feat: defining map region unit un-/registering behaviour

modules/wave_survival/map_region.cpp

@@ -1,7 +1,45 @@
 #include "map_region.h"
+#include "enemy_body.h"
 
 String const MapRegion::sig_phase_changed{ "phase_changed" };
 
 void MapRegion::_bind_methods() {
 	ADD_SIGNAL(MethodInfo(sig_phase_changed, PropertyInfo(Variant::BOOL, "hunt_phase")));
 }
+
+void MapRegion::on_node_entered(Node *node) {
+	if (EnemyBody * body{ cast_to<EnemyBody>(node) }) {
+		if (!this->units.has(body->get_unit())) {
+			body->get_unit()->set_region(this);
+		}
+	}
+}
+
+void MapRegion::ready() {
+	connect("body_entered", callable_mp(this, &self_type::on_node_entered));
+}
+
+void MapRegion::_notification(int what) {
+	if (Engine::get_singleton()->is_editor_hint()) {
+		return;
+	}
+	switch (what) {
+		default:
+			return;
+		case NOTIFICATION_READY:
+			ready();
+			return;
+	}
+}
+
+void MapRegion::register_unit(NpcUnit *unit) {
+	if (!this->units.has(unit)) {
+		this->units.insert(unit);
+	}
+}
+
+void MapRegion::remove_unit(NpcUnit *unit) {
+	if (this->units.has(unit)) {
+		this->units.erase(unit);
+	}
+}