element-web/src/components/structures/RoomView.js

/*
Copyright 2015, 2016 OpenMarket 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.
*/

// TODO: This component is enormous! There's several things which could stand-alone:
//  - Aux component
//  - Search results component
//  - Drag and drop
//  - File uploading - uploadFile()
//  - Timeline component (alllll the logic in getEventTiles())

var React = require("react");
var ReactDOM = require("react-dom");
var q = require("q");
var classNames = require("classnames");
var Matrix = require("matrix-js-sdk");
var EventTimeline = Matrix.EventTimeline;

var MatrixClientPeg = require("../../MatrixClientPeg");
var ContentMessages = require("../../ContentMessages");
var Modal = require("../../Modal");
var sdk = require('../../index');
var CallHandler = require('../../CallHandler');
var TabComplete = require("../../TabComplete");
var MemberEntry = require("../../TabCompleteEntries").MemberEntry;
var CommandEntry = require("../../TabCompleteEntries").CommandEntry;
var Resend = require("../../Resend");
var SlashCommands = require("../../SlashCommands");
var dis = require("../../dispatcher");
var Tinter = require("../../Tinter");
var rate_limited_func = require('../../ratelimitedfunc');

var PAGINATE_SIZE = 20;
var INITIAL_SIZE = 20;
var SEND_READ_RECEIPT_DELAY = 2000;
var TIMELINE_CAP = 1000; // the most events to show in a timeline

var DEBUG_SCROLL = false;

if (DEBUG_SCROLL) {
    // using bind means that we get to keep useful line numbers in the console
    var debuglog = console.log.bind(console);
} else {
    var debuglog = function () {};
}

module.exports = React.createClass({
    displayName: 'RoomView',
    propTypes: {
        ConferenceHandler: React.PropTypes.any,

        roomId: React.PropTypes.string.isRequired,

        // id of an event to jump to. If not given, will go to the end of the
        // live timeline.
        eventId: React.PropTypes.string,

        // where to position the event given by eventId, in pixels from the
        // bottom of the viewport. If not given, will try to put the event in the
        // middle of the viewprt.
        eventPixelOffset: React.PropTypes.number,

        // ID of an event to highlight. If undefined, no event will be highlighted.
        // Typically this will either be the same as 'eventId', or undefined.
        highlightedEventId: React.PropTypes.string,
    },

    /* properties in RoomView objects include:
     *
     * eventNodes: a map from event id to DOM node representing that event
     */
    getInitialState: function() {
        var room = this.props.roomId ? MatrixClientPeg.get().getRoom(this.props.roomId) : null;
        return {
            room: room,
            events: [],
            canBackPaginate: true,
            paginating: room != null,
            editingRoomSettings: false,
            uploadingRoomSettings: false,
            numUnreadMessages: 0,
            draggingFile: false,
            searching: false,
            searchResults: null,
            hasUnsentMessages: this._hasUnsentMessages(room),
            callState: null,
            timelineLoading: true, // track whether our room timeline is loading
            guestsCanJoin: false,
            canPeek: false,
            readMarkerEventId: room ? room.getEventReadUpTo(MatrixClientPeg.get().credentials.userId) : null,
            readMarkerGhostEventId: undefined,

            // this is true if we are fully scrolled-down, and are looking at
            // the end of the live timeline. It has the effect of hiding the
            // 'scroll to bottom' knob, among a couple of other things.
            atEndOfLiveTimeline: true,
        }
    },

    componentWillMount: function() {
        this.last_rr_sent_event_id = undefined;
        this.dispatcherRef = dis.register(this.onAction);
        MatrixClientPeg.get().on("Room", this.onRoom);
        MatrixClientPeg.get().on("Room.timeline", this.onRoomTimeline);
        MatrixClientPeg.get().on("Room.name", this.onRoomName);
        MatrixClientPeg.get().on("Room.accountData", this.onRoomAccountData);
        MatrixClientPeg.get().on("Room.receipt", this.onRoomReceipt);
        MatrixClientPeg.get().on("RoomMember.typing", this.onRoomMemberTyping);
        MatrixClientPeg.get().on("RoomState.members", this.onRoomStateMember);
        // xchat-style tab complete, add a colon if tab
        // completing at the start of the text
        this.tabComplete = new TabComplete({
            allowLooping: false,
            autoEnterTabComplete: true,
            onClickCompletes: true,
            onStateChange: (isCompleting) => {
                this.forceUpdate();
            }
        });


        // to make the timeline load work correctly, build up a chain of promises which
        // take us through the necessary steps.

        // First of all, we may need to load the room. Construct a promise
        // which resolves to the Room object.
        var roomProm;

        // if this is an unknown room then we're in one of three states:
        // - This is a room we can peek into (search engine) (we can /peek)
        // - This is a room we can publicly join or were invited to. (we can /join)
        // - This is a room we cannot join at all. (no action can help us)
        // We can't try to /join because this may implicitly accept invites (!)
        // We can /peek though. If it fails then we present the join UI. If it
        // succeeds then great, show the preview (but we still may be able to /join!).
        if (!this.state.room) {
            console.log("Attempting to peek into room %s", this.props.roomId);

            roomProm = MatrixClientPeg.get().peekInRoom(this.props.roomId).then((room) => {
                this.setState({
                    room: room
                });
                return room;
            });
        } else {
            roomProm = q(this.state.room);
        }

        // Next, load the timeline.
        roomProm.then((room) => {
            this._calculatePeekRules(room);
            return this._initTimeline(this.props);
        }).catch((err) => {
            // This won't necessarily be a MatrixError, but we duck-type
            // here and say if it's got an 'errcode' key with the right value,
            // it means we can't peek.
            if (err.errcode == "M_GUEST_ACCESS_FORBIDDEN") {
                // This is fine: the room just isn't peekable (we assume).
                this.setState({
                    timelineLoading: false,
                });
            } else {
                throw err;
            }
        }).done();
    },

    _initTimeline: function(props) {
        var initialEvent = props.eventId;
        var pixelOffset = props.eventPixelOffset;
        return this._loadTimeline(initialEvent, pixelOffset);
    },

