override subscribe

#!/usr/bin/env dub
/+ dub.sdl:
    name "rx_filter_subject"
  dependency "rx" version="*"
  dependency "rtree" version="*"
+/

import std.stdio : writeln;
import rx;
import rtree;

struct message {
  int x;
  int y;
}

static class myWidget : Observer!message {
  this(int x0, int y0, int x1, int y1){
    x[0] = x0;
    x[1] = x1;

    y[0] = y0;
    y[1] = y1;
  }

  void put(message obj) {hit();}
  void completed() {}
  void failure(Exception ex) {}

  void hit(){writeln("Hit!");}

  int[2] x;
  int[2] y;
}

alias SI = RTree!(long, int, 2, float); // datatype, index element type, dimensions, fractional index element type

static class FilterSubject : SubjectObject!message {

  SI spitialIndex;

  this(){
    spitialIndex = new SI();
  }

  // alias subscribe = typeof(super).subscribe;
  Disposable subscribe(myWidget observer){
    spitialIndex.insert(observer.x, observer.y, cast(long)cast(void*)observer);

    return NopDisposable.instance;
  }
}

void main() {
  auto rx_message = new FilterSubject;

  message a;
  a.x = 1;
  a.y = 1;

  // nothing happens, nothing subscribed
  rx_message.put(a);

  // nothing happens, subscribe is a noop
  auto widget = new myWidget(1,1,3,3);
  rx_message.subscribe(widget);
  rx_message.put(a);
}