IriSP.ArrowWidget = function(Popcorn, config, Serializer) {

  IriSP.Widget.call(this, Popcorn, config, Serializer);

  this._oldAnnotation = null;

  this._blockArrow = false;

};

IriSP.ArrowWidget.prototype = new IriSP.Widget();

IriSP.ArrowWidget.prototype.clear = function() {

};

IriSP.ArrowWidget.prototype.clearWidget = function() {

};

IriSP.ArrowWidget.prototype.draw = function() {

  var templ = Mustache.to_html(IriSP.arrowWidget_template, {});

  this.selector.append(templ);

  this._Popcorn.listen("timeupdate", IriSP.wrap(this, this.timeUpdateHandler));

  this._Popcorn.listen("IriSP.ArrowWidget.blockArrow", IriSP.wrap(this, this.blockArrow));

  this._Popcorn.listen("IriSP.ArrowWidget.releaseArrow", IriSP.wrap(this, this.releaseArrow));

};

IriSP.ArrowWidget.prototype.timeUpdateHandler = function(percents) {

  if (this._blockArrow)

    return;

  var currentTime = this._Popcorn.currentTime();

  var currentAnnotation = this._serializer.currentAnnotations(currentTime)[0]; // FIXME : use the others ?

  /* move the arrow only if the current annotation changes */

  if (currentAnnotation != this._oldAnnotation) {

    var begin = (+ currentAnnotation.begin) / 1000;

    var end = (+ currentAnnotation.end) / 1000;

    var duration = +this._serializer.currentMedia().meta["dc:duration"] / 1000;

    var middle_time = (begin + end) / 2;

    var percents = middle_time / duration;

    // we need to apply a fix because the arrow has a certain length

    // it's half the length of the arrow (27 / 2). We need to convert

    // it in percents though.

    var totalWidth = this.selector.width();

    var pixels = percents * totalWidth;

    var correction = (27 / 2);

    var corrected_pixels = pixels - correction;

    /* make sure that the arrow is aligned with the pattern

       of the widget under it */

    if (corrected_pixels % 3 != 0)

      corrected_pixels -= (corrected_pixels % 3 - 1);

    /* don't move out of the screen */

    if (corrected_pixels <= 0)

      corrected_pixels = 0;

    if (corrected_pixels <= 15) {

      var left_edge_img_templ = IriSP.templToHTML("url('{{img_dir}}/left_edge_arrow.png')"); 

      this.selector.children(".Ldt-arrowWidget").css("background-image", left_edge_img_templ); 

    } else if (corrected_pixels >= totalWidth - 25) {

      var right_edge_img_templ = IriSP.templToHTML("url('{{img_dir}}/right_edge_arrow.png')"); 

      this.selector.children(".Ldt-arrowWidget").css("background-image", right_edge_img_templ);

    } else {

      var img_templ = IriSP.templToHTML("url('{{img_dir}}/arrow.png')"); 

      this.selector.children(".Ldt-arrowWidget").css("background-image", img_templ);

    }

    this.selector.children(".Ldt-arrowWidget").animate({"left" : corrected_pixels + "px"});

    this._oldAnnotation = currentAnnotation;

  }

};

/** Block the arrow for instance when the user is annotating */

IriSP.ArrowWidget.prototype.blockArrow = function() {

  this._blockArrow = true;

};

IriSP.ArrowWidget.prototype.releaseArrow = function() {

  this._blockArrow = false;   

};