Add potion effect tier (#4632)

* add potion effect tier

src/main/java/ch/njol/skript/expressions/ExprPotionEffectTier.java

@@ -0,0 +1,93 @@
+/**
+ * This file is part of Skript.
+ *
+ * Skript is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Skript is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Skript.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright Peter Güttinger, SkriptLang team and contributors
+ */
+package ch.njol.skript.expressions;
+
+import ch.njol.skript.Skript;
+import ch.njol.skript.doc.Description;
+import ch.njol.skript.doc.Examples;
+import ch.njol.skript.doc.Name;
+import ch.njol.skript.doc.Since;
+import ch.njol.skript.lang.Expression;
+import ch.njol.skript.lang.ExpressionType;
+import ch.njol.skript.lang.SkriptParser.ParseResult;
+import ch.njol.skript.lang.util.SimpleExpression;
+import ch.njol.util.Kleenean;
+import org.bukkit.entity.LivingEntity;
+import org.bukkit.event.Event;
+import org.bukkit.potion.PotionEffect;
+import org.bukkit.potion.PotionEffectType;
+import org.eclipse.jdt.annotation.Nullable;
+
+import java.util.ArrayList;
+import java.util.List;
+
+@Name("Potion Effect Tier")
+@Description("An expression to obtain the amplifier of a potion effect applied to an entity.")
+@Examples("if the amplifier of haste of player >= 3:")
+@Since("INSERT VERSION")
+public class ExprPotionEffectTier extends SimpleExpression<Integer> {
+
+	static {
+		Skript.registerExpression(ExprPotionEffectTier.class, Integer.class, ExpressionType.COMBINED,
+				"[the] [potion] (tier|amplifier|level) of %potioneffecttypes% (of|for|on) %livingentities%"
+		);
+	}
+
+	private Expression<PotionEffectType> typeExpr;
+	private Expression<LivingEntity> entityExpr;
+
+	@Override
+	@SuppressWarnings("unchecked")
+	public boolean init(Expression<?>[] exprs, int matchedPattern, Kleenean isDelayed, ParseResult parseResult) {
+		typeExpr = (Expression<PotionEffectType>) exprs[0];
+		entityExpr = (Expression<LivingEntity>) exprs[1];
+		return true;
+	}
+
+	@Override
+	@Nullable
+	protected Integer[] get(Event event) {
+		PotionEffectType[] types = typeExpr.getArray(event);
+		LivingEntity[] entities = entityExpr.getArray(event);
+		List<Integer> result = new ArrayList<>();
+		for (LivingEntity entity : entities) {
+			for (PotionEffectType type : types) {
+				PotionEffect effect = entity.getPotionEffect(type);
+				result.add(effect == null ? 0 : effect.getAmplifier() + 1);
+			}
+		}
+		return result.toArray(new Integer[0]);
+	}
+
+	@Override
+	public boolean isSingle() {
+		return true;
+	}
+
+	@Override
+	public Class<? extends Integer> getReturnType() {
+		return Integer.class;
+	}
+
+	@Override
+	public String toString(@Nullable Event event, boolean debug) {
+		return "potion tier of " + typeExpr.toString(event, debug) + " of " + entityExpr.toString(event, debug);
+	}
+
+}