[WHO] Implement Start the TARDIS (#11311)

Create a new effect PlaneswalkEffect, moving existing code from the planechase roll of chaos dice.

Mage/src/main/java/mage/abilities/effects/common/PlaneswalkEffect.java

@@ -0,0 +1,95 @@
+package mage.abilities.effects.common;
+
+import mage.abilities.Ability;
+import mage.abilities.effects.ContinuousEffect;
+import mage.abilities.effects.Effect;
+import mage.abilities.effects.OneShotEffect;
+import mage.constants.Outcome;
+import mage.constants.Planes;
+import mage.game.Game;
+import mage.game.command.CommandObject;
+import mage.game.command.Plane;
+import mage.players.Player;
+
+import java.util.List;
+
+/**
+ * @author Susucr
+ */
+public class PlaneswalkEffect extends OneShotEffect {
+
+    private final boolean optional;
+
+    public PlaneswalkEffect(boolean optional) {
+        super(Outcome.Neutral);
+        this.optional = optional;
+        staticText = optional ? "you may planeswalk" : "you planeswalk";
+    }
+
+    protected PlaneswalkEffect(final PlaneswalkEffect effect) {
+        super(effect);
+        this.optional = effect.optional;
+    }
+
+    @Override
+    public boolean apply(Game game, Ability source) {
+        Player controller = game.getPlayer(source.getControllerId());
+        if (controller == null) {
+            return false;
+        }
+
+        // As of now, a player may planeswalk iff there are planes in the command zone.
+        boolean canPlaneswalk = game.getState().getCommand().stream().anyMatch(obj -> obj instanceof Plane);
+        if (!canPlaneswalk) {
+            return true; // Not playing with planeswalk enabled.
+        }
+
+        if (optional && !controller.chooseUse(outcome, "Planeswalk?", source, game)) {
+            return true;
+        }
+
+        // Steps: 1) Remove the last plane and set its effects to discarded
+        for (CommandObject cobject : game.getState().getCommand()) {
+            if (cobject instanceof Plane) {
+                if (cobject.getAbilities() != null) {
+                    for (Ability ability : cobject.getAbilities()) {
+                        for (Effect effect : ability.getEffects()) {
+                            if (effect instanceof ContinuousEffect) {
+                                ((ContinuousEffect) effect).discard();
+                            }
+                        }
+                    }
+                }
+                game.getState().removeTriggersOfSourceId(cobject.getId());
+                game.getState().getCommand().remove(cobject);
+                break;
+            }
+        }
+
+        // 2) Choose a new random plane we haven't been to, or reset if we've been everywhere
+        List<String> planesVisited = game.getState().getSeenPlanes();
+        if (game.getState().getSeenPlanes() != null) {
+            if (planesVisited.size() == Planes.values().length) {
+                game.getState().resetSeenPlanes();
+            }
+        }
+
+        boolean foundNextPlane = false;
+        while (!foundNextPlane) {
+            Plane plane = Plane.createRandomPlane();
+            try {
+                if (plane != null && !planesVisited.contains(plane.getName())) {
+                    foundNextPlane = true;
+                    game.addPlane(plane, controller.getId());
+                }
+            } catch (Exception ex) {
+            }
+        }
+        return true;
+    }
+
+    @Override
+    public PlaneswalkEffect copy() {
+        return new PlaneswalkEffect(this);
+    }
+}