text: /*
    Copyright (c) 2015 Jean-Marc VIGLINO, 
    released under the CeCILL-B license (http://www.cecill.info/).
    
    ol/interaction/SelectCluster is an interaction for selecting vector features in a cluster.
  */
  
  import ol_ext_inherits from '../util/ext'
  import ol_Map from 'ol/Map'
  import ol_Collection from 'ol/Collection'
  import ol_layer_Vector from 'ol/layer/Vector'
  import ol_source_Vector from 'ol/source/Vector'
  import ol_interaction_Select from 'ol/interaction/Select'
  import ol_Feature from 'ol/Feature'
  import ol_geom_LineString from 'ol/geom/LineString'
  import {unByKey as ol_Observable_unByKey} from 'ol/Observable'
  import {easeOut as ol_easing_easeOut} from 'ol/easing'
  import ol_geom_Point from 'ol/geom/Point'
  import ol_style_Style from 'ol/style/Style'
  import ol_style_Circle from 'ol/style/Circle'
  import ol_render_getVectorContext from '../util/getVectorContext';
  import { createEmpty as ol_extent_createEmpty } from 'ol/extent'
  import { extend as ol_extent_extend } from 'ol/extent'
  
  /**
   * @classdesc
   * Interaction for selecting vector features in a cluster. 
   * It can be used as an ol.interaction.Select. 
   * When clicking on a cluster, it springs apart to reveal the features in the cluster.
   * Revealed features are selectable and you can pick the one you meant.
   * Revealed features are themselves a cluster with an attribute features that contain the original feature.
   * 
   * @constructor
   * @extends {ol.interaction.Select}
   * @param {olx.interaction.SelectOptions=} options SelectOptions.
   *  @param {ol.style} options.featureStyle used to style the revealed features as options.style is used by the Select interaction.
   * 	@param {boolean} options.selectCluster false if you don't want to get cluster selected
   * 	@param {Number} options.pointRadius to calculate distance between the features
   * 	@param {bool} options.spiral means you want the feature to be placed on a spiral (or a circle)
   * 	@param {Number} options.circleMaxObjects number of object that can be place on a circle
   * 	@param {Number} options.maxObjects number of object that can be drawn, other are hidden
   * 	@param {bool} options.animate if the cluster will animate when features spread out, default is false
   * 	@param {Number} options.animationDuration animation duration in ms, default is 500ms
   * @fires ol.interaction.SelectEvent
   * @api stable
   */
  var ol_interaction_SelectCluster = function(options) {
    options = options || {};
  
    this.pointRadius = options.pointRadius || 12;
    this.circleMaxObjects = options.circleMaxObjects || 10;
    this.maxObjects = options.maxObjects || 60;
    this.spiral = (options.spiral !== false);
    this.animate = options.animate;
    this.animationDuration = options.animationDuration || 500;
    this.selectCluster_ = (options.selectCluster !== false);
  
    // Create a new overlay layer for 
    var overlay = this.overlayLayer_ = new ol_layer_Vector({
      source: new ol_source_Vector({
        features: new ol_Collection(),
        wrapX: options.wrapX,
        useSpatialIndex: true
      }),
      name:'Cluster overlay',
      updateWhileAnimating: true,
      updateWhileInteracting: true,
      displayInLayerSwitcher: false,
      style: options.featureStyle
    });
  
    // Add the overlay to selection
    if (options.layers) {
      if (typeof(options.layers) == "function") {
        var fnLayers = options.layers;
        options.layers = function(layer) {
          return (layer===overlay || fnLayers(layer));
        };
      } else if (options.layers.push) {
        options.layers.push(this.overlayLayer_);
      }
    }
  
    // Don't select links
    if (options.filter) {
      var fnFilter = options.filter;
      options.filter = function(f,l){
        //if (l===overlay && f.get("selectclusterlink")) return false;
        if (!l && f.get("selectclusterlink")) return false;
        else return fnFilter(f,l);
      };
    } else options.filter = function(f,l) {
      //if (l===overlay && f.get("selectclusterlink")) return false; 
      if (!l && f.get("selectclusterlink")) return false; 
      else return true;
    };
    this.filter_ = options.filter;
  
    ol_interaction_Select.call(this, options);
    this.on("select", this.selectCluster.bind(this));
  };
  
  ol_ext_inherits(ol_interaction_SelectCluster, ol_interaction_Select);
  
