import {
  buildModuleUrl,
  Check,
  Color,
  defined,
  destroyObject,
  getElement,
} from "@cesium/engine";
import knockout from "../ThirdParty/knockout.js";
import subscribeAndEvaluate from "../subscribeAndEvaluate.js";
import InfoBoxViewModel from "./InfoBoxViewModel.js";

/**
 * A widget for displaying information or a description.
 *
 * @alias InfoBox
 * @constructor
 *
 * @param {Element|string} container The DOM element or ID that will contain the widget.
 *
 * @exception {DeveloperError} Element with id "container" does not exist in the document.
 */
function InfoBox(container) {
  //>>includeStart('debug', pragmas.debug);
  Check.defined("container", container);
  //>>includeEnd('debug')

  container = getElement(container);

  const infoElement = document.createElement("div");
  infoElement.className = "cesium-infoBox";
  infoElement.setAttribute(
    "data-bind",
    '\
css: { "cesium-infoBox-visible" : showInfo, "cesium-infoBox-bodyless" : _bodyless }'
  );
  container.appendChild(infoElement);

  const titleElement = document.createElement("div");
  titleElement.className = "cesium-infoBox-title";
  titleElement.setAttribute("data-bind", "text: titleText");
  infoElement.appendChild(titleElement);

  const cameraElement = document.createElement("button");
  cameraElement.type = "button";
  cameraElement.className = "cesium-button cesium-infoBox-camera";
  cameraElement.setAttribute(
    "data-bind",
    '\
attr: { title: "Focus camera on object" },\
click: function () { cameraClicked.raiseEvent(this); },\
enable: enableCamera,\
cesiumSvgPath: { path: cameraIconPath, width: 32, height: 32 }'
  );
  infoElement.appendChild(cameraElement);

  const closeElement = document.createElement("button");
  closeElement.type = "button";
  closeElement.className = "cesium-infoBox-close";
  closeElement.setAttribute(
    "data-bind",
    "\
click: function () { closeClicked.raiseEvent(this); }"
  );
  closeElement.innerHTML = "×";
  infoElement.appendChild(closeElement);

  const frame = document.createElement("iframe");
  frame.className = "cesium-infoBox-iframe";
  frame.setAttribute("sandbox", "allow-same-origin allow-popups allow-forms"); //allow-pointer-lock allow-scripts allow-top-navigation
  frame.setAttribute(
    "data-bind",
    "style : { maxHeight : maxHeightOffset(40) }"
  );
  frame.setAttribute("allowfullscreen", true);
  infoElement.appendChild(frame);

  const viewModel = new InfoBoxViewModel();
  knockout.applyBindings(viewModel, infoElement);

  this._container = container;
  this._element = infoElement;
  this._frame = frame;
  this._viewModel = viewModel;
  this._descriptionSubscription = undefined;

  const that = this;
  //We can't actually add anything into the frame until the load event is fired
  frame.addEventListener("load", function () {
    const frameDocument = frame.contentDocument;

    //We inject default css into the content iframe,
    //end users can remove it or add their own via the exposed frame property.
    const cssLink = frameDocument.createElement("link");
    cssLink.href = buildModuleUrl("Widgets/InfoBox/InfoBoxDescription.css");
    cssLink.rel = "stylesheet";
    cssLink.type = "text/css";

    //div to use for description content.
    const frameContent = frameDocument.createElement("div");
    frameContent.className = "cesium-infoBox-description";

    frameDocument.head.appendChild(cssLink);
    frameDocument.body.appendChild(frameContent);

    //We manually subscribe to the description event rather than through a binding for two reasons.
    //1. It's an easy way to ensure order of operation so that we can adjust the height.
    //2. Knockout does not bind to elements inside of an iFrame, so we would have to apply a second binding
    //   model anyway.
    that._descriptionSubscription = subscribeAndEvaluate(
      viewModel,
      "description",
      function (value) {
        // Set the frame to small height, force vertical scroll bar to appear, and text to wrap accordingly.
        frame.style.height = "5px";
        frameContent.innerHTML = value;

        //If the snippet is a single element, then use its background
        //color for the body of the InfoBox. This makes the padding match
        //the content and produces much nicer results.
        let background = null;
        const firstElementChild = frameContent.firstElementChild;
        if (
          firstElementChild !== null &&
          frameContent.childNodes.length === 1
        ) {
          const style = window.getComputedStyle(firstElementChild);
          if (style !== null) {
            const backgroundColor = style["background-color"];
            const color = Color.fromCssColorString(backgroundColor);
            if (defined(color) && color.alpha !== 0) {
              background = style["background-color"];
            }
          }
        }
        infoElement.style["background-color"] = background;

        // Measure and set the new custom height, based on text wrapped above.
        const height = frameContent.getBoundingClientRect().height;
        frame.style.height = `${height}px`;
      }
    );
  });

  //Chrome does not send the load event unless we explicitly set a src
  frame.setAttribute("src", "about:blank");
}

Object.defineProperties(InfoBox.prototype, {
  /**
   * Gets the parent container.
   * @memberof InfoBox.prototype
   *
   * @type {Element}
   */
  container: {
    get: function () {
      return this._container;
    },
  },

  /**
   * Gets the view model.
   * @memberof InfoBox.prototype
   *
   * @type {InfoBoxViewModel}
   */
  viewModel: {
    get: function () {
      return this._viewModel;
    },
  },

  /**
   * Gets the iframe used to display the description.
   * @memberof InfoBox.prototype
   *
   * @type {HTMLIFrameElement}
   */
  frame: {
    get: function () {
      return this._frame;
    },
  },
});

/**
 * @returns {boolean} true if the object has been destroyed, false otherwise.
 */
InfoBox.prototype.isDestroyed = function () {
  return false;
};

/**
 * Destroys the widget.  Should be called if permanently
 * removing the widget from layout.
 */
InfoBox.prototype.destroy = function () {
  const container = this._container;
  knockout.cleanNode(this._element);
  container.removeChild(this._element);

  if (defined(this._descriptionSubscription)) {
    this._descriptionSubscription.dispose();
  }

  return destroyObject(this);
};
export default InfoBox;