var UploadProgress = {
  uploading: null,
  monitor: function(upid,progress_bar) {
    if(!this.periodicExecuter) {
      this.periodicExecuter = new PeriodicalExecuter(function() {
        if(!UploadProgress.uploading) return;
        new Ajax.Request('/progress?upload_id=' + upid);
      }, 1);
    }
    this.uploading = true;
    this.progress_bar = progress_bar;
    this.progress_bar.reset();
    $('results').innerHTML = '<small>Upload is starting...</small>';
    $('progress_bar').show();
  },

  update: function(total, current) {
    if(!this.uploading) return;
    var status = current / total;
    this.progress_bar.setProgress(parseInt(status.toPercentage()));
    $('results').innerHTML   = "<small>" + current.toHumanSize() + ' of ' + total.toHumanSize() + " uploaded.</small>";
    
  },
  
  finish: function() {
    this.uploading = false;
    $('results').innerHTML = '<small>finished!</small>';
    $('progress_bar').hide(); 
  },
  
  cancel: function(msg) {
    if(!this.uploading) return;
    this.uploading = false;
  },
  
  
  FileField: {
    add: function() {
      new Insertion.Bottom('file-fields', '<p style="display:none"><input id="data" name="data" type="file" /> <a href="#" onclick="UploadProgress.FileField.remove(this);return false;">x</a></p>')
      $$('#file-fields p').last().visualEffect('blind_down', {duration:0.3});
    },
    
    remove: function(anchor) {
      anchor.parentNode.visualEffect('drop_out', {duration:0.25});
    }
  }
}

Number.prototype.bytes     = function() { return this; };
Number.prototype.kilobytes = function() { return this *  1024; };
Number.prototype.megabytes = function() { return this * (1024).kilobytes(); };
Number.prototype.gigabytes = function() { return this * (1024).megabytes(); };
Number.prototype.terabytes = function() { return this * (1024).gigabytes(); };
Number.prototype.petabytes = function() { return this * (1024).terabytes(); };
Number.prototype.exabytes =  function() { return this * (1024).petabytes(); };
['byte', 'kilobyte', 'megabyte', 'gigabyte', 'terabyte', 'petabyte', 'exabyte'].each(function(meth) {
  Number.prototype[meth] = Number.prototype[meth+'s'];
});

Number.prototype.toPrecision = function() {
  var precision = arguments[0] || 2;
  var s         = Math.round(this * Math.pow(10, precision)).toString();
  var pos       = s.length - precision;
  var last      = s.substr(pos, precision);
  return s.substr(0, pos) + (last.match("^0{" + precision + "}$") ? '' : '.' + last);
}

// (1/10).toPercentage()
// # => '10'
Number.prototype.toPercentage = function() {
  return Math.round(this * 100);
}

Number.prototype.toHumanSize = function() {
  if(this < (1).kilobyte())  return this + " Bytes";
  if(this < (1).megabyte())  return (this / (1).kilobyte()).toPrecision()  + ' KB';
  if(this < (1).gigabytes()) return (this / (1).megabyte()).toPrecision()  + ' MB';
  if(this < (1).terabytes()) return (this / (1).gigabytes()).toPrecision() + ' GB';
  if(this < (1).petabytes()) return (this / (1).terabytes()).toPrecision() + ' TB';
  if(this < (1).exabytes())  return (this / (1).petabytes()).toPrecision() + ' PB';
                             return (this / (1).exabytes()).toPrecision()  + ' EB';
}