element-web/src/utils/EventUtils.ts

/*
Copyright 2024 New Vector Ltd.
Copyright 2019-2022 The Matrix.org Foundation C.I.C.

SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only
Please see LICENSE files in the repository root for full details.
*/

import {
    EventStatus,
    MatrixEvent,
    EventType,
    EVENT_VISIBILITY_CHANGE_TYPE,
    MsgType,
    RelationType,
    MatrixClient,
    THREAD_RELATION_TYPE,
    M_POLL_END,
    M_POLL_START,
    M_LOCATION,
    M_BEACON_INFO,
} from "matrix-js-sdk/src/matrix";
import { logger } from "matrix-js-sdk/src/logger";

import shouldHideEvent from "../shouldHideEvent";
import { GetRelationsForEvent } from "../components/views/rooms/EventTile";
import SettingsStore from "../settings/SettingsStore";
import defaultDispatcher from "../dispatcher/dispatcher";
import { TimelineRenderingType } from "../contexts/RoomContext";
import { launchPollEditor } from "../components/views/messages/MPollBody";
import { Action } from "../dispatcher/actions";
import { ViewRoomPayload } from "../dispatcher/payloads/ViewRoomPayload";
import { VoiceBroadcastInfoEventType, VoiceBroadcastInfoState } from "../voice-broadcast/types";

/**
 * Returns whether an event should allow actions like reply, reactions, edit, etc.
 * which effectively checks whether it's a regular message that has been sent and that we
 * can display.
 *
 * @param {MatrixEvent} mxEvent The event to check
 * @returns {boolean} true if actionable
 */
export function isContentActionable(mxEvent: MatrixEvent): boolean {
    const { status: eventStatus } = mxEvent;

    // status is SENT before remote-echo, null after
    const isSent = !eventStatus || eventStatus === EventStatus.SENT;

    if (isSent && !mxEvent.isRedacted()) {
        if (mxEvent.getType() === "m.room.message") {
            const content = mxEvent.getContent();
            if (content.msgtype && content.msgtype !== "m.bad.encrypted" && content.hasOwnProperty("body")) {
                return true;
            }
        } else if (
            mxEvent.getType() === "m.sticker" ||
            M_POLL_START.matches(mxEvent.getType()) ||
            M_POLL_END.matches(mxEvent.getType()) ||
            M_BEACON_INFO.matches(mxEvent.getType()) ||
            (mxEvent.getType() === VoiceBroadcastInfoEventType &&
                mxEvent.getContent()?.state === VoiceBroadcastInfoState.Started)
        ) {
            return true;
        }
    }

    return false;
}

export function canEditContent(matrixClient: MatrixClient, mxEvent: MatrixEvent): boolean {
    const isCancellable = mxEvent.getType() === EventType.RoomMessage || M_POLL_START.matches(mxEvent.getType());

    if (
        !isCancellable ||
        mxEvent.status === EventStatus.CANCELLED ||
        mxEvent.isRedacted() ||
        mxEvent.isRelation(RelationType.Replace) ||
        mxEvent.getSender() !== matrixClient.getUserId()
    ) {
        return false;
    }

    const { msgtype, body } = mxEvent.getOriginalContent();
    return (
        M_POLL_START.matches(mxEvent.getType()) ||
        ((msgtype === MsgType.Text || msgtype === MsgType.Emote) && !!body && typeof body === "string")
    );
}

export function canEditOwnEvent(matrixClient: MatrixClient, mxEvent: MatrixEvent): boolean {
    // for now we only allow editing
    // your own events. So this just call through
    // In the future though, moderators will be able to
    // edit other people's messages as well but we don't
    // want findEditableEvent to return other people's events
    // hence this method.
    return canEditContent(matrixClient, mxEvent);
}

const MAX_JUMP_DISTANCE = 100;
export function findEditableEvent({
    matrixClient,
    events,
    isForward,
    fromEventId,
}: {
    matrixClient: MatrixClient;
    events: MatrixEvent[];
    isForward: boolean;
    fromEventId?: string;
}): MatrixEvent | undefined {
    if (!events.length) return;
    const maxIdx = events.length - 1;
    const inc = isForward ? 1 : -1;
    const beginIdx = isForward ? 0 : maxIdx;
    let endIdx = isForward ? maxIdx : 0;
    if (!fromEventId) {
        endIdx = Math.min(Math.max(0, beginIdx + inc * MAX_JUMP_DISTANCE), maxIdx);
    }
    let foundFromEventId = !fromEventId;
    for (let i = beginIdx; i !== endIdx + inc; i += inc) {
        const e = events[i];
        // find start event first
        if (!foundFromEventId && e.getId() === fromEventId) {
            foundFromEventId = true;
            // don't look further than MAX_JUMP_DISTANCE events from `fromEventId`
            // to not iterate potentially 1000nds of events on key up/down
            endIdx = Math.min(Math.max(0, i + inc * MAX_JUMP_DISTANCE), maxIdx);
        } else if (foundFromEventId && !shouldHideEvent(e) && canEditOwnEvent(matrixClient, e)) {
            // otherwise look for editable event
            return e;
        }
    }
}

