Models/UserDrawing.js

"use strict";

var MapInteractionMode = require("../Models/MapInteractionMode");
var DragPoints = require("../Map/DragPoints");

var DeveloperError = require("terriajs-cesium/Source/Core/DeveloperError")
  .default;
var defined = require("terriajs-cesium/Source/Core/defined").default;
var defaultValue = require("terriajs-cesium/Source/Core/defaultValue").default;
var Color = require("terriajs-cesium/Source/Core/Color").default;
var PolylineGlowMaterialProperty = require("terriajs-cesium/Source/DataSources/PolylineGlowMaterialProperty")
  .default;
var CustomDataSource = require("terriajs-cesium/Source/DataSources/CustomDataSource")
  .default;
var CallbackProperty = require("terriajs-cesium/Source/DataSources/CallbackProperty")
  .default;
var PolygonHierarchy = require("terriajs-cesium/Source/Core/PolygonHierarchy")
  .default;
var knockout = require("terriajs-cesium/Source/ThirdParty/knockout").default;
var Entity = require("terriajs-cesium/Source/DataSources/Entity.js").default;
var when = require("terriajs-cesium/Source/ThirdParty/when").default;
var Cartesian3 = require("terriajs-cesium/Source/Core/Cartesian3").default;
var i18next = require("i18next").default;

/**
 * Callback for when a point is clicked.
 * @callback PointClickedCallback
 * @param {CustomDataSource} customDataSource Contains all point entities that user has selected so far
 */

/**
 * Callback for when a point is moved.
 * @callback PointMovedCallback
 * @param {CustomDataSource} customDataSource Contains all point entities that user has selected so far
 */

/**
 * Callback for when clean up is happening, i.e., for done or cancel.
 * @callback CleanUpCallback
 */

/**
 * Callback for when the dialog is displayed, to provide a custom message
 * @callback MakeDialogMessageCallback
 * @return {String} Message to add to dialog
 */

/**
 * For user drawings, which includes lines and/or a polygon
 *
 * @alias UserDrawing
 * @constructor
 *
 * @param {Object} options Object with the following properties:
 * @param {Terria} options.terria The Terria instance.
 * @param {String} [options.messageHeader='Draw on Map'] Heading for the dialog which pops up when in user drawing mode
 * @param {Bool}   [options.allowPolygon=true] Let the user click on first point to close loop
 * @param {PointClickedCallback} [options.onPointClicked] Way to subscribe to point clicks
 * @param {PointMovedCallback} [options.onPointMoved] Way to subscribe to point moves
 * @param {CleanUpCallback} [options.onCleanUp] Way to add own cleanup
 * @param {MakeDialogMessageCallback} [options.onMakeDialogMessage] Way to customise dialog message
 */
var UserDrawing = function(options) {
  options = defaultValue(options, defaultValue.EMPTY_OBJECT);
  if (!defined(options.terria)) {
    throw new DeveloperError(i18next.t("models.userDrawing.devError"));
  }

  /**
   * Text that appears at the top of the dialog when drawmode is active.
   * @type {String}
   * @default 'Draw on Map'
   */
  this.messageHeader = defaultValue(
    options.messageHeader,
    i18next.t("models.userDrawing.messageHeader")
  );

  /**
   * If true, user can click on first point to close the line, turning it into a polygon.
   * @type {Bool}
   * @default true
   */
  this.allowPolygon = defaultValue(options.allowPolygon, true);

  /**
   * Callback that occurs when point is clicked (may be added or removed). Function takes a CustomDataSource which is
   * a list of PointEntities.
   * @type {PointClickedCallback}
   * @default undefined
   */
  this.onPointClicked = options.onPointClicked;

  /**
   * Callback that occurs when point is moved. Function takes a CustomDataSource which is a list of PointEntities.
   * @type {PointMovedCallback}
   * @default undefined
   */
  this.onPointMoved = options.onPointMoved;

  /**
   * Callback that occurs on clean up, i.e. when drawing is done or cancelled.
   * @type {CleanUpCallback}
   * @default undefined
   */
  this.onCleanUp = options.onCleanUp;