    /**
     * (re)-load the event timeline, and initialise the scroll state, centered
     * around the given event.
     *
     * @param {string?}  eventId the event to focus on. If undefined, will
     *    scroll to the bottom of the room.
     *
     * @param {number?} pixelOffset   offset to position the given event at
     *    (pixels from the bottom of the view). If undefined, will put the
     *    event in the middle of the view.
     *
     * returns a promise which will resolve when the load completes.
     */
    _loadTimeline: function(eventId, pixelOffset) {
        // TODO: we could optimise this, by not resetting the window if the
        // event is in the current window (though it's not obvious how we can
        // tell if the current window is on the live event stream)

        this.setState({
            events: [],
            searchResults: null, // we may have arrived here by clicking on a
                                 // search result. Hide the results.
            timelineLoading: true,
        });

        this._timelineWindow = new Matrix.TimelineWindow(
            MatrixClientPeg.get(), this.state.room,
            {windowLimit: TIMELINE_CAP});

        return this._timelineWindow.load(eventId, INITIAL_SIZE).then(() => {
            debuglog("RoomView: timeline loaded");
            this._onTimelineUpdated(true);
        }).finally(() => {
            this.setState({
                timelineLoading: false,
            }, () => {
                // initialise the scroll state of the message panel
                if (!this.refs.messagePanel) {
                    // this shouldn't happen.
                    console.log("can't initialise scroll state because " +
                                "messagePanel didn't load");
                    return;
                }
                if (eventId) {
                    this.refs.messagePanel.scrollToToken(eventId, pixelOffset);
                } else {
                    this.refs.messagePanel.scrollToBottom();
                }

                this.sendReadReceipt();
            });
        });
    },

    componentWillUnmount: function() {
        // set a boolean to say we've been unmounted, which any pending
        // promises can use to throw away their results.
        //
        // (We could use isMounted, but facebook have deprecated that.)
        this.unmounted = true;

        if (this.refs.roomView) {
            // disconnect the D&D event listeners from the room view. This
            // is really just for hygiene - we're going to be
            // deleted anyway, so it doesn't matter if the event listeners
            // don't get cleaned up.
            var roomView = ReactDOM.findDOMNode(this.refs.roomView);
            roomView.removeEventListener('drop', this.onDrop);
            roomView.removeEventListener('dragover', this.onDragOver);
            roomView.removeEventListener('dragleave', this.onDragLeaveOrEnd);
            roomView.removeEventListener('dragend', this.onDragLeaveOrEnd);
        }
        dis.unregister(this.dispatcherRef);
        if (MatrixClientPeg.get()) {
            MatrixClientPeg.get().removeListener("Room", this.onRoom);
            MatrixClientPeg.get().removeListener("Room.timeline", this.onRoomTimeline);
            MatrixClientPeg.get().removeListener("Room.name", this.onRoomName);
            MatrixClientPeg.get().removeListener("Room.accountData", this.onRoomAccountData);
            MatrixClientPeg.get().removeListener("Room.receipt", this.onRoomReceipt);
            MatrixClientPeg.get().removeListener("RoomMember.typing", this.onRoomMemberTyping);
            MatrixClientPeg.get().removeListener("RoomState.members", this.onRoomStateMember);
        }

        window.removeEventListener('resize', this.onResize);        

        Tinter.tint(); // reset colourscheme
    },

    onAction: function(payload) {
        switch (payload.action) {
            case 'message_send_failed':
            case 'message_sent':
                this.setState({
                    hasUnsentMessages: this._hasUnsentMessages(this.state.room)
                });
            case 'message_resend_started':
                this.setState({
                    room: MatrixClientPeg.get().getRoom(this.props.roomId)
                });
                this.forceUpdate();
                break;
            case 'notifier_enabled':
            case 'upload_failed':
            case 'upload_started':
            case 'upload_finished':
                this.forceUpdate();
                break;
            case 'call_state':
                // don't filter out payloads for room IDs other than props.room because
                // we may be interested in the conf 1:1 room

                if (!payload.room_id) {
                    return;
                }

                var call = CallHandler.getCallForRoom(payload.room_id);
                var callState;

                if (call) {
                    callState = call.call_state;
                }
                else {
                    callState = "ended";
                }

                // possibly remove the conf call notification if we're now in
                // the conf
                this._updateConfCallNotification();

                this.setState({
                    callState: callState
                });

                break;
            case 'user_activity':
            case 'user_activity_end':
                // we could treat user_activity_end differently and not
                // send receipts for messages that have arrived between
                // the actual user activity and the time they stopped
                // being active, but let's see if this is actually
                // necessary.
                this.sendReadReceipt();
                break;
        }
    },

    componentWillReceiveProps: function(newProps) {
        if (newProps.roomId != this.props.roomId) {
            throw new Error("changing room on a RoomView is not supported");
        }

        if (newProps.eventId != this.props.eventId) {
            console.log("RoomView switching to eventId " + newProps.eventId +
                        " (was " + this.props.eventId + ")");
            return this._initTimeline(newProps);
        }
    },

    onRoomTimeline: function(ev, room, toStartOfTimeline, removed, data) {
        if (this.unmounted) return;

        // ignore events for other rooms
        if (room.roomId != this.props.roomId) return;

        // ignore anything but real-time updates at the end of the room:
        // updates from pagination will happen when the paginate completes.
        if (toStartOfTimeline || !data || !data.liveEvent) return;

        // no point handling anything while we're waiting for the join to finish:
        // we'll only be showing a spinner.
        if (this.state.joining) return;

        if (ev.getSender() !== MatrixClientPeg.get().credentials.userId) {
            // update unread count when scrolled up
            if (!this.state.searchResults && this.state.atEndOfLiveTimeline) {
                // no change
            }
            else {
                this.setState((state, props) => { 
                    return {numUnreadMessages: state.numUnreadMessages + 1};
                });
            }
        }

        // tell the messagepanel to go paginate itself. This in turn will cause
        // onMessageListFillRequest to be called, which will call
        // _onTimelineUpdated, which will update the state with the new event -
        // so there is no need update the state here.
        //
        if (this.refs.messagePanel) {
            this.refs.messagePanel.checkFillState();
        }
    },

    _calculatePeekRules: function(room) {
        var guestAccessEvent = room.currentState.getStateEvents("m.room.guest_access", "");
        if (guestAccessEvent && guestAccessEvent.getContent().guest_access === "can_join") {
            this.setState({
                guestsCanJoin: true
            });
        }

        var historyVisibility = room.currentState.getStateEvents("m.room.history_visibility", "");
        if (historyVisibility && historyVisibility.getContent().history_visibility === "world_readable") {
            this.setState({
                canPeek: true
            });
        }
    },

    onRoom: function(room) {
        // This event is fired when the room is 'stored' by the JS SDK, which
        // means it's now a fully-fledged room object ready to be used, so
        // set it in our state and start using it (ie. init the timeline)
        // This will happen if we start off viewing a room we're not joined,
        // then join it whilst RoomView is looking at that room.
        if (room.roomId == this.props.roomId) {
            this.setState({
                room: room
            });
            this._initTimeline(this.props).done();
        }
    },

    onRoomName: function(room) {
        if (room.roomId == this.props.roomId) {
            this.setState({
                room: room
            });
        }
    },

    updateTint: function() {
        var room = MatrixClientPeg.get().getRoom(this.props.roomId);
        if (!room) return;

        var color_scheme_event = room.getAccountData("org.matrix.room.color_scheme");
        var color_scheme = {};
        if (color_scheme_event) {
            color_scheme = color_scheme_event.getContent();
            // XXX: we should validate the event
        }                
        Tinter.tint(color_scheme.primary_color, color_scheme.secondary_color);
    },

    onRoomAccountData: function(room, event) {
        if (room.roomId == this.props.roomId) {
            if (event.getType === "org.matrix.room.color_scheme") {
                var color_scheme = event.getContent();
                // XXX: we should validate the event
                Tinter.tint(color_scheme.primary_color, color_scheme.secondary_color);
            }
        }
    },

    onRoomReceipt: function(receiptEvent, room) {
        if (room.roomId == this.props.roomId) {
            var readMarkerEventId = this.state.room.getEventReadUpTo(MatrixClientPeg.get().credentials.userId);
            var readMarkerGhostEventId = this.state.readMarkerGhostEventId;
            if (this.state.readMarkerEventId !== undefined && this.state.readMarkerEventId != readMarkerEventId) {
                readMarkerGhostEventId = this.state.readMarkerEventId;
            }