  
  /**
   * Remove the interaction from its current map, if any,  and attach it to a new
   * map, if any. Pass `null` to just remove the interaction from the current map.
   * @param {ol.Map} map Map.
   * @api stable
   */
  ol_interaction_SelectCluster.prototype.setMap = function(map) {
    if (this.getMap()) {
      this.getMap().removeLayer(this.overlayLayer_);
    }
    if (this._listener) ol_Observable_unByKey(this._listener);
    this._listener = null;
  
    ol_interaction_Select.prototype.setMap.call (this, map);
    this.overlayLayer_.setMap(map);
    // map.addLayer(this.overlayLayer_);
  
    if (map && map.getView()) {
      this._listener = map.getView().on('change:resolution', this.clear.bind(this));
    }
  };
  
  /**
   * Clear the selection, close the cluster and remove revealed features
   * @api stable
   */
  ol_interaction_SelectCluster.prototype.clear = function() {
    this.getFeatures().clear();
    this.overlayLayer_.getSource().clear();
  };
  
  /**
   * Get the layer for the revealed features
   * @api stable
   */
  ol_interaction_SelectCluster.prototype.getLayer = function() {
    return this.overlayLayer_;
  };
  
  /**
   * Select a cluster 
   * @param {ol.SelectEvent | ol.Feature} a cluster feature ie. a feature with a 'features' attribute.
   * @api stable
   */
  ol_interaction_SelectCluster.prototype.selectCluster = function (e) {
    // It's a feature => convert to SelectEvent
    if (e instanceof ol_Feature) {
      e = { selected: [e] };
    }
    // Nothing selected
    if (!e.selected.length) {
      this.clear();
      return;
    }
  
    // Get selection
    var feature = e.selected[0];
    // It's one of ours
    if (feature.get('selectclusterfeature')) return;
    
    // Clic out of the cluster => close it
    var source = this.overlayLayer_.getSource();
    source.clear();
  
    var cluster = feature.get('features');
    // Not a cluster (or just one feature)
    if (!cluster || cluster.length==1) return;
  
    // Remove cluster from selection
    if (!this.selectCluster_) this.getFeatures().clear();
  
    var center = feature.getGeometry().getCoordinates();
    // Pixel size in map unit
    var pix = this.getMap().getView().getResolution();
    var r, a, i, max;
    var p, cf, lk;
  
    // The features
    var features = [];
  
    // Draw on a circle
    if (!this.spiral || cluster.length <= this.circleMaxObjects) {
      max = Math.min(cluster.length, this.circleMaxObjects);
      r = pix * this.pointRadius * (0.5 + max / 4);
      for (i=0; i<max; i++) {
        a = 2*Math.PI*i/max;
        if (max==2 || max == 4) a += Math.PI/4;
        p = [ center[0]+r*Math.sin(a), center[1]+r*Math.cos(a) ];
        cf = new ol_Feature({ 'selectclusterfeature':true, 'features':[cluster[i]], geometry: new ol_geom_Point(p) });
        cf.setStyle(cluster[i].getStyle());
        features.push(cf);
        lk = new ol_Feature({ 'selectclusterlink':true, geometry: new ol_geom_LineString([center,p]) });
        features.push(lk);
      }
    }
    // Draw on a spiral
    else {
      // Start angle
      a = 0;
      var d = 2*this.pointRadius;
      max = Math.min (this.maxObjects, cluster.length);
      // Feature on a spiral
      for (i=0; i<max; i++) {
        // New radius => increase d in one turn
        r = d/2 + d*a/(2*Math.PI);
        // Angle
        a = a + (d+0.1)/r;
        var dx = pix*r*Math.sin(a)
        var dy = pix*r*Math.cos(a)
        p = [ center[0]+dx, center[1]+dy ];
        cf = new ol_Feature({ 'selectclusterfeature':true, 'features':[cluster[i]], geometry: new ol_geom_Point(p) });
        cf.setStyle(cluster[i].getStyle()); 
        features.push(cf);
        lk = new ol_Feature({ 'selectclusterlink':true, geometry: new ol_geom_LineString([center,p]) });
        features.push(lk);
      }
    }
  
    source.clear();
    if (this.animate) {
      this.animateCluster_(center, features);
    } else {
      source.addFeatures(features);
    }
  };
  
