[TLA] Implement Firebender Ascension

Also implemented an OptionalOneShotEffect for ease of stapling together a mandatory effect and an optional effect on the same ability.

Mage/src/main/java/mage/abilities/decorator/OptionalOneShotEffect.java

@@ -0,0 +1,85 @@
+package mage.abilities.decorator;
+
+import mage.abilities.Ability;
+import mage.abilities.Mode;
+import mage.abilities.effects.Effects;
+import mage.abilities.effects.OneShotEffect;
+import mage.game.Game;
+import mage.players.Player;
+import mage.target.targetpointer.TargetPointer;
+import mage.util.CardUtil;
+
+/**
+ * Adds condition to {@link OneShotEffect}. Acts as decorator.
+ *
+ * @author Grath
+ */
+public class OptionalOneShotEffect extends OneShotEffect {
+
+    private final Effects effects = new Effects();
+
+    public OptionalOneShotEffect(OneShotEffect effect, String text) {
+        super(effect.getOutcome());
+        if (effect != null) {
+            this.effects.add(effect);
+        }
+        this.staticText = text;
+    }
+
+    protected OptionalOneShotEffect(final OptionalOneShotEffect effect) {
+        super(effect);
+        this.effects.addAll(effect.effects.copy());
+    }
+
+    @Override
+    public boolean apply(Game game, Ability source) {
+        // nothing to do - no problem
+        if (effects.isEmpty()) {
+            return true;
+        }
+        Player player = game.getPlayer(source.getControllerId());
+        if (player != null && player.chooseUse(outcome, staticText, source, game)) {
+            effects.setTargetPointer(this.getTargetPointer().copy());
+            effects.forEach(effect -> effect.apply(game, source));
+            return true;
+        }
+        return false;
+    }
+
+    public OptionalOneShotEffect addEffect(OneShotEffect effect) {
+        this.effects.add(effect);
+        return this;
+    }
+
+    @Override
+    public void setValue(String key, Object value) {
+        super.setValue(key, value);
+        this.effects.setValue(key, value);
+    }
+
+    @Override
+    public OptionalOneShotEffect copy() {
+        return new OptionalOneShotEffect(this);
+    }
+
+    @Override
+    public String getText(Mode mode) {
+        if (staticText != null && !staticText.isEmpty()) {
+            return staticText;
+        }
+        return "you may " + CardUtil.getTextWithFirstCharLowerCase(effects.getText(mode));
+    }
+
+    @Override
+    public OptionalOneShotEffect setTargetPointer(TargetPointer targetPointer) {
+        effects.setTargetPointer(targetPointer);
+        super.setTargetPointer(targetPointer);
+        return this;
+    }
+
+    @Override
+    public OptionalOneShotEffect withTargetDescription(String target) {
+        effects.forEach(effect -> effect.withTargetDescription(target));
+        return this;
+    }
+}