// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

part of $LIBRARYNAME;

/**
 * Base class that supports listening for and dispatching browser events.
 *
 * Normally events are accessed via the Stream getter:
 *
 *     element.onMouseOver.listen((e) => print('Mouse over!'));
 *
 * To access bubbling events which are declared on one element, but may bubble
 * up to another element type (common for MediaElement events):
 *
 *     MediaElement.pauseEvent.forTarget(document.body).listen(...);
 *
 * To useCapture on events:
 *
 *     Element.keyDownEvent.forTarget(element, useCapture: true).listen(...);
 *
 * Custom events can be declared as:
 *
 *     class DataGenerator {
 *       static EventStreamProvider<Event> dataEvent =
 *           new EventStreamProvider('data');
 *     }
 *
 * Then listeners should access the event with:
 *
 *     DataGenerator.dataEvent.forTarget(element).listen(...);
 *
 * Custom events can also be accessed as:
 *
 *     element.on['some_event'].listen(...);
 *
 * This approach is generally discouraged as it loses the event typing and
 * some DOM events may have multiple platform-dependent event names under the
 * covers. By using the standard Stream getters you will get the platform
 * specific event name automatically.
 */
class Events {
  /* Raw event target. */
  final EventTarget _ptr;

  Events(this._ptr);

  Stream operator [](String type) {
    return new _EventStream(_ptr, type, false);
  }
}

class ElementEvents extends Events {
  /* Raw event target. */
  final Element _ptr;
  static final webkitEvents = {
    'animationend' : 'webkitAnimationEnd', 
    'animationiteration' : 'webkitAnimationIteration', 
    'animationstart' : 'webkitAnimationStart', 
    'fullscreenchange' : 'webkitfullscreenchange', 
    'fullscreenerror' : 'webkitfullscreenerror',
    'keyadded' : 'webkitkeyadded', 
    'keyerror' : 'webkitkeyerror', 
    'keymessage' : 'webkitkeymessage', 
    'needkey' : 'webkitneedkey', 
    'pointerlockchange' : 'webkitpointerlockchange', 
    'pointerlockerror' : 'webkitpointerlockerror', 
    'resourcetimingbufferfull' : 'webkitresourcetimingbufferfull', 
    'transitionend': 'webkitTransitionEnd',
    'speechchange' : 'webkitSpeechChange'
  };

  ElementEvents(Element ptr) : this._ptr = ptr, super(ptr);

  Stream operator [](String type) {
    if (webkitEvents.keys.contains(type.toLowerCase())) {
      if (Device.isWebKit) {
        return new _ElementEventStreamImpl(
            _ptr, webkitEvents[type.toLowerCase()], false);
      }
    }
    return new _ElementEventStreamImpl(_ptr, type, false);
  }
}

/**
 * Base class for all browser objects that support events.
 *
 * Use the [on] property to add, and remove events
 * for compile-time type checks and a more concise API.
 */
$(ANNOTATIONS)$(NATIVESPEC)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS {

$if DARTIUM
  // Default constructor to allow other classes e.g. GlobalEventHandlers to be
  // constructed using _internalWrap when mapping Blink object to Dart class.
  EventTarget();

$endif
  // Custom element created callback.
  EventTarget._created();

  /**
   * This is an ease-of-use accessor for event streams which should only be
   * used when an explicit accessor is not available.
   */
  Events get on => new Events(this);

  void addEventListener(String type, EventListener listener, [bool useCapture]) {
    // TODO(leafp): This check is avoid a bug in our dispatch code when
    // listener is null.  The browser treats this call as a no-op in this
    // case, so it's fine to short-circuit it, but we should not have to.
    if (listener != null) {
      _addEventListener(type, listener, useCapture);
    }
  }

  void removeEventListener(String type, EventListener listener, [bool useCapture]) {
    // TODO(leafp): This check is avoid a bug in our dispatch code when
    // listener is null.  The browser treats this call as a no-op in this
    // case, so it's fine to short-circuit it, but we should not have to.
    if (listener != null) {
      _removeEventListener(type, listener, useCapture);
    }
  }

$!MEMBERS
}