(function($) {

var opts = {};

$.fn.dropzone = function(options) {

// Extend our default options with those provided.
opts = $.extend( {}, $.fn.dropzone.defaults, options);

var id = this.attr("id");
var dropzone = document.getElementById(id);

log("adding dnd-file-upload functionalities to element with id: " + id);

// hack for safari on windows: due to not supported drop/dragenter/dragover events we have to create a invisible <input type="file" /> tag instead
if ($.client.browser == "Safari" && $.client.os == "Windows") {
var fileInput = $("<input>");
fileInput.attr( {
type : "file"
});
fileInput.bind("change", change);
fileInput.css( {
'opacity' : '0',
'width' : '100%',
'height' : '100%'
});
fileInput.attr("multiple", "multiple");
fileInput.click(function() {
return false;
});
this.append(fileInput);
} else {
dropzone.addEventListener("drop", drop, true);
var jQueryDropzone = $("#" + id);
jQueryDropzone.bind("dragenter", dragenter);
jQueryDropzone.bind("dragover", dragover);
}

return this;
};

$.fn.dropzone.defaults = {
url : "",
method : "POST",
numConcurrentUploads : 3,
printLogs : false,
// update upload speed every second
uploadRateRefreshTime : 1000
};

// invoked when new files are dropped
$.fn.dropzone.newFilesDropped = function() {
};

// invoked when the upload for given file has been started
$.fn.dropzone.uploadStarted = function(fileIndex, file) {
};

// invoked when the upload for given file has been finished
$.fn.dropzone.uploadFinished = function(fileIndex, file, time) {
};

// invoked when the progress for given file has changed
$.fn.dropzone.fileUploadProgressUpdated = function(fileIndex, file,
newProgress) {
};

// invoked when the upload speed of given file has changed
$.fn.dropzone.fileUploadSpeedUpdated = function(fileIndex, file,
KBperSecond) {
};

function dragenter(event) {
event.stopPropagation();
event.preventDefault();
return false;
}

function dragover(event) {
event.stopPropagation();
event.preventDefault();
return false;
}

function drop(event) {
var dt = event.dataTransfer;
var files = dt.files;

event.preventDefault();
uploadFiles(files);

return false;
}

function log(logMsg) {
if (opts.printLogs) {
// console && console.log(logMsg);
}
}
var xhr=false;
function uploadFiles(files) {
$.fn.dropzone.newFilesDropped();
for ( var i = 0; i < files.length; i++) {
var file = files[i];

// create a new xhr object
xhr = new XMLHttpRequest();
var upload = xhr.upload;
upload.fileIndex = i;
upload.fileObj = file;
upload.downloadStartTime = new Date().getTime();
upload.currentStart = upload.downloadStartTime;
upload.currentProgress = 0;
upload.startData = 0;

// add listeners
upload.addEventListener("progress", progress, false);
upload.addEventListener("load", load, false);

xhr.onreadystatechange = alertContents;
xhr.open(opts.method, opts.url);
xhr.setRequestHeader("Cache-Control", "no-cache");
xhr.setRequestHeader("X-Requested-With", "XMLHttpRequest");
xhr.setRequestHeader("X-File-Name", file.fileName);
xhr.setRequestHeader("X-File-Size", file.fileSize);
xhr.setRequestHeader("Content-Type", "multipart/form-data");
xhr.send(file);

$.fn.dropzone.uploadStarted(i, file);
}
}
function alertContents() {
  if (xhr.readyState == 4) {
	 if (xhr.status == 200) {
		result = xhr.responseText;
	    document.getElementById('drop-div').innerHTML += result;
	    var session=document.getElementById('session4script').value;
	    var path=document.getElementById('path4script').value;
	    location.href=path+"index.jsp"+session+"?action=9";
	 } else {
		alert('There was a problem with the request.');
	 }
  }
}
function load(event) {
var now = new Date().getTime();
var timeDiff = now - this.downloadStartTime;
$.fn.dropzone.uploadFinished(this.fileIndex, this.fileObj, timeDiff);
log("finished loading of file " + this.fileIndex);
}

function progress(event) {
if (event.lengthComputable) {
var percentage = Math.round((event.loaded * 100) / event.total);
if (this.currentProgress != percentage) {

// log(this.fileIndex + " --> " + percentage + "%");

this.currentProgress = percentage;
$.fn.dropzone.fileUploadProgressUpdated(this.fileIndex, this.fileObj, this.currentProgress);

var elapsed = new Date().getTime();
var diffTime = elapsed - this.currentStart;
if (diffTime >= opts.uploadRateRefreshTime) {
var diffData = event.loaded - this.startData;
var speed = diffData / diffTime; // in KB/sec

$.fn.dropzone.fileUploadSpeedUpdated(this.fileIndex, this.fileObj, speed);

this.startData = event.loaded;
this.currentStart = elapsed;
}
}
}
}

// invoked when the input field has changed and new files have been dropped
// or selected
function change(event) {
event.preventDefault();

// get all files ...
var files = this.files;

// ... and upload them
uploadFiles(files);
}

})(jQuery);