var Sui = {
        ready: (callback) => {
            document.addEventListener("DOMContentLoaded", function() {
                callback();
            }, false);
        },
        select: (selector) => {
            return document.querySelectorAll(selector);
        },
        link: (node) => {
            return (actuator) => {
                let update = function(endpoint, method, props) {
                    Sui.http.ajax({
                        method: method,
                        endpoint: node.api[endpoint] + (props ? props.join('/') : ''),
                        cache: false
                    }, actuator.onResponse || null);
                };
                Sui.select(actuator.selector).forEach( (domEl) =>{
                    let handle = function(event) {
                        update.call(this, 
                            actuator.api, 
                            'GET', 
                            actuator.data ? 
                                actuator.data.call(this) : [this.value]
                        );
                    }
                    $(domEl).on(actuator.event, handle) 
                });
            };
        },
        util: {
            
            /**
             * serialize a flat json object
             */
            serialize: (obj) => {
                var str = [];
                for(var p in obj){
                    str.push(encodeURIComponent(p) + "=" + encodeURIComponent(obj[p]));
                }
                return str.join("&");
            }
        },      
        http: {
    
            /**
             * ajax request
             * {
             *      method: <'GET', 'POST', whatever >,
             *      endpoint: <URL to the service endpoint>,
             *      async: <true or false>, (default true)
             *      data: <json object with data to transmit>,
             *      cache: <true or false> (default false)
             *  }
             */
            ajax: (config, callback) => {
                var cache = config.cache || false;
                var data = config.data || {};
                if(!cache) {
                    data['_'] = new Date().getTime();
                }
                var serializedData =  Sui.util.serialize(data);
                var endPointUrl = (config.method === 'GET' || config.method === 'DELETE') && data ? config.endpoint+'?'+serializedData : config.endpoint;
                var postData = config.method === 'POST' || config.method === 'PUT' ? serializedData : null;
    
                var request = new XMLHttpRequest();
                request.open(config.method, endPointUrl, config.async || true);
                request.onreadystatechange = function () {
                    // TODO handle response properly
                    callback ? callback(request.responseText, request.status) : undefined;
                };
                request.send(postData);
            }
        }
    };