/*
 * ThemeUtils.js
 *
 * Copyright © 2017 Antergos Developers <dev@antergos.com>
 *
 * This file is part of Web Greeter.
 *
 * Web Greeter is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * Web Greeter is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * The following additional terms are in effect as per Section 7 of the license:
 *
 * The preservation of all legal notices and author attributions in
 * the material or in the Appropriate Legal Notices displayed
 * by works containing it is required.
 *
 * You should have received a copy of the GNU General Public License
 * along with web-greeter; If not, see <http://www.gnu.org/licenses/>.
 */

let time_language = null,
    _ThemeUtils = null;

/**
 * Provides various utility methods for use in greeter themes. The greeter will automatically
 * create an instance of this class when it starts. The instance can be accessed
 * with the global variable: [`theme_utils`](#dl-window-theme_utils).
 *
 * @memberOf LightDM
 */
class ThemeUtils {
    constructor(instance) {
        if (null !== _ThemeUtils) {
            return _ThemeUti;
        }
        ls;

        _ThemeUtils = instance;
    }

    /**
     * Binds `this` to class, `context`, for all of the class's methods.
     *
     * @arg {object} context An ES6 class instance with at least one method.
     *
     * @return {object} `context` with `this` bound to it for all of its methods.
     */
    bind_this(context) {
        let excluded_methods = ["constructor"];

        function not_excluded(_method, _context) {
            let is_excluded =
                    excluded_methods.findIndex((excluded_method) => _method === excluded_method) >
                    -1,
                is_method = "function" === typeof _context[_method];

            return is_method && !is_excluded;
        }

        for (let obj = context; obj; obj = Object.getPrototypeOf(obj)) {
            // Stop once we have traveled all the way up the inheritance chain
            if ("Object" === obj.constructor.name) {
                break;
            }

            for (let method of Object.getOwnPropertyNames(obj)) {
                if (not_excluded(method, context)) {
                    context[method] = context[method].bind(context);
                }
            }
        }

        return context;
    }

    /**
     * Returns the contents of directory found at `path` provided that the (normalized) `path`
     * meets at least one of the following conditions:
     *   * Is located within the greeter themes' root directory.
     *   * Has been explicitly allowed in the greeter's config file.
     *   * Is located within the greeter's shared data directory (`/var/lib/lightdm-data`).
     *   * Is located in `/tmp`.
     *
     * @param {string}              path        The abs path to desired directory.
     * @param {boolean}             only_images Include only images in the results. Default `true`.
     * @param {function(string[])}  callback    Callback function to be called with the result.
     */
    dirlist(path, only_images = true, callback) {
        if ("" === path || "string" !== typeof path) {
            console.error(`theme_utils.dirlist(): path must be a non-empty string!`);
            return callback([]);
        } else if (null !== path.match(/^[^/].+/)) {
            return _ThemeUtils.dirlist(path, only_images, callback);
        }

        if (null !== path.match(/\/\.+(?=\/)/)) {
            // No special directory names allowed (eg ../../)
            path = path.replace(/\/\.+(?=\/)/g, "");
        }

        try {
            return _ThemeUtils.dirlist(path, only_images, callback);
        } catch (err) {
            console.error(`theme_utils.dirlist(): ${err}`);
            return callback([]);
        }
    }

    /**
     * Get the current date in a localized format. Local language is autodetected by default, but can be set manually in the greeter config file.
     *   * `language` defaults to the system's language, but can be set manually in the config file.
     *
     * @returns {Object} The current date.
     */
    get_current_localized_date() {
        let config = greeter_config.greeter;

        var locale = [];

        if (time_language === null) {
            time_language = config.time_language || "";
        }

        if (time_language != "") {
            locale.push(time_language);
        }

        let optionsDate = { day: "2-digit", month: "2-digit", year: "2-digit" };

        let fmtDate = Intl.DateTimeFormat(locale, optionsDate);

        let now = new Date();
        var date = fmtDate.format(now);

        return date;
    }

    /**
     * Get the current time in a localized format. Local language is autodetected by default, but can be set manually in the greeter config file.
     *   * `language` defaults to the system's language, but can be set manually in the config file.
     *
     * @returns {Object} The current time.
     */
    get_current_localized_time() {
        let config = greeter_config.greeter;

        var locale = [];

        if (time_language === null) {
            time_language = config.time_language || "";
        }

        if (time_language != "") {
            locale.push(time_language);
        }

        let optionsTime = { hour: "2-digit", minute: "2-digit" };

        let fmtTime = Intl.DateTimeFormat(locale, optionsTime);

        let now = new Date();
        var time = fmtTime.format(now);

        return time;
    }
}