zulip/web/src/message_util.ts

import assert from "minimalistic-assert";

import {all_messages_data} from "./all_messages_data";
import type {MessageList, RenderInfo} from "./message_list";
import type {MessageListData} from "./message_list_data";
import * as message_lists from "./message_lists";
import * as message_store from "./message_store";
import type {Message} from "./message_store";
import * as people from "./people";
import * as pm_conversations from "./pm_conversations";
import * as unread from "./unread";
import * as unread_ui from "./unread_ui";

type DirectMessagePermissionHints = {
    is_known_empty_conversation: boolean;
    is_local_echo_safe: boolean;
};

export function do_unread_count_updates(messages: Message[], expect_no_new_unreads = false): void {
    const any_new_unreads = unread.process_loaded_messages(messages, expect_no_new_unreads);

    if (any_new_unreads) {
        // The following operations are expensive, and thus should
        // only happen if we found any unread messages justifying it.
        unread_ui.update_unread_counts();
    }
}

export function add_messages(
    messages: Message[],
    msg_list: MessageList,
    append_to_view_opts: {messages_are_new: boolean},
): RenderInfo | undefined {
    if (!messages) {
        return undefined;
    }

    const render_info = msg_list.add_messages(messages, append_to_view_opts);

    return render_info;
}

export function add_old_messages(
    messages: Message[],
    msg_list: MessageList,
): RenderInfo | undefined {
    return add_messages(messages, msg_list, {messages_are_new: false});
}

export function add_new_messages(
    messages: Message[],
    msg_list: MessageList,
): RenderInfo | undefined {
    if (!msg_list.data.fetch_status.has_found_newest()) {
        // We don't render newly received messages for the message list,
        // if we haven't found the latest messages to be displayed in the
        // narrow. Otherwise the new message would be rendered just after
        // the previously fetched messages when that's inaccurate.
        msg_list.data.fetch_status.update_expected_max_message_id(messages);
        return undefined;
    }
    return add_messages(messages, msg_list, {messages_are_new: true});
}

export function add_new_messages_data(
    messages: Message[],
    msg_list_data: MessageListData,
):
    | {
          top_messages: Message[];
          bottom_messages: Message[];
          interior_messages: Message[];
      }
    | undefined {
    if (!msg_list_data.fetch_status.has_found_newest()) {
        const filtered_msgs = msg_list_data.valid_non_duplicated_messages(messages);
        // The reasoning in add_new_messages applies here as well;
        // we're trying to maintain a data structure that's a
        // contiguous range of message history, so we can't append a
        // new message that might not be adjacent to that range.
        msg_list_data.fetch_status.update_expected_max_message_id(filtered_msgs);
        return undefined;
    }
    return msg_list_data.add_messages(messages);
}

export function get_messages_in_topic(stream_id: number, topic: string): Message[] {
    return all_messages_data
        .all_messages()
        .filter(
            (x) =>
                x.type === "stream" &&
                x.stream_id === stream_id &&
                x.topic.toLowerCase() === topic.toLowerCase(),
        );
}

export function get_messages_in_dm_conversations(user_ids_strings: Set<string>): Message[] {
    return all_messages_data
        .all_messages()
        .filter((x) => x.type === "private" && user_ids_strings.has(x.to_user_ids));
}

export function get_max_message_id_in_stream(stream_id: number): number {
    let max_message_id = 0;
    for (const msg of all_messages_data.all_messages()) {
        if (msg.type === "stream" && msg.stream_id === stream_id && msg.id > max_message_id) {
            max_message_id = msg.id;
        }
    }
    return max_message_id;
}

export function get_topics_for_message_ids(message_ids: number[]): Map<string, [number, string]> {
    const topics = new Map<string, [number, string]>(); // key = stream_id:topic
    for (const msg_id of message_ids) {
        // message_store still has data on deleted messages when this runs.
        const message = message_store.get(msg_id);
        if (message === undefined) {
            // We may not have the deleted message cached locally in
            // message_store; if so, we can just skip processing it.
            continue;
        }
        if (message.type === "stream") {
            // Create unique keys for stream_id and topic.
            const topic_key = message.stream_id + ":" + message.topic;
            topics.set(topic_key, [message.stream_id, message.topic]);
        }
    }
    return topics;
}

export function get_direct_message_permission_hints(
    recipient_ids_string: string,
): DirectMessagePermissionHints {
    // Check if there are any previous messages in the DM conversation.
    const have_conversation_in_cache =
        pm_conversations.recent.has_conversation(recipient_ids_string);
    if (have_conversation_in_cache) {
        return {is_known_empty_conversation: false, is_local_echo_safe: true};
    }

    // If not, we need to check if the current filter matches the DM view we
    // are composing to.
    const dm_conversation = message_lists.current?.data?.filter.operands("dm")[0];
    if (dm_conversation) {
        const current_user_ids_string = people.emails_strings_to_user_ids_string(dm_conversation);
        assert(current_user_ids_string !== undefined);
        // If it matches and the messages for the current filter are fetched,
        // then there are certainly no messages in the conversation.
        if (
            people.pm_lookup_key(recipient_ids_string) ===
                people.pm_lookup_key(current_user_ids_string) &&
            message_lists.current?.data?.fetch_status.has_found_newest()
        ) {
            return {is_known_empty_conversation: true, is_local_echo_safe: true};
        }
    }

    // If it does not match, then there can be messages in the DM conversation
    // which are not fetched locally and hence we disable local echo for clean
    // error handling in case there are no messages in the conversation and
    // user is not allowed to initiate DM conversations.
    return {is_known_empty_conversation: false, is_local_echo_safe: false};
}

export function user_can_send_direct_message(user_ids_string: string): boolean {
    return (
        (!get_direct_message_permission_hints(user_ids_string).is_known_empty_conversation ||
            people.user_can_initiate_direct_message_thread(user_ids_string)) &&
        people.user_can_direct_message(user_ids_string)
    );
}