/* 
 * heatmap.js GMaps overlay
 *
 * Copyright (c) 2011, Patrick Wied (http://www.patrick-wied.at)
 * Dual-licensed under the MIT (http://www.opensource.org/licenses/mit-license.php)
 * and the Beerware (http://en.wikipedia.org/wiki/Beerware) license.
 */ 
 
function HeatmapOverlay(map, cfg){

	this.heatmap = null;
	this.conf = cfg;
	this.latlngs = [];
  this.bounds = null;
	this.setMap(map);
  var me = this;
  google.maps.event.addListener(map, 'idle', function() { me.draw() });
}

HeatmapOverlay.prototype = new google.maps.OverlayView();

HeatmapOverlay.prototype.onAdd = function(){
	
	var panes = this.getPanes();
    
    var w = this.getMap().getDiv().clientWidth;
    var h = this.getMap().getDiv().clientHeight;	
	var el = document.createElement("div");
    el.style.position = "absolute";
    el.style.top = 0;
    el.style.left = 0;
    el.style.width = w + "px";
    el.style.height = h + "px";
    el.style.border = 0;
	
	this.conf.element = el;
	panes.overlayLayer.appendChild(el);

	this.heatmap = h337.create(this.conf);
}

HeatmapOverlay.prototype.onRemove = function(){
    // Empty for now.
}

HeatmapOverlay.prototype.draw = function(){
    console.log("drawing");
    
    var overlayProjection = this.getProjection();
    var currentBounds = this.map.getBounds();
    if (currentBounds.equals(this.bounds)) {
      return;
    }
    this.bounds = currentBounds;
    var ne = overlayProjection.fromLatLngToDivPixel(currentBounds.getNorthEast());
    var sw = overlayProjection.fromLatLngToDivPixel(currentBounds.getSouthWest());
    var topY = ne.y;
    var leftX = sw.x;
  var h = sw.y - ne.y;
  var w = ne.x - sw.x;

    this.conf.element.style.left = leftX + 'px';
    this.conf.element.style.top = topY + 'px';
  this.conf.element.style.width = w + 'px';
  this.conf.element.style.height = h + 'px';
  this.heatmap.store.get("heatmap").resize();
            
	if(this.latlngs.length > 0){
		this.heatmap.clear();
		var len = this.latlngs.length,
		projection = this.getProjection();

                var c = 0;
		var d = {
			//max: this.heatmap.store.max,
			data: []
		};

		while(len--){
			var latlng = this.latlngs[len].latlng;
			if(!currentBounds.contains(latlng)) { continue; }
                        c++;
			
			// DivPixel is pixel in overlay pixel coordinates... we need
			// to transform to screen coordinates so it'll match the canvas
			// which is continually repositioned to follow the screen.
			var divPixel = projection.fromLatLngToDivPixel(latlng);
			var screenPixel = new google.maps.Point(
			        divPixel.x - leftX,
			        divPixel.y - topY);
			var roundedPoint = this.pixelTransform(screenPixel);
			d.data.push({ 
			    x: roundedPoint.x,
			    y: roundedPoint.y,
			    count: this.latlngs[len].c
			});
		}
                d.max = Math.log(c)/Math.log(10);
                console.log("adding " + d.data.length + " datapoints");
                console.log("d max is " + d.max);
		this.heatmap.store.setDataSet(d);
	}

}

HeatmapOverlay.prototype.pixelTransform = function(p){
	var w = this.heatmap.get("width"),
	h = this.heatmap.get("height");

	while(p.x < 0)
		p.x+=w;
	
	while(p.x > w)
		p.x-=w;
		
	while(p.y < 0)
		p.y+=h;
	
	while(p.y > h)
		p.y-=h;
	
	// fast rounding - thanks to Seb Lee-Delisle for this neat hack
	p.x = ~~ (p.x+0.5);
	p.y = ~~ (p.y+0.5);
	
	return p;
}

HeatmapOverlay.prototype.setDataSet = function(data){

	var mapdata = {
	    max: data.max,
	    data: []
	};
	var d = data.data;
	var dlen = d.length;
	var projection = this.getProjection();
	while(dlen--){	
		var latlng = new google.maps.LatLng(d[dlen].lat, d[dlen].lng);
		this.latlngs.push({latlng: latlng, c: d[dlen].count});
		var point = this.pixelTransform(projection.fromLatLngToDivPixel(latlng));
		mapdata.data.push({x: point.x, y: point.y, count: d[dlen].count});
	}
	this.heatmap.clear();
	this.heatmap.store.setDataSet(mapdata);

}

HeatmapOverlay.prototype.addDataPoint = function(lat, lng, count){

	var projection = this.getProjection(),
	latlng = new google.maps.LatLng(lat, lng),
	point = this.pixelTransform(projection.fromLatLngToDivPixel(latlng));
	this.heatmap.store.addDataPoint(point.x, point.y, count);
	this.latlngs.push({ latlng: latlng, c: count });
}

HeatmapOverlay.prototype.toggle = function(){
	this.heatmap.toggleDisplay();
}