// Clusterer.js - marker clustering routines for Google Maps apps
//
// Using these routines is very simple.
//
// 1) Load the routines into your code:
//    <script src="http://www.acme.com/resources/javascript/Clusterer.js" type="text/javascript"></script>
//
// 2) Create a Clusterer object, passing it your map object:
//
//        var clusterer = new Clusterer( map );
//
// 3) Wherever you now do map.addOverlay( marker ), instead call
//    clusterer.AddMarker( marker, title ).  The title is just a
//    short descriptive string to use in the cluster info-boxes.
//
// 4) If you are doing any map.removeOverlay( marker ) calls, change those
//    to clusterer.RemoveMarker( marker ).
//
// That's it!  Everything else happens automatically.
//
//
// Copyright © 2005 by Jef Poskanzer <jef@mail.acme.com>.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// 1. Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
//    documentation and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
// OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
// OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
// SUCH DAMAGE.
//
// For commentary on this license please see http://www.acme.com/license.html


var defaultMaxVisibleMarkers = 150;
var defaultGridSize = 5;
var defaultMinMarkersPerCluster = 5;
var defaultMaxLinesPerInfoBox = 10;

var defaultIcon = new GIcon();
defaultIcon.image = 'http://www.acme.com/resources/images/markers/blue_large.PNG';
defaultIcon.shadow = 'http://www.acme.com/resources/images/markers/shadow_large.PNG';
defaultIcon.iconSize = new GSize( 30, 51 );
defaultIcon.shadowSize = new GSize( 56, 51 );
defaultIcon.iconAnchor = new GPoint( 13, 34 );
defaultIcon.infoWindowAnchor = new GPoint( 13, 3 );
defaultIcon.infoShadowAnchor = new GPoint( 27, 37 );


// Constructor.
function Clusterer( map )
    {
    this.map = map;
    this.markers = [];
    this.clusters = [];
    this.timeout = null;
    this.currentZoomLevel = map.getZoomLevel();

    this.maxVisibleMarkers = defaultMaxVisibleMarkers;
    this.gridSize = defaultGridSize;
    this.minMarkersPerCluster = defaultMinMarkersPerCluster;
    this.maxLinesPerInfoBox = defaultMaxLinesPerInfoBox;
    this.icon = defaultIcon;

    GEvent.addListener( map, 'zoom', ClustererMakeCaller( ClustererDisplay, this ) );
    GEvent.addListener( map, 'moveend', ClustererMakeCaller( ClustererDisplay, this ) );
    GEvent.addListener( map, 'infowindowclose', ClustererMakeCaller( ClustererPopDown, this ) );
    }


// Call this to change the cluster icon.
Clusterer.prototype.SetIcon = function ( icon )
    {
    this.icon = icon;
    }


// Call this to add a marker.
Clusterer.prototype.AddMarker = function ( marker, title )
    {
    // Putting the map into a marker property is not mentioned in the API,
    // but it lets up pop up an infobox for markers which have not yet been
    // added to the map.
    marker.map = this.map;
    marker.title = title;
    this.markers.push( marker );
    this.DisplayLater();
    }


// Call this to remove a marker.
Clusterer.prototype.RemoveMarker = function ( marker )
    {
    for ( var i = 0; i < this.markers.length; ++i )
	if ( this.markers[i] == marker )
	    {
	    if ( marker.onMap )
		this.map.removeOverlay( marker );
	    for ( j = 0; j < this.clusters.length; ++j )
		{
		cluster = clusterer.clusters[j];
		if ( cluster != null )
		    {
		    for ( k = 0; k < cluster.markers.length; ++k )
			if ( cluster.markers[k] == marker )
			    {
			    cluster.markers[k] = null;
			    --cluster.markerCount;
			    break;
			    }
		    if ( cluster.markerCount == 0 )
			{
			this.ClearCluster( cluster );
			clusterer.clusters[j] = null;
			}
		    else if ( cluster == this.poppedUpCluster )
			ClustererRePop( this );
		    }
		}
	    this.markers[i] = null;
	    break;
	    }
    this.DisplayLater();
    }

