(function(addon) {

    var component;

    if (window.UIkit) {
        component = addon(UIkit);
    }

    if (typeof define == "function" && define.amd) {
        define("uikit-upload", ["uikit"], function(){
            return component || addon(UIkit);
        });
    }

})(function(UI){

    "use strict";

    UI.component('uploadSelect', {

        init: function() {

            var $this = this;

            this.on("change", function() {
                xhrupload($this.element[0].files, $this.options);
                var twin = $this.element.clone(true).data('uploadSelect', $this);
                $this.element.replaceWith(twin);
                $this.element = twin;
            });
        }
    });

    UI.component('uploadDrop', {

        defaults: {
            'dragoverClass': 'uk-dragover'
        },

        init: function() {

            var $this = this, hasdragCls = false;

            this.on("drop", function(e){

                if (e.originalEvent.dataTransfer && e.originalEvent.dataTransfer.files) {

                    e.stopPropagation();
                    e.preventDefault();

                    $this.element.removeClass($this.options.dragoverClass);
                    $this.element.trigger('dropped.uk.upload', [e.originalEvent.dataTransfer.files]);

                    xhrupload(e.originalEvent.dataTransfer.files, $this.options);
                }

            }).on("dragenter", function(e){
                e.stopPropagation();
                e.preventDefault();
            }).on("dragover", function(e){
                e.stopPropagation();
                e.preventDefault();

                if (!hasdragCls) {
                    $this.element.addClass($this.options.dragoverClass);
                    hasdragCls = true;
                }
            }).on("dragleave", function(e){
                e.stopPropagation();
                e.preventDefault();
                $this.element.removeClass($this.options.dragoverClass);
                hasdragCls = false;
            });
        }
    });


    UI.support.ajaxupload = (function() {

        function supportFileAPI() {
            var fi = document.createElement('INPUT'); fi.type = 'file'; return 'files' in fi;
        }

        function supportAjaxUploadProgressEvents() {
            var xhr = new XMLHttpRequest(); return !! (xhr && ('upload' in xhr) && ('onprogress' in xhr.upload));
        }

        function supportFormData() {
            return !! window.FormData;
        }

        return supportFileAPI() && supportAjaxUploadProgressEvents() && supportFormData();
    })();


    function xhrupload(files, settings) {

        if (!UI.support.ajaxupload){
            return this;
        }

        settings = UI.$.extend({}, xhrupload.defaults, settings);

        if (!files.length){
            return;
        }

        if (settings.allow !== '*.*') {

            for(var i=0,file;file=files[i];i++) {

                if(!matchName(settings.allow, file.name)) {

                    if(typeof(settings.notallowed) == 'string') {
                       alert(settings.notallowed);
                    } else {
                       settings.notallowed(file, settings);
                    }
                    return;
                }
            }
        }

        var complete = settings.complete;

        if (settings.single){

            var count    = files.length,
                uploaded = 0,
                allow    = true;

                settings.beforeAll(files);

                settings.complete = function(response, xhr){

                    uploaded = uploaded + 1;

                    complete(response, xhr);

                    if (settings.filelimit && uploaded >= settings.filelimit){
                        allow = false;
                    }

                    if (allow && uploaded<count){
                        upload([files[uploaded]], settings);
                    } else {
                        settings.allcomplete(response, xhr);
                    }
                };

                upload([files[0]], settings);

        } else {

            settings.complete = function(response, xhr){
                complete(response, xhr);
                settings.allcomplete(response, xhr);
            };

            upload(files, settings);
        }

        function upload(files, settings){

            // upload all at once
            var formData = new FormData(), xhr = new XMLHttpRequest();

            if (settings.before(settings, files)===false) return;

            for (var i = 0, f; f = files[i]; i++) { formData.append(settings.param, f); }
            for (var p in settings.params) { formData.append(p, settings.params[p]); }

            // Add any event handlers here...
            xhr.upload.addEventListener("progress", function(e){
                var percent = (e.loaded / e.total)*100;
                settings.progress(percent, e);
            }, false);

            xhr.addEventListener("loadstart", function(e){ settings.loadstart(e); }, false);
            xhr.addEventListener("load",      function(e){ settings.load(e);      }, false);
            xhr.addEventListener("loadend",   function(e){ settings.loadend(e);   }, false);
            xhr.addEventListener("error",     function(e){ settings.error(e);     }, false);
            xhr.addEventListener("abort",     function(e){ settings.abort(e);     }, false);

            xhr.open(settings.method, settings.action, true);

            if (settings.type=="json") {
                xhr.setRequestHeader("Accept", "application/json");
            }

            xhr.onreadystatechange = function() {

                settings.readystatechange(xhr);

                if (xhr.readyState==4){

                    var response = xhr.responseText;

                    if (settings.type=="json") {
                        try {
                            response = UI.$.parseJSON(response);
                        } catch(e) {
                            response = false;
                        }
                    }

                    settings.complete(response, xhr);
                }
            };
            settings.beforeSend(xhr);
            xhr.send(formData);
        }
    }

    xhrupload.defaults = {
        'action': '',
        'single': true,
        'method': 'POST',
        'param' : 'files[]',
        'params': {},
        'allow' : '*.*',
        'type'  : 'text',
        'filelimit': false,

        // events
        'before'          : function(o){},
        'beforeSend'      : function(xhr){},
        'beforeAll'       : function(){},
        'loadstart'       : function(){},
        'load'            : function(){},
        'loadend'         : function(){},
        'error'           : function(){},
        'abort'           : function(){},
        'progress'        : function(){},
        'complete'        : function(){},
        'allcomplete'     : function(){},
        'readystatechange': function(){},
        'notallowed'      : function(file, settings){ alert('Only the following file types are allowed: '+settings.allow); }
    };

    function matchName(pattern, path) {

        var parsedPattern = '^' + pattern.replace(/\//g, '\\/').
            replace(/\*\*/g, '(\\/[^\\/]+)*').
            replace(/\*/g, '[^\\/]+').
            replace(/((?!\\))\?/g, '$1.') + '$';

        parsedPattern = '^' + parsedPattern + '$';

        return (path.match(new RegExp(parsedPattern, 'i')) !== null);
    }

    UI.Utils.xhrupload = xhrupload;

    return xhrupload;
});