function sendRequest(data, callBack = null, args = null) {
    var http = new XMLHttpRequest();
    var url = window.location.origin + '/wp-admin/admin-ajax.php';
    http.onreadystatechange = function() {
        if (this.readyState == 4 && this.status == 200) {
            if (callBack) {
                window[callBack](this.responseText, args);
            }
        }
    };
    http.open("POST", url, true);
    http.timeout = 40000;
    data = prepareHttpRequestData('MANABOOM_PUBLIC_REQUEST', data);
    http.send(data);
}

function handleResponse(response, args = null) { // response is a JSON {'status', 'result'}
    response = JSON.parse(response);
    let msgId = 'mana-msg'
    if (args != null && args.msgId) {
        msgId = args.msgId;
    }
    let msg = document.getElementById(msgId);
    let msgBox = msg.querySelectorAll('span')[0];
    msg.classList.add("mana-hide");
    if (response['status'] == 'OK') {
        msgBox.innerHTML = " " + response['result'];
        msg.classList.remove("mana-hide");
        msg.classList.remove('error');
        msg.classList.add('updated');

    } else if (response['status'] == 'ERROR') {
        msgBox.innerHTML = " " + response['result'];
        msg.classList.remove("mana-hide");
        msg.classList.remove('updated');
        msg.classList.add('error');
    } else {
        msgBox.innerHTML = "Invalid response.";
        msg.classList.remove("mana-hide");
    }
}

function prepareHttpRequestData(action, data) {
    let formData = new FormData();
    formData.append('action', action);
    for (key in data) {
        formData.append(key, data[key]);
    }
    return formData;
}

function sendForm(formId) {
    let formToSend = document.getElementById(formId);
    let data = {};
    let msg = document.getElementById('mana-msg');
    let msgBox = document.getElementById('mana-msg-value');
    msgBox.innerHTML = "Connecting...";
    msg.classList.remove("mana-hide");
    Array.prototype.forEach.call(formToSend.elements, function(element) {
        data[element.name] = element.value;
    });
    sendRequest(data, 'handleResponse');
}

function checkDomain(isSubdomain, domain) {
    sendRequest();
}