Clusterer.prototype.DisplayLater = function ()
    {
    if ( this.timeout != null )
	window.clearTimeout( this.timeout );
    this.timeout = window.setTimeout( ClustererMakeCaller( ClustererDisplay, this ), 50 );
    }


function ClustererDisplay( clusterer )
    {
    var i, j, marker, cluster, point;

    window.clearTimeout( clusterer.timeout );

    var newZoomLevel = clusterer.map.getZoomLevel();
    if ( newZoomLevel != clusterer.currentZoomLevel )
	{
	// When the zoom level changes, we have to remove all the clusters.
	for ( i = 0; i < clusterer.clusters.length; ++i )
	    if ( clusterer.clusters[i] != null )
		{
		clusterer.ClearCluster( clusterer.clusters[i] );
		clusterer.clusters[i] = null;
		}
	clusterer.clusters.length = 0;
	clusterer.currentZoomLevel = newZoomLevel;
	}

    // Get the current bounds of the visible area.
    var bounds = clusterer.map.getBoundsLatLng();

    // Expand the bounds a little, so things look smoother when scrolling
    // by small amounts.
    var dx = bounds.maxX - bounds.minX;
    var dy = bounds.maxY - bounds.minY;
    dx *= 0.10;
    dy *= 0.10;
    bounds.maxX += dx;
    bounds.minX -= dx;
    bounds.maxY += dy;
    bounds.minY -= dy;

    // Partition the markers into visible and non-visible lists.
    var visibleMarkers = [];
    var nonvisibleMarkers = [];
    for ( i = 0; i < clusterer.markers.length; ++i )
	{
	marker = clusterer.markers[i];
	if ( marker != null )
	    if ( ClustererPointInBounds( marker.point, bounds ) )
		visibleMarkers.push( marker );
	    else
		nonvisibleMarkers.push( marker );
	}

    // Take down the non-visible markers.
    for ( i = 0; i < nonvisibleMarkers.length; ++i )
	{
	marker = nonvisibleMarkers[i];
	if ( marker.onMap )
	    {
	    clusterer.map.removeOverlay( marker );
	    marker.onMap = false;
	    }
	}

    // Take down the non-visible clusters.
    for ( i = 0; i < clusterer.clusters.length; ++i )
	{
	cluster = clusterer.clusters[i];
	if ( cluster != null && ! ClustererPointInBounds( cluster.marker.point, bounds ) && cluster.onMap )
	    {
	    clusterer.map.removeOverlay( cluster.marker );
	    cluster.onMap = false;
	    }
	}

    // Clustering!  This is some complicated stuff.  We have three goals
    // here.  One, limit the number of markers & clusters displayed, so the
    // maps code doesn't slow to a crawl.  Two, when possible keep existing
    // clusters instead of replacing them with new ones, so that the app pans
    // better.  And three, of course, be CPU and memory efficient.
    if ( visibleMarkers.length > clusterer.maxVisibleMarkers )
	{
	// Add to the list of clusters by splitting up the current bounds
	// into a grid.
	var latRange = bounds.maxY - bounds.minY;
	var latInc = latRange / clusterer.gridSize;
	var lonInc = latInc / Math.cos( ( bounds.maxY + bounds.minY ) / 2.0 * Math.PI / 180.0 );
	for ( var lat = bounds.minY; lat <= bounds.maxY; lat += latInc )
	    for ( var lon = bounds.minX; lon <= bounds.maxX; lon += lonInc )
		{
		cluster = new Object();
		cluster.clusterer = clusterer;
		cluster.bounds = new GBounds( lon, lat, lon + lonInc, lat + latInc );
		cluster.markers = [];
		cluster.markerCount = 0;
		cluster.onMap = false;
		cluster.marker = null;
		clusterer.clusters.push( cluster );
		}

	// Put all the unclustered visible markers into a cluster - the first
	// one it fits in, which favors pre-existing clusters.
	for ( i = 0; i < visibleMarkers.length; ++i )
	    {
	    marker = visibleMarkers[i];
	    if ( marker != null && ! marker.inCluster )
		{
		for ( j = 0; j < clusterer.clusters.length; ++j )
		    {
		    cluster = clusterer.clusters[j];
		    if ( cluster != null && ClustererPointInBounds( marker.point, cluster.bounds ) )
			{
			cluster.markers.push( marker );
			++cluster.markerCount;
			marker.inCluster = true;
			}
		    }
		}
	    }

