Fix Shield and Mine destructing Portal

src/de/steamwar/misslewars/listener/ItemListener.java

@@ -31,6 +31,7 @@ import com.sk89q.worldedit.world.World;
 import de.steamwar.misslewars.Config;
 import de.steamwar.misslewars.FightState;
 import de.steamwar.misslewars.MissileWars;
+import de.steamwar.misslewars.items.Missile;
 import de.steamwar.misslewars.items.SpecialItem;
 import org.bukkit.Bukkit;
 import org.bukkit.Location;
@@ -101,6 +102,7 @@ public class ItemListener extends BasicListener {
 		if (e.getEntity() instanceof Snowball) {
 			Bukkit.getScheduler().runTaskLater(MissileWars.getPlugin(), () -> {
 				Location l = e.getEntity().getLocation();
+				if (!validSpawn(l)) return;
 				BlockVector3 paste = BlockVector3.at(l.getX(), l.getY(), l.getZ()).subtract(offsetShield);
 
 				EditSession editSession = WorldEdit.getInstance().getEditSessionFactory().getEditSession(world, -1);
@@ -111,6 +113,7 @@ public class ItemListener extends BasicListener {
 		if (e.getEntity() instanceof Egg) {
 			Bukkit.getScheduler().runTaskLater(MissileWars.getPlugin(), () -> {
 				Location l = e.getEntity().getLocation();
+				if (!validSpawn(l)) return;
 				BlockVector3 paste = BlockVector3.at(l.getX(), l.getY(), l.getZ()).subtract(offsetMine);
 
 				EditSession editSession = WorldEdit.getInstance().getEditSessionFactory().getEditSession(world, -1);
@@ -119,4 +122,27 @@ public class ItemListener extends BasicListener {
 			}, Config.ShieldFlyTime);
 		}
 	}
+
+	private boolean validSpawn(Location location) {
+		int bz = MissileWars.getBlueTeam().getPortalZ();
+		int rz = MissileWars.getRedTeam().getPortalZ();
+
+		int offset = sign(bz - rz) * 5;
+
+		int blockZ = location.getBlockZ();
+		if (offset > 0) {
+			if (blockZ > bz - offset) return false;
+			if (blockZ < rz + offset) return false;
+		} else {
+			if (blockZ < bz - offset) return false;
+			if (blockZ > rz + offset) return false;
+		}
+		return true;
+	}
+
+	private int sign(int i) {
+		if (i < 0) return -1;
+		return i > 0 ? 1 : 0;
+	}
+
 }