/**
 * How we should render a message depending on its moderation state.
 */
export enum MessageModerationState {
    /**
     * The message is visible to all.
     */
    VISIBLE_FOR_ALL = "VISIBLE_FOR_ALL",
    /**
     * The message is hidden pending moderation and we're not a user who should
     * see it nevertheless.
     */
    HIDDEN_TO_CURRENT_USER = "HIDDEN_TO_CURRENT_USER",
    /**
     * The message is hidden pending moderation and we're either the author of
     * the message or a moderator. In either case, we need to see the message
     * with a marker.
     */
    SEE_THROUGH_FOR_CURRENT_USER = "SEE_THROUGH_FOR_CURRENT_USER",
}

// This is lazily initialized and cached since getMessageModerationState needs it,
// and is called on timeline rendering hot-paths
let msc3531Enabled: boolean | null = null;
const getMsc3531Enabled = (): boolean => {
    if (msc3531Enabled === null) {
        msc3531Enabled = SettingsStore.getValue("feature_msc3531_hide_messages_pending_moderation");
    }
    return msc3531Enabled!;
};

/**
 * Determine whether a message should be displayed as hidden pending moderation.
 *
 * If MSC3531 is deactivated in settings, all messages are considered visible
 * to all.
 */
export function getMessageModerationState(mxEvent: MatrixEvent, client: MatrixClient): MessageModerationState {
    if (!getMsc3531Enabled()) {
        return MessageModerationState.VISIBLE_FOR_ALL;
    }
    const visibility = mxEvent.messageVisibility();
    if (visibility.visible) {
        return MessageModerationState.VISIBLE_FOR_ALL;
    }

    // At this point, we know that the message is marked as hidden
    // pending moderation. However, if we're the author or a moderator,
    // we still need to display it.

    if (mxEvent.sender?.userId === client.getUserId()) {
        // We're the author, show the message.
        return MessageModerationState.SEE_THROUGH_FOR_CURRENT_USER;
    }

    const room = client.getRoom(mxEvent.getRoomId());
    if (
        EVENT_VISIBILITY_CHANGE_TYPE.name &&
        room?.currentState.maySendStateEvent(EVENT_VISIBILITY_CHANGE_TYPE.name, client.getUserId()!)
    ) {
        // We're a moderator (as indicated by prefixed event name), show the message.
        return MessageModerationState.SEE_THROUGH_FOR_CURRENT_USER;
    }
    if (
        EVENT_VISIBILITY_CHANGE_TYPE.altName &&
        room?.currentState.maySendStateEvent(EVENT_VISIBILITY_CHANGE_TYPE.altName, client.getUserId()!)
    ) {
        // We're a moderator (as indicated by unprefixed event name), show the message.
        return MessageModerationState.SEE_THROUGH_FOR_CURRENT_USER;
    }
    // For everybody else, hide the message.
    return MessageModerationState.HIDDEN_TO_CURRENT_USER;
}

export function isVoiceMessage(mxEvent: MatrixEvent): boolean {
    const content = mxEvent.getContent();
    // MSC2516 is a legacy identifier. See https://github.com/matrix-org/matrix-doc/pull/3245
    return !!content["org.matrix.msc2516.voice"] || !!content["org.matrix.msc3245.voice"];
}

export async function fetchInitialEvent(
    client: MatrixClient,
    roomId: string,
    eventId: string,
): Promise<MatrixEvent | null> {
    let initialEvent: MatrixEvent | null;

    try {
        const eventData = await client.fetchRoomEvent(roomId, eventId);
        initialEvent = new MatrixEvent(eventData);
    } catch {
        logger.warn("Could not find initial event: " + eventId);
        initialEvent = null;
    }

    if (client.supportsThreads() && initialEvent?.isRelation(THREAD_RELATION_TYPE.name) && !initialEvent.getThread()) {
        const threadId = initialEvent.threadRootId!;
        const room = client.getRoom(roomId);
        const mapper = client.getEventMapper();
        const rootEvent = room?.findEventById(threadId) ?? mapper(await client.fetchRoomEvent(roomId, threadId));
        try {
            room?.createThread(threadId, rootEvent, [initialEvent], true);
        } catch {
            logger.warn("Could not find root event: " + threadId);
        }
    }

    return initialEvent;
}

export function editEvent(
    matrixClient: MatrixClient,
    mxEvent: MatrixEvent,
    timelineRenderingType: TimelineRenderingType,
    getRelationsForEvent?: GetRelationsForEvent,
): void {
    if (!canEditContent(matrixClient, mxEvent)) return;

    if (M_POLL_START.matches(mxEvent.getType())) {
        launchPollEditor(mxEvent, getRelationsForEvent);
    } else {
        defaultDispatcher.dispatch({
            action: Action.EditEvent,
            event: mxEvent,
            timelineRenderingType: timelineRenderingType,
        });
    }
}

export function canCancel(status?: EventStatus | null): boolean {
    return status === EventStatus.QUEUED || status === EventStatus.NOT_SENT || status === EventStatus.ENCRYPTING;
}

export const isLocationEvent = (event: MatrixEvent): boolean => {
    const eventType = event.getType();
    return (
        M_LOCATION.matches(eventType) ||
        (eventType === EventType.RoomMessage && M_LOCATION.matches(event.getContent().msgtype!))
    );
};

export function hasThreadSummary(event: MatrixEvent): boolean {
    return event.isThreadRoot && !!event.getThread()?.length && !!event.getThread()!.replyToEvent;
}

export const highlightEvent = (roomId: string, eventId: string): void => {
    defaultDispatcher.dispatch<ViewRoomPayload>({
        action: Action.ViewRoom,
        event_id: eventId,
        highlighted: true,
        room_id: roomId,
        metricsTrigger: undefined, // room doesn't change
    });
};