define(
        [
                'knockout', 'jquery', 'leaflet', 'text!./map.html'
        ],
        function(ko, jquery, leaflet, htmlString) {

            function ViewModel(params, componentInfo) {
                var self = this;

                self.element = componentInfo.element;
                self.followAircraft = ko.observable(true);

                self.altitude = ko.observable(0).extend({
                    fgprop : 'altitude'
                });

                self.tas = ko.observable(0).extend({
                    fgprop : 'groundspeed'
                });

                self.heading = ko.observable(0).extend({
                    fgprop : 'heading'
                });

                $(self.element).height($(self.element).width());

                self.map = leaflet.map(self.element).setView([
                        53.5, 10.0
                ], 13);

                var osmLayer = new leaflet.TileLayer('http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png', {
                    maxZoom : 18,
                    attribution : 'Map data © <a href="http://openstreetmap.org">OpenStreetMap</a> contributors'
                });
                self.map.addLayer(osmLayer);

                L.RotatedMarker = L.Marker.extend({
                    options : {
                        angle : 0
                    },

                    _setPos : function(pos) {
                        L.Marker.prototype._setPos.call(this, pos);
                        this._icon.style[L.DomUtil.TRANSFORM] += ' rotate(' + this.options.angle + 'deg)';
                    }
                });

                L.AircraftMarker = L.RotatedMarker
                        .extend({
                            options : {
                                angle : 0,
                                clickable : false,
                                keyboard : false,
                                icon : L
                                        .divIcon({
                                            iconSize : [
                                                    60, 60
                                            ],
                                            iconAnchor : [
                                                    30, 30
                                            ],
                                            className : 'aircraft-marker-icon',
                                            html : '<svg xmlns="http://www.w3.org/2000/svg" height="100%" width="100%" viewBox="0 0 500 500" preserveAspectRatio="xMinYMin meet"><path d="M250.2,59.002c11.001,0,20.176,9.165,20.176,20.777v122.24l171.12,95.954v42.779l-171.12-49.501v89.227l40.337,29.946v35.446l-60.52-20.18-60.502,20.166v-35.45l40.341-29.946v-89.227l-171.14,49.51v-42.779l171.14-95.954v-122.24c0-11.612,9.15-20.777,20.16-20.777z" fill="#808080" stroke="black" stroke-width="5"/></svg>',
                                        }),
                                zIndexOffset : 10000,
                                updateInterval : 100,
                            },

                            initialize : function(latlng, options) {
                                L.RotatedMarker.prototype.initialize(latlng, options);
                                L.Util.setOptions(this, options);
                            },

                            onAdd : function(map) {
                                L.RotatedMarker.prototype.onAdd.call(this, map);
                                this.popup = L.popup({
                                    autoPan : false,
                                    keepInView : false,
                                    closeButton : false,
                                    className : 'aircraft-marker-popup',
                                    closeOnClick : false,
                                    maxWidth : 200,
                                    minWidth : 120,
                                    offset : [
                                            30, 30
                                    ],
                                }, this);
                                this.popup
                                        .setContent( '<div class="aircraft-marker aircraft-marker-altitude"><span data-bind="text: altitude().toFixed(0)"></span>ft</div>'
                                                + '<div class="aircraft-marker aircraft-marker-heading"><span data-bind="text: heading().toFixed(0)"></span>&deg</div>'
                                                + '<div class="aircraft-marker aircraft-marker-tas"><span data-bind="text: tas().toFixed(0)"></span>kt</div><div style="clear: both"/>'
                                            );
                                this.bindPopup(this.popup);
                                this.addTo(this._map);
                                this.openPopup();
                            },

                            onRemove : function(map) {
                                if (this.timeoutid != null)
                                    clearTimeout(this.timeoutid);
                                L.RotatedMarker.prototype.onRemove.call(this, map);
                            },

                        });

                L.aircraftMarker = function(latlng, options) {
                    return new L.AircraftMarker(latlng, options);
                }

                var aircraftMarker = L.aircraftMarker(self.map.getCenter());

                aircraftMarker.addTo(self.map);

                var aircraftTrack = L.polyline([], {
                    color : 'red'
                }).addTo(self.map);

                self.latitude = ko.observable(0).extend({
                    fgprop : 'latitude'
                });

                self.longitude = ko.observable(0).extend({
                    fgprop : 'longitude'
                });

                self.heading = ko.observable(0).extend({
                    fgprop : 'heading'
                });

                self.position = ko.computed(function() {
                    return leaflet.latLng(self.latitude(), self.longitude());
                }).extend({
                    rateLimit : 200
                });

                self.position.subscribe(function(newValue) {
                    aircraftMarker.setLatLng(newValue);
                });

                self.heading.subscribe(function(newValue) {
                    aircraftMarker.options.angle = newValue;
                });

                self.mapCenter = ko.computed(function() {
                    return leaflet.latLng(self.latitude(), self.longitude());
                }).extend({
                    rateLimit : 2000
                });

                self.aircraftTrailLength = 60;

                self.mapCenter.subscribe(function(newValue) {
                    if (self.followAircraft()) {
                        self.map.setView(newValue);
                    }

                    var trail = aircraftTrack.getLatLngs();
                    while (trail.length > self.aircraftTrailLength)
                        trail.shift();
                    trail.push(newValue);
                    aircraftTrack.setLatLngs(trail);
                });
            }

            // Return component definition
            return {
                viewModel : {
                    createViewModel : function(params, componentInfo) {
                        return new ViewModel(params, componentInfo);
                    },
                },
                template : htmlString,
            };
        });