/**
 * @license
 * Copyright Google LLC All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */

/** Creates a browser MouseEvent with the specified options. */
export function createMouseEvent(type: string, x = 0, y = 0) {
  const event = document.createEvent('MouseEvent');

  event.initMouseEvent(type,
    false, /* canBubble */
    false, /* cancelable */
    window, /* view */
    0, /* detail */
    x, /* screenX */
    y, /* screenY */
    x, /* clientX */
    y, /* clientY */
    false, /* ctrlKey */
    false, /* altKey */
    false, /* shiftKey */
    false, /* metaKey */
    0, /* button */
    null /* relatedTarget */);

  return event;
}

/** Creates a browser TouchEvent with the specified pointer coordinates. */
export function createTouchEvent(type: string, pageX = 0, pageY = 0) {
  // In favor of creating events that work for most of the browsers, the event is created
  // as a basic UI Event. The necessary details for the event will be set manually.
  const event = document.createEvent('UIEvent');
  const touchDetails = {pageX, pageY};

  event.initUIEvent(type, true, true, window, 0);

  // Most of the browsers don't have a "initTouchEvent" method that can be used to define
  // the touch details.
  Object.defineProperties(event, {
    touches: {value: [touchDetails]}
  });

  return event;
}

/** Dispatches a keydown event from an element. */
export function createKeyboardEvent(type: string, keyCode: number, target?: Element, key?: string) {
  let event = document.createEvent('KeyboardEvent') as any;
  // Firefox does not support `initKeyboardEvent`, but supports `initKeyEvent`.
  let initEventFn = (event.initKeyEvent || event.initKeyboardEvent).bind(event);
  let originalPreventDefault = event.preventDefault;

  initEventFn(type, true, true, window, 0, 0, 0, 0, 0, keyCode);

  // Webkit Browsers don't set the keyCode when calling the init function.
  // See related bug https://bugs.webkit.org/show_bug.cgi?id=16735
  Object.defineProperties(event, {
    keyCode: { get: () => keyCode },
    key: { get: () => key },
    target: { get: () => target }
  });

  // IE won't set `defaultPrevented` on synthetic events so we need to do it manually.
  event.preventDefault = function() {
    Object.defineProperty(event, 'defaultPrevented', { get: () => true });
    return originalPreventDefault.apply(this, arguments);
  };

  return event;
}

/** Creates a fake event object with any desired event type. */
export function createFakeEvent(type: string, canBubble = true, cancelable = true) {
  const event = document.createEvent('Event');
  event.initEvent(type, canBubble, cancelable);
  return event;
}