public void checkTriggers(GameEvent event, Game game) {
-        if (this.size() > 0) {
+        // TODO: add same integrity checks as TriggeredAbilities?!
-            for (Iterator<DelayedTriggeredAbility> it = this.iterator(); it.hasNext(); ) {
+        for (Iterator<DelayedTriggeredAbility> it = this.iterator(); it.hasNext(); ) {
-                DelayedTriggeredAbility ability = it.next();
+            DelayedTriggeredAbility ability = it.next();
-                if (ability.getDuration() == Duration.Custom) {
+            if (ability.getDuration() == Duration.Custom) {
-                    if (ability.isInactive(game)) {
+                if (ability.isInactive(game)) {
-                        it.remove();
+                    it.remove();
-                        continue;
-                    }
-                }
-                if (!ability.checkEventType(event, game)) {
                     continue;
                 }
-                if (ability.checkTrigger(event, game)) {
+            }
-                    ability.trigger(game, ability.controllerId, event);
+            if (!ability.checkEventType(event, game)) {
-                    if (ability.getTriggerOnlyOnce()) {
+                continue;
-                        it.remove();
+            }
-                    }
+            if (ability.checkTrigger(event, game)) {
+                ability.trigger(game, ability.controllerId, event);
+                if (ability.getTriggerOnlyOnce()) {
+                    it.remove();
                 }
             }
         }

Mage/src/main/java/mage/abilities/PlayLandAbility.java

@@ -6,7 +6,9 @@ import mage.constants.AbilityType;
 import mage.constants.AsThoughEffectType;
 import mage.constants.Zone;
 import mage.game.Game;
+import mage.players.Player;
 
+import java.util.HashMap;
 import java.util.Set;
 import java.util.UUID;
 

Mage/src/main/java/mage/abilities/TriggeredAbilities.java

@@ -8,56 +8,203 @@ import mage.game.events.NumberOfTriggersEvent;
 import mage.game.permanent.Permanent;
 import mage.game.stack.Spell;
 import mage.util.CardUtil;
+import mage.util.Copyable;
 import org.apache.log4j.Logger;
 
 import java.util.*;
-import java.util.concurrent.ConcurrentHashMap;
+import java.util.stream.Collectors;
 
 /**
- * @author BetaSteward_at_googlemail.com
+ * @author BetaSteward_at_googlemail.com, JayDi85
- * <p>
- * This class uses ConcurrentHashMap to avoid ConcurrentModificationExceptions.
- * See ticket https://github.com/magefree/mage/issues/966 and
- * https://github.com/magefree/mage/issues/473
  */
-public class TriggeredAbilities extends ConcurrentHashMap<String, TriggeredAbility> {
+public class TriggeredAbilities extends LinkedHashMap<String, TriggeredAbility> implements Copyable<TriggeredAbilities> {
 
     private static final Logger logger = Logger.getLogger(TriggeredAbilities.class);
 
     private final Map<String, List<UUID>> sources = new HashMap<>();
 
+    // data integrity check for triggers
+    // reason: game engine can generate additional events and triggers while checking another one,
+    // it can generate multiple bugs, freeze, etc, see https://github.com/magefree/mage/issues/8426
+    // all checks can be catches by existing tests
+    private boolean enableIntegrityCheck1_MustKeepSameTriggersOrder = true; // good
+    private boolean enableIntegrityCheck2_MustKeepSameTriggersList = false; // bad, impossible to fix due dynamic triggers gen
+    private boolean enableIntegrityCheck3_CantStartEventProcessingBeforeFinishPrev = false; // bad, impossible to fix due dynamic triggers gen
+    private boolean enableIntegrityCheck4_EventMustProcessAllOldTriggers = true; // good
+    private boolean enableIntegrityCheck5_EventMustProcessInSameOrder = true; // good
+    private boolean enableIntegrityCheck6_EventMustNotProcessNewTriggers = false; // bad, impossible to fix due dynamic triggers gen
+    private boolean enableIntegrityLogs = false; // debug only
+    private boolean processingStarted = false;
+    private GameEvent.EventType processingStartedEvent = null; // null for game state triggers
+    private List<TriggeredAbility> processingNeed = new ArrayList<>();
+    private List<TriggeredAbility> processingDone = new ArrayList<>();
+
     public TriggeredAbilities() {
     }
 