  /**
   * Callback that occurs when the dialog is redrawn, to add additional information to dialog.
   * @type {MakeDialogMessageCallback}
   * @default undefined
   */
  this.onMakeDialogMessage = options.onMakeDialogMessage;

  /**
   * Instance of Terria
   * @type {Terria}
   * @default undefined
   */
  this.terria = options.terria;

  /**
   * Storage for points that will be drawn
   * @type {CustomDataSource}
   */
  this.pointEntities = new CustomDataSource(
    i18next.t("models.userDrawing.pointEntities")
  );

  /**
   * Storage for line that connects the points, and polygon if the first and last point are the same
   * @type {CustomDataSource}
   */
  this.otherEntities = new CustomDataSource(
    i18next.t("models.userDrawing.otherEntities")
  );

  /**
   * Polygon that will be drawn if the user drawing is a closed shape
   * @type {Entity}
   */
  this.polygon = undefined;

  /**
   * Whether to interpret user clicks as drawing
   * @type {Bool}
   */
  this.inDrawMode = false;

  /**
   * Whether the first and last point in the user drawing are the same
   * @type {Bool}
   */
  this.closeLoop = false;

  /**
   * SVG element for point drawn when user clicks.
   * http://stackoverflow.com/questions/24869733/how-to-draw-custom-dynamic-billboards-in-cesium-js
   */
  var svgDataDeclare = "data:image/svg+xml,";
  var svgPrefix =
    '<svg version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px" width="20px" height="20px" xml:space="preserve">';
  var svgCircle =
    '<circle cx="10" cy="10" r="5" stroke="rgb(0,170,215)" stroke-width="4" fill="white" /> ';
  var svgSuffix = "</svg>";
  var svgString = svgPrefix + svgCircle + svgSuffix;

  // create the cesium entity
  this.svgPoint = svgDataDeclare + svgString;

  // helper for dragging points around
  var that = this;
  this.dragHelper = new DragPoints(options.terria, function(customDataSource) {
    if (typeof that.onPointMoved === "function") {
      that.onPointMoved(customDataSource);
    }
    that._prepareToAddNewPoint();
  });
};

/**
 * Start interpreting user clicks as placing or removing points.
 */
UserDrawing.prototype.enterDrawMode = function() {
  this.dragHelper.setUp();

  // If we have finished a polygon, don't allow more points to be drawn. In future, perhaps support multiple polygons.
  if (this.inDrawMode || this.closeLoop) {
    // Do nothing
    return;
  }

  this.inDrawMode = true;

  if (defined(this.terria.cesium)) {
    this.terria.cesium.viewer.canvas.setAttribute("style", "cursor: crosshair");
  } else if (defined(this.terria.leaflet)) {
    document
      .getElementById("cesiumContainer")
      .setAttribute("style", "cursor: crosshair");
  }

  // Cancel any feature picking already in progress and disable feature info requests.
  this.terria.pickedFeatures = undefined;
  this.terria.allowFeatureInfoRequests = false;
  var that = this;

  // Line will show up once user has drawn some points. Vertices of line are user points.
  this.otherEntities.entities.add({
    name: i18next.t("models.userDrawing.line"),
    polyline: {
      positions: new CallbackProperty(function(date, result) {
        var pos = that._getPointsForShape();
        if (that.closeLoop) {
          pos.push(pos[0]);
        }
        return pos;
      }, false),

      material: new PolylineGlowMaterialProperty({
        color: new Color(0.0, 0.0, 0.0, 0.1),
        glowPower: 0.25
      }),
      width: 20
    }
  });
  this.terria.dataSources.add(this.pointEntities);
  this.terria.dataSources.add(this.otherEntities);

  // Listen for user clicks on map
  const pickPointMode = new MapInteractionMode({
    message: this._getDialogMessage(),
    buttonText: this._getButtonText(),
    onCancel: function() {
      that.terria.mapInteractionModeStack.pop();
      that._cleanUp();
    }
  });
  this.terria.mapInteractionModeStack.push(pickPointMode);