            // if the event after the one referenced in the read receipt if sent by us, do nothing since
            // this is a temporary period before the synthesized receipt for our own message arrives
            var readMarkerGhostEventIndex;
            for (var i = 0; i < this.state.events.length; ++i) {
                if (this.state.events[i].getId() == readMarkerGhostEventId) {
                    readMarkerGhostEventIndex = i;
                    break;
                }
            }
            if (readMarkerGhostEventIndex + 1 < this.state.events.length) {
                var nextEvent = this.state.events[readMarkerGhostEventIndex + 1];
                if (nextEvent.sender && nextEvent.sender.userId == MatrixClientPeg.get().credentials.userId) {
                    readMarkerGhostEventId = undefined;
                }
            }

            this.setState({
                readMarkerEventId: readMarkerEventId,
                readMarkerGhostEventId: readMarkerGhostEventId,
            });
        }
    },

    onRoomMemberTyping: function(ev, member) {
        this.forceUpdate();
    },

    onRoomStateMember: function(ev, state, member) {
        if (member.roomId === this.props.roomId) {
            // a member state changed in this room, refresh the tab complete list
            this._updateTabCompleteList();

            var room = MatrixClientPeg.get().getRoom(this.props.roomId);
            if (!room) return;
            var me = MatrixClientPeg.get().credentials.userId;
            if (this.state.joining && room.hasMembershipState(me, "join")) {
                this.setState({
                    joining: false
                });
            }
        }

        if (!this.props.ConferenceHandler) {
            return;
        }
        if (member.roomId !== this.props.roomId ||
                member.userId !== this.props.ConferenceHandler.getConferenceUserIdForRoom(member.roomId)) {
            return;
        }
        this._updateConfCallNotification();
    },

    _hasUnsentMessages: function(room) {
        return this._getUnsentMessages(room).length > 0;
    },

    _getUnsentMessages: function(room) {
        if (!room) { return []; }
        // TODO: It would be nice if the JS SDK provided nicer constant-time
        // constructs rather than O(N) (N=num msgs) on this.
        return room.timeline.filter(function(ev) {
            return ev.status === Matrix.EventStatus.NOT_SENT;
        });
    },

    _updateConfCallNotification: function() {
        var room = MatrixClientPeg.get().getRoom(this.props.roomId);
        if (!room || !this.props.ConferenceHandler) {
            return;
        }
        var confMember = room.getMember(
            this.props.ConferenceHandler.getConferenceUserIdForRoom(this.props.roomId)
        );

        if (!confMember) {
            return;
        }
        var confCall = this.props.ConferenceHandler.getConferenceCallForRoom(confMember.roomId);

        // A conf call notification should be displayed if there is an ongoing
        // conf call but this cilent isn't a part of it.
        this.setState({
            displayConfCallNotification: (
                (!confCall || confCall.call_state === "ended") &&
                confMember.membership === "join"
            )
        });
    },

    componentDidMount: function() {
        if (this.refs.messagePanel) {
            this._initialiseMessagePanel();
        }

        var call = CallHandler.getCallForRoom(this.props.roomId);
        var callState = call ? call.call_state : "ended";
        this.setState({
            callState: callState
        });

        this._updateConfCallNotification();

        window.addEventListener('resize', this.onResize);
        this.onResize();

        if (this.refs.roomView) {
            var roomView = ReactDOM.findDOMNode(this.refs.roomView);
            roomView.addEventListener('drop', this.onDrop);
            roomView.addEventListener('dragover', this.onDragOver);
            roomView.addEventListener('dragleave', this.onDragLeaveOrEnd);
            roomView.addEventListener('dragend', this.onDragLeaveOrEnd);
        }

        this._updateTabCompleteList();

        // XXX: EVIL HACK to autofocus inviting on empty rooms.
        // We use the setTimeout to avoid racing with focus_composer.
        if (this.state.room && this.state.room.getJoinedMembers().length == 1) {
            var inviteBox = document.getElementById("mx_SearchableEntityList_query");
            setTimeout(function() {
                if (inviteBox) {
                    inviteBox.focus();
                }
            }, 50);
        }
    },

    _updateTabCompleteList: new rate_limited_func(function() {
        if (!this.state.room || !this.tabComplete) {
            return;
        }
        this.tabComplete.setCompletionList(
            MemberEntry.fromMemberList(this.state.room.getJoinedMembers()).concat(
                CommandEntry.fromCommands(SlashCommands.getCommandList())
            )
        );
    }, 500),

    _initialiseMessagePanel: function() {
        var messagePanel = ReactDOM.findDOMNode(this.refs.messagePanel);
        this.refs.messagePanel.initialised = true;
        this.updateTint();
    },

    componentDidUpdate: function() {
        // we need to initialise the messagepanel if we've just joined the
        // room. TODO: we really really ought to factor out messagepanel to a
        // separate component to avoid this ridiculous dance.
        if (!this.refs.messagePanel) return;

        if (!this.refs.messagePanel.initialised) {
            this._initialiseMessagePanel();
        }
    },

    _onTimelineUpdated: function(gotResults) {
        // we might have switched rooms since the load started - just bin
        // the results if so.
        if (this.unmounted) return;

        this.setState({
            paginating: false,
        });

        if (gotResults) {
            this.setState({
                events: this._timelineWindow.getEvents(),
                canBackPaginate: this._timelineWindow.canPaginate(EventTimeline.BACKWARDS),
            });
        }
    },

    onSearchResultsFillRequest: function(backwards) {
        if (!backwards)
            return q(false);

        if (this.state.searchResults.next_batch) {
            debuglog("requesting more search results");
            var searchPromise = MatrixClientPeg.get().backPaginateRoomEventsSearch(
                this.state.searchResults);
            return this._handleSearchResult(searchPromise);
        } else {
            debuglog("no more search results");
            return q(false);
        }
    },

