function get_filename(){
  var basename = $("#url").val().replace(/^.*\//,"").replace(/\..*$/,"").replace(/[^-_ a-zA-Z0-9]/g,"")
  var username = user.username
  var filename = basename + "-" + username + "-" + (+new Date()) + ".gif"
  return filename.replace(/ /g,"_").replace(/-+/g,"-")
}
function save (){
  if (! lastGif) return;
  var filename = get_filename()
  var blob = dataUriToBlob(lastGif)
  saveAs(blob, filename);
}
function saveJSON (data, filename) {
  var bytes = JSON.stringify(data)
  var buf = new ArrayBuffer(bytes.length);
  var arr = new Uint8Array(buf);
  for (var i = 0; i < bytes.length; i++) {
    arr[i] = bytes.charCodeAt(i);
  }

  var blob = new Blob([arr], { type: "text/json" });
  blob.slice = blob.slice || blob.webkitSlice;
  
  saveAs(blob, filename);
}

function upload(uri, filename, tag){
  filename = filename || get_filename()
  uri = uri || lastGif
  tag = tag || "shader"
  var blob = dataUriToBlob(uri)
  uploadImage({
    blob: blob,
    filename: filename,
    username: user.username,
    tag: tag,
    success: function(data){

      // data.url
      // data.filesize
      // data.success

      console.log(data);
      $("#uploaded-url").show().focus().val(data.url)
      $("#uploaded-url + br").show()
      status && status("uploaded");
    },
    error: function(data){
      console.log(data)
      status("error uploading: " + data.error)
    }
  });
}