Feat(meeting): minimise sequential user pick (#13831)

Updating random user picker to reduce the probability that the exact same viewers would be selected first in successive random-pick runs

akka-bbb-apps/src/main/scala/org/bigbluebutton/SystemConfiguration.scala

@@ -50,6 +50,8 @@ trait SystemConfiguration {
   lazy val endMeetingWhenNoMoreAuthedUsers = Try(config.getBoolean("apps.endMeetingWhenNoMoreAuthedUsers")).getOrElse(false)
   lazy val endMeetingWhenNoMoreAuthedUsersAfterMinutes = Try(config.getInt("apps.endMeetingWhenNoMoreAuthedUsersAfterMinutes")).getOrElse(2)
 
+  lazy val reduceDuplicatedPick = Try(config.getBoolean("apps.reduceDuplicatedPick")).getOrElse(false)
+  
   // Redis server configuration
   lazy val redisHost = Try(config.getString("redis.host")).getOrElse("127.0.0.1")
   lazy val redisPort = Try(config.getInt("redis.port")).getOrElse(6379)

akka-bbb-apps/src/main/scala/org/bigbluebutton/core/apps/users/SelectRandomViewerReqMsgHdlr.scala

@@ -5,6 +5,7 @@ import org.bigbluebutton.core.running.{ LiveMeeting, OutMsgRouter }
 import org.bigbluebutton.core.models.{ UserState, Users2x }
 import org.bigbluebutton.core.apps.{ PermissionCheck, RightsManagementTrait }
 import org.bigbluebutton.core2.MeetingStatus2x
+import org.bigbluebutton.SystemConfiguration
 import scala.util.Random
 
 trait SelectRandomViewerReqMsgHdlr extends RightsManagementTrait {
@@ -15,7 +16,7 @@ trait SelectRandomViewerReqMsgHdlr extends RightsManagementTrait {
   def handleSelectRandomViewerReqMsg(msg: SelectRandomViewerReqMsg): Unit = {
     log.debug("Received SelectRandomViewerReqMsg {}", SelectRandomViewerReqMsg)
 
-    def broadcastEvent(msg: SelectRandomViewerReqMsg, users: Vector[String], choice: Integer): Unit = {
+    def broadcastEvent(msg: SelectRandomViewerReqMsg, users: Vector[String], choice: String): Unit = {
       val routing = Routing.addMsgToClientRouting(MessageTypes.BROADCAST_TO_MEETING, liveMeeting.props.meetingProp.intId, msg.header.userId)
       val envelope = BbbCoreEnvelope(SelectRandomViewerRespMsg.NAME