  // Handle what happens when user picks a point
  knockout
    .getObservable(pickPointMode, "pickedFeatures")
    .subscribe(function(pickedFeatures) {
      when(pickedFeatures.allFeaturesAvailablePromise, function() {
        if (defined(pickedFeatures.pickPosition)) {
          var pickedPoint = pickedFeatures.pickPosition;
          that._addPointToPointEntities(
            i18next.t("models.userDrawing.firstPoint"),
            pickedPoint
          );
          that._prepareToAddNewPoint();
        }
      });
    });
};

/**
 * Create the HTML message in the dialog box.
 * Example:
 *
 *     Measuring Tool
 *     373.45 km
 *     Click to add another point
 *
 * @private
 */
UserDrawing.prototype._getDialogMessage = function() {
  var message = "<strong>" + this.messageHeader + "</strong></br>";

  var innerMessage = "";
  if (typeof this.onMakeDialogMessage === "function") {
    innerMessage = this.onMakeDialogMessage();
  }
  if (innerMessage !== "") {
    message += innerMessage + "</br>";
  }

  if (this.pointEntities.entities.values.length > 0) {
    message +=
      "<i>" + i18next.t("models.userDrawing.clickToAddAnotherPoint") + "</i>";
  } else {
    message +=
      "<i>" + i18next.t("models.userDrawing.clickToAddFirstPoint") + "</i>";
  }
  // htmlToReactParser will fail if html doesn't have only one root element.
  return "<div>" + message + "</div>";
};

/**
 * Figure out the text for the dialog button.
 * @private
 */
UserDrawing.prototype._getButtonText = function() {
  var buttonText = i18next.t("models.userDrawing.btnCancel");
  if (this.pointEntities.entities.values.length >= 2) {
    buttonText = i18next.t("models.userDrawing.btnDone");
  }
  return buttonText;
};

/**
 * User has finished or cancelled; restore initial state.
 * @private
 */
UserDrawing.prototype._cleanUp = function() {
  this.terria.dataSources.remove(this.pointEntities);
  this.pointEntities = new CustomDataSource(
    i18next.t("models.userDrawing.pointEntities")
  );
  this.terria.dataSources.remove(this.otherEntities);
  this.otherEntities = new CustomDataSource(
    i18next.t("models.userDrawing.otherEntities")
  );

  this.terria.allowFeatureInfoRequests = true;

  this.inDrawMode = false;
  this.closeLoop = false;

  // Return cursor to original state
  if (defined(this.terria.cesium)) {
    this.terria.cesium.viewer.canvas.setAttribute("style", "cursor: auto");
  } else if (defined(this.terria.leaflet)) {
    document
      .getElementById("cesiumContainer")
      .setAttribute("style", "cursor: auto");
  }

  // Allow client to clean up too
  if (typeof this.onCleanUp === "function") {
    this.onCleanUp();
  }
};

/**
 * Called after a point has been added, this updates the MapInteractionModeStack with a listener for another point.
 * @private
 */
UserDrawing.prototype._mapInteractionModeUpdate = function() {
  this.terria.mapInteractionModeStack.pop();
  var that = this;
  const pickPointMode = new MapInteractionMode({
    message: this._getDialogMessage(),
    buttonText: this._getButtonText(),
    onCancel: function() {
      that.terria.mapInteractionModeStack.pop();
      that._cleanUp();
    }
  });
  this.terria.mapInteractionModeStack.push(pickPointMode);
  return pickPointMode;
};

/**
 * Called after a point has been added, prepares to add and draw another point, as well as updating the dialog.
 * @private
 */
UserDrawing.prototype._prepareToAddNewPoint = function() {
  var pickPointMode = this._mapInteractionModeUpdate();
  var that = this;

  knockout
    .getObservable(pickPointMode, "pickedFeatures")
    .subscribe(function(pickedFeatures) {
      when(pickedFeatures.allFeaturesAvailablePromise, function() {
        if (defined(pickedFeatures.pickPosition)) {
          var pickedPoint = pickedFeatures.pickPosition;
          // If existing point was picked, _clickedExistingPoint handles that, and returns true.
          // getDragCount helps us determine if the point was actually dragged rather than clicked. If it was
          // dragged, we shouldn't treat it as a clicked-existing-point scenario.
          if (
            that.dragHelper.getDragCount() < 10 &&
            !that._clickedExistingPoint(pickedFeatures.features)
          ) {
            // No existing point was picked, so add a new point
            that._addPointToPointEntities(
              i18next.t("models.userDrawing.anotherPoint"),
              pickedPoint
            );
          } else {
            that.dragHelper.resetDragCount();
          }
          that._prepareToAddNewPoint();
        }
      });
    });
};

