// @flow

import { CONNECTION_WILL_CONNECT, SET_LOCATION_URL } from '../connection';
import { JitsiConferenceErrors } from '../lib-jitsi-meet';
import { assign, ReducerRegistry, set } from '../redux';
import { LOCKED_LOCALLY, LOCKED_REMOTELY } from '../../room-lock';

import {
    AUTH_STATUS_CHANGED,
    CONFERENCE_FAILED,
    CONFERENCE_JOINED,
    CONFERENCE_LEFT,
    CONFERENCE_SUBJECT_CHANGED,
    CONFERENCE_WILL_JOIN,
    CONFERENCE_WILL_LEAVE,
    LOCK_STATE_CHANGED,
    P2P_STATUS_CHANGED,
    SET_AUDIO_ONLY,
    SET_DESKTOP_SHARING_ENABLED,
    SET_FOLLOW_ME,
    SET_MAX_RECEIVER_VIDEO_QUALITY,
    SET_PASSWORD,
    SET_PENDING_SUBJECT_CHANGE,
    SET_PREFERRED_RECEIVER_VIDEO_QUALITY,
    SET_ROOM,
    SET_SIP_GATEWAY_ENABLED,
    SET_START_MUTED_POLICY
} from './actionTypes';
import { VIDEO_QUALITY_LEVELS } from './constants';
import { isRoomValid } from './functions';

const DEFAULT_STATE = {
    conference: undefined,
    joining: undefined,
    leaving: undefined,
    locked: undefined,
    maxReceiverVideoQuality: VIDEO_QUALITY_LEVELS.HIGH,
    password: undefined,
    passwordRequired: undefined,
    preferredReceiverVideoQuality: VIDEO_QUALITY_LEVELS.HIGH
};

/**
 * Listen for actions that contain the conference object, so that it can be
 * stored for use by other action creators.
 */
ReducerRegistry.register(
    'features/base/conference',
    (state = DEFAULT_STATE, action) => {
        switch (action.type) {
        case AUTH_STATUS_CHANGED:
            return _authStatusChanged(state, action);

        case CONFERENCE_FAILED:
            return _conferenceFailed(state, action);

        case CONFERENCE_JOINED:
            return _conferenceJoined(state, action);

        case CONFERENCE_SUBJECT_CHANGED:
            return set(state, 'subject', action.subject);

        case CONFERENCE_LEFT:
        case CONFERENCE_WILL_LEAVE:
            return _conferenceLeftOrWillLeave(state, action);

        case CONFERENCE_WILL_JOIN:
            return _conferenceWillJoin(state, action);

        case CONNECTION_WILL_CONNECT:
            return set(state, 'authRequired', undefined);

        case LOCK_STATE_CHANGED:
            return _lockStateChanged(state, action);

        case P2P_STATUS_CHANGED:
            return _p2pStatusChanged(state, action);

        case SET_AUDIO_ONLY:
            return _setAudioOnly(state, action);

        case SET_DESKTOP_SHARING_ENABLED:
            return _setDesktopSharingEnabled(state, action);

        case SET_FOLLOW_ME:
            return set(state, 'followMeEnabled', action.enabled);

        case SET_LOCATION_URL:
            return set(state, 'room', undefined);

        case SET_MAX_RECEIVER_VIDEO_QUALITY:
            return set(
                state,
                'maxReceiverVideoQuality',
                action.maxReceiverVideoQuality);

        case SET_PASSWORD:
            return _setPassword(state, action);

        case SET_PENDING_SUBJECT_CHANGE:
            return set(state, 'pendingSubjectChange', action.subject);

        case SET_PREFERRED_RECEIVER_VIDEO_QUALITY:
            return set(
                state,
                'preferredReceiverVideoQuality',
                action.preferredReceiverVideoQuality);

        case SET_ROOM:
            return _setRoom(state, action);

        case SET_SIP_GATEWAY_ENABLED:
            return _setSIPGatewayEnabled(state, action);

        case SET_START_MUTED_POLICY:
            return {
                ...state,
                startAudioMutedPolicy: action.startAudioMutedPolicy,
                startVideoMutedPolicy: action.startVideoMutedPolicy
            };
        }

        return state;
    });

/**
 * Reduces a specific Redux action AUTH_STATUS_CHANGED of the feature
 * base/conference.
 *
 * @param {Object} state - The Redux state of the feature base/conference.
 * @param {Action} action - The Redux action AUTH_STATUS_CHANGED to reduce.
 * @private
 * @returns {Object} The new state of the feature base/conference after the
 * reduction of the specified action.
 */
function _authStatusChanged(state, { authEnabled, authLogin }) {
    return assign(state, {
        authEnabled,
        authLogin
    });
}