    // set off a pagination request.
    onMessageListFillRequest: function(backwards) {
        var dir = backwards ? EventTimeline.BACKWARDS : EventTimeline.FORWARDS;
        if(!this._timelineWindow.canPaginate(dir)) {
            debuglog("RoomView: can't paginate at this time; backwards:"+backwards);
            return q(false);
        }
        this.setState({paginating: true});

        debuglog("RoomView: Initiating paginate; backwards:"+backwards);
        return this._timelineWindow.paginate(dir, PAGINATE_SIZE).then((r) => {
            debuglog("RoomView: paginate complete backwards:"+backwards+"; success:"+r);
            this._onTimelineUpdated(r);
            return r;
        });
    },

    onResendAllClick: function() {
        var eventsToResend = this._getUnsentMessages(this.state.room);
        eventsToResend.forEach(function(event) {
            Resend.resend(event);
        });
    },

    onJoinButtonClicked: function(ev) {
        var self = this;

        var cli = MatrixClientPeg.get();
        var display_name_promise = q();
        // if this is the first room we're joining, check the user has a display name
        // and if they don't, prompt them to set one.
        // NB. This unfortunately does not re-use the ChangeDisplayName component because
        // it doesn't behave quite as desired here (we want an input field here rather than
        // content-editable, and we want a default).
        if (cli.getRooms().filter((r) => {
            return r.hasMembershipState(cli.credentials.userId, "join");
        })) {
            display_name_promise = cli.getProfileInfo(cli.credentials.userId).then((result) => {
                if (!result.displayname) {
                    var SetDisplayNameDialog = sdk.getComponent('views.dialogs.SetDisplayNameDialog');
                    var dialog_defer = q.defer();
                    var dialog_ref;
                    var modal;
                    var dialog_instance = <SetDisplayNameDialog currentDisplayName={result.displayname} ref={(r) => {
                            dialog_ref = r;
                    }} onFinished={() => {
                        cli.setDisplayName(dialog_ref.getValue()).done(() => {
                            dialog_defer.resolve();
                        });
                        modal.close();
                    }} />
                    modal = Modal.createDialogWithElement(dialog_instance);
                    return dialog_defer.promise;
                }
            });
        }

        display_name_promise.then(() => {
            return MatrixClientPeg.get().joinRoom(this.props.roomId)
        }).done(function() {
            // It is possible that there is no Room yet if state hasn't come down
            // from /sync - joinRoom will resolve when the HTTP request to join succeeds,
            // NOT when it comes down /sync. If there is no room, we'll keep the
            // joining flag set until we see it. Likewise, if our state is not
            // "join" we'll keep this flag set until it comes down /sync.

            // We'll need to initialise the timeline when joining, but due to
            // the above, we can't do it here: we do it in onRoom instead,
            // once we have a useable room object.
            var room = MatrixClientPeg.get().getRoom(self.props.roomId);
            var me = MatrixClientPeg.get().credentials.userId;
            self.setState({
                joining: room ? !room.hasMembershipState(me, "join") : true,
                room: room
            });
        }, function(error) {
            self.setState({
                joining: false,
                joinError: error
            });
            var msg = error.message ? error.message : JSON.stringify(error);
            var ErrorDialog = sdk.getComponent("dialogs.ErrorDialog");
            Modal.createDialog(ErrorDialog, {
                title: "Failed to join room",
                description: msg
            });
        });
        this.setState({
            joining: true
        });
    },

    onMessageListScroll: function(ev) {
        if (this.refs.messagePanel.isAtBottom() &&
                !this._timelineWindow.canPaginate(EventTimeline.FORWARDS)) {
            if (this.state.numUnreadMessages != 0) {
                this.setState({ numUnreadMessages: 0 });
            }
            if (!this.state.atEndOfLiveTimeline) {
                this.setState({ atEndOfLiveTimeline: true });
            }
        }
        else {
            if (this.state.atEndOfLiveTimeline) {
                this.setState({ atEndOfLiveTimeline: false });
            }
        }
    },

    onDragOver: function(ev) {
        ev.stopPropagation();
        ev.preventDefault();

        ev.dataTransfer.dropEffect = 'none';

        var items = ev.dataTransfer.items;
        if (items.length == 1) {
            if (items[0].kind == 'file') {
                this.setState({ draggingFile : true });
                ev.dataTransfer.dropEffect = 'copy';
            }
        }
    },

    onDrop: function(ev) {
        ev.stopPropagation();
        ev.preventDefault();
        this.setState({ draggingFile : false });
        var files = ev.dataTransfer.files;
        if (files.length == 1) {
            this.uploadFile(files[0]);
        }
    },

    onDragLeaveOrEnd: function(ev) {
        ev.stopPropagation();
        ev.preventDefault();
        this.setState({ draggingFile : false });
    },

    uploadFile: function(file) {
        var self = this;
        ContentMessages.sendContentToRoom(
            file, this.props.roomId, MatrixClientPeg.get()
        ).done(undefined, function(error) {
            var ErrorDialog = sdk.getComponent("dialogs.ErrorDialog");
            Modal.createDialog(ErrorDialog, {
                title: "Failed to upload file",
                description: error.toString()
            });
        });
    },

    onSearch: function(term, scope) {
        this.setState({
            searchTerm: term,
            searchScope: scope,
            searchResults: {},
            searchHighlights: [],
        });

        // if we already have a search panel, we need to tell it to forget
        // about its scroll state.
        if (this.refs.searchResultsPanel) {
            this.refs.searchResultsPanel.resetScrollState();
        }

        // make sure that we don't end up showing results from
        // an aborted search by keeping a unique id.
        //
        // todo: should cancel any previous search requests.
        this.searchId = new Date().getTime();

        var filter;
        if (scope === "Room") {
            filter = {
                // XXX: it's unintuitive that the filter for searching doesn't have the same shape as the v2 filter API :(
                rooms: [
                    this.props.roomId
                ]
            };
        }

        debuglog("sending search request");

        var searchPromise = MatrixClientPeg.get().searchRoomEvents({
            filter: filter,
            term: term,
        });
        this._handleSearchResult(searchPromise).done();
    },

    _handleSearchResult: function(searchPromise) {
        var self = this;

        // keep a record of the current search id, so that if the search terms
        // change before we get a response, we can ignore the results.
        var localSearchId = this.searchId;

        this.setState({
            searchInProgress: true,
        });

        return searchPromise.then(function(results) {
            debuglog("search complete");
            if (self.unmounted || !self.state.searching || self.searchId != localSearchId) {
                console.error("Discarding stale search results");
                return;
            }

            // postgres on synapse returns us precise details of the strings
            // which actually got matched for highlighting.
            //
            // In either case, we want to highlight the literal search term
            // whether it was used by the search engine or not.

            var highlights = results.highlights;
            if (highlights.indexOf(self.state.searchTerm) < 0) {
                highlights = highlights.concat(self.state.searchTerm);
            }

            // For overlapping highlights,
            // favour longer (more specific) terms first
            highlights = highlights.sort(function(a, b) {
                return b.length - a.length });

            self.setState({
                searchHighlights: highlights,
                searchResults: results,
            });
        }, function(error) {
            var ErrorDialog = sdk.getComponent("dialogs.ErrorDialog");
            Modal.createDialog(ErrorDialog, {
                title: "Search failed",
                description: error.toString()
            });
        }).finally(function() {
            self.setState({
                searchInProgress: false
            });
        });
    },

    _onSearchResultSelected: function(result) {
        var event = result.context.getEvent();
        dis.dispatch({
            action: 'view_room',
            room_id: event.getRoomId(),
            event_id: event.getId(),
        });
    },

    getSearchResultTiles: function() {
        var EventTile = sdk.getComponent('rooms.EventTile');
        var SearchResultTile = sdk.getComponent('rooms.SearchResultTile');
        var cli = MatrixClientPeg.get();

        // XXX: todo: merge overlapping results somehow?
        // XXX: why doesn't searching on name work?

