import { PARTICIPANT_LEFT } from '../participants';
import { MiddlewareRegistry } from '../redux';

import { disposeLib, initLib, setWebRTCReady } from './actions';
import { LIB_DID_INIT, LIB_INIT_ERROR, SET_CONFIG } from './actionTypes';
import { WEBRTC_NOT_READY, WEBRTC_NOT_SUPPORTED } from './constants';

/**
 * Middleware that captures PARTICIPANT_LEFT action for a local participant
 * (which signalizes that we finally left the app) and disposes lib-jitsi-meet.
 * Also captures SET_CONFIG action and disposes previous instance (if any) of
 * lib-jitsi-meet, and initializes a new one with new config.
 *
 * @param {Store} store - Redux store.
 * @returns {Function}
 * @private
 */
MiddlewareRegistry.register(store => next => action => {
    switch (action.type) {
    case LIB_DID_INIT:
        store.dispatch(setWebRTCReady(true));
        break;

    case LIB_INIT_ERROR:
        return _libInitError(store, next, action);

    case PARTICIPANT_LEFT:
        action.participant.local && store.dispatch(disposeLib());
        break;

    case SET_CONFIG:
        return _setConfig(store, next, action);
    }

    return next(action);
});

/**
 * Notifies the feature base/lib-jitsi-meet that the action LIB_INIT_ERROR is
 * being dispatched within a specific Redux store.
 *
 * @param {Store} store - The Redux store in which the specified action is being
 * dispatched.
 * @param {Dispatch} next - The Redux dispatch function to dispatch the
 * specified action to the specified store.
 * @param {Action} action - The Redux action LIB_INIT_ERROR which is being
 * dispatched in the specified store.
 * @returns {Object} The new state that is the result of the reduction of the
 * specified action.
 * @private
 */
function _libInitError(store, next, action) {
    const nextState = next(action);

    const error = action.error;

    if (error) {
        let webRTCReady;

        switch (error.name) {
        case WEBRTC_NOT_READY:
            webRTCReady = error.webRTCReadyPromise;
            break;

        case WEBRTC_NOT_SUPPORTED:
            webRTCReady = false;
            break;
        }
        typeof webRTCReady === 'undefined'
            || store.dispatch(setWebRTCReady(webRTCReady));
    }

    return nextState;
}

/**
 * Notifies the feature base/lib-jitsi-meet that the action SET_CONFIG is being
 * dispatched within a specific Redux store.
 *
 * @param {Store} store - The Redux store in which the specified action is being
 * dispatched.
 * @param {Dispatch} next - The Redux dispatch function to dispatch the
 * specified action to the specified store.
 * @param {Action} action - The Redux action SET_CONFIG which is being
 * dispatched in the specified store.
 * @returns {Object} The new state that is the result of the reduction of the
 * specified action.
 * @private
 */
function _setConfig(store, next, action) {
    const { dispatch, getState } = store;
    const { initialized } = getState()['features/base/lib-jitsi-meet'];

    // XXX Since the config is changing, the library lib-jitsi-meet must be
    // initialized again with the new config. Consequntly, it may need to be
    // disposed of first.
    // TODO Currently, disposeLib actually does not dispose of lib-jitsi-meet
    // because lib-jitsi-meet does not implement such functionality.
    const disposeLibPromise
        = initialized ? dispatch(disposeLib()) : Promise.resolve();

    // Let the new config into the Redux store (because initLib will read it
    // from there).
    const nextState = next(action);

    disposeLibPromise.then(dispatch(initLib()));

    return nextState;
}