goog.provide('ol.renderer.dom.ImageLayer');

goog.require('goog.asserts');
goog.require('goog.dom');
goog.require('goog.dom.TagName');
goog.require('goog.vec.Mat4');
goog.require('ol.ImageBase');
goog.require('ol.ViewHint');
goog.require('ol.dom');
goog.require('ol.extent');
goog.require('ol.layer.Image');
goog.require('ol.proj');
goog.require('ol.renderer.dom.Layer');
goog.require('ol.vec.Mat4');



/**
 * @constructor
 * @extends {ol.renderer.dom.Layer}
 * @param {ol.layer.Image} imageLayer Image layer.
 */
ol.renderer.dom.ImageLayer = function(imageLayer) {
  var target = goog.dom.createElement(goog.dom.TagName.DIV);
  target.style.position = 'absolute';

  goog.base(this, imageLayer, target);

  /**
   * The last rendered image.
   * @private
   * @type {?ol.ImageBase}
   */
  this.image_ = null;

  /**
   * @private
   * @type {goog.vec.Mat4.Number}
   */
  this.transform_ = goog.vec.Mat4.createNumberIdentity();

};
goog.inherits(ol.renderer.dom.ImageLayer, ol.renderer.dom.Layer);


/**
 * @inheritDoc
 */
ol.renderer.dom.ImageLayer.prototype.clearFrame = function() {
  goog.dom.removeChildren(this.target);
  this.image_ = null;
};


/**
 * @inheritDoc
 */
ol.renderer.dom.ImageLayer.prototype.prepareFrame =
    function(frameState, layerState) {

  var viewState = frameState.viewState;
  var viewCenter = viewState.center;
  var viewResolution = viewState.resolution;
  var viewRotation = viewState.rotation;

  var image = this.image_;
  var imageLayer = this.getLayer();
  goog.asserts.assertInstanceof(imageLayer, ol.layer.Image,
      'layer is an instance of ol.layer.Image');
  var imageSource = imageLayer.getSource();

  var hints = frameState.viewHints;

  var renderedExtent = frameState.extent;
  if (goog.isDef(layerState.extent)) {
    renderedExtent = ol.extent.getIntersection(
        renderedExtent, layerState.extent);
  }

  if (!hints[ol.ViewHint.ANIMATING] && !hints[ol.ViewHint.INTERACTING] &&
      !ol.extent.isEmpty(renderedExtent)) {
    var projection = viewState.projection;
    var sourceProjection = imageSource.getProjection();
    if (!goog.isNull(sourceProjection)) {
      goog.asserts.assert(ol.proj.equivalent(projection, sourceProjection),
          'projection and sourceProjection are equivalent');
      projection = sourceProjection;
    }
    var image_ = imageSource.getImage(renderedExtent, viewResolution,
        frameState.pixelRatio, projection);
    if (!goog.isNull(image_)) {
      var loaded = this.loadImage(image_);
      if (loaded) {
        image = image_;
      }
    }
  }

  if (!goog.isNull(image)) {
    var imageExtent = image.getExtent();
    var imageResolution = image.getResolution();
    var transform = goog.vec.Mat4.createNumber();
    ol.vec.Mat4.makeTransform2D(transform,
        frameState.size[0] / 2, frameState.size[1] / 2,
        imageResolution / viewResolution, imageResolution / viewResolution,
        viewRotation,
        (imageExtent[0] - viewCenter[0]) / imageResolution,
        (viewCenter[1] - imageExtent[3]) / imageResolution);
    if (image != this.image_) {
      var imageElement = image.getImage(this);
      // Bootstrap sets the style max-width: 100% for all images, which breaks
      // prevents the image from being displayed in FireFox.  Workaround by
      // overriding the max-width style.
      imageElement.style.maxWidth = 'none';
      imageElement.style.position = 'absolute';
      goog.dom.removeChildren(this.target);
      goog.dom.appendChild(this.target, imageElement);
      this.image_ = image;
    }
    this.setTransform_(transform);
    this.updateAttributions(frameState.attributions, image.getAttributions());
    this.updateLogos(frameState, imageSource);
  }

  return true;
};


/**
 * @param {goog.vec.Mat4.Number} transform Transform.
 * @private
 */
ol.renderer.dom.ImageLayer.prototype.setTransform_ = function(transform) {
  if (!ol.vec.Mat4.equals2D(transform, this.transform_)) {
    ol.dom.transformElement2D(this.target, transform, 6);
    goog.vec.Mat4.setFromArray(this.transform_, transform);
  }
};