/* $Id */
/**
 * Chunk Markerloader
 * This is a simple marker loader to load markers from the map settings array in chunks, 
 * so that the browser doesn't appear to have crashed while it freezes the UI and loads many markers.
 */

// Add a gmap handler
Drupal.gmap.addHandler('gmap', function(elem) {
  var obj = this;
  var markers = obj.vars.markers;

  if (markers) {
    // Start loading chunks of markers as soon as the icons are ready.
    obj.bind('iconsready', function(){ obj.loadChunkMarkers(); });

    // The number of markers to add in each chunk.
    var chunkSize = Drupal.settings.loadChunkMarkers.chunkSize;
    var chunkIndex = 0;

    // Loads chunks of markers, recursively, until there are no more markers left.
    obj.loadChunkMarkers = function() {
      // For each marker in this chunk.
      for (var i = chunkIndex * chunkSize; i < markers.length; i++) {
        if (i >= chunkIndex * chunkSize + chunkSize) {
          // We've reached the end of this chunk, kill the loop.
          break;
        }

        // Get this marker.
        var marker = markers[i];

        // Clean the marker before passing around for bindings to modify.
        if (!marker.opts) marker.opts = {};
        obj.change('preparemarker',-1,marker);

        // Add the marker.
        obj.change('addmarker',-1,marker);
      }

      // Increment the chunkIndex counter.
      chunkIndex++;

      // Are there more chunks to load?
      if (i < markers.length) {
        // Wait a few seconds then invoke loadChunkMarkers recursively.
        setTimeout(function(){ obj.loadChunkMarkers(); }, Drupal.settings.loadChunkMarkers.chunkDelay);
      }
      else {
        // We've finished loading all of the markers.  Let the bindings know.
        obj.change('markersready',-1);
      }
    }
  }
});