function getCookie(name) {
    var cookieValue = null;
    if (document.cookie && document.cookie !== '') {
        var cookies = document.cookie.split(';');
        for (var i = 0; i < cookies.length; i++) {
            var cookie = cookies[i];
            // Does this cookie string begin with the name we want?
            if (cookie.substring(0, name.length + 1) === (name + '=')) {
                cookieValue = decodeURIComponent(cookie.substring(name.length + 1));
                break;
            }
        }
    }
    return cookieValue;
}

function get_price() {
    $.ajax({
        url: "/dtys/info/",
        method: "GET",
        // beforeSend: function(xhr) {
        //     // var csrftoken = getCookie("csrftoken");

        //     // if (csrftoken) {
        //     //     xhr.setRequestHeader("X-CSRFToken", csrftoken);
        //     // }
        // },
        success: function(data, textStatus, jqXHR) {
            // console.log("DTYS data", data);
            if (data.dtys_list.length > 0) {
                var active = data.dtys_list;

                active.forEach(function(i, idx, list) {
                    var product = $("#dtys_product_" + i.id);
                    var add_to_cart_btn = product.find(".add-to-cart");
                    var fake_add_to_cart_btn = product.find(".fake-add-to-cart");

                    if (i.stopped) {
                        product.addClass("stopped");
                        fake_add_to_cart_btn.show();
                        add_to_cart_btn.hide();
                    } else {
                        product.removeClass("stopped");
                        product.find(".price").text(i.current_price);
                        fake_add_to_cart_btn.hide();
                        add_to_cart_btn.show();
                    }
                });
            }
        },
        error: function(jqXHR, textStatus, errorThrow) {
            console.log("что-то пошло не так, сервер не отвечает");
        }
    });
};

var Updater = function(){
    this.params = {
        period:         3000,
        url:            '',
        onModified:     function(data,x,modified){},
        bgPause:        false
    };

    this.interval = null;
    this.ETag = '';
    this.lastModified = '';

    this.init = function(params){
        var me = this;
        this.params = $.extend(this.params, params);

        if(this.params.bgPause){
            $(window).blur(function(){ me.pause() });
            $(window).focus(function(){ me.resume() });
        }
    };

    this.start = function(){
        var me = this;
        this.interval = setInterval(function(){ me.doUpdate() }, this.params.period);
    };

    this.doUpdate = function(){
        var me = this;
        $.ajax(this.params.url, {
            success: function(data,status,x){
                if(me.ETag != x.getResponseHeader('ETag')){
                    me.params.onModified(data,x,me.lastModified);
                    me.lastModified = x.getResponseHeader('Last-Modified');
                }
                me.ETag = x.getResponseHeader('ETag');
            },
            beforeSend: function(x){
                if(me.ETag != '') { x.setRequestHeader('If-None-Match', me.ETag); }
            },
            cache: false
        });
    };

    this.pause = function(){
        clearInterval(this.interval);
        this.interval = null;
    };

    this.resume = function(){
        if(this.interval != null) return;
        this.start();
    };
};

$(function(){
    var upd = new Updater();

    upd.init({
        url: "/dtys/etg/",
        onModified: function(data, x, modified) {
            get_price();
            console.log(data, x, modified);
        }
    });

    upd.start();
});