Explosive Entity Yield Expressions (#2782)

* Add expressions

* Creeper Support / Suggestions

* Make Requested Changes

* Cleanup

* Rename element files and update formatting

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

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+/**
+ *   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 2011-2017 Peter Güttinger and contributors
+ */
+package ch.njol.skript.expressions;
+
+import org.bukkit.event.Event;
+import org.bukkit.event.entity.ExplosionPrimeEvent;
+import org.eclipse.jdt.annotation.Nullable;
+
+import ch.njol.skript.ScriptLoader;
+import ch.njol.skript.Skript;
+import ch.njol.skript.classes.Changer.ChangeMode;
+import ch.njol.skript.doc.Description;
+import ch.njol.skript.doc.Events;
+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.skript.log.ErrorQuality;
+import ch.njol.util.Kleenean;
+import ch.njol.util.coll.CollectionUtils;
+
+@Name("Explosion Yield")
+@Description({"The yield of the explosion in an explosion prime event. This is how big the explosion is.",
+				" When changing the yield, values less than 0 will be ignored.",
+				" Read <a href='https://minecraft.gamepedia.com/Explosion'>this wiki page</a> for more information"})
+@Examples({"on explosion prime:",
+		"\tset the yield of the explosion to 10"})
+@Events("explosion prime")
+@Since("INSERT VERSION")
+public class ExprExplosionYield extends SimpleExpression<Number> {
+
+	static {
+		Skript.registerExpression(ExprExplosionYield.class, Number.class, ExpressionType.SIMPLE,
+			"[the] explosion (yield|radius|size)",
+			"[the] (yield|radius|size) of [the] explosion"
+		);
+	}
+
+	@Override
+	public boolean init(Expression<?>[] exprs, int matchedPattern, Kleenean isDelayed, ParseResult parseResult) {
+		if (!ScriptLoader.isCurrentEvent(ExplosionPrimeEvent.class)) {
+			Skript.error("The explosion radius is only usable in explosion prime events", ErrorQuality.SEMANTIC_ERROR);
+			return false;
+		}
+		return true;
+	}
+
+	@Override
+	@Nullable
+	protected Number[] get(Event e) {
+		return new Number[]{((ExplosionPrimeEvent) e).getRadius()};
+	}
+
+	@Override
+	@Nullable
+	public Class<?>[] acceptChange(final ChangeMode mode) {
+		if (mode == ChangeMode.REMOVE_ALL || mode == ChangeMode.RESET)
+			return null;
+		return CollectionUtils.array(Number.class);
+	}
+
+	@Override
+	public void change(final Event event, final @Nullable Object[] delta, final ChangeMode mode) {
+		float f = delta == null ? 0 : ((Number) delta[0]).floatValue();
+		if (f < 0) // Negative values will throw an error.
+			return;
+		ExplosionPrimeEvent e = (ExplosionPrimeEvent) event;
+		switch (mode) {
+			case SET:
+				e.setRadius(f);
+				break;
+			case ADD:
+				float add = e.getRadius() + f;
+				if (add < 0)
+					return;
+				e.setRadius(add);
+				break;
+			case REMOVE:
+				float subtract = e.getRadius() - f;
+				if (subtract < 0)
+					return;
+				e.setRadius(subtract);
+				break;
+			case DELETE:
+				e.setRadius(0);
+				break;
+			case REMOVE_ALL:
+			case RESET:
+				assert false;
+		}
+	}
+
+	@Override
+	public boolean isSingle() {
+		return true;
+	}
+
+	@Override
+	public Class<? extends Number> getReturnType() {
+		return Number.class;
+	}
+
+	@Override
+	public String toString(@Nullable Event e, boolean debug) {
+		return "the yield of the explosion";
+	}
+
+}

