[FIX] livechat/rooms endpoint not working with big amount of livechats (#16623)

* Remove aggregate to improve performance

* Use a cursor to run query only once

* Do not use toArray in model

Co-authored-by: Diego Sampaio <chinello@gmail.com>

app/livechat/server/api/lib/rooms.js

@@ -1,4 +1,4 @@
-import { LivechatRooms } from '../../../../models/server/raw';
+import { LivechatRooms, LivechatDepartment } from '../../../../models/server/raw';
 
 export async function findRooms({
 	agents,
@@ -16,18 +16,7 @@ export async function findRooms({
 		sort,
 	},
 }) {
-	const total = (await LivechatRooms.findRoomsWithCriteria({
-		agents,
-		roomName,
-		departmentId,
-		open,
-		createdAt,
-		closedAt,
-		tags,
-		customFields,
-	})).length;
-
-	const rooms = await LivechatRooms.findRoomsWithCriteria({
+	const cursor = LivechatRooms.findRoomsWithCriteria({
 		agents,
 		roomName,
 		departmentId,
@@ -44,6 +33,24 @@ export async function findRooms({
 		},
 	});
 
+	const total = await cursor.count();
+
+	const rooms = await cursor.toArray();
+
+	const departmentsIds = [...new Set(rooms.map((room) => room.departmentId).filter(Boolean))];
+	if (departmentsIds.length) {
+		const departments = await LivechatDepartment.findInIds(departmentsIds, { fields: { name: 1 } }).toArray();
+
+		rooms.forEach((room) => {
+			if (!room.departmentId) {
+				return;
+			}
+			const department = departments.find((dept) => dept._id === room.departmentId);
+			if (department) {
+				room.department = department;
+			}
+		});
+	}
 	return {
 		rooms,
 		count: rooms.length,

app/models/server/raw/LivechatDepartment.js

@@ -1,6 +1,8 @@
 import { BaseRaw } from './BaseRaw';
 
 export class LivechatDepartmentRaw extends BaseRaw {
-
-
+	findInIds(departmentsIds, options) {
+		const query = { _id: { $in: departmentsIds } };
+		return this.find(query, options);
+	}
 }

app/models/server/raw/LivechatRooms.js

@@ -1099,73 +1099,45 @@ export class LivechatRoomsRaw extends BaseRaw {
 	}
 
 	findRoomsWithCriteria({ agents, roomName, departmentId, open, createdAt, closedAt, tags, customFields, options = {} }) {
-		const match = {
-			$match: {
-				t: 'l',
-			},
+		const query = {
+			t: 'l',
 		};
 		if (agents) {
-			match.$match.$or = [{ 'servedBy._id': { $in: agents } }, { 'servedBy.username': { $in: agents } }];
+			query.$or = [{ 'servedBy._id': { $in: agents } }, { 'servedBy.username': { $in: agents } }];
 		}
 		if (roomName) {
-			match.$match.fname = new RegExp(roomName, 'i');
+			query.fname = new RegExp(roomName, 'i');
 		}
 		if (departmentId) {
-			match.$match.departmentId = departmentId;
+			query.departmentId = departmentId;
 		}
 		if (open !== undefined) {
-			match.$match.open = { $exists: open };
+			query.open = { $exists: open };
 		}
 		if (createdAt) {
-			match.$match.ts = {};
+			query.ts = {};
 			if (createdAt.start) {
-				match.$match.ts.$gte = new Date(createdAt.start);
+				query.ts.$gte = new Date(createdAt.start);
 			}
 			if (createdAt.end) {
-				match.$match.ts.$lte = new Date(createdAt.end);
+				query.ts.$lte = new Date(createdAt.end);
 			}
 		}
 		if (closedAt) {
-			match.$match.closedAt = {};
+			query.closedAt = {};
 			if (closedAt.start) {
-				match.$match.closedAt.$gte = new Date(closedAt.start);
+				query.closedAt.$gte = new Date(closedAt.start);
 			}
 			if (closedAt.end) {
-				match.$match.closedAt.$lte = new Date(closedAt.end);
+				query.closedAt.$lte = new Date(closedAt.end);
 			}
 		}
 		if (tags) {
-			match.$match.tags = { $in: tags };
+			query.tags = { $in: tags };
 		}
 		if (customFields) {
-			match.$match.$and = Object.keys(customFields).map((key) => ({ [`livechatData.${ key }`]: new RegExp(customFields[key], 'i') }));
-		}
-		const sort = { $sort: options.sort || { name: 1 } };
-		const firstParams = [match, sort];
-		if (options.offset) {
-			firstParams.push({ $skip: options.offset });
+			query.$and = Object.keys(customFields).map((key) => ({ [`livechatData.${ key }`]: new RegExp(customFields[key], 'i') }));
 		}
-		if (options.count) {
-			firstParams.push({ $limit: options.count });
-		}
-		const lookup = {
-			$lookup: {
-				from: 'rocketchat_livechat_department',
-				localField: 'departmentId',
-				foreignField: '_id',
-				as: 'department',
-			},
-		};
-		const unwind = {
-			$unwind: {
-				path: '$department',
-				preserveNullAndEmptyArrays: true,
-			},
-		};
-		const params = [...firstParams, lookup, unwind];
-		if (options.fields) {
-			params.push({ $project: options.fields });
-		}
-		return this.col.aggregate(params).toArray();
+		return this.find(query, { sort: options.sort || { name: 1 }, skip: options.offset, limit: options.count });
 	}
 }