import $ from 'jquery';
import {isNumber, isObject} from './../../../js/utils/type';
import {eventType} from './../../../js/utils/events';

/**
 * @module Modules
 */

const MS_ONE_DAY = 86400000;
const STORE_DISABLED = Number.NEGATIVE_INFINITY;

const CONFIGS = {
    key: 'ls_CookieNote_storage',
    expire: 30, //days
};



// internally used utilities
// =========================
// getStored : () -> Integer
const getStored = () => {
    // gives back the last timestamp a visitor has visited the page, means it
    // returns a integer value if localStorage is available. otherwise it
    //     returns negative infinity
    var r;
    try {
        r = localStorage.getItem(CONFIGS.key);
        return r == null ? 0 : parseInt(r, 10);
    } catch (exc) {
        return STORE_DISABLED;
    }
}

// setStored : () -> Boolean
const setStored = () => {
    // saves a timestamp into the localStorage which represents the last time
    //     a visitor has accepted the CookieNote. returns 'true' if the
    //     localStorage is available, returns 'false' otherwise
    try {
        localStorage.setItem(CONFIGS.key, +new Date());
        return true;
    } catch (exc) {
        return false;
    }
}





/**
 * The CookieNote module allows to show/hide layers with information about
 *     the use of cookies on the website(s)
 * @class Modules.CookieNote
 * @constructor
 * @param {DOMNode} rootNode The root node of the widget
 * @return {CookieNote} A new instance
 */
class CookieNote {
    constructor(rootNode) {
        this.$rootNode = this.$root = $(rootNode).css({display: 'block'});
        this.$root.on(eventType.CLICK, '[data-action="close"]', CookieNote.accept(this));
    }

    /*
     * Used to remove any CookieNote related DOMNodes if the layer does not
     *     have to be shown
     * @method hide
     * @for Modules.CookieNote
     * @static
     * @param {DOMNode} rootNode The root node to remove
     * @return {jQuery} A jQuery collection containing the removed DOM node
     */
    static hide (rootNode) {
        return $(rootNode).remove();
    }

    /*
     * Used to remove a visible information layer and store the current timestamp
     * @method accept
     * @for Modules.CookieNote
     * @static
     * @param {CookieNote} self The layer instance to manage
     * @return {function} A procedure as event handler function
     */
    static accept (self) {
        return function (event) {
            event.preventDefault();
            CookieNote.hide(self.$root);
            setStored();
        }
    }

    /**
     * Allows to configure global settings for all CookieNote instances
     * @method config
     * @for Modules.CookieNote
     * @static
     * @param {object} options Object of configurable fields
     * @param {integer} options.expiresAfter Number of days the layers keep hidden
     * @return {Module} The CookieNote module itself
     */
    static config (options) {
        if (isObject(options)) {
            CONFIGS.expire = Math.abs(options.expiresAfter || CONFIGS.expire);
            CONFIGS.key = options.storageKey || CONFIGS.key;
        }
    }
    
    static of (node) {
        return new CookieNote({container: node});
    }

    /**
     * Starts the CookieNote module, means it initializes all CookieNote DOM
     *     nodes at once
     * @method startUp
     * @for Modules.CookieNote
     * @static
     * @return {undefined} Nothing
     */
    static startUp () {
        var now = +new Date(),
            last = getStored();

        // getStored() returns Number.NEGATIVE_INFINITY if localStorage is not
        //   available, we use that to indicate a disabled storage and display
        //   the cookie information
        if (last === STORE_DISABLED) {
            return CookieNote.of('[data-widget="CookieNote"]');
        }

        // revisiting user found with elapsed date of expiration, show layer
        if (isNumber(last) && now - last > MS_ONE_DAY * CONFIGS.expiresAfter) {
            return CookieNote.of('[data-widget="CookieNote"]');
        }

        // if none of the above conditions passes, simply remove the whole layer
        //   element from the DOM
        CookieNote.hide('[data-widget="CookieNote"]');
    }
}


export default CookieNote;