import { ReducerRegistry } from '../redux';

import { SET_CONFIG } from './actionTypes';

/**
 * The initial state of the feature base/config. The mandatory configuration to
 * be passed to JitsiMeetJS#init(). The app will download config.js from the
 * Jitsi Meet deployment and take its values into account but the values bellow
 * will be enforced (because they are essential to the correct execution of the
 * application).
 *
 * @type {Object}
 */
const INITIAL_STATE = {
    // FIXME The support for audio levels in lib-jitsi-meet polls the statistics
    // of WebRTC at a short interval multiple times a second. Unfortunately,
    // React Native is slow to fetch these statistics from the native WebRTC
    // API, through the React Native bridge and eventually to JavaScript.
    // Because the audio levels are of no interest to the mobile app, it is
    // fastest to merely disable them.
    disableAudioLevels: true,

    // FIXME Lib-jitsi-meet uses HTML script elements to asynchronously load
    // certain pieces of JavaScript. Unfortunately, the technique doesn't work
    // on React Native (because there are no HTML elements in the first place).
    // Fortunately, these pieces of JavaScript currently involve third parties
    // and we can temporarily disable them (until we implement an alternative to
    // async script elements on React Native).
    disableThirdPartyRequests: true
};

ReducerRegistry.register(
    'features/base/config',
    (state = INITIAL_STATE, action) => {
        switch (action.type) {
        case SET_CONFIG:
            return _setConfig(state, action);

        default:
            return state;
        }
    });

/**
 * Reduces a specific Redux action SET_CONFIG of the feature
 * base/lib-jitsi-meet.
 *
 * @param {Object} state - The Redux state of the feature base/lib-jitsi-meet.
 * @param {Action} action - The Redux action SET_CONFIG to reduce.
 * @private
 * @returns {Object} The new state of the feature base/lib-jitsi-meet after the
 * reduction of the specified action.
 */
function _setConfig(state, action) {
    return {
        ...action.config,

        // The config of INITIAL_STATE is meant to override the config
        // downloaded from the Jitsi Meet deployment because the former contains
        // values that are mandatory.
        ...INITIAL_STATE
    };
}