/**
 * Ajax upload plugin for jQuery
 * Project page - http://valums.com/ajax-upload/
 * Copyright (c) 2008 Andris Valums, http://valums.com
 * Licensed under the MIT license (http://valums.com/mit-license/)
 */
(function($){
    // we need jQuery to run
    if ( ! $) return;

    /**
     * Function generates unique id
     */        
    var get_uid = function(){
        var uid = 0;
        return function(){
            return uid++;
        }
    }();

    /**
     * button - jQuery element
     * option - hash of options :
     *   action - URL which iframe will use to post data
     *   name - file input name
     *   data - extra data hash to post within the file
     *   onSubmit - callback to fire on file submit
     *   onComplete - callback to fire when iframe has finished loading
     */
    window.Ajax_upload = function(button, options){
        // make sure it is jquery object
        button = $(button);
        
        if (button.size() != 1 ){
            console.error('You passed ', button.size(),' elements to ajax_upload at once');
            return false;
        }
                
        this.button = button;
                
        this.wrapper = null;
        this.form = null;
        this.input = null;
        this.iframe = null;        

        this.disabled = false;
        this.submitting = false;
                
        this.settings = {
            // Location of the server-side upload script
            action: 'upload.php',            
            // File upload name
            name: 'userfile',
            // Additional data to send
            data: {},
            // Callback to fire when user selects file
            // You can return false to cancel upload
            onSubmit: function(file, extension) {},
            // Fired when file upload is completed
            onComplete: function(file, response) {}
        };

        // Merge the users options with our defaults    
        $.extend(this.settings, options);
        
        this.create_wrapper();
        this.create_input();
        
        if (jQuery.browser.msie){
            // fix ie transparent background bug
            this.make_parent_opaque();
        }
        
        this.create_iframe();        
    }
    
    // assigning methods to our class
    Ajax_upload.prototype = {
        set_data : function(data){
            this.settings.data = data;
        },
        disable : function(){
            this.disabled = true;
            if ( ! this.submitting){
                this.input.attr('disabled', true);
                this.button.removeClass('hover');    
            }            
        },
        enable : function(){
            this.disabled = false;
            this.input.attr('disabled', false);                            
        },
        /**
         * Creates wrapper for button and invisible file input
         */
        create_wrapper : function(){
            // Shorten names            
            var button = this.button, wrapper;
            
            wrapper = this.wrapper = $('<div></div>')
                .insertAfter(button)
                .append(button);            

            // wait a bit because of FF bug
            // it can't properly calculate the outerHeight
            setTimeout(function(){
                wrapper.css({
                    position: 'relative'
                    ,display: 'block'
                    ,overflow: 'hidden'

                    // we need dimensions because of ie bug that allows to move 
                    // input outside even if overflow set to hidden                    
                    //,height: button.outerHeight(true)
                    //,width: button.outerWidth(true)
                    ,height: 50
                    ,width: 300
                });                        
            }, 1);
            
            var self = this;
            wrapper.mousemove(function(e){
                // Move the input with the mouse, so the user can't misclick it
                if (!self.input) {
                    return;
                }
                                    
                self.input.css({
                    top: e.pageY - wrapper.offset().top - 5 + 'px'
                    ,left: e.pageX - wrapper.offset().left - 170 + 'px'
                });
            });

    
        },
        /**
         * Creates invisible file input above the button 
         */
        create_input : function(){
            var self = this;

            this.input = 
                $('<input type="file" />')
                .attr('name', this.settings.name)                
                .css({
                    'position' : 'absolute'
                    ,'margin': 0
                    ,'padding': 0
                    ,'width': '220px'
                    ,'height': '10px'                                        
                    ,'opacity': 0                                
                })
                .change(function(){
                    if ($(this).val() == ''){
                        // there is no file
                        return;
                    }
                    
                    // we need to lock "disable" method
                    self.submitting = true;
                    
                    // Submit form when value is changed
                    self.submit();
                    
                    if (self.disabled){
                        self.disable();                    
                    }                        
                    // unlock "disable" method
                    self.submitting = false;                    
                })
                .appendTo(this.wrapper)
                
                // Emulate button hover effect                
                .hover(
                    function(){self.button.addClass('hover');}
                    ,function(){self.button.removeClass('hover');}
                );
                
            if (this.disabled){
                this.input.attr('disabled', true);
            }

        },
        /**
         * Creates iframe with unique name
         */
        create_iframe : function(){
            // unique name
            // We cannot use getTime, because it sometimes return
            // same value in safari :(
            var id = 'valums97hhu' + get_uid();
            
            // create iframe, so we dont need to refresh page
            this.iframe = 
                $('<iframe id="' + id + '" name="' + id + '"></iframe>')
                .css('display', 'none')
                .appendTo('body');                                    
        },
        /**
         * Upload file without refreshing the page
         */
        submit : function(){            
            var self = this, settings = this.settings;            
            
            // get filename from input
            var file = this.file_from_path(this.input.val());            

            // execute user event
            if (settings.onSubmit.call(this, file, this.get_ext(file)) === false){
                // Do not continue if user function returns false                        
                return;
            }            

            this.create_form();
            this.input.appendTo(this.form);            
            this.form.submit();            
            
            this.input.remove(); this.input = null;
            this.form.remove();    this.form = null;

            this.submitting = false;
            
            // create new input
            this.create_input();    
    
            var iframe = this.iframe;
            iframe.load(function(){
                var response = iframe.contents().find('body').html();    
        
                settings.onComplete.call(self, file, response);                
                /// Workaround for FF2 bug, which causes cursor to be in busy state after post.
                setTimeout(function(){
                    iframe.remove();
                }, 1);                
            });
            
            // Create new iframe, so we can have multiple uploads at once
            this.create_iframe();        
        },        
        /**
         * Creates form, that will be submitted to iframe
         */
        create_form : function(){
            // method, enctype must be specified here
            // because changing this attr on the fly is not allowed in IE 6/7
            this.form = 
                $('<form method="post" enctype="multipart/form-data"></form>')                
                .attr({
                    "action" : this.settings.action
                    ,"target" : this.iframe.attr('name')                    
                })
                .appendTo('body');            
            
            // Create hidden input element for each data key
            for (var i in this.settings.data){
                $('<input type="hidden" />')
                    .appendTo(this.form)
                    .attr({
                        'name': i
                        ,'value': this.settings.data[i]
                    });
            }
        },        
        file_from_path : function(file){
            return file.replace(/.*(\/|\\)/, "");            
        },
        get_ext : function(file){
            return (/[.]/.exec(file)) ? /[^.]+$/.exec(file.toLowerCase()) : '';
        },
        make_parent_opaque : function(){
            // ie transparent background bug
            this.button.add(this.button.parents()).each(function(){                
                var color = $(this).css('backgroundColor');
                var image = $(this).css('backgroundImage');
    
                if ( color != 'transparent' ||  image != 'none'){
                    $(this).css('opacity', 1);
                    return false;
                }
            });            
        }
        
    };
})(jQuery);