/* --------------------------------------------------------------
 lang.js 2016-08-23
 Gambio GmbH
 http://www.gambio.de
 Copyright (c) 2016 Gambio GmbH
 Released under the GNU General Public License (Version 2)
 [http://www.gnu.org/licenses/gpl-2.0.html]
 --------------------------------------------------------------
 */

jse.core.lang = jse.core.lang || {};

/**
 * JSE Localization Library
 *
 * The global Lang object contains language information that can be easily used in your
 * JavaScript code. The object contains constance translations and dynamic sections that
 * can be loaded and used in different page.
 *
 * #### Important
 * The engine will automatically load translation sections that are present in the
 * `window.JSEngineConfiguration.translations` property upon initialization. For more
 * information look at the "core/initialize" page of documentation reference.
 *
 * ```javascript
 * jse.core.lang.addSection('sectionName', { translationKey: 'translationValue' }); // Add translation section.
 * jse.core.translate('translationKey', 'sectionName'); // Get the translated string.
 * jse.core.getSections(); // returns array with sections e.g. ['admin_buttons', 'general']
 * ```
 *
 * @module JSE/Core/lang
 */
(function (exports) {

    'use strict';

    // ------------------------------------------------------------------------
    // VARIABLES
    // ------------------------------------------------------------------------

    /**
     * Contains various translation sections.
     *
     * @type {Object}
     */
    const sections = {};

    // ------------------------------------------------------------------------
    // PUBLIC METHODS
    // ------------------------------------------------------------------------

    /**
     * Add a translation section.
     *
     * @param {String} name Name of the section, used later for accessing translation strings.
     * @param {Object} translations Key - value object containing the translations.
     *
     * @throws {Error} If "name" or "translations" arguments are invalid.
     */
    exports.addSection = function (name, translations) {
        if (typeof name !== 'string' || typeof translations !== 'object' || translations === null) {
            throw new Error(`window.gx.core.lang.addSection: Invalid arguments provided (name: ${typeof name}, `
                + `translations: ${typeof translations}).`);
        }
        sections[name] = translations;
    };

    /**
     * Get loaded translation sections.
     *
     * Useful for asserting present translation sections.
     *
     * @return {Array} Returns array with the existing sections.
     */
    exports.getSections = function () {
        const result = [];

        for (let section in sections) {
            result.push(section);
        }

        return result;
    };

    /**
     * Translate string in Javascript code.
     *
     * @param {String} phrase Name of the phrase containing the translation.
     * @param {String} section Section name containing the translation string.
     *
     * @return {String} Returns the translated string.
     *
     * @throws {Error} If provided arguments are invalid.
     * @throws {Error} If required section does not exist or translation could not be found.
     */
    exports.translate = function (phrase, section) {
        // Validate provided arguments.
        if (typeof phrase !== 'string' || typeof section !== 'string') {
            throw new Error(`Invalid arguments provided in translate method (phrase: ${typeof phrase}, `
                + `section: ${typeof section}).`);
        }

        // Check if translation exists.
        if (sections[section] === undefined || sections[section][phrase] === undefined) {
            jse.core.debug.warn(`Could not found requested translation (phrase: ${phrase}, section: ${section}).`);
            return '{' + section + '.' + phrase + '}';
        }

        return sections[section][phrase];
    };

}(jse.core.lang));