CondDamageCause.java

package ch.njol.skript.conditions;

import org.bukkit.event.Event;
import org.bukkit.event.entity.EntityDamageEvent.DamageCause;
import org.jetbrains.annotations.Nullable;

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.expressions.base.EventValueExpression;
import ch.njol.skript.lang.Condition;
import ch.njol.skript.lang.Expression;
import ch.njol.skript.lang.SkriptParser.ParseResult;
import ch.njol.util.Kleenean;
import org.skriptlang.skript.lang.simplification.Simplifiable;

/**
 * @author Peter Güttinger
 */
@Name("Damage Cause")
@Description("Tests what kind of damage caused a <a href='events.html#damage'>damage event</a>. Refer to the <a href='classes.html#damagecause'>Damage Cause</a> type for a list of all possible causes.")
@Examples({"# make players use their potions of fire resistance whenever they take any kind of fire damage",
		"on damage:",
		"\tdamage was caused by lava, fire or burning",
		"\tvictim is a player",
		"\tvictim has a potion of fire resistance",
		"\tcancel event",
		"\tapply fire resistance to the victim for 30 seconds",
		"\tremove 1 potion of fire resistance from the victim",
		"# prevent mobs from dropping items under certain circumstances",
		"on death:",
		"\tentity is not a player",
		"\tdamage wasn't caused by a block explosion, an attack, a projectile, a potion, fire, burning, thorns or poison",
		"\tclear drops"})
@Since("2.0")
public class CondDamageCause extends Condition {
	
	static {
		Skript.registerCondition(CondDamageCause.class, "[the] damage (was|is|has)(0¦|1¦n('|o)t) [been] (caused|done|made) by %damagecause%");
	}
	
	@SuppressWarnings("null")
	private Expression<DamageCause> cause;
	@SuppressWarnings("null")
	private Expression<DamageCause> expected;
	
	@SuppressWarnings({"unchecked", "null"})
	@Override
	public boolean init(final Expression<?>[] exprs, final int matchedPattern, final Kleenean isDelayed, final ParseResult parseResult) {
		cause = new EventValueExpression<>(DamageCause.class);
		expected = (Expression<DamageCause>) exprs[0];
		setNegated(parseResult.mark == 1);
		return ((EventValueExpression<DamageCause>) cause).init();
	}
	
	@Override
	public boolean check(final Event e) {
		final DamageCause cause = this.cause.getSingle(e);
		if (cause == null)
			return false;
		return expected.check(e,
				other -> cause == other,
				isNegated());
	}

	@Override
	public Condition simplify(Step step, @Nullable Simplifiable<?> source) {
		expected = simplifyChild(expected, step, source);
		return this;
	}

	@Override
	public String toString(final @Nullable Event e, final boolean debug) {
		return "damage was" + (isNegated() ? " not" : "") + " caused by " + expected.toString(e, debug);
	}
	
}