	// Get rid of any clusters containing only a few markers.
	for ( i = 0; i < clusterer.clusters.length; ++i )
	    if ( clusterer.clusters[i] != null && clusterer.clusters[i].markerCount < clusterer.minMarkersPerCluster )
		{
		clusterer.ClearCluster( clusterer.clusters[i] );
		clusterer.clusters[i] = null;
		}

	// Shrink the clusters list.
	for ( i = clusterer.clusters.length - 1; i >= 0; --i )
	    if ( clusterer.clusters[i] != null )
		break;
	    else
		--clusterer.clusters.length;

	// Ok, we have our clusters.  Go through the markers in each
	// cluster and remove them from the map if they are currently up.
	for ( i = 0; i < clusterer.clusters.length; ++i )
	    {
	    cluster = clusterer.clusters[i];
	    if ( cluster != null )
		{
		for ( j = 0; j < cluster.markers.length; ++j )
		    {
		    marker = cluster.markers[j];
		    if ( marker != null && marker.onMap )
			{
			clusterer.map.removeOverlay( marker );
			marker.onMap = false;
			}
		    }
		}
	    }

	// Now make cluster-markers for any clusters that need one.
	for ( i = 0; i < clusterer.clusters.length; ++i )
	    {
	    cluster = clusterer.clusters[i];
	    if ( cluster != null && cluster.marker == null )
		{
		// Figure out the average coordinates of the markers in this
		// cluster.
		var xTotal = 0.0, yTotal = 0.0;
		for ( j = 0; j < cluster.markers.length; ++j )
		    {
		    marker = cluster.markers[j];
		    if ( marker != null )
			{
			xTotal += ( + marker.point.x );
			yTotal += ( + marker.point.y );
			}
		    }
		point = new GPoint( xTotal / cluster.markerCount, yTotal / cluster.markerCount );
		marker = new GMarker( point, clusterer.icon );
		cluster.marker = marker;
		GEvent.addListener( marker, 'click', ClustererMakeCaller( ClustererPopUp, cluster ) );
		}
	    }
	}

    // Display the visible markers not already up and not in clusters.
    for ( i = 0; i < visibleMarkers.length; ++i )
	{
	marker = visibleMarkers[i];
	if ( marker != null && ! marker.onMap && ! marker.inCluster )
	    {
	    clusterer.map.addOverlay( marker );
	    var title = marker.title;
	    if ( title )
		ClustererSetTooltip( marker, title );
	    marker.onMap = true;
	    }
	}

    // Display the visible clusters not already up.
    for ( i = 0; i < clusterer.clusters.length; ++i )
	{
	cluster = clusterer.clusters[i];
	if ( cluster != null && ! cluster.onMap && ClustererPointInBounds( cluster.marker.point, bounds ) )
	    {
	    clusterer.map.addOverlay( cluster.marker );
	    cluster.onMap = true;
	    }
	}

    // In case a cluster is currently popped-up, re-pop to get any new
    // markers into the infobox.
    ClustererRePop( clusterer );
    }


function ClustererPopUp( cluster )
    {
    var clusterer = cluster.clusterer;
    var html = '<table width="300">';
    var n = 0;
    for ( var i = 0; i < cluster.markers.length; ++i )
	{
	var marker = cluster.markers[i];
	if ( marker != null )
	    {
	    ++n;
	    html += '<tr><td>';
	    if ( marker.icon.smallImage )
		html += '<img src="' + marker.icon.smallImage + '">';
	    else
		html += '<img src="' + marker.icon.image + '" width="' + ( marker.icon.iconSize.width / 2 ) + '" height="' + ( marker.icon.iconSize.height / 2 ) + '">';
	    html += '</td><td>' + marker.title + '</td></tr>';
	    if ( n == clusterer.maxLinesPerInfoBox - 1 && cluster.markerCount > clusterer.maxLinesPerInfoBox  )
		{
		html += '<tr><td colspan="2">...and ' + ( cluster.markerCount - n ) + ' more</td></tr>';
		break;
		}
	    }
	}
    html += '</table>';
    clusterer.poppedUpCluster = cluster;
    cluster.marker.openInfoWindowHtml( html );
    }


function ClustererRePop( clusterer )
    {
    if ( clusterer.poppedUpCluster != null )
	ClustererPopUp( poppedUpCluster );
    }


function ClustererPopDown( clusterer )
    {
    clusterer.poppedUpCluster = null;
    }


