// Streams, StreamController, StreamSink
import "dart:async";
import "dart:math";
import "dart:html";

/// stream - the object that blindly sends out data
/// streamcontroller - adds to the stream, and tells the status of the stream
// can close only if not actively sending data
/// streamsink - a hole to put stuff into it, like a stream - not always needed, implements streamconsumer
/// streamconsumer - abstract - superclass for sink
/// streamsubscription - abstract - superclass for listen - created when some type of listening is done
/// streamTransformer - ???
/// completer - not sure if needed

void main() {
  InputElement submit = querySelector("#submit");
  InputElement add1 = querySelector("#add1");
  InputElement add2 = querySelector("#add2");
  InputElement remove = querySelector("#remove");
  Stream<int> a = _ints();
  StreamController<dynamic> sc = StreamController();
  sc.stream.listen((e) {
    print(e);
  });

  add1.onClick.listen((e) {
    sc.addStream(a);
  });
  add2.onClick.listen((e) {
    sc.sink.add("I added something");
  });
  remove.onClick.listen((e) {
    sc.close(); //can only close when data not actively streaming
  });
  submit.onClick.listen((e) {
    sc.addError("oops");
  });
}

Stream<int> _numbers() async* {
  for (int i = 0; i < 10; i++) {
    yield i;
  }
}

Stream<int> _ints() async* {
  yield* Stream.periodic(Duration(seconds: 1), (int a) {
    return a++;
  });
}

Stream<String> _strings() async* {
  String a = "qwertyuiopasdfghjklzxcvbnm";
  Random r = Random();
  yield* Stream.periodic(Duration(seconds: 2), (_) {
    return a[r.nextInt(a.length)];
  });
}