// The Flux architecture style code is in this file
// Please note that these are not split into separate modules due to:
//    1) small nature of this example
//    2) limitations of gists
// Additionally, most of this code is derived from the Flux + React.js TodoMVC
// for more information, and to properly learn about the concepts I recommend
// reviewing the tutorial or code there:
// http://facebook.github.io/react/docs/flux-todo-list.html
// https://github.com/facebook/react/tree/master/examples/todomvc-flux

// Dispatching (Additionally, this could be handled using d3.dispatch
// (e.g: http://bl.ocks.org/milroc/10606529))
var Dispatcher = (function() {
  var _callbacks = [];
  var _promises = [];

  var _addPromise = function(callback, payload) {
    _promises.push(new Promise(function(resolve, reject) {
      if (callback(payload)) {
        resolve(payload);
      } else {
        reject(new Error('Dispatcher callback unsuccessful'));
      }
    }));
  };

  var _clearPromises = function() {
    _promises = [];
  };

  var Dispatcher = function() {};

  Dispatcher.prototype.register = function(callback) {
    _callbacks.push(callback);
    return _callbacks.length - 1; // index
  };

  Dispatcher.prototype.dispatch = function(payload) {
    _callbacks.forEach(function(callback) {
      _addPromise(callback, payload);
    });
    Promise.all(_promises).then(_clearPromises);
  };

  return Dispatcher;
})();

var AppDispatcher = (function() {
  var AppDispatcher = function() {};

  AppDispatcher.prototype = new Dispatcher();

  AppDispatcher.prototype.handleViewAction = function(action) {
    this.dispatch({
      source: 'VIEW_ACTION',
      action: action
    });
  };

  return new AppDispatcher(); // a bit of a hack
})();

// Actions
var ChartActions = {
  range: function(extent, x) {
    AppDispatcher.handleViewAction({
      actionType: 'range',
      extent: extent,
      x: x,
    });
  },
  update: function() {
    AppDispatcher.handleViewAction({
      actionType: 'update',
    });
  }
};