Arrows stuck in entities expression (#1655)

* Create ExprArrowsStuck.java

* Improved Expression Pattern

* Create ExprArrowsStuck.sk

* Update ExprArrowsStuck.java

* Update ExprArrowsStuck.sk

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

@@ -0,0 +1,100 @@
+/**
+ *   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.LivingEntity;
+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.Since;
+import ch.njol.skript.expressions.base.SimplePropertyExpression;
+import ch.njol.skript.lang.ExpressionType;
+import ch.njol.util.coll.CollectionUtils;
+
+@Name("Arrows Stuck")
+@Description("The number of arrows stuck in a living entity.")
+@Examples("set arrows stuck in player to 5")
+@Since("INSERT VERSION")
+public class ExprArrowsStuck extends SimplePropertyExpression<LivingEntity, Number> {
+
+    static {
+    	if (Skript.methodExists(LivingEntity.class, "getArrowsStuck")) {
+    		Skript.registerExpression(ExprArrowsStuck.class, Number.class, ExpressionType.PROPERTY,
+    				"[number of] arrow[s] stuck in %livingentities%");
+    	}
+    }
+
+    @Override
+    public Number convert(LivingEntity le) {
+        return le.getArrowsStuck();
+    }
+
+	@Override
+	@Nullable
+	public Class<?>[] acceptChange(final ChangeMode mode) {
+		if (mode == ChangeMode.REMOVE_ALL)
+			return null;
+		return CollectionUtils.array(Number.class);
+	}
+
+	@Override
+	public void change(final Event e, final @Nullable Object[] delta, final ChangeMode mode) {
+		int d = delta == null ? 0 : ((Number) delta[0]).intValue();
+		for (LivingEntity le : getExpr().getArray(e)) {
+			switch (mode) {
+				case ADD:
+					int r1 = le.getArrowsStuck() + d;
+					if (r1 < 0) r1 = 0;
+					le.setArrowsStuck(r1);
+					break;
+				case SET:
+					le.setArrowsStuck(d);
+					break;
+				case DELETE:
+				case RESET:
+					le.setArrowsStuck(0);
+					break;
+				case REMOVE:
+					int r2 = le.getArrowsStuck() - d;
+					if (r2 < 0) r2 = 0;
+					le.setArrowsStuck(r2);
+					break;
+				case REMOVE_ALL:
+					assert false;		
+			}
+		}
+	}
+
+    @Override
+    protected String getPropertyName() {
+        return "arrows stuck";
+    }
+
+    @Override
+    public Class<? extends Number> getReturnType() {
+        return Number.class;
+    }
+
+}

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

@@ -0,0 +1,18 @@
+test "arrows stuck":
+	spawn zombie at location(0, 64, 0, world "world")
+	set {_m} to last spawned zombie
+	assert arrows stuck in {_m} is 0 with "entity spawned with arrows stuck"
+	set arrows stuck in {_m} to 31
+	assert arrows stuck in {_m} is 31 with "arrows stuck set failed"
+	add 5 to arrows stuck in {_m}
+	assert arrows stuck in {_m} is 36 with "arrows stuck add ##1 failed"
+	remove 10 from arrows stuck in {_m}
+	assert arrows stuck in {_m} is 26 with "arrows stuck remove ##1 failed"
+	remove 999 from arrows stuck in {_m}
+	assert arrows stuck in {_m} is 0 with "arrows stuck remove ##2 failed"
+	remove -2 from arrows stuck in {_m}
+	assert arrows stuck in {_m} is 2 with "arrows stuck remove ##3 failed"
+	add -1 to arrows stuck in {_m}
+	assert arrows stuck in {_m} is 1 with "arrows stuck add ##2 failed"
+	delete arrows stuck in {_m}
+	assert arrows stuck in {_m} is 0 with "arrows stuck delete failed"