// Store API key;
const CLIENT_API_KEY = 'a5cbba9ef8049f80e856';

// Allowed calls (e.g.: piacter('banner', ...)
const supportedAPI = [
    'init',
    'banner',
    'ad-carousel',
    'ad-self',
    'profile'
];

const apiUrl = 'https://agrarpiacter.agroforum.hu/api/widget';

/**
 The main entry of the application
 */
function app(window) {

    // Default configurations
    let configurations = {
    };

    let globalObject = window[window['AP-Widget']];

    // Get the queued calls from the client
    let queue = globalObject.q;

    // Dispatch calls
    if (queue) {
        // API calls
        for (var i = 0; i < queue.length; i++) {
            apiHandler(queue[i][0], queue[i][1]);
        }
    }

    // Override temporary (until the app loaded) handler for widget's API calls
    globalObject = apiHandler;
    globalObject.configurations = configurations;
}

/**
 Method that handles all API calls
 */
function apiHandler(api, params) {

    // Validate API call
    if (!api) throw Error('API method required');
    api = api.toLowerCase();
    if (supportedAPI.indexOf(api) === -1) throw Error(`Method ${api} is not supported`);

    // Add key to params
    params.key = CLIENT_API_KEY;

    // Get response for the selected API from the server
    let url = apiUrl + '/' + api + '/' + new URLSearchParams(params).toString();
    load(url, function(response) {

        // Dispatch job according to the selected API
        switch (api) {

            case 'banner':
                document.querySelector(params.container).insertAdjacentHTML('afterbegin', response);
                break;

            case 'ad-carousel':
                document.querySelector(params.container).insertAdjacentHTML('afterbegin', response);
                break;

            default:
                console.warn(`Api does not exist: ${api}`);
        }
    })
}

/**
 * Add configuration passed in the init call
 */
function extendObject(a, b) {
    for (var key in b)
        if (b.hasOwnProperty(key))
            a[key] = b[key];
    return a;
}

/**
 * AJAX helper
 */
function load(url, callback) {
    var xhr = new XMLHttpRequest();

    xhr.onreadystatechange = function() {
        if (xhr.readyState === 4) {
            callback(xhr.response);
        }
    };

    xhr.open('GET', url, true);
    xhr.send('');
}

/**
 * Run app
 */
app(window);