// Copyright 2006 The Closure Library Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS-IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

/**
 * @fileoverview Client positioning class.
 *
 * @author eae@google.com (Emil A Eklund)
 * @author chrishenry@google.com (Chris Henry)
 */

goog.provide('goog.positioning.ClientPosition');

goog.require('goog.asserts');
goog.require('goog.dom');
goog.require('goog.math.Coordinate');
goog.require('goog.positioning');
goog.require('goog.positioning.AbstractPosition');
goog.require('goog.style');



/**
 * Encapsulates a popup position where the popup is positioned relative to the
 * window (client) coordinates. This calculates the correct position to
 * use even if the element is relatively positioned to some other element. This
 * is for trying to position an element at the spot of the mouse cursor in
 * a MOUSEMOVE event. Just use the event.clientX and event.clientY as the
 * parameters.
 *
 * @param {number|goog.math.Coordinate} arg1 Left position or coordinate.
 * @param {number=} opt_arg2 Top position.
 * @constructor
 * @extends {goog.positioning.AbstractPosition}
 */
goog.positioning.ClientPosition = function(arg1, opt_arg2) {
  /**
   * Coordinate to position popup at.
   * @type {goog.math.Coordinate}
   */
  this.coordinate = arg1 instanceof goog.math.Coordinate ? arg1 :
      new goog.math.Coordinate(/** @type {number} */ (arg1), opt_arg2);
};
goog.inherits(goog.positioning.ClientPosition,
              goog.positioning.AbstractPosition);


/**
 * Repositions the popup according to the current state
 *
 * @param {Element} movableElement The DOM element of the popup.
 * @param {goog.positioning.Corner} movableElementCorner The corner of
 *     the popup element that that should be positioned adjacent to
 *     the anchorElement.  One of the goog.positioning.Corner
 *     constants.
 * @param {goog.math.Box=} opt_margin A margin specified in pixels.
 * @param {goog.math.Size=} opt_preferredSize Preferred size of the element.
 * @override
 */
goog.positioning.ClientPosition.prototype.reposition = function(
    movableElement, movableElementCorner, opt_margin, opt_preferredSize) {
  goog.asserts.assert(movableElement);

  // Translates the coordinate to be relative to the page.
  var viewportOffset = goog.style.getViewportPageOffset(
      goog.dom.getOwnerDocument(movableElement));
  var x = this.coordinate.x + viewportOffset.x;
  var y = this.coordinate.y + viewportOffset.y;

  // Translates the coordinate to be relative to the offset parent.
  var movableParentTopLeft =
      goog.positioning.getOffsetParentPageOffset(movableElement);
  x -= movableParentTopLeft.x;
  y -= movableParentTopLeft.y;

  goog.positioning.positionAtCoordinate(
      new goog.math.Coordinate(x, y), movableElement, movableElementCorner,
      opt_margin, null, null, opt_preferredSize);
};