     protected TriggeredAbilities(final TriggeredAbilities abilities) {
+        makeSureNotProcessing(null);
+
         for (Map.Entry<String, TriggeredAbility> entry : abilities.entrySet()) {
             this.put(entry.getKey(), entry.getValue().copy());
         }
         for (Map.Entry<String, List<UUID>> entry : abilities.sources.entrySet()) {
             sources.put(entry.getKey(), entry.getValue());
         }
+
+        this.enableIntegrityCheck1_MustKeepSameTriggersOrder = abilities.enableIntegrityCheck1_MustKeepSameTriggersOrder;
+        this.enableIntegrityCheck2_MustKeepSameTriggersList = abilities.enableIntegrityCheck2_MustKeepSameTriggersList;
+        this.enableIntegrityCheck3_CantStartEventProcessingBeforeFinishPrev = abilities.enableIntegrityCheck3_CantStartEventProcessingBeforeFinishPrev;
+        this.enableIntegrityCheck4_EventMustProcessAllOldTriggers = abilities.enableIntegrityCheck4_EventMustProcessAllOldTriggers;
+        this.enableIntegrityCheck5_EventMustProcessInSameOrder = abilities.enableIntegrityCheck5_EventMustProcessInSameOrder;
+        this.enableIntegrityCheck6_EventMustNotProcessNewTriggers = abilities.enableIntegrityCheck6_EventMustNotProcessNewTriggers;
+
+        this.enableIntegrityLogs = abilities.enableIntegrityLogs;
+        this.processingStarted = abilities.processingStarted;
+        this.processingStartedEvent = abilities.processingStartedEvent;
+        this.processingNeed = CardUtil.deepCopyObject(abilities.processingNeed);
+        this.processingDone = CardUtil.deepCopyObject(abilities.processingDone);
+
+        // runtime check: triggers order (not required by paper rules, by required by xmage to make same result for all game instances)
+        if (this.enableIntegrityCheck1_MustKeepSameTriggersOrder) {
+            if (!Objects.equals(this.values().stream().findFirst().orElse(null) + "",
+                    abilities.values().stream().findFirst().orElse(null) + "")) {
+                // how-to fix: use LinkedHashMap instead HashMap/ConcurrentHashMap
+                throw new IllegalStateException("Triggers integrity failed: triggers order changed");
+            }
+        }
     }
 
     public void checkStateTriggers(Game game) {
-        for (Iterator<TriggeredAbility> it = this.values().iterator(); it.hasNext(); ) {
+        makeSureNotProcessing(null);
-            TriggeredAbility ability = it.next();
+
-            if (ability instanceof StateTriggeredAbility && ((StateTriggeredAbility) ability).canTrigger(game)) {
+        processingStart(null);
-                checkTrigger(ability, null, game);
+        boolean needErrorChecksOnEnd = true;
+        try {
+            for (Iterator<TriggeredAbility> it = this.values().iterator(); it.hasNext(); ) {
+                TriggeredAbility ability = it.next();
+                if (ability instanceof StateTriggeredAbility && ((StateTriggeredAbility) ability).canTrigger(game)) {
+                    checkTrigger(ability, null, game);
+                }
+                this.processingDone(ability);
             }
+        } catch (Exception e) {
+            // need additional catch to show inner errors
+            needErrorChecksOnEnd = false;
+            throw e;
+        } finally {
+            processingEnd(needErrorChecksOnEnd);
         }
     }
 