/**
 * Return a list of the coords for the user drawing
 * @return {Array} An array of coordinates for the user-drawn shape
 * @private
 */
UserDrawing.prototype._getPointsForShape = function() {
  if (defined(this.pointEntities.entities)) {
    var pos = [];
    for (var i = 0; i < this.pointEntities.entities.values.length; i++) {
      var obj = this.pointEntities.entities.values[i];
      if (defined(obj.position)) {
        var position = obj.position.getValue(this.terria.clock.currentTime);
        pos.push(position);
      }
    }
    return pos;
  }
};

/**
 * Find out if user clicked an existing point and handle appropriately.
 * @param {PickedFeatures} features Feature/s that are under the point the user picked
 * @return {Bool} Whether user had clicked an existing point
 * @private
 */
UserDrawing.prototype._clickedExistingPoint = function(features) {
  var userClickedExistingPoint = false;

  if (features.length < 1) {
    return userClickedExistingPoint;
  }

  var that = this;

  features.forEach(feature => {
    var index = -1;
    for (var i = 0; i < this.pointEntities.entities.values.length; i++) {
      var pointFeature = this.pointEntities.entities.values[i];
      if (pointFeature.id === feature.id) {
        index = i;
        break;
      }
    }

    if (index === -1) {
      // Probably a layer or feature that has nothing to do with what we're drawing.
      return;
    } else if (index === 0 && !this.closeLoop && this.allowPolygon) {
      // Index is zero if it's the first point, meaning we have a closed shape
      this.polygon = this.otherEntities.entities.add({
        name: i18next.t("models.userDrawing.userPolygon"),
        polygon: {
          hierarchy: new CallbackProperty(function(date, result) {
            return new PolygonHierarchy(that._getPointsForShape());
          }, false),
          material: new Color(0.0, 0.666, 0.843, 0.25),
          outlineColor: new Color(1.0, 1.0, 1.0, 1.0),
          perPositionHeight: true
        }
      });
      this.closeLoop = true;
      // A point has not been added, but conceptually it has because the first point is now also the last point.
      if (typeof that.onPointClicked === "function") {
        that.onPointClicked(that.pointEntities);
      }
      userClickedExistingPoint = true;
      return;
    } else {
      // User clicked on a point that's not the end of the loop. Remove it.
      this.pointEntities.entities.removeById(feature.id);
      // If it gets down to 2 points, it should stop acting like a polygon.
      if (this.pointEntities.entities.values.length < 2 && this.closeLoop) {
        this.closeLoop = false;
        this.otherEntities.entities.remove(this.polygon);
      }
      // Also let client of UserDrawing know if a point has been removed.
      if (typeof that.onPointClicked === "function") {
        that.onPointClicked(that.pointEntities);
      }
      userClickedExistingPoint = true;
      return;
    }
  });
  return userClickedExistingPoint;
};

/**
 * Add new point to list of pointEntities
 * @param {String} name What to call new point
 * @param {Cartesian3} position Position of new point
 * @private
 */
UserDrawing.prototype._addPointToPointEntities = function(name, position) {
  var pointEntity = new Entity({
    name: name,
    position: position,
    billboard: {
      image: this.svgPoint,
      eyeOffset: new Cartesian3(0.0, 0.0, -50.0)
    }
  });
  this.pointEntities.entities.add(pointEntity);
  this.dragHelper.updateDraggableObjects(this.pointEntities);
  if (typeof this.onPointClicked === "function") {
    this.onPointClicked(this.pointEntities);
  }
};

module.exports = UserDrawing;