        if (this.state.searchResults.results === undefined) {
            // awaiting results
            return [];
        }

        var ret = [];

        if (!this.state.searchResults.next_batch) {
            if (this.state.searchResults.results.length == 0) {
                ret.push(<li key="search-top-marker">
                         <h2 className="mx_RoomView_topMarker">No results</h2>
                         </li>
                        );
            } else {
                ret.push(<li key="search-top-marker">
                         <h2 className="mx_RoomView_topMarker">No more results</h2>
                         </li>
                        );
            }
        }

        var lastRoomId;

        for (var i = this.state.searchResults.results.length - 1; i >= 0; i--) {
            var result = this.state.searchResults.results[i];

            var mxEv = result.context.getEvent();

            if (!EventTile.haveTileForEvent(mxEv)) {
                // XXX: can this ever happen? It will make the result count
                // not match the displayed count.
                continue;
            }

            if (this.state.searchScope === 'All') {
                var roomId = mxEv.getRoomId();
                if(roomId != lastRoomId) {
                    var room = cli.getRoom(roomId);

                    // XXX: if we've left the room, we might not know about
                    // it. We should tell the js sdk to go and find out about
                    // it. But that's not an issue currently, as synapse only
                    // returns results for rooms we're joined to.
                    var roomName = room ? room.name : "Unknown room "+roomId;

                    ret.push(<li key={mxEv.getId() + "-room"}>
                                 <h1>Room: { roomName }</h1>
                             </li>);
                    lastRoomId = roomId;
                }
            }

            ret.push(<SearchResultTile key={mxEv.getId()}
                     searchResult={result}
                     searchHighlights={this.state.searchHighlights}
                     onSelect={this._onSearchResultSelected.bind(this, result)}/>);
        }
        return ret;
    },

    getEventTiles: function() {
        var DateSeparator = sdk.getComponent('messages.DateSeparator');

        var ret = [];
        var count = 0;

        var EventTile = sdk.getComponent('rooms.EventTile');

        var prevEvent = null; // the last event we showed
        var ghostIndex;
        var readMarkerIndex;
        for (var i = 0; i < this.state.events.length; i++) {
            var mxEv = this.state.events[i];

            if (!EventTile.haveTileForEvent(mxEv)) {
                continue;
            }
            if (this.props.ConferenceHandler && mxEv.getType() === "m.room.member") {
                if (this.props.ConferenceHandler.isConferenceUser(mxEv.getSender()) ||
                        this.props.ConferenceHandler.isConferenceUser(mxEv.getStateKey())) {
                    continue; // suppress conf user join/parts
                }
            }

            // now we've decided whether or not to show this message,
            // add the read up to marker if appropriate
            // doing this here means we implicitly do not show the marker
            // if it's at the bottom
            // NB. it would be better to decide where the read marker was going
            // when the state changed rather than here in the render method, but
            // this is where we decide what messages we show so it's the only
            // place we know whether we're at the bottom or not.
            var self = this;
            var mxEvSender = mxEv.sender ? mxEv.sender.userId : null;
            if (prevEvent && prevEvent.getId() == this.state.readMarkerEventId && mxEvSender != MatrixClientPeg.get().credentials.userId) {
                var hr;
                hr = (<hr className="mx_RoomView_myReadMarker" style={{opacity: 1, width: '99%'}} ref={function(n) {
                    self.readMarkerNode = n;
                }} />);
                readMarkerIndex = ret.length;
                ret.push(<li key="_readupto" className="mx_RoomView_myReadMarker_container">{hr}</li>);
            }

            // is this a continuation of the previous message?
            var continuation = false;
            if (prevEvent !== null) {
                if (mxEv.sender &&
                    prevEvent.sender &&
                    (mxEv.sender.userId === prevEvent.sender.userId) &&
                    (mxEv.getType() == prevEvent.getType())
                    )
                {
                    continuation = true;
                }
            }

            // do we need a date separator since the last event?
            var ts1 = mxEv.getTs();
            if ((prevEvent == null && !this.state.canBackPaginate) ||
                (prevEvent != null &&
                 new Date(prevEvent.getTs()).toDateString() !== new Date(ts1).toDateString())) {
                var dateSeparator = <li key={ts1}><DateSeparator key={ts1} ts={ts1}/></li>;
                ret.push(dateSeparator);
                continuation = false;
            }

            var last = false;
            if (i == this.state.events.length - 1) {
                // XXX: we might not show a tile for the last event.
                last = true;
            }

            var eventId = mxEv.getId();
            var highlight = (eventId == this.props.highlightedEventId);

            // we can't use local echoes as scroll tokens, because their event IDs change.
            // Local echos have a send "status".
            var scrollToken = mxEv.status ? undefined : eventId;

            ret.push(
                <li key={eventId} 
                        ref={this._collectEventNode.bind(this, eventId)} 
                        data-scroll-token={scrollToken}>
                    <EventTile mxEvent={mxEv} continuation={continuation}
                        last={last} isSelectedEvent={highlight}/>
                </li>
            );

            // A read up to marker has died and returned as a ghost!
            // Lives in the dom as the ghost of the previous one while it fades away
            if (eventId == this.state.readMarkerGhostEventId) {
                ghostIndex = ret.length;
            }

            prevEvent = mxEv;
        }

        // splice the read marker ghost in now that we know whether the read receipt
        // is the last element or not, because we only decide as we're going along.
        if (readMarkerIndex === undefined && ghostIndex && ghostIndex <= ret.length) {
            var hr;
            hr = (<hr className="mx_RoomView_myReadMarker" style={{opacity: 1, width: '99%'}} ref={function(n) {
                Velocity(n, {opacity: '0', width: '10%'}, {duration: 400, easing: 'easeInSine', delay: 1000, complete: function() {
                    if (!self.unmounted) self.setState({readMarkerGhostEventId: undefined});
                }});
            }} />);
            ret.splice(ghostIndex, 0, (
                <li key="_readuptoghost" className="mx_RoomView_myReadMarker_container">{hr}</li>
            ));
        }

        return ret;
    },

    _collectEventNode: function(eventId, node) {
        if (this.eventNodes == undefined) this.eventNodes = {};
        this.eventNodes[eventId] = node;
    },

    _indexForEventId(evId) {
        for (var i = 0; i < this.state.events.length; ++i) {
            if (evId == this.state.events[i].getId()) {
                return i;
            }
        }
        return null;
    },

    sendReadReceipt: function() {
        if (!this.state.room) return;
        if (!this.refs.messagePanel) return;

        // we don't want to see our RR marker dropping down as we scroll
        // through old history. For now, do this just by leaving the RR where
        // it is until we hit the bottom of the room, though ultimately we
        // probably want to keep sending RR, but hide the RR until we reach
        // the bottom of the room again, or something.
        if (!this.state.atEndOfLiveTimeline) return;

        var currentReadUpToEventId = this.state.room.getEventReadUpTo(MatrixClientPeg.get().credentials.userId);
        var currentReadUpToEventIndex = this._indexForEventId(currentReadUpToEventId);

