text: /**
   * @module ol/Feature
   */
  import {assert} from './asserts.js';
  import {listen, unlisten, unlistenByKey} from './events.js';
  import EventType from './events/EventType.js';
  import {inherits} from './index.js';
  import BaseObject from './Object.js';
  import Geometry from './geom/Geometry.js';
  import Style from './style/Style.js';
  
  /**
   * @classdesc
   * A vector object for geographic features with a geometry and other
   * attribute properties, similar to the features in vector file formats like
   * GeoJSON.
   *
   * Features can be styled individually with `setStyle`; otherwise they use the
   * style of their vector layer.
   *
   * Note that attribute properties are set as {@link ol.Object} properties on
   * the feature object, so they are observable, and have get/set accessors.
   *
   * Typically, a feature has a single geometry property. You can set the
   * geometry using the `setGeometry` method and get it with `getGeometry`.
   * It is possible to store more than one geometry on a feature using attribute
   * properties. By default, the geometry used for rendering is identified by
   * the property name `geometry`. If you want to use another geometry property
   * for rendering, use the `setGeometryName` method to change the attribute
   * property associated with the geometry for the feature.  For example:
   *
   * ```js
   * var feature = new ol.Feature({
   *   geometry: new ol.geom.Polygon(polyCoords),
   *   labelPoint: new ol.geom.Point(labelCoords),
   *   name: 'My Polygon'
   * });
   *
   * // get the polygon geometry
   * var poly = feature.getGeometry();
   *
   * // Render the feature as a point using the coordinates from labelPoint
   * feature.setGeometryName('labelPoint');
   *
   * // get the point geometry
   * var point = feature.getGeometry();
   * ```
   *
   * @constructor
   * @extends {ol.Object}
   * @param {ol.geom.Geometry|Object.<string, *>=} opt_geometryOrProperties
   *     You may pass a Geometry object directly, or an object literal
   *     containing properties.  If you pass an object literal, you may
   *     include a Geometry associated with a `geometry` key.
   * @api
   */
  const Feature = function(opt_geometryOrProperties) {
  
    BaseObject.call(this);
  
    /**
     * @private
     * @type {number|string|undefined}
     */
    this.id_ = undefined;
  
    /**
     * @type {string}
     * @private
     */
    this.geometryName_ = 'geometry';
  
    /**
     * User provided style.
     * @private
     * @type {ol.style.Style|Array.<ol.style.Style>|
     *     ol.FeatureStyleFunction}
     */
    this.style_ = null;
  
    /**
     * @private
     * @type {ol.FeatureStyleFunction|undefined}
     */
    this.styleFunction_ = undefined;
  
    /**
     * @private
     * @type {?ol.EventsKey}
     */
    this.geometryChangeKey_ = null;
  
    listen(
      this, BaseObject.getChangeEventType(this.geometryName_),
      this.handleGeometryChanged_, this);
  
    if (opt_geometryOrProperties !== undefined) {
      if (opt_geometryOrProperties instanceof Geometry ||
          !opt_geometryOrProperties) {
        const geometry = opt_geometryOrProperties;
        this.setGeometry(geometry);
      } else {
        /** @type {Object.<string, *>} */
        const properties = opt_geometryOrProperties;
        this.setProperties(properties);
      }
    }
  };
  
  inherits(Feature, BaseObject);
  
  
  /**
   * Clone this feature. If the original feature has a geometry it
   * is also cloned. The feature id is not set in the clone.
   * @return {ol.Feature} The clone.
   * @api
   */
  Feature.prototype.clone = function() {
    const clone = new Feature(this.getProperties());
    clone.setGeometryName(this.getGeometryName());
    const geometry = this.getGeometry();
    if (geometry) {
      clone.setGeometry(geometry.clone());
    }
    const style = this.getStyle();
    if (style) {
      clone.setStyle(style);
    }
    return clone;
  };
  
  
  /**
   * Get the feature's default geometry.  A feature may have any number of named
   * geometries.  The "default" geometry (the one that is rendered by default) is
   * set when calling {@link ol.Feature#setGeometry}.
   * @return {ol.geom.Geometry|undefined} The default geometry for the feature.
   * @api
   * @observable
   */
  Feature.prototype.getGeometry = function() {
    return /** @type {ol.geom.Geometry|undefined} */ (
      this.get(this.geometryName_));
  };
  
  
  /**
   * Get the feature identifier.  This is a stable identifier for the feature and
   * is either set when reading data from a remote source or set explicitly by
   * calling {@link ol.Feature#setId}.
   * @return {number|string|undefined} Id.
   * @api
   */
  Feature.prototype.getId = function() {
    return this.id_;
  };
  