Clusterer.prototype.ClearCluster = function ( cluster )
    {
    var i, marker;

    for ( i = 0; i < cluster.markers.length; ++i )
	if ( cluster.markers[i] != null )
	    {
	    cluster.markers[i].inCluster = false;
	    cluster.markers[i] = null;
	    }
    cluster.markers.length = 0;
    cluster.markerCount = 0;
    if ( cluster == this.poppedUpCluster )
	this.map.closeInfoWindow();
    if ( cluster.onMap )
	{
	this.map.removeOverlay( cluster.marker );
	cluster.onMap = false;
	}
    }


function ClustererPointInBounds( point, bounds )
    {
    var x = ( + point.x );
    var y = ( + point.y );
    return x >= bounds.minX && x <= bounds.maxX &&
	   y >= bounds.minY && y <= bounds.maxY;
    }


// This returns a function closure that calls the given routine with the
// specified arg.
function ClustererMakeCaller( func, arg )
    {
    return function () { func( arg ); };
    }


function ClustererSetTooltip( marker, title )
    {
    // Tooltips are in text, not HTML, so we have to strip any HTML stuff
    // out of the title.
    var textTitle = ClustererDeHtmlize( title );

    // Now add the title to whichever parts of the marker are present.
    if ( marker.transparentIcon )
	marker.transparentIcon.setAttribute( 'title' , textTitle );
    if ( marker.imageMap )
	marker.imageMap.setAttribute( 'title' , textTitle );
    if ( marker.iconImage )
	marker.iconImage.setAttribute( 'title' , textTitle );
    }


