element-web/src/components/views/rooms/RoomBreadcrumbs.js

/*
Copyright 2019 New Vector Ltd

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

'use strict';
import React from "react";
import dis from "../../../dispatcher";
import MatrixClientPeg from "../../../MatrixClientPeg";
import AccessibleButton from '../elements/AccessibleButton';
import RoomAvatar from '../avatars/RoomAvatar';
import classNames from 'classnames';

const MAX_ROOMS = 20;

export default class RoomBreadcrumbs extends React.Component {
    constructor(props) {
        super(props);
        this.state = {rooms: []};
        this.onAction = this.onAction.bind(this);
        this._previousRoomId = null;
        this._dispatcherRef = null;
    }

    componentWillMount() {
        this._dispatcherRef = dis.register(this.onAction);
    }

    componentWillUnmount() {
        dis.unregister(this._dispatcherRef);
    }

    componentDidUpdate() {
        const rooms = this.state.rooms.slice();
        if (rooms.length) {
            const {room, animated} = rooms[0];
            if (!animated) {
                rooms[0] = {room, animated: true};
                setTimeout(() => this.setState({rooms}), 0);
            }
        }
    }

    onAction(payload) {
        switch (payload.action) {
            case 'view_room':
                if (this._previousRoomId) {
                    this._appendRoomId(this._previousRoomId);
                }
                this._previousRoomId = payload.room_id;
        }
    }

    _appendRoomId(roomId) {
        const room = MatrixClientPeg.get().getRoom(roomId);
        if (!room) {
            return;
        }
        const rooms = this.state.rooms.slice();
        const existingIdx = rooms.findIndex((r) => r.room.roomId === room.roomId);
        if (existingIdx !== -1) {
            rooms.splice(existingIdx, 1);
        }
        rooms.splice(0, 0, {room, animated: false});
        if (rooms.length > MAX_ROOMS) {
            rooms.splice(MAX_ROOMS, rooms.length - MAX_ROOMS);
        }
        this.setState({rooms});
    }

    _viewRoom(room) {
        dis.dispatch({action: "view_room", room_id: room.roomId});
    }

    render() {
        // check for collapsed here and
        // not at parent so we keep
        // rooms in our state
        // when collapsing and expanding
        if (this.props.collapsed) {
            return null;
        }
        const rooms = this.state.rooms;
        const avatars = rooms.map(({room, animated}, i) => {
            const isFirst = i === 0;
            const classes = classNames({
                "mx_RoomBreadcrumbs_preAnimate": isFirst && !animated,
                "mx_RoomBreadcrumbs_animate": isFirst,
            });
            return (
                <AccessibleButton className={classes} key={room.roomId} title={room.name} onClick={() => this._viewRoom(room)}>
                    <RoomAvatar room={room} width={32} height={32} />
                </AccessibleButton>
            );
        });
        return (<div className="mx_RoomBreadcrumbs">{ avatars }</div>);
    }
}