     public void checkTriggers(GameEvent event, Game game) {
-        for (Iterator<TriggeredAbility> it = this.values().iterator(); it.hasNext(); ) {
+        processingStart(event);
-            TriggeredAbility ability = it.next();
+        boolean needErrorChecksOnEnd = true;
-            if (ability.checkEventType(event, game)) {
+        // must keep real object refs (not copies), cause check trigger code can change trigger's and effect's data like targets
-                checkTrigger(ability, event, game);
+        ArrayList<TriggeredAbility> currentTriggers = new ArrayList<>(this.values());
+        try {
+            for (TriggeredAbility ability : currentTriggers) {
+                if (ability.checkEventType(event, game)) {
+                    checkTrigger(ability, event, game);
+                }
+                this.processingDone(ability);
+            }
+        } catch (Exception e) {
+            // need additional catch to show inner errors
+            needErrorChecksOnEnd = false;
+            throw e;
+        } finally {
+            processingEnd(needErrorChecksOnEnd);
+        }
+    }
+
+    private void makeSureNotProcessing(GameEvent newEvent) {
+        if (this.enableIntegrityCheck2_MustKeepSameTriggersList
+                && this.processingStarted) {
+            List<String> info = new ArrayList<>();
+            info.add("old event: " + this.processingStartedEvent);
+            info.add("new event: " + newEvent.getType());
+            // how-to fix: impossible until mana events/triggers rework cause one mana event can generate additional events/triggers
+            throw new IllegalArgumentException("Triggers integrity failed: triggers can't be modified while processing - "
+                    + String.join(", ", info));
+        }
+    }
+
+    private void processingStart(GameEvent newEvent) {
+        makeSureNotProcessing(newEvent);
+
+        this.processingStarted = true;
+        this.processingStartedEvent = newEvent == null ? null : newEvent.getType();
+        this.processingNeed.clear();
+        this.processingNeed.addAll(this.values());
+        this.processingDone.clear();
+    }
+
+    private void processingDone(TriggeredAbility trigger) {
+        this.processingDone.add(trigger);
+    }
+
+    private void processingEnd(boolean needErrorChecks) {
+        if (needErrorChecks) {
+            if (this.enableIntegrityCheck3_CantStartEventProcessingBeforeFinishPrev
+                    && !this.processingStarted) {
+                throw new IllegalArgumentException("Triggers integrity failed: can't finish event before start");
+            }
+
+            // must use ability's id to check equal (rules can be diff due usage of dynamic values - alternative to card hints)
+            List<UUID> needIds = new ArrayList<>();
+            String needInfo = this.processingNeed.stream()
+                    .peek(a -> needIds.add(a.getId()))
+                    .map(t -> "- " + t)
+                    .sorted()
+                    .collect(Collectors.joining("\n"));
+            List<UUID> doneIds = new ArrayList<>();
+            String doneInfo = this.processingDone.stream()
+                    .peek(a -> doneIds.add(a.getId()))
+                    .map(t -> "- " + t)
+                    .sorted()
+                    .collect(Collectors.joining("\n"));
+            String errorInfo = ""
+                    + "\n" + "Need: "
+                    + "\n" + (needInfo.isEmpty() ? "-" : needInfo)
+                    + "\n" + "Done: "
+                    + "\n" + (doneInfo.isEmpty() ? "-" : doneInfo);
+
+            if (this.enableIntegrityCheck4_EventMustProcessAllOldTriggers
+                    && this.processingDone.size() < this.processingNeed.size()) {
+                throw new IllegalArgumentException("Triggers integrity failed: event processing miss some triggers" + errorInfo);
+            }
+
+            if (this.enableIntegrityCheck5_EventMustProcessInSameOrder
+                    && this.processingDone.size() > 0
+                    && this.processingDone.size() == this.processingNeed.size()
+                    && !needIds.toString().equals(doneIds.toString())) {
+                throw new IllegalArgumentException("Triggers integrity failed: event processing used wrong order" + errorInfo);
+            }
+
+            if (this.enableIntegrityCheck6_EventMustNotProcessNewTriggers
+                    && this.processingDone.size() > this.processingNeed.size()) {
+                throw new IllegalArgumentException("Triggers integrity failed: event processing must not process new triggers" + errorInfo);
             }
         }
+
+        this.processingStarted = false;
+        this.processingStartedEvent = null;
+        this.processingNeed.clear();
+        this.processingDone.clear();
     }
 