/**
 * Reduces a specific Redux action CONFERENCE_FAILED of the feature
 * base/conference.
 *
 * @param {Object} state - The Redux state of the feature base/conference.
 * @param {Action} action - The Redux action CONFERENCE_FAILED to reduce.
 * @private
 * @returns {Object} The new state of the feature base/conference after the
 * reduction of the specified action.
 */
function _conferenceFailed(state, { conference, error }) {
    // The current (similar to getCurrentConference in
    // base/conference/functions.js) conference which is joining or joined:
    const conference_ = state.conference || state.joining;

    if (conference_ && conference_ !== conference) {
        return state;
    }

    let authRequired;
    let passwordRequired;

    switch (error.name) {
    case JitsiConferenceErrors.AUTHENTICATION_REQUIRED:
        authRequired = conference;
        break;

    case JitsiConferenceErrors.PASSWORD_REQUIRED:
        passwordRequired = conference;
        break;
    }

    return assign(state, {
        authRequired,
        conference: undefined,
        error,
        joining: undefined,
        leaving: undefined,

        /**
         * The indicator of how the conference/room is locked. If falsy, the
         * conference/room is unlocked; otherwise, it's either
         * {@code LOCKED_LOCALLY} or {@code LOCKED_REMOTELY}.
         *
         * @type {string}
         */
        locked: passwordRequired ? LOCKED_REMOTELY : undefined,
        password: undefined,

        /**
         * The JitsiConference instance which requires a password to join.
         *
         * @type {JitsiConference}
         */
        passwordRequired
    });
}

/**
 * Reduces a specific Redux action CONFERENCE_JOINED of the feature
 * base/conference.
 *
 * @param {Object} state - The Redux state of the feature base/conference.
 * @param {Action} action - The Redux action CONFERENCE_JOINED to reduce.
 * @private
 * @returns {Object} The new state of the feature base/conference after the
 * reduction of the specified action.
 */
function _conferenceJoined(state, { conference }) {
    // FIXME The indicator which determines whether a JitsiConference is locked
    // i.e. password-protected is private to lib-jitsi-meet. However, the
    // library does not fire LOCK_STATE_CHANGED upon joining a JitsiConference
    // with a password.
    // FIXME Technically JitsiConference.room is a private field.
    const locked = conference.room && conference.room.locked ? LOCKED_REMOTELY : undefined;

    return assign(state, {
        authRequired: undefined,

        /**
         * The JitsiConference instance represented by the Redux state of the
         * feature base/conference.
         *
         * @type {JitsiConference}
         */
        conference,
        joining: undefined,
        leaving: undefined,

        /**
         * The indicator which determines whether the conference is locked.
         *
         * @type {boolean}
         */
        locked,
        passwordRequired: undefined
    });
}

/**
 * Reduces a specific redux action {@link CONFERENCE_LEFT} or
 * {@link CONFERENCE_WILL_LEAVE} for the feature base/conference.
 *
 * @param {Object} state - The redux state of the feature base/conference.
 * @param {Action} action - The redux action {@code CONFERENCE_LEFT} or
 * {@code CONFERENCE_WILL_LEAVE} to reduce.
 * @private
 * @returns {Object} The next/new state of the feature base/conference after the
 * reduction of the specified action.
 */
function _conferenceLeftOrWillLeave(state, { conference, type }) {
    const nextState = { ...state };

    // The redux action CONFERENCE_LEFT is the last time that we should be
    // hearing from a JitsiConference instance.
    //
    // The redux action CONFERENCE_WILL_LEAVE represents the order of the user
    // to leave a JitsiConference instance. From the user's perspective, there's
    // no going back (with respect to the instance itself). The app will perform
    // due clean-up like leaving the associated room, but the instance is no
    // longer the focus of the attention of the user and, consequently, the app.
    for (const p in state) {
        if (state[p] === conference) {
            nextState[p] = undefined;

            switch (p) {
            case 'conference':
            case 'passwordRequired':
                // XXX Clear/unset locked & password for a conference which has
                // been LOCKED_LOCALLY or LOCKED_REMOTELY.
                delete nextState.locked;
                delete nextState.password;
                break;
            }
        }
    }

    if (type === CONFERENCE_WILL_LEAVE) {
        // A CONFERENCE_WILL_LEAVE is of further consequence only if it is
        // expected i.e. if the specified conference is joining or joined.
        if (conference === state.joining || conference === state.conference) {
            /**
             * The JitsiConference instance which is currently in the process of
             * being left.
             *
             * @type {JitsiConference}
             */
            nextState.leaving = conference;
        }
    }

    return nextState;
}

/**
 * Reduces a specific Redux action CONFERENCE_WILL_JOIN of the feature
 * base/conference.
 *
 * @param {Object} state - The Redux state of the feature base/conference.
 * @param {Action} action - The Redux action CONFERENCE_WILL_JOIN to reduce.
 * @private
 * @returns {Object} The new state of the feature base/conference after the
 * reduction of the specified action.
 */
function _conferenceWillJoin(state, { conference }) {
    return assign(state, {
        error: undefined,
        joining: conference
    });
}

