szurubooru/public_html/js/Controls/FileDropper.js

var App = App || {};
App.Controls = App.Controls || {};

App.Controls.FileDropper = function($fileInput) {
	var _ = App.DI.get('_');
	var jQuery = App.DI.get('jQuery');

	var options = {
		onChange: null,
		setNames: false,
	};

	var $dropDiv = jQuery('<div class="file-handler"></div>');
	var allowMultiple = $fileInput.attr('multiple');
	$dropDiv.html((allowMultiple ? 'Drop files here!' : 'Drop file here!') + '<br/>Or just click on this box.');
	$dropDiv.insertBefore($fileInput);
	$fileInput.attr('multiple', allowMultiple);
	$fileInput.hide();

	$fileInput.change(function(e) {
		addFiles(this.files);
	});

	$dropDiv.on('dragenter', function(e) {
		$dropDiv.addClass('active');
	}).on('dragleave', function(e) {
		$dropDiv.removeClass('active');
	}).on('dragover', function(e) {
		e.preventDefault();
	}).on('drop', function(e) {
		e.preventDefault();
		addFiles(e.originalEvent.dataTransfer.files);
	}).on('click', function(e) {
		$fileInput.show().focus().trigger('click').hide();
		$dropDiv.addClass('active');
	});

	function addFiles(files) {
		$dropDiv.removeClass('active');
		if (!allowMultiple && files.length > 1) {
			window.alert('Cannot select multiple files.');
			return;
		}
		if (typeof(options.onChange) !== 'undefined') {
			options.onChange(files);
		}
		if (options.setNames && !allowMultiple) {
			$dropDiv.text(files[0].name);
		}
	}

	function readAsDataURL(file, callback) {
		var reader = new FileReader();
		reader.onloadend = function() {
			callback(reader.result);
		};
		reader.readAsDataURL(file);
	}

	_.extend(options, {
		readAsDataURL: readAsDataURL,
	});

	return options;
};