     private void checkTrigger(TriggeredAbility ability, GameEvent event, Game game) {
         // for effects like when leaves battlefield or destroyed use ShortLKI to check if permanent was in the correct zone before (e.g. Oblivion Ring or Karmic Justice)
+        if (this.enableIntegrityLogs) {
+            logger.info("---");
+            logger.info("checking trigger: " + ability);
+            logger.info("playable state: " + game.inCheckPlayableState());
+            logger.info(game);
+            logger.info("battlefield:" + "\n" + game.getBattlefield().getAllPermanents().stream()
+                    .map(p -> "- " + p.toString())
+                    .collect(Collectors.joining("\n")) + "\n");
+        }
         MageObject object = game.getObject(ability.getSourceId());
         if (ability.isInUseableZone(game, object, event)) {
             if (event == null || !game.getContinuousEffects().preventedByRuleModification(event, ability, game, false)) {
@@ -99,6 +246,9 @@ public class TriggeredAbilities extends ConcurrentHashMap<String, TriggeredAbili
                     if (event == null || !game.replaceEvent(numberOfTriggersEvent, ability)) {
                         int numTriggers = ability.getTriggersOnceEachTurn() ? 1 : numberOfTriggersEvent.getAmount();
                         for (int i = 0; i < numTriggers; i++) {
+                            if (this.enableIntegrityLogs) {
+                                logger.info("trigger will be USED: " + ability);
+                            }
                             ability.trigger(game, ability.getControllerId(), event);
                         }
                     }
@@ -115,6 +265,7 @@ public class TriggeredAbilities extends ConcurrentHashMap<String, TriggeredAbili
      * @param attachedTo - the object that gained the ability
      */
     public void add(TriggeredAbility ability, UUID sourceId, MageObject attachedTo) {
+        makeSureNotProcessing(null);
         if (sourceId == null) {
             add(ability, attachedTo);
         } else if (attachedTo == null) {
@@ -130,6 +281,7 @@ public class TriggeredAbilities extends ConcurrentHashMap<String, TriggeredAbili
     }
 
     public void add(TriggeredAbility ability, MageObject attachedTo) {
+        makeSureNotProcessing(null);
         this.put(getKey(ability, attachedTo), ability);
     }
 
@@ -162,8 +314,8 @@ public class TriggeredAbilities extends ConcurrentHashMap<String, TriggeredAbili
 
     }
 
+    @Override
     public TriggeredAbilities copy() {
         return new TriggeredAbilities(this);
     }
-
 }

Mage/src/main/java/mage/game/Game.java

@@ -269,12 +269,18 @@ public interface Game extends MageItem, Serializable, Copyable<Game> {
 
     boolean isSimulation();
 
-    void setSimulation(boolean checkPlayableState);
+    /**
+     * Prepare game for any simulations like AI or effects calc
+     */
+    Game createSimulationForAI();
+
+    /**
+     * Prepare game for any playable calc (available mana/abilities)
+     */
+    Game createSimulationForPlayableCalc();
 
     boolean inCheckPlayableState();
 
-    void setCheckPlayableState(boolean checkPlayableState);
-
     MageObject getLastKnownInformation(UUID objectId, Zone zone);
 
     CardState getLastKnownInformationCard(UUID objectId, Zone zone);

Mage/src/main/java/mage/game/GameImpl.java

@@ -98,8 +98,10 @@ public abstract class GameImpl implements Game {
 
     private transient Object customData; // temporary data, used in AI simulations
     private transient Player losingPlayer; // temporary data, used in AI simulations
-    protected boolean simulation = false;
+
-    protected boolean checkPlayableState = false;
+    protected boolean simulation = false; // for inner simulations (game without user messages)
+    protected boolean aiGame = false; // for inner simulations (ai game, debug only)
+    protected boolean checkPlayableState = false; // for inner playable calculations (game without user dialogs)
 
     protected AtomicInteger totalErrorsCount = new AtomicInteger(); // for debug only: error stats
 
@@ -180,6 +182,7 @@ public abstract class GameImpl implements Game {
     protected GameImpl(final GameImpl game) {
         //this.customData = game.customData; // temporary data, no need on game copy
         //this.losingPlayer = game.losingPlayer; // temporary data, no need on game copy
+        this.aiGame = game.aiGame;
         this.simulation = game.simulation;
         this.checkPlayableState = game.checkPlayableState;
 