/**
 * Reduces a specific Redux action LOCK_STATE_CHANGED of the feature
 * base/conference.
 *
 * @param {Object} state - The Redux state of the feature base/conference.
 * @param {Action} action - The Redux action LOCK_STATE_CHANGED to reduce.
 * @private
 * @returns {Object} The new state of the feature base/conference after the
 * reduction of the specified action.
 */
function _lockStateChanged(state, { conference, locked }) {
    if (state.conference !== conference) {
        return state;
    }

    return assign(state, {
        locked: locked ? state.locked || LOCKED_REMOTELY : undefined,
        password: locked ? state.password : undefined
    });
}

/**
 * Reduces a specific Redux action P2P_STATUS_CHANGED of the feature
 * base/conference.
 *
 * @param {Object} state - The Redux state of the feature base/conference.
 * @param {Action} action - The Redux action P2P_STATUS_CHANGED to reduce.
 * @private
 * @returns {Object} The new state of the feature base/conference after the
 * reduction of the specified action.
 */
function _p2pStatusChanged(state, action) {
    return set(state, 'p2p', action.p2p);
}

/**
 * Reduces a specific Redux action SET_AUDIO_ONLY of the feature
 * base/conference.
 *
 * @param {Object} state - The Redux state of the feature base/conference.
 * @param {Action} action - The Redux action SET_AUDIO_ONLY to reduce.
 * @private
 * @returns {Object} The new state of the feature base/conference after the
 * reduction of the specified action.
 */
function _setAudioOnly(state, action) {
    return set(state, 'audioOnly', action.audioOnly);
}

/**
 * Reduces a specific Redux action SET_DESKTOP_SHARING_ENABLED of the feature
 * base/conference.
 *
 * @param {Object} state - The Redux state of the feature base/conference.
 * @param {Action} action - The Redux action SET_DESKTOP_SHARING_ENABLED to
 * reduce.
 * @private
 * @returns {Object} The new state of the feature base/conference after the
 * reduction of the specified action.
 */
function _setDesktopSharingEnabled(state, action) {
    return set(state, 'desktopSharingEnabled', action.desktopSharingEnabled);
}

/**
 * Reduces a specific Redux action SET_PASSWORD of the feature base/conference.
 *
 * @param {Object} state - The Redux state of the feature base/conference.
 * @param {Action} action - The Redux action SET_PASSWORD to reduce.
 * @private
 * @returns {Object} The new state of the feature base/conference after the
 * reduction of the specified action.
 */
function _setPassword(state, { conference, method, password }) {
    switch (method) {
    case conference.join:
        if (state.passwordRequired === conference) {
            return assign(state, {
                // XXX 1. The JitsiConference which transitions away from
                // passwordRequired MUST remain in the redux state
                // features/base/conference until it transitions into
                // conference; otherwise, there is a span of time during which
                // the redux state does not even know that there is a
                // JitsiConference whatsoever.
                //
                // 2. The redux action setPassword will attempt to join the
                // JitsiConference so joining is an appropriate transitional
                // redux state.
                //
                // 3. The redux action setPassword will perform the same check
                // before it proceeds with the re-join.
                joining: state.conference ? state.joining : conference,
                locked: LOCKED_REMOTELY,

                /**
                 * The password with which the conference is to be joined.
                 *
                 * @type {string}
                 */
                password,
                passwordRequired: undefined
            });
        }
        break;

    case conference.lock:
        return assign(state, {
            locked: password ? LOCKED_LOCALLY : undefined,
            password
        });
    }

    return state;
}

/**
 * Reduces a specific Redux action SET_ROOM of the feature base/conference.
 *
 * @param {Object} state - The Redux state of the feature base/conference.
 * @param {Action} action - The Redux action SET_ROOM to reduce.
 * @private
 * @returns {Object} The new state of the feature base/conference after the
 * reduction of the specified action.
 */
function _setRoom(state, action) {
    let { room } = action;

    if (!isRoomValid(room)) {
        // Technically, there are multiple values which don't represent valid
        // room names. Practically, each of them is as bad as the rest of them
        // because we can't use any of them to join a conference.
        room = undefined;
    }

    /**
     * The name of the room of the conference (to be) joined.
     *
     * @type {string}
     */
    return assign(state, {
        error: undefined,
        room
    });
}

/**
 * Reduces a specific Redux action SET_SIP_GATEWAY_ENABLED of the feature
 * base/conference.
 *
 * @param {Object} state - The Redux state of the feature base/conference.
 * @param {Action} action - The Redux action SET_SIP_GATEWAY_ENABLED to reduce.
 * @private
 * @returns {Object} The new state of the feature base/conference after the
 * reduction of the specified action.
 */
function _setSIPGatewayEnabled(state, action) {
    return set(state, 'isSIPGatewayEnabled', action.isSIPGatewayEnabled);
}