var map;
var markers = [];
var infowindow;

function retrieveData() {
  var query = "PREFIX : <http://dbpedia.org/resource/> PREFIX dbp: <http://dbpedia.org/ontology/> PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> PREFIX dbpprop: <http://dbpedia.org/property/> SELECT ?event ?date ?place ?lat_lng WHERE { ?event rdf:type dbp:Event . OPTIONAL { ?event dbp:place ?place . ?place grs:point ?lat_lng } OPTIONAL { ?event dbp:date ?date .} FILTER ( ?date >= '1538-03-25'^^xsd:date && ?date < '1612-02-06'^^xsd:date )} GROUP BY ?event ?date ?place";
  
  var url = 'http://dbpedia.org/sparql?default-graph-uri=http%3A%2F%2Fdbpedia.org&query=' + encodeURIComponent(query) + '&output=json';

  console.log(url);
  
  $.ajax({			 
    url: url,
    dataType: "json",
    success: function (data) {
      $('#raw_output').text(JSON.stringify(data, null, 3));

      deleteMarkers();
      show_events(data["results"]["bindings"]);
    },
    error: function(e) {}
  });
}

function init() {
  var mapOptions = {
    center: new google.maps.LatLng(0.0, 0.0),
    minZoom: 2,
    zoom: 2,
    mapTypeId: google.maps.MapTypeId.ROADMAP
  };

  map = new google.maps.Map(document.getElementById("map-canvas"), mapOptions);
  infowindow = new google.maps.InfoWindow();
}

function show_events(data) {
  infowindow = new google.maps.InfoWindow();

  for (i = 0; i < data.length; i++) {
    if (data[i]["lat_lng"] != null) {
      var lat_lng = data[i]["lat_lng"]["value"];
      var array = lat_lng.split(" ");

      var title = data[i]["event"]["value"].split("/");
      title = title[4].replace(/_/g, "");

      var latlng = new google.maps.LatLng(array[0], array[1]);
      var content = data[i]["event"]["value"].split("/")[4].replace(/_/g, " ");

      var marker = new google.maps.Marker({
        position: latlng,
        map: map,
        content: content
      })

      markers.push(marker);

      google.maps.event.addListener(marker, 'click', function() {
        infowindow.open(map, this);
        infowindow.setContent(this.content);
      });
    }
  }
}

function deleteMarkers() {
  setAllMap(null);
  markers = [];
}
function setAllMap(map) {
  for (var i = 0; i < markers.length; i++) {
    markers[i].setMap(map);
  }
}