        // We want to avoid sending out read receipts when we are looking at
        // events in the past which are before the latest RR.
        //
        // For now, let's apply a heuristic: if (a) the event corresponding to
        // the latest RR (either from the server, or sent by ourselves) doesn't
        // appear in our timeline, and (b) we could forward-paginate the event
        // timeline, then don't send any more RRs.
        //
        // This isn't watertight, as we could be looking at a section of
        // timeline which is *after* the latest RR (so we should actually send
        // RRs) - but that is a bit of a niche case. It will sort itself out when
        // the user eventually hits the live timeline.
        //
        if (currentReadUpToEventId && currentReadUpToEventIndex === null &&
                this._timelineWindow.canPaginate(EventTimeline.FORWARDS)) {
            return;
        }

        var lastReadEventIndex = this._getLastDisplayedEventIndexIgnoringOwn();
        if (lastReadEventIndex === null) return;

        var lastReadEvent = this.state.events[lastReadEventIndex];

        // we also remember the last read receipt we sent to avoid spamming the same one at the server repeatedly
        if (lastReadEventIndex > currentReadUpToEventIndex && this.last_rr_sent_event_id != lastReadEvent.getId()) {
            this.last_rr_sent_event_id = lastReadEvent.getId();
            MatrixClientPeg.get().sendReadReceipt(lastReadEvent).catch(() => {
                // it failed, so allow retries next time the user is active
                this.last_rr_sent_event_id = undefined;
            });
        }
    },

    _getLastDisplayedEventIndexIgnoringOwn: function() {
        if (this.eventNodes === undefined) return null;

        var messageWrapper = this.refs.messagePanel;
        if (messageWrapper === undefined) return null;
        var wrapperRect = ReactDOM.findDOMNode(messageWrapper).getBoundingClientRect();

        for (var i = this.state.events.length-1; i >= 0; --i) {
            var ev = this.state.events[i];

            if (ev.sender && ev.sender.userId == MatrixClientPeg.get().credentials.userId) {
                continue;
            }

            var node = this.eventNodes[ev.getId()];
            if (!node) continue;

            var boundingRect = node.getBoundingClientRect();

            if (boundingRect.bottom < wrapperRect.bottom) {
                return i;
            }
        }
        return null;
    },

    onSettingsClick: function() {
        this.showSettings(true);
    },

    onSettingsSaveClick: function() {
        this.setState({
            uploadingRoomSettings: true,
        });
        
        this.refs.room_settings.setName(this.refs.header.getRoomName());
        this.refs.room_settings.setTopic(this.refs.header.getTopic());
        
        this.refs.room_settings.save().then((results) => {
            var fails = results.filter(function(result) { return result.state !== "fulfilled" });
            console.log("Settings saved with %s errors", fails.length);
            if (fails.length) {
                fails.forEach(function(result) {
                    console.error(result.reason);
                });
                var ErrorDialog = sdk.getComponent("dialogs.ErrorDialog");
                Modal.createDialog(ErrorDialog, {
                    title: "Failed to save settings",
                    description: fails.map(function(result) { return result.reason }).join("\n"),
                });
                // still editing room settings
            }
            else {
                this.setState({
                    editingRoomSettings: false
                });
            }
        }).finally(() => {
            this.setState({
                uploadingRoomSettings: false,
                editingRoomSettings: false
            });
        }).done();
    },

    onCancelClick: function() {
        this.updateTint();
        this.setState({editingRoomSettings: false});
    },

    onLeaveClick: function() {
        dis.dispatch({
            action: 'leave_room',
            room_id: this.props.roomId,
        });
    },

    onForgetClick: function() {
        MatrixClientPeg.get().forget(this.props.roomId).done(function() {
            dis.dispatch({ action: 'view_next_room' });
        }, function(err) {
            var errCode = err.errcode || "unknown error code";
            var ErrorDialog = sdk.getComponent("dialogs.ErrorDialog");
            Modal.createDialog(ErrorDialog, {
                title: "Error",
                description: `Failed to forget room (${errCode})`
            });
        });
    },

    onRejectButtonClicked: function(ev) {
        var self = this;
        this.setState({
            rejecting: true
        });
        MatrixClientPeg.get().leave(this.props.roomId).done(function() {
            dis.dispatch({ action: 'view_next_room' });
            self.setState({
                rejecting: false
            });
        }, function(error) {
            console.error("Failed to reject invite: %s", error);

            var msg = error.message ? error.message : JSON.stringify(error);
            var ErrorDialog = sdk.getComponent("dialogs.ErrorDialog");
            Modal.createDialog(ErrorDialog, {
                title: "Failed to reject invite",
                description: msg
            });

            self.setState({
                rejecting: false,
                rejectError: error
            });
        });
    },

    onSearchClick: function() {
        this.setState({ searching: true });
    },

    onCancelSearchClick: function () {
        this.setState({
            searching: false,
            searchResults: null,
        });
    },

    onConferenceNotificationClick: function() {
        dis.dispatch({
            action: 'place_call',
            type: "video",
            room_id: this.props.roomId
        });
    },

    // jump down to the bottom of this room, where new events are arriving
    jumpToLiveTimeline: function() {
        // if we can't forward-paginate the existing timeline, then there
        // is no point reloading it - just jump straight to the bottom.
        //
        // Otherwise, reload the timeline rather than trying to paginate
        // through all of space-time.
        if (this._timelineWindow.canPaginate(EventTimeline.FORWARDS)) {
            this._loadTimeline();
        } else {
            if (this.refs.messagePanel) {
                this.refs.messagePanel.scrollToBottom();
            }
        }
    },

    // get the current scroll position of the room, so that it can be
    // restored when we switch back to it.
    //
    // If there is no special scroll state (ie, we are following the live
    // timeline), returns null. Otherwise, returns an object with the following
    // properties:
    //
    //    focussedEvent: the ID of the 'focussed' event. Typically this is the
    //        last event fully visible in the viewport, though if we have done
    //        an explicit scroll to an explicit event, it will be that event.
    //
    //    pixelOffset: the number of pixels the window is scrolled down from
    //        the focussedEvent.
    //
    //
    getScrollState: function() {
        var messagePanel = this.refs.messagePanel;
        if (!messagePanel) return null;

        // if we're following the live timeline, we want to return null; that
        // means that, if we switch back, we will jump to the read-up-to mark.
        //
        // That should be more intuitive than slavishly preserving the current
        // scroll state, in the case where the room advances in the meantime
        // (particularly in the case that the user reads some stuff on another
        // device).
        //
        if (this.state.atEndOfLiveTimeline) {
            return null;
        }

        var scrollState = messagePanel.getScrollState();

        if (scrollState.stuckAtBottom) {
            // we don't really expect to be in this state, but it will
            // occasionally happen when no scroll state has been set on the
            // messagePanel (ie, we didn't have an initial event (so it's
            // probably a new room), there has been no user-initiated scroll, and
            // no read-receipts have arrived to update the scroll position).
            //
            // Return null, which will cause us to scroll to last unread on
            // reload.
            return null;
        }

        return {
            focussedEvent: scrollState.trackedScrollToken,
            pixelOffset: scrollState.pixelOffset,
        };
    },

    onResize: function(e) {
        // It seems flexbox doesn't give us a way to constrain the auxPanel height to have
        // a minimum of the height of the video element, whilst also capping it from pushing out the page
        // so we have to do it via JS instead.  In this implementation we cap the height by putting
        // a maxHeight on the underlying remote video tag.