  
  /**
   * Get the name of the feature's default geometry.  By default, the default
   * geometry is named `geometry`.
   * @return {string} Get the property name associated with the default geometry
   *     for this feature.
   * @api
   */
  Feature.prototype.getGeometryName = function() {
    return this.geometryName_;
  };
  
  
  /**
   * Get the feature's style. Will return what was provided to the
   * {@link ol.Feature#setStyle} method.
   * @return {ol.style.Style|Array.<ol.style.Style>|
   *     ol.FeatureStyleFunction|ol.StyleFunction} The feature style.
   * @api
   */
  Feature.prototype.getStyle = function() {
    return this.style_;
  };
  
  
  /**
   * Get the feature's style function.
   * @return {ol.FeatureStyleFunction|undefined} Return a function
   * representing the current style of this feature.
   * @api
   */
  Feature.prototype.getStyleFunction = function() {
    return this.styleFunction_;
  };
  
  
  /**
   * @private
   */
  Feature.prototype.handleGeometryChange_ = function() {
    this.changed();
  };
  
  
  /**
   * @private
   */
  Feature.prototype.handleGeometryChanged_ = function() {
    if (this.geometryChangeKey_) {
      unlistenByKey(this.geometryChangeKey_);
      this.geometryChangeKey_ = null;
    }
    const geometry = this.getGeometry();
    if (geometry) {
      this.geometryChangeKey_ = listen(geometry,
        EventType.CHANGE, this.handleGeometryChange_, this);
    }
    this.changed();
  };
  
  
  /**
   * Set the default geometry for the feature.  This will update the property
   * with the name returned by {@link ol.Feature#getGeometryName}.
   * @param {ol.geom.Geometry|undefined} geometry The new geometry.
   * @api
   * @observable
   */
  Feature.prototype.setGeometry = function(geometry) {
    this.set(this.geometryName_, geometry);
  };
  
  
  /**
   * Set the style for the feature.  This can be a single style object, an array
   * of styles, or a function that takes a resolution and returns an array of
   * styles. If it is `null` the feature has no style (a `null` style).
   * @param {ol.style.Style|Array.<ol.style.Style>|
   *     ol.FeatureStyleFunction|ol.StyleFunction} style Style for this feature.
   * @api
   * @fires ol.events.Event#event:change
   */
  Feature.prototype.setStyle = function(style) {
    this.style_ = style;
    this.styleFunction_ = !style ?
      undefined : Feature.createStyleFunction(style);
    this.changed();
  };
  
  
  /**
   * Set the feature id.  The feature id is considered stable and may be used when
   * requesting features or comparing identifiers returned from a remote source.
   * The feature id can be used with the {@link ol.source.Vector#getFeatureById}
   * method.
   * @param {number|string|undefined} id The feature id.
   * @api
   * @fires ol.events.Event#event:change
   */
  Feature.prototype.setId = function(id) {
    this.id_ = id;
    this.changed();
  };
  
  
  /**
   * Set the property name to be used when getting the feature's default geometry.
   * When calling {@link ol.Feature#getGeometry}, the value of the property with
   * this name will be returned.
   * @param {string} name The property name of the default geometry.
   * @api
   */
  Feature.prototype.setGeometryName = function(name) {
    unlisten(
      this, BaseObject.getChangeEventType(this.geometryName_),
      this.handleGeometryChanged_, this);
    this.geometryName_ = name;
    listen(
      this, BaseObject.getChangeEventType(this.geometryName_),
      this.handleGeometryChanged_, this);
    this.handleGeometryChanged_();
  };
  
  
  /**
   * Convert the provided object into a feature style function.  Functions passed
   * through unchanged.  Arrays of ol.style.Style or single style objects wrapped
   * in a new feature style function.
   * @param {ol.FeatureStyleFunction|!Array.<ol.style.Style>|!ol.style.Style} obj
   *     A feature style function, a single style, or an array of styles.
   * @return {ol.FeatureStyleFunction} A style function.
   */
  Feature.createStyleFunction = function(obj) {
    let styleFunction;
  
    if (typeof obj === 'function') {
      if (obj.length == 2) {
        styleFunction = function(resolution) {
          return /** @type {ol.StyleFunction} */ (obj)(this, resolution);
        };
      } else {
        styleFunction = obj;
      }
    } else {
      /**
       * @type {Array.<ol.style.Style>}
       */
      let styles;
      if (Array.isArray(obj)) {
        styles = obj;
      } else {
        assert(obj instanceof Style,
          41); // Expected an `ol.style.Style` or an array of `ol.style.Style`
        styles = [obj];
      }
      styleFunction = function() {
        return styles;
      };
    }
    return styleFunction;
  };
  export default Feature;
  