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

@@ -0,0 +1,144 @@
+/**
+ *   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 2011-2017 Peter Güttinger and contributors
+ */
+package ch.njol.skript.expressions;
+
+import org.bukkit.entity.Creeper;
+import org.bukkit.entity.Entity;
+import org.bukkit.entity.Explosive;
+import org.bukkit.event.Event;
+import org.eclipse.jdt.annotation.Nullable;
+
+import ch.njol.skript.Skript;
+import ch.njol.skript.classes.Changer.ChangeMode;
+import ch.njol.skript.doc.Description;
+import ch.njol.skript.doc.Examples;
+import ch.njol.skript.doc.Name;
+import ch.njol.skript.doc.RequiredPlugins;
+import ch.njol.skript.doc.Since;
+import ch.njol.skript.expressions.base.SimplePropertyExpression;
+import ch.njol.util.coll.CollectionUtils;
+
+@Name("Explosive Yield")
+@Description({"The yield of an explosive (creeper, primed tnt, fireball, etc.). This is how big of an explosion is caused by the entity.",
+				"Read <a href='https://minecraft.gamepedia.com/Explosion'>this wiki page</a> for more information"})
+@Examples({"on spawn of a creeper:",
+			"\tset the explosive yield of the event-entity to 10"})
+@RequiredPlugins("Minecraft 1.12 or newer for creepers")
+@Since("INSERT VERSION")
+public class ExprExplosiveYield extends SimplePropertyExpression<Entity, Number> {
+
+	static {
+		register(ExprExplosiveYield.class, Number.class, "explosive (yield|radius|size)", "entities");
+	}
+
+	private final static boolean CREEPER_USABLE = Skript.methodExists(Creeper.class, "getExplosionRadius");
+
+	@Override
+	public Number convert(Entity e) {
+		if (e instanceof Explosive)
+			return ((Explosive) e).getYield();
+		if (CREEPER_USABLE && e instanceof Creeper)
+			return ((Creeper) e).getExplosionRadius();
+		return 0;
+	}
+
+	@Override
+	@Nullable
+	public Class<?>[] acceptChange(final ChangeMode mode) {
+		if (mode == ChangeMode.REMOVE_ALL || mode == ChangeMode.RESET)
+			return null;
+		return CollectionUtils.array(Number.class);
+	}
+
+	@Override
+	public void change(final Event event, final @Nullable Object[] delta, final ChangeMode mode) {
+		Number change = delta != null ? (Number) delta[0] : 0;
+		for (Entity entity : getExpr().getArray(event)) {
+			if (entity instanceof Explosive) {
+				Explosive e = (Explosive) entity;
+				float f = change.floatValue();
+				if (f < 0) // Negative values will throw an error.
+					return;
+				switch (mode) {
+					case SET:
+						e.setYield(f);
+						break;
+					case ADD:
+						float add = e.getYield() + f;
+						if (add < 0)
+							return;
+						e.setYield(add);
+						break;
+					case REMOVE:
+						float subtract = e.getYield() - f;
+						if (subtract < 0)
+							return;
+						e.setYield(subtract);
+						break;	
+					case DELETE:
+						e.setYield(0);
+						break;
+					case REMOVE_ALL:
+					case RESET:
+						assert false;
+				}
+			} else if (CREEPER_USABLE && entity instanceof Creeper) {
+				Creeper c = (Creeper) entity;
+				int i = change.intValue();
+				if (i < 0) // Negative values will throw an error.
+					return;
+				switch (mode) {
+					case SET:
+						c.setExplosionRadius(i);
+						break;
+					case ADD:
+						int add = c.getExplosionRadius() + i;
+						if (add < 0)
+							return;
+						c.setExplosionRadius(add);
+						break;
+					case REMOVE:
+						int subtract = c.getExplosionRadius() - i;
+						if (subtract < 0)
+							return;
+						c.setExplosionRadius(subtract);
+						break;	
+					case DELETE:
+						c.setExplosionRadius(0);
+						break;
+					case REMOVE_ALL:
+					case RESET:
+						assert false;
+				}
+			}
+		}
+	}
+
+	@Override
+	public Class<Number> getReturnType() {
+		return Number.class;
+	}
+
+	@Override
+	protected String getPropertyName() {
+		return "explosive yield";
+	}
+
+}

src/test/skript/tests/syntaxes/expressions/ExprExplosiveYield.sk

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+test "explosive yield":
+	spawn a primed tnt at spawn of world "world"
+	assert explosive yield of last spawned tnt is 4 with "explosive yield of tnt is 4 by default"
+	set explosive yield of last spawned tnt to 10
+	assert explosive yield of last spawned tnt is 10 with "an explosive's explosive yield should be 10 if it is set to 10"
+	delete last spawned primed tnt
+
+test "creeper explosive yield" when minecraft version is "1.12.2":
+	spawn a creeper at spawn of world "world"
+	assert explosive yield of last spawned creeper is 3 with "explosive yield of a creeper is 3 by default"
+	set explosive yield of last spawned creeper to 10
+	assert explosive yield of last spawned creeper is 10 with "a creeper's explosive yield should be 10 if it is set to 10"
+	delete last spawned creeper