        // header + footer + status + give us at least 120px of scrollback at all times.
        var auxPanelMaxHeight = window.innerHeight -
                (83 + // height of RoomHeader
                 36 + // height of the status area
                 72 + // minimum height of the message compmoser
                 (this.state.editingRoomSettings ? (window.innerHeight * 0.3) : 120)); // amount of desired scrollback

        // XXX: this is a bit of a hack and might possibly cause the video to push out the page anyway
        // but it's better than the video going missing entirely
        if (auxPanelMaxHeight < 50) auxPanelMaxHeight = 50;

        if (this.refs.callView) {
            var video = this.refs.callView.getVideoView().getRemoteVideoElement();

            video.style.maxHeight = auxPanelMaxHeight + "px";
        }

        // we need to do this for general auxPanels too
        if (this.refs.auxPanel) {
            this.refs.auxPanel.style.maxHeight = auxPanelMaxHeight + "px";
        }

        // the above might have made the aux panel resize itself, so now
        // we need to tell the gemini panel to adapt.
        this.onChildResize();
    },

    onFullscreenClick: function() {
        dis.dispatch({
            action: 'video_fullscreen',
            fullscreen: true
        }, true);
    },

    onMuteAudioClick: function() {
        var call = CallHandler.getCallForRoom(this.props.roomId);
        if (!call) {
            return;
        }
        var newState = !call.isMicrophoneMuted();
        call.setMicrophoneMuted(newState);
        this.setState({
            audioMuted: newState
        });
    },

    onMuteVideoClick: function() {
        var call = CallHandler.getCallForRoom(this.props.roomId);
        if (!call) {
            return;
        }
        var newState = !call.isLocalVideoMuted();
        call.setLocalVideoMuted(newState);
        this.setState({
            videoMuted: newState
        });
    },

    onChildResize: function() {
        // When the video or the message composer resizes, the scroll panel
        // also changes size.  Work around GeminiScrollBar fail by telling it
        // about it. This also ensures that the scroll offset is updated.
        if (this.refs.messagePanel) {
            this.refs.messagePanel.forceUpdate();
        }
    },

    showSettings: function(show) {
        // XXX: this is a bit naughty; we should be doing this via props
        if (show) {
            this.setState({editingRoomSettings: true});
            var self = this;
            setTimeout(function() { self.onResize() }, 0);
        }
    },

    render: function() {
        var RoomHeader = sdk.getComponent('rooms.RoomHeader');
        var MessageComposer = sdk.getComponent('rooms.MessageComposer');
        var CallView = sdk.getComponent("voip.CallView");
        var RoomSettings = sdk.getComponent("rooms.RoomSettings");
        var SearchBar = sdk.getComponent("rooms.SearchBar");
        var ScrollPanel = sdk.getComponent("structures.ScrollPanel");
        var TintableSvg = sdk.getComponent("elements.TintableSvg");
        var RoomPreviewBar = sdk.getComponent("rooms.RoomPreviewBar");
        var Loader = sdk.getComponent("elements.Spinner");

        if (!this._timelineWindow) {
            if (this.props.roomId) {
                if (this.state.timelineLoading) {
                    return (
                        <div className="mx_RoomView">
                            <Loader />
                        </div>
                    );                
                }
                else {
                    return (
                        <div className="mx_RoomView">
                            <RoomHeader ref="header" room={this.state.room} simpleHeader="Join room"/>
                            <div className="mx_RoomView_auxPanel">
                                <RoomPreviewBar onJoinClick={ this.onJoinButtonClicked } 
                                                canJoin={ true } canPreview={ false }
                                                spinner={this.state.joining}
                                />
                            </div>
                            <div className="mx_RoomView_messagePanel"></div>
                        </div>
                    );                    
                }
            }
            else {
                return (
                    <div />
                );
            }
        }

        var myUserId = MatrixClientPeg.get().credentials.userId;
        var myMember = this.state.room.getMember(myUserId);
        if (myMember && myMember.membership == 'invite') {
            if (this.state.joining || this.state.rejecting) {
                return (
                    <div className="mx_RoomView">
                        <Loader />
                    </div>
                );
            } else {
                var inviteEvent = myMember.events.member;
                var inviterName = inviteEvent.sender ? inviteEvent.sender.name : inviteEvent.getSender();

                // We deliberately don't try to peek into invites, even if we have permission to peek
                // as they could be a spam vector.
                // XXX: in future we could give the option of a 'Preview' button which lets them view anyway.

                return (
                    <div className="mx_RoomView">
                        <RoomHeader ref="header" room={this.state.room}/>
                        <div className="mx_RoomView_auxPanel">
                            <RoomPreviewBar onJoinClick={ this.onJoinButtonClicked } 
                                            onRejectClick={ this.onRejectButtonClicked }
                                            inviterName={ inviterName }
                                            canJoin={ true } canPreview={ false }
                                            spinner={this.state.joining}
                            />
                        </div>
                        <div className="mx_RoomView_messagePanel"></div>
                    </div>
                );
            }
        }

        // We have successfully loaded this room, and are not previewing.
        // Display the "normal" room view.

        var call = CallHandler.getCallForRoom(this.props.roomId);
        var inCall = false;
        if (call && (this.state.callState !== 'ended' && this.state.callState !== 'ringing')) {
            inCall = true;
        }

        var scrollheader_classes = classNames({
            mx_RoomView_scrollheader: true,
            loading: this.state.paginating
        });

        var statusBar;

        // for testing UI...
        // this.state.upload = {
        //     uploadedBytes: 123493,
        //     totalBytes: 347534,
        //     fileName: "testing_fooble.jpg",
        // }

        if (ContentMessages.getCurrentUploads().length > 0) {
            var UploadBar = sdk.getComponent('structures.UploadBar');
            statusBar = <UploadBar room={this.state.room} />
        } else if (!this.state.searchResults) {
            var RoomStatusBar = sdk.getComponent('structures.RoomStatusBar');
            var tabEntries = this.tabComplete.isTabCompleting() ?
                this.tabComplete.peek(6) : null;

            statusBar = <RoomStatusBar
                room={this.state.room}
                tabCompleteEntries={tabEntries}
                numUnreadMessages={this.state.numUnreadMessages}
                hasUnsentMessages={this.state.hasUnsentMessages}
                atEndOfLiveTimeline={this.state.atEndOfLiveTimeline}
                hasActiveCall={inCall}
                onResendAllClick={this.onResendAllClick}
                onScrollToBottomClick={this.jumpToLiveTimeline}
                />
        }

        var aux = null;
        if (this.state.editingRoomSettings) {
            aux = <RoomSettings ref="room_settings" onSaveClick={this.onSettingsSaveClick} onCancelClick={this.onCancelClick} room={this.state.room} />;
        }
        else if (this.state.uploadingRoomSettings) {
            aux = <Loader/>;
        }
        else if (this.state.searching) {
            aux = <SearchBar ref="search_bar" searchInProgress={this.state.searchInProgress } onCancelClick={this.onCancelSearchClick} onSearch={this.onSearch}/>;
        }
        else if (this.state.guestsCanJoin && MatrixClientPeg.get().isGuest() &&
                (!myMember || myMember.membership !== "join")) {
            aux = (
                <RoomPreviewBar onJoinClick={this.onJoinButtonClicked} canJoin={true}
                                spinner={this.state.joining}
                />
            );
        }
        else if (this.state.canPeek &&
                (!myMember || myMember.membership !== "join")) {
            aux = (
                <RoomPreviewBar onJoinClick={this.onJoinButtonClicked} canJoin={true}
                                spinner={this.state.joining}
                />
            );
        }