function ClustererEntityToIso8859( inStr )
    {
    var outStr = '';
    for ( var i = 0; i < inStr.length; ++i )
	{
	var c = inStr.charAt( i );
	if ( c != '&' )
	    outStr += c;
	else
	    {
	    var semi = inStr.indexOf( ';', i );
	    if ( semi == -1 )
		outStr += c;
	    else
		{
		var entity = inStr.substring( i + 1, semi );
		if ( entity == 'iexcl' ) outStr += '¡';
		else if ( entity == 'copy' ) outStr += '©';
		else if ( entity == 'laquo' ) outStr += '«';
		else if ( entity == 'reg' ) outStr += '®';
		else if ( entity == 'deg' ) outStr += '°';
		else if ( entity == 'raquo' ) outStr += '»';
		else if ( entity == 'iquest' ) outStr += '¿';
		else if ( entity == 'Agrave' ) outStr += 'À';
		else if ( entity == 'Aacute' ) outStr += 'Á';
		else if ( entity == 'Acirc' ) outStr += 'Â';
		else if ( entity == 'Atilde' ) outStr += 'Ã';
		else if ( entity == 'Auml' ) outStr += 'Ä';
		else if ( entity == 'Aring' ) outStr += 'Å';
		else if ( entity == 'AElig' ) outStr += 'Æ';
		else if ( entity == 'Ccedil' ) outStr += 'Ç';
		else if ( entity == 'Egrave' ) outStr += 'È';
		else if ( entity == 'Eacute' ) outStr += 'É';
		else if ( entity == 'Ecirc' ) outStr += 'Ê';
		else if ( entity == 'Euml' ) outStr += 'Ë';
		else if ( entity == 'Igrave' ) outStr += 'Ì';
		else if ( entity == 'Iacute' ) outStr += 'Í';
		else if ( entity == 'Icirc' ) outStr += 'Î';
		else if ( entity == 'Iuml' ) outStr += 'Ï';
		else if ( entity == 'Ntilde' ) outStr += 'Ñ';
		else if ( entity == 'Ograve' ) outStr += 'Ò';
		else if ( entity == 'Oacute' ) outStr += 'Ó';
		else if ( entity == 'Ocirc' ) outStr += 'Ô';
		else if ( entity == 'Otilde' ) outStr += 'Õ';
		else if ( entity == 'Ouml' ) outStr += 'Ö';
		else if ( entity == 'Oslash' ) outStr += 'Ø';
		else if ( entity == 'Ugrave' ) outStr += 'Ù';
		else if ( entity == 'Uacute' ) outStr += 'Ú';
		else if ( entity == 'Ucirc' ) outStr += 'Û';
		else if ( entity == 'Uuml' ) outStr += 'Ü';
		else if ( entity == 'Yacute' ) outStr += 'Ý';
		else if ( entity == 'szlig' ) outStr += 'ß';
		else if ( entity == 'agrave' ) outStr += 'à';
		else if ( entity == 'aacute' ) outStr += 'á';
		else if ( entity == 'acirc' ) outStr += 'â';
		else if ( entity == 'atilde' ) outStr += 'ã';
		else if ( entity == 'auml' ) outStr += 'ä';
		else if ( entity == 'aring' ) outStr += 'å';
		else if ( entity == 'aelig' ) outStr += 'æ';
		else if ( entity == 'ccedil' ) outStr += 'ç';
		else if ( entity == 'egrave' ) outStr += 'è';
		else if ( entity == 'eacute' ) outStr += 'é';
		else if ( entity == 'ecirc' ) outStr += 'ê';
		else if ( entity == 'euml' ) outStr += 'ë';
		else if ( entity == 'igrave' ) outStr += 'ì';
		else if ( entity == 'iacute' ) outStr += 'í';
		else if ( entity == 'icirc' ) outStr += 'î';
		else if ( entity == 'iuml' ) outStr += 'ï';
		else if ( entity == 'ntilde' ) outStr += 'ñ';
		else if ( entity == 'ograve' ) outStr += 'ò';
		else if ( entity == 'oacute' ) outStr += 'ó';
		else if ( entity == 'ocirc' ) outStr += 'ô';
		else if ( entity == 'otilde' ) outStr += 'õ';
		else if ( entity == 'ouml' ) outStr += 'ö';
		else if ( entity == 'oslash' ) outStr += 'ø';
		else if ( entity == 'ugrave' ) outStr += 'ù';
		else if ( entity == 'uacute' ) outStr += 'ú';
		else if ( entity == 'ucirc' ) outStr += 'û';
		else if ( entity == 'uuml' ) outStr += 'ü';
		else if ( entity == 'yacute' ) outStr += 'ý';
		else if ( entity == 'yuml' ) outStr += 'ÿ';
		else if ( entity == 'nbsp' ) outStr += ' ';
		else if ( entity == 'lt' ) outStr += '<';
		else if ( entity == 'gt' ) outStr += '>';
		else if ( entity == 'amp' ) outStr += '&';
		else outStr += '&' + entity + ';';
		i += entity.length + 1;
		}
	    }
	}
    return outStr;
    }


function ClustererDeEntityize( inStr )
    {
    var outStr = '';
    for ( var i = 0; i < inStr.length; ++i )
	{
	var c = inStr.charAt( i );
	if ( c != '&' )
	    outStr += c;
	else
	    {
	    var semi = inStr.indexOf( ';', i );
	    if ( semi != -1 )
		i = semi;
	    }
	}
    return outStr;
    }


function ClustererDeElementize( inStr )
    {
    var outStr = '';
    for ( var i = 0; i < inStr.length; ++i )
	{
	var c = inStr.charAt( i );
	if ( c != '<' )
	    outStr += c;
	else
	    {
	    var gt = inStr.indexOf( '>', i );
	    if ( gt != -1 )
		i = gt;
	    }
	}
    return outStr;
    }


function ClustererDeHtmlize( str )
    {
    return ClustererDeEntityize( ClustererEntityToIso8859( ClustererDeElementize( str ) ) );
    }
