// Clusterer.js - marker clustering routines for Google Maps apps
//
// Using these routines is very easy.
//
// 1) Load the routines into your code:
//
//        <script src="http://www.acme.com/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.
//
//
// The current version of this code is always available at:
// http://www.acme.com/javascript/
//
//
// Copyright © 2005,2006 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


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

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

    GEvent.addListener(map, 'zoomend', Clusterer.MakeCaller(Clusterer.Display, this));
    GEvent.addListener(map, 'moveend', Clusterer.MakeCaller(Clusterer.Display, this));
    GEvent.addListener(map, 'infowindowclose', Clusterer.MakeCaller(Clusterer.PopDown, this));
};


Clusterer.defaultMaxVisibleMarkers = 25;
Clusterer.defaultGridSize = 6;
Clusterer.defaultMinMarkersPerCluster = 10;
Clusterer.defaultMaxLinesPerInfoBox = 10;

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


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


// Changes the maximum number of visible markers before clustering kicks in.
Clusterer.prototype.SetMaxVisibleMarkers = function (n)
{
    this.maxVisibleMarkers = n;
};


// Sets the minumum number of markers for a cluster.
Clusterer.prototype.SetMinMarkersPerCluster = function (n)
{
    this.minMarkersPerCluster = n;
};


// Sets the maximum number of lines in an info box.
Clusterer.prototype.SetMaxLinesPerInfoBox = function (n)
{
    this.maxLinesPerInfoBox = n;
};


// Call this to add a marker.
Clusterer.prototype.AddMarker = function (marker, title)
{
    if (marker.setMap != null)
        marker.setMap(this.map);

    marker.title = title;
    marker.onMap = false;
    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 (var j = 0; j < this.clusters.length; ++j)
            {
                var cluster = this.clusters[j];
                if (cluster != null)
                {
                    for (var 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);
                        this.clusters[j] = null;
                    }
                    else if (cluster == this.poppedUpCluster)
                        Clusterer.RePop(this);
                }
            }
            this.markers[i] = null;
            break;
        }
    this.DisplayLater();
};


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


Clusterer.Display = function (clusterer)
{
    var i, j, marker, cluster;

    clearTimeout(clusterer.timeout);

    var newZoomLevel = clusterer.map.getZoom();
    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.getBounds();

    // Expand the bounds a little, so things look smoother when scrolling
    // by small amounts.
    var sw = bounds.getSouthWest();
    var ne = bounds.getNorthEast();
    var dx = ne.lng() - sw.lng();
    var dy = ne.lat() - sw.lat();
    if (dx < 300 && dy < 150)
    {
        dx *= 0.10;
        dy *= 0.10;
        bounds = new GLatLngBounds(
                new GLatLng(sw.lat() - dy, sw.lng() - dx),
                new GLatLng(ne.lat() + dy, ne.lng() + dx));
    }

    // 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 (bounds.contains(marker.getPoint()))
                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 && ! bounds.contains(cluster.marker.getPoint()) && 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.getNorthEast().lat() - bounds.getSouthWest().lat();
        var latInc = latRange / clusterer.gridSize;
        var lngInc = latInc / Math.cos(( bounds.getNorthEast().lat() + bounds.getSouthWest().lat() ) / 2.0 * Math.PI / 180.0);
        for (var lat = bounds.getSouthWest().lat(); lat <= bounds.getNorthEast().lat(); lat += latInc)
            for (var lng = bounds.getSouthWest().lng(); lng <= bounds.getNorthEast().lng(); lng += lngInc)
            {
                cluster = new Object();
                cluster.clusterer = clusterer;
                cluster.bounds = new GLatLngBounds(new GLatLng(lat, lng), new GLatLng(lat + latInc, lng + lngInc));
                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 && cluster.bounds.contains(marker.getPoint()))
                    {
                        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.getPoint().lng() );
                        yTotal += ( + marker.getPoint().lat() );
                    }
                }
                var location = new GLatLng(yTotal / cluster.markerCount, xTotal / cluster.markerCount);
                marker = new GMarker(location, { icon: clusterer.icon });
                cluster.marker = marker;
                GEvent.addListener(marker, 'click', Clusterer.MakeCaller(Clusterer.PopUp, 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);
            if (marker.addedToMap != null)
                marker.addedToMap();
            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 && bounds.contains(cluster.marker.getPoint()))
        {
            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.
    Clusterer.RePop(clusterer);
};


Clusterer.PopUp = function (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.getIcon().smallImage != null)
                html += '<img src="' + marker.getIcon().smallImage + '">';
            else
                html += '<img src="' + marker.getIcon().image + '" width="' + ( marker.getIcon().iconSize.width / 2 ) + '" height="' + ( marker.getIcon().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.map.closeInfoWindow();
    cluster.marker.openInfoWindowHtml(html);
    clusterer.poppedUpCluster = cluster;
};


Clusterer.RePop = function (clusterer)
{
    if (clusterer.poppedUpCluster != null)
        Clusterer.PopUp(clusterer.poppedUpCluster);
};


Clusterer.PopDown = function (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;
    }
};


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


// Augment GMarker so it handles markers that have been created but
// not yet addOverlayed.

GMarker.prototype.setMap = function (map)
{
    this.map = map;
};

GMarker.prototype.addedToMap = function ()
{
    this.map = null;
};

GMarker.prototype.origOpenInfoWindow = GMarker.prototype.openInfoWindow;
GMarker.prototype.openInfoWindow = function (node, opts)
{
    if (this.map != null)
        return this.map.openInfoWindow(this.getPoint(), node, opts);
    else
        return this.origOpenInfoWindow(node, opts);
};

GMarker.prototype.origOpenInfoWindowHtml = GMarker.prototype.openInfoWindowHtml;
GMarker.prototype.openInfoWindowHtml = function (html, opts)
{
    if (this.map != null)
        return this.map.openInfoWindowHtml(this.getPoint(), html, opts);
    else
        return this.origOpenInfoWindowHtml(html, opts);
};

GMarker.prototype.origOpenInfoWindowTabs = GMarker.prototype.openInfoWindowTabs;
GMarker.prototype.openInfoWindowTabs = function (tabNodes, opts)
{
    if (this.map != null)
        return this.map.openInfoWindowTabs(this.getPoint(), tabNodes, opts);
    else
        return this.origOpenInfoWindowTabs(tabNodes, opts);
};

GMarker.prototype.origOpenInfoWindowTabsHtml = GMarker.prototype.openInfoWindowTabsHtml;
GMarker.prototype.openInfoWindowTabsHtml = function (tabHtmls, opts)
{
    if (this.map != null)
        return this.map.openInfoWindowTabsHtml(this.getPoint(), tabHtmls, opts);
    else
        return this.origOpenInfoWindowTabsHtml(tabHtmls, opts);
};

GMarker.prototype.origShowMapBlowup = GMarker.prototype.showMapBlowup;
GMarker.prototype.showMapBlowup = function (opts)
{
    if (this.map != null)
        return this.map.showMapBlowup(this.getPoint(), opts);
    else
        return this.origShowMapBlowup(opts);
};