        var conferenceCallNotification = null;
        if (this.state.displayConfCallNotification) {
            var supportedText;
            if (!MatrixClientPeg.get().supportsVoip()) {
                supportedText = " (unsupported)";
            }
            conferenceCallNotification = (
                <div className="mx_RoomView_ongoingConfCallNotification" onClick={this.onConferenceNotificationClick}>
                    Ongoing conference call {supportedText}
                </div>
            );
        }

        var fileDropTarget = null;
        if (this.state.draggingFile) {
            fileDropTarget = <div className="mx_RoomView_fileDropTarget">
                                <div className="mx_RoomView_fileDropTargetLabel" title="Drop File Here">
                                    <TintableSvg src="img/upload-big.svg" width="45" height="59"/><br/>
                                    Drop file here to upload
                                </div>
                             </div>;
        }

        var messageComposer, searchInfo;
        var canSpeak = (
            // joined and not showing search results
            myMember && (myMember.membership == 'join') && !this.state.searchResults
        );
        if (canSpeak) {
            messageComposer =
                <MessageComposer
                    room={this.state.room} onResize={this.onChildResize} uploadFile={this.uploadFile}
                    callState={this.state.callState} tabComplete={this.tabComplete} />
        }

        // TODO: Why aren't we storing the term/scope/count in this format
        // in this.state if this is what RoomHeader desires?
        if (this.state.searchResults) {
            searchInfo = {
                searchTerm : this.state.searchTerm,
                searchScope : this.state.searchScope,
                searchCount : this.state.searchResults.count,
            };
        }

        if (inCall) {
            var zoomButton, voiceMuteButton, videoMuteButton;

            if (call.type === "video") {
                zoomButton = (
                    <div className="mx_RoomView_voipButton" onClick={this.onFullscreenClick} title="Fill screen">
                        <TintableSvg src="img/fullscreen.svg" width="29" height="22" style={{ marginTop: 1, marginRight: 4 }}/>
                    </div>
                );

                videoMuteButton =
                    <div className="mx_RoomView_voipButton" onClick={this.onMuteVideoClick}>
                        <img src={call.isLocalVideoMuted() ? "img/video-unmute.svg" : "img/video-mute.svg"}
                             alt={call.isLocalVideoMuted() ? "Click to unmute video" : "Click to mute video"}
                             width="31" height="27"/>
                    </div>
            }
            voiceMuteButton =
                <div className="mx_RoomView_voipButton" onClick={this.onMuteAudioClick}>
                    <img src={call.isMicrophoneMuted() ? "img/voice-unmute.svg" : "img/voice-mute.svg"} 
                         alt={call.isMicrophoneMuted() ? "Click to unmute audio" : "Click to mute audio"} 
                         width="21" height="26"/>
                </div>

            // wrap the existing status bar into a 'callStatusBar' which adds more knobs.
            statusBar =
                <div className="mx_RoomView_callStatusBar">
                    { voiceMuteButton }
                    { videoMuteButton }
                    { zoomButton }
                    { statusBar }
                    <TintableSvg className="mx_RoomView_voipChevron" src="img/voip-chevron.svg" width="22" height="17"/>
                </div>
        }

        // if we have search results, we keep the messagepanel (so that it preserves its
        // scroll state), but hide it.
        var searchResultsPanel;
        var hideMessagePanel = false;

        if (this.state.searchResults) {
            searchResultsPanel = (
                <ScrollPanel ref="searchResultsPanel" className="mx_RoomView_messagePanel"
                        onFillRequest={ this.onSearchResultsFillRequest }>
                    <li className={scrollheader_classes}></li>
                    {this.getSearchResultTiles()}
                </ScrollPanel>
            );
            hideMessagePanel = true;
        }

        var messagePanel;

        // just show a spinner while the timeline loads.
        //
        // put it in a div of the right class (mx_RoomView_messagePanel) so
        // that the order in the roomview flexbox is correct, and
        // mx_RoomView_messageListWrapper to position the inner div in the
        // right place.
        //
        // Note that the click-on-search-result functionality relies on the
        // fact that the messagePanel is hidden while the timeline reloads,
        // but that the RoomHeader (complete with search term) continues to
        // exist.
        if (this.state.timelineLoading) {
            messagePanel = (
                    <div className="mx_RoomView_messagePanel mx_RoomView_messageListWrapper">
                        <Loader />
                    </div>
            );
        } else {
            // give the messagepanel a stickybottom if we're at the end of the
            // live timeline, so that the arrival of new events triggers a
            // scroll.
            //
            // Make sure that stickyBottom is *false* if we can paginate
            // forwards, otherwise if somebody hits the bottom of the loaded
            // events when viewing historical messages, we get stuck in a loop
            // of paginating our way through the entire history of the room.
            var stickyBottom = !this._timelineWindow.canPaginate(EventTimeline.FORWARDS);

            messagePanel = (
                <ScrollPanel ref="messagePanel" className="mx_RoomView_messagePanel"
                        onScroll={ this.onMessageListScroll } 
                        onFillRequest={ this.onMessageListFillRequest }
                        style={ hideMessagePanel ? { display: 'none' } : {} }
                        stickyBottom={ stickyBottom }>
                    <li className={scrollheader_classes}></li>
                    {this.getEventTiles()}
                </ScrollPanel>
            );
        }

        return (
            <div className={ "mx_RoomView" + (inCall ? " mx_RoomView_inCall" : "") } ref="roomView">
                <RoomHeader ref="header" room={this.state.room} searchInfo={searchInfo}
                    editing={this.state.editingRoomSettings}
                    onSearchClick={this.onSearchClick}
                    onSettingsClick={this.onSettingsClick}
                    onSaveClick={this.onSettingsSaveClick}
                    onCancelClick={this.onCancelClick}
                    onForgetClick={
                        (myMember && myMember.membership === "leave") ? this.onForgetClick : null
                    }
                    onLeaveClick={
                        (myMember && myMember.membership === "join") ? this.onLeaveClick : null
                    } />
                <div className="mx_RoomView_auxPanel" ref="auxPanel">
                    { fileDropTarget }    
                    <CallView ref="callView" room={this.state.room} ConferenceHandler={this.props.ConferenceHandler}
                        onResize={this.onChildResize} />
                    { conferenceCallNotification }
                    { aux }
                </div>
                { messagePanel }
                { searchResultsPanel }
                <div className="mx_RoomView_statusArea">
                    <div className="mx_RoomView_statusAreaBox">
                        <div className="mx_RoomView_statusAreaBox_line"></div>
                        { statusBar }
                    </div>
                </div>
                { messageComposer }
            </div>
        );
    },
});