@@ -248,13 +251,19 @@ public abstract class GameImpl implements Game {
     }
 
     @Override
-    public void setSimulation(boolean simulation) {
+    public Game createSimulationForAI() {
-        this.simulation = simulation;
+        Game res = this.copy();
+        ((GameImpl) res).simulation = true;
+        ((GameImpl) res).aiGame = true;
+        return res;
     }
 
     @Override
-    public void setCheckPlayableState(boolean checkPlayableState) {
+    public Game createSimulationForPlayableCalc() {
-        this.checkPlayableState = checkPlayableState;
+        Game res = this.copy();
+        ((GameImpl) res).simulation = true;
+        ((GameImpl) res).checkPlayableState = true;
+        return res;
     }
 
     @Override
@@ -1602,6 +1611,10 @@ public abstract class GameImpl implements Game {
 
     @Override
     public void playPriority(UUID activePlayerId, boolean resuming) {
+        if (!this.isSimulation() && this.inCheckPlayableState()) {
+            throw new IllegalStateException("Wrong code usage. Only simulation games can be in CheckPlayableState");
+        }
+
         int priorityErrorsCount = 0;
         infiniteLoopCounter = 0;
         int rollbackBookmarkOnPriorityStart = 0;
@@ -1711,7 +1724,7 @@ public abstract class GameImpl implements Game {
                             throw new MageException(UNIT_TESTS_ERROR_TEXT);
                         }
                     } finally {
-                        setCheckPlayableState(false);
+                        //setCheckPlayableState(false); // TODO: delete
                     }
                     state.getPlayerList().getNext();
                 }
@@ -1730,7 +1743,7 @@ public abstract class GameImpl implements Game {
         } finally {
             resetLKI();
             clearAllBookmarks();
-            setCheckPlayableState(false);
+            //setCheckPlayableState(false);
         }
     }
 
@@ -4045,8 +4058,24 @@ public abstract class GameImpl implements Game {
     @Override
     public String toString() {
         Player activePayer = this.getPlayer(this.getActivePlayerId());
+
+        // show non-standard game state (not part of the real game, e.g. AI or mana calculation)
+        List<String> simInfo = new ArrayList<>();
+        if (this.simulation) {
+            simInfo.add("SIMULATION");
+        }
+        if (this.aiGame) {
+            simInfo.add("AI");
+        }
+        if (this.checkPlayableState) {
+            simInfo.add("PLAYABLE CALC");
+        }
+        if (!ThreadUtils.isRunGameThread()) {
+            simInfo.add("NOT GAME THREAD");
+        }
+
         StringBuilder sb = new StringBuilder()
-                .append(this.isSimulation() ? "!!!SIMULATION!!! " : "")
+                .append(!simInfo.isEmpty() ? "!!!" + String.join(", ", simInfo) + "!!! " : "")
                 .append(this.getGameType().toString())
                 .append("; ").append(CardUtil.getTurnInfo(this))
                 .append("; active: ").append((activePayer == null ? "none" : activePayer.getName()))

Mage/src/main/java/mage/players/Player.java

@@ -820,7 +820,7 @@ public interface Player extends MageItem, Copyable<Player> {
 
     void updateRange(Game game);
 
-    ManaOptions getManaAvailable(Game game);
+    ManaOptions getManaAvailable(Game originalGame);
 
     void addAvailableTriggeredMana(List<Mana> netManaAvailable);
 
@@ -832,7 +832,7 @@ public interface Player extends MageItem, Copyable<Player> {
 
     PlayableObjectsList getPlayableObjects(Game game, Zone zone);
 
-    Map<UUID, ActivatedAbility> getPlayableActivatedAbilities(MageObject object, Zone zone, Game game);
+    Map<UUID, ActivatedAbility> getPlayableActivatedAbilities(MageObject object, Zone zone, Game originalGame);
 
     boolean addCounters(Counter counter, UUID playerAddingCounters, Ability source, Game game);
 

