Rocket.Chat/packages/rocketchat-lib/server/functions/loadMessageHistory.js

import _ from 'underscore';

const hideMessagesOfType = [];

RocketChat.settings.get(/Message_HideType_.+/, function(key, value) {
	const type = key.replace('Message_HideType_', '');
	const types = type === 'mute_unmute' ? ['user-muted', 'user-unmuted'] : [type];

	return types.forEach((type) => {
		const index = hideMessagesOfType.indexOf(type);

		if (value === true && index === -1) {
			return hideMessagesOfType.push(type);
		}

		if (index > -1) {
			return hideMessagesOfType.splice(index, 1);
		}
	});
});

RocketChat.loadMessageHistory = function loadMessageHistory({ userId, rid, end, limit = 20, ls }) {
	const options = {
		sort: {
			ts: -1
		},
		limit
	};

	if (!RocketChat.settings.get('Message_ShowEditedStatus')) {
		options.fields = {
			editedAt: 0
		};
	}

	let records;
	if (end != null) {
		records = RocketChat.models.Messages.findVisibleByRoomIdBeforeTimestampNotContainingTypes(rid, end, hideMessagesOfType, options).fetch();
	} else {
		records = RocketChat.models.Messages.findVisibleByRoomIdNotContainingTypes(rid, hideMessagesOfType, options).fetch();
	}

	const UI_Use_Real_Name = RocketChat.settings.get('UI_Use_Real_Name') === true;

	const messages = records.map((message) => {
		message.starred = _.findWhere(message.starred, {
			_id: userId
		});
		if (message.u && message.u._id && UI_Use_Real_Name) {
			const user = RocketChat.models.Users.findOneById(message.u._id);
			message.u.name = user && user.name;
		}
		if (message.mentions && message.mentions.length && UI_Use_Real_Name) {
			message.mentions.forEach((mention) => {
				const user = RocketChat.models.Users.findOneById(mention._id);
				mention.name = user && user.name;
			});
		}
		return message;
	});

	let unreadNotLoaded = 0;
	let firstUnread;

	if (ls != null) {
		const firstMessage = messages[messages.length - 1];

		if ((firstMessage != null ? firstMessage.ts : undefined) > ls) {
			delete options.limit;

			const unreadMessages = RocketChat.models.Messages.findVisibleByRoomIdBetweenTimestampsNotContainingTypes(rid, ls, firstMessage.ts, hideMessagesOfType, {
				limit: 1,
				sort: {
					ts: 1
				}
			});

			firstUnread = unreadMessages.fetch()[0];
			unreadNotLoaded = unreadMessages.count();
		}
	}

	return {
		messages,
		firstUnread,
		unreadNotLoaded
	};
};