  /**
   * Animate the cluster and spread out the features
   * @param {ol.Coordinates} the center of the cluster
   */
  ol_interaction_SelectCluster.prototype.animateCluster_ = function(center, features) {
    // Stop animation (if one is running)
    if (this.listenerKey_) {
      ol_Observable_unByKey(this.listenerKey_);
    }
    
    // Features to animate
    // var features = this.overlayLayer_.getSource().getFeatures();
    if (!features.length) return;
    
    var style = this.overlayLayer_.getStyle();
    var stylefn = (typeof(style) == 'function') ? style : style.length ? function(){ return style; } : function(){ return [style]; } ;
    var duration = this.animationDuration || 500;
    var start = new Date().getTime();
    
    // Animate function
    function animate(event) {
      var vectorContext = event.vectorContext || ol_render_getVectorContext(event);
      // Retina device
      var ratio = event.frameState.pixelRatio;
      var res = this.getMap().getView().getResolution();
      var e = ol_easing_easeOut((event.frameState.time - start) / duration);
      for (var i=0, feature; feature = features[i]; i++) if (feature.get('features')) {
        var pt = feature.getGeometry().getCoordinates();
        pt[0] = center[0] + e * (pt[0]-center[0]);
        pt[1] = center[1] + e * (pt[1]-center[1]);
        var geo = new ol_geom_Point(pt);
        // Image style
        var st = stylefn(feature, res);
        for (var s=0; s<st.length; s++) {
          var sc;
          // OL < v4.3 : setImageStyle doesn't check retina
          var imgs = ol_Map.prototype.getFeaturesAtPixel ? false : st[s].getImage();
          if (imgs) {
            sc = imgs.getScale();
            imgs.setScale(ratio); 
          }
          // OL3 > v3.14
          if (vectorContext.setStyle) {
            vectorContext.setStyle(st[s]);
            vectorContext.drawGeometry(geo);
          }
          // older version
          else {
            vectorContext.setImageStyle(imgs);
            vectorContext.drawPointGeometry(geo);
          }
          if (imgs) imgs.setScale(sc);
        }
      }
      // Stop animation and restore cluster visibility
      if (e > 1.0) {
        ol_Observable_unByKey(this.listenerKey_);
        this.overlayLayer_.getSource().addFeatures(features);
        this.overlayLayer_.changed();
        return;
      }
  
      
      // tell OL3 to continue postcompose animation
      event.frameState.animate = true;
    }
  
    // Start a new postcompose animation
    this.listenerKey_ = this.overlayLayer_.on(['postcompose','postrender'], animate.bind(this));
    // Start animation with a ghost feature
    var feature = new ol_Feature(new ol_geom_Point(this.getMap().getView().getCenter()));
    feature.setStyle(new ol_style_Style({ image: new ol_style_Circle({}) }));
    this.overlayLayer_.getSource().addFeature(feature);
  };
  
  
  /** Helper function to get the extent of a cluster
   * @param {ol.feature} feature
   * @return {ol.extent|null} the extent or null if extent is empty (no cluster or superimposed points)
   */
  ol_interaction_SelectCluster.prototype.getClusterExtent = function(feature) {
    if (!feature.get('features')) return null;
    var extent = ol_extent_createEmpty();
    feature.get('features').forEach(function(f) {
      extent = ol_extent_extend(extent, f.getGeometry().getExtent());
    });
    if (extent[0]===extent[2] && extent[1]===extent[3]) return null;
    return extent;
  };
  
  export default ol_interaction_SelectCluster
  