Mage/src/main/java/mage/players/PlayerImpl.java

@@ -181,6 +181,7 @@ public abstract class PlayerImpl implements Player, Serializable {
     //
     // A card may be able to cast multiple way with multiple methods.
     // The specific MageIdentifier should be checked, before checking null as a fallback.
+    // TODO: must rework playable methods to static
     protected Map<UUID, Set<MageIdentifier>> castSourceIdWithAlternateMana = new HashMap<>();
     protected Map<UUID, Map<MageIdentifier, ManaCosts<ManaCost>>> castSourceIdManaCosts = new HashMap<>();
     protected Map<UUID, Map<MageIdentifier, Costs<Cost>>> castSourceIdCosts = new HashMap<>();
@@ -1755,23 +1756,19 @@ public abstract class PlayerImpl implements Player, Serializable {
         if (object instanceof StackAbility || object == null) {
             return useable;
         }
-        boolean previousState = game.inCheckPlayableState();
-        game.setCheckPlayableState(true);
-        try {
-            // collect and filter playable activated abilities
-            // GUI: user clicks on card, but it must activate ability from ANY card's parts (main, left, right)
-            Set<UUID> needIds = CardUtil.getObjectParts(object);
 
-            // workaround to find all abilities first and filter it for one object
+        // collect and filter playable activated abilities
-            List<ActivatedAbility> allPlayable = getPlayable(game, true, zone, false);
+        // GUI: user clicks on card, but it must activate ability from ANY card's parts (main, left, right)
-            for (ActivatedAbility ability : allPlayable) {
+        Set<UUID> needIds = CardUtil.getObjectParts(object);
-                if (needIds.contains(ability.getSourceId())) {
+
-                    useable.putIfAbsent(ability.getId(), ability);
+        // workaround to find all abilities first and filter it for one object
-                }
+        List<ActivatedAbility> allPlayable = getPlayable(game, true, zone, false);
+        for (ActivatedAbility ability : allPlayable) {
+            if (needIds.contains(ability.getSourceId())) {
+                useable.putIfAbsent(ability.getId(), ability);
             }
-        } finally {
-            game.setCheckPlayableState(previousState);
         }
+
         return useable;
     }
 
@@ -3376,13 +3373,13 @@ public abstract class PlayerImpl implements Player, Serializable {
      * combinations of mana are available to cast spells or activate abilities
      * etc.
      *
-     * @param game
+     * @param originalGame
      * @return
      */
     @Override
-    public ManaOptions getManaAvailable(Game game) {
+    public ManaOptions getManaAvailable(Game originalGame) {
-        boolean oldState = game.inCheckPlayableState();
+        // workaround to fix a triggers list modification bug (game must be immutable on playable calculations)
-        game.setCheckPlayableState(true);
+        Game game = originalGame.createSimulationForPlayableCalc();
 
         ManaOptions availableMana = new ManaOptions();
         availableMana.addMana(manaPool.getMana());
@@ -3477,8 +3474,9 @@ public abstract class PlayerImpl implements Player, Serializable {
 
         availableMana.removeFullyIncludedVariations();
         availableMana.remove(new Mana()); // Remove any empty mana that was left over from the way the code is written
-        game.setCheckPlayableState(oldState);
+
-        return availableMana;
+        // make sure it independent of sim game
+        return availableMana.copy();
     }
 
     /**
@@ -3596,6 +3594,7 @@ public abstract class PlayerImpl implements Player, Serializable {
             }
 
