// 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;

$(ANNOTATIONS)class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {

  factory WheelEvent(String type,
      {Window view, int deltaX: 0, int deltaY: 0,
      int detail: 0, int screenX: 0, int screenY: 0, int clientX: 0,
      int clientY: 0, int button: 0, bool canBubble: true,
      bool cancelable: true, bool ctrlKey: false, bool altKey: false,
      bool shiftKey: false, bool metaKey: false, EventTarget relatedTarget}) {

    if (view == null) {
      view = window;
    }
    var eventType = 'WheelEvent';
    if (_Device.isFirefox) {
      eventType = 'MouseScrollEvents';
    }
    final event = document.$dom_createEvent(eventType);
$if DART2JS
    if (event._hasInitWheelEvent) {
      var modifiers = [];
      if (ctrlKey) {
        modifiers.push('Control');
      }
      if (altKey) {
        modifiers.push('Alt');
      }
      if (shiftKey) {
        modifiers.push('Shift');
      }
      if (metaKey) {
        modifiers.push('Meta');
      }
      event._initWheelEvent(type, canBubble, cancelable, view, detail, screenX,
          screenY, clientX, clientY, button, relatedTarget, modifiers.join(' '),
          deltaX, deltaY, 0, 0);
    } else if (event._hasInitMouseScrollEvent) {
      var axis = 0;
      var detail = 0;
      if (deltaX != 0 && deltaY != 0) {
        throw UnsupportedError(
            'Cannot modify deltaX and deltaY simultaneously');
      }
      if (deltaY != 0) {
        detail = deltaY;
        axis = JS('int', 'MouseScrollEvent.VERTICAL_AXIS');
      } else if (deltaX != 0) {
        detail = deltaX;
        axis = JS('int', 'MouseScrollEvent.HORIZONTAL_AXIS');
      }
      event._initMouseScrollEvent(type, canBubble, cancelable, view, detail,
          screenX, screenY, clientX, clientY, ctrlKey, altKey, shiftKey,
          metaKey, button, relatedTarget, axis);
    } else {
$endif
      // Fallthrough for Dartium.
      event.$dom_initMouseEvent(type, canBubble, cancelable, view, detail,
          screenX, screenY, clientX, clientY, ctrlKey, altKey, shiftKey,
          metaKey, button, relatedTarget);
      event.$dom_initWebKitWheelEvent(deltaX,
          deltaY ~/ 120, // Chrome does an auto-convert to pixels.
          view, screenX, screenY, clientX, clientY, ctrlKey, altKey, shiftKey,
          metaKey);
$if DART2JS
    }
$endif

    return event;
  }

$!MEMBERS

$if DART2JS
  @DomName('WheelEvent.deltaY')
  num get deltaY {
    if (JS('bool', '#.deltaY !== undefined', this)) {
      // W3C WheelEvent
      return this._deltaY;
    } else if (JS('bool', '#.wheelDelta !== undefined', this)) {
      // Chrome and IE
      return this._wheelDelta;
    } else if (JS('bool', '#.detail !== undefined', this)) {
      // Firefox

      // Handle DOMMouseScroll case where it uses detail and the axis to
      // differentiate.
      if (JS('bool', '#.axis == MouseScrollEvent.VERTICAL_AXIS', this)) {
        var detail = this._detail;
        // Firefox is normally the number of lines to scale (normally 3)
        // so multiply it by 40 to get pixels to move, matching IE & WebKit.
        if (detail < 100) {
          return detail * 40;
        }
        return detail;
      }
      return 0;
    }
    throw new UnsupportedError(
        'deltaY is not supported');
  }

  @DomName('WheelEvent.deltaX')
  num get deltaX {
    if (JS('bool', '#.deltaX !== undefined', this)) {
      // W3C WheelEvent
      return this._deltaX;
    } else if (JS('bool', '#.wheelDeltaX !== undefined', this)) {
      // Chrome
      return this._wheelDeltaX;
    } else if (JS('bool', '#.detail !== undefined', this)) {
      // Firefox and IE.
      // IE will have detail set but will not set axis.

      // Handle DOMMouseScroll case where it uses detail and the axis to
      // differentiate.
      if (JS('bool', '#.axis !== undefined && '
        '#.axis == MouseScrollEvent.HORIZONTAL_AXIS', this, this)) {
        var detail = this._detail;
        // Firefox is normally the number of lines to scale (normally 3)
        // so multiply it by 40 to get pixels to move, matching IE & WebKit.
        if (detail < 100) {
          return detail * 40;
        }
        return detail;
      }
      return 0;
    }
    throw new UnsupportedError(
        'deltaX is not supported');
  }

  int get deltaMode {
    if (JS('bool', '!!#.deltaMode', this)) {
      // If not available then we're poly-filling and doing pixel scroll.
      return 0;
    }
    return this._deltaMode;
  }

  num get _deltaY => JS('num', '#.deltaY', this);
  num get _deltaX => JS('num', '#.deltaX', this);
  num get _wheelDelta => JS('num', '#.wheelDelta', this);
  num get _wheelDeltaX => JS('num', '#.wheelDeltaX', this);
  num get _detail => JS('num', '#.detail', this);
  int get _deltaMode => JS('int', '#.deltaMode', this);

  bool get _hasInitMouseScrollEvent =>
      JS('bool', '!!(#.initMouseScrollEvent)', this);

  @JSName('initMouseScrollEvent')
  void _initMouseScrollEvent(
      String type,
      bool canBubble,
      bool cancelable,
      Window view,
      int detail,
      int screenX,
      int screenY,
      int clientX,
      int clientY,
      bool ctrlKey,
      bool altKey,
      bool shiftKey,
      bool metaKey,
      int button,
      EventTarget relatedTarget,
      int axis) native;

  bool get _hasInitWheelEvent =>
      JS('bool', '!!(#.initWheelEvent)', this);
  @JSName('initWheelEvent')
  void _initWheelEvent(
      String eventType,
      bool canBubble,
      bool cancelable,
      Window view,
      int detail,
      int screenX,
      int screenY,
      int clientX,
      int clientY,
      int button,
      EventTarget relatedTarget,
      String modifiersList,
      int deltaX,
      int deltaY,
      int deltaZ,
      int deltaMode) native;

$else
  @DomName('WheelEvent.deltaX')
  num get deltaX => $dom_wheelDeltaX;
  @DomName('WheelEvent.deltaY')
  num get deltaY => $dom_wheelDeltaY;
  @DomName('WheelEvent.deltaMode')
  int get deltaMode => 0;

$endif
}