             // ALTERNATIVE COST FROM dynamic effects
+
             for (MageIdentifier identifier : getCastSourceIdWithAlternateMana().getOrDefault(copy.getSourceId(), new HashSet<>())) {
                 ManaCosts alternateCosts = getCastSourceIdManaCosts().get(copy.getSourceId()).get(identifier);
                 Costs<Cost> costs = getCastSourceIdCosts().get(copy.getSourceId()).get(identifier);
@@ -4001,6 +4000,14 @@ public abstract class PlayerImpl implements Player, Serializable {
                     approvingObjects = game.getContinuousEffects().asThough(object.getId(),
                             AsThoughEffectType.CAST_ADVENTURE_FROM_NOT_OWN_HAND_ZONE, ability, this.getId(), game);
                 }
+
+                // TODO: warning, PLAY_FROM_NOT_OWN_HAND_ZONE save some playable info in player's castSourceXXX fields
+                //  it must be reworked (available/playable methods must be static, all play info must be stored in GameState)
+                // Current workaround to sync sim info with real game, remove here and from regexp search: asThough\(.+AsThoughEffectType.PLAY_FROM_NOT_OWN_HAND_ZONE
+                Player simPlayer = game.getPlayer(this.getId());
+                this.castSourceIdCosts = new HashMap<>(simPlayer.getCastSourceIdCosts());
+                this.castSourceIdManaCosts = new HashMap<>(simPlayer.getCastSourceIdManaCosts());
+                this.castSourceIdWithAlternateMana = new HashMap<>(simPlayer.getCastSourceIdWithAlternateMana());
             } else {
                 // other abilities from direct zones
                 approvingObjects = new HashSet<>();
@@ -4057,21 +4064,20 @@ public abstract class PlayerImpl implements Player, Serializable {
      * currently cast/activate with his available resources.
      * Without target validation.
      *
-     * @param game
+     * @param originalGame
      * @param hidden                  also from hidden objects (e.g. turned face down cards ?)
      * @param fromZone                of objects from which zone (ALL = from all zones)
      * @param hideDuplicatedAbilities if equal abilities exist return only the
      *                                first instance
      * @return
      */
-    public List<ActivatedAbility> getPlayable(Game game, boolean hidden, Zone fromZone, boolean hideDuplicatedAbilities) {
+    public List<ActivatedAbility> getPlayable(Game originalGame, boolean hidden, Zone fromZone, boolean hideDuplicatedAbilities) {
         List<ActivatedAbility> playable = new ArrayList<>();
-        if (shouldSkipGettingPlayable(game)) {
+        if (shouldSkipGettingPlayable(originalGame)) {
             return playable;
         }
 
-        boolean previousState = game.inCheckPlayableState();
+        Game game = originalGame.createSimulationForPlayableCalc();
-        game.setCheckPlayableState(true);
         try {
             ManaOptions availableMana = getManaAvailable(game); // get available mana options (mana pool and conditional mana added (but conditional still lose condition))
             boolean fromAll = fromZone.equals(Zone.ALL);
@@ -4241,10 +4247,13 @@ public abstract class PlayerImpl implements Player, Serializable {
                 playable.addAll(activatedAll);
             }
         } finally {
-            game.setCheckPlayableState(previousState);
+            //game.setCheckPlayableState(previousState); // TODO: delete
         }
 
-        return playable;
+        // make sure it independent of sim game
+        return playable.stream()
+                .map(ActivatedAbility::copy)
+                .collect(Collectors.toList());
     }
 
     /**
@@ -4306,7 +4315,7 @@ public abstract class PlayerImpl implements Player, Serializable {
      * @param game
      * @return
      */
-    private boolean shouldSkipGettingPlayable(Game game) {
+    static private boolean shouldSkipGettingPlayable(Game game) {
         if (game.getStep() == null) { // happens at the start of the game
             return true;
         }

Mage/src/main/java/mage/util/ThreadUtils.java

@@ -55,11 +55,27 @@ public final class ThreadUtils {
     }
 
     public static void ensureRunInGameThread() {
-        String name = Thread.currentThread().getName();
+        if (!isRunGameThread()) {
-        if (!name.startsWith("GAME")) {
+            // for real games
             // how-to fix: use signal logic to inform a game about new command to execute instead direct execute (see example with WantConcede)
             // reason: user responses/commands are received by network/call thread, but must be processed by game thread
-            throw new IllegalArgumentException("Wrong code usage: game related code must run in GAME thread, but it used in " + name, new Throwable());
+            //
+            // for unit tests
+            // how-to fix: if your test runner uses a diff thread name to run tests then add it to isRunGameThread
+            throw new IllegalArgumentException("Wrong code usage: game related code must run in GAME thread, but it used in " + Thread.currentThread().getName(), new Throwable());
+        }
+    }
+
+    public static boolean isRunGameThread() {
+        String name = Thread.currentThread().getName();
+        if (name.startsWith("GAME ")) {
+            // server game
+            return true;
+        } else if (name.equals("main")) {
+            // unit test
+            return true;
+        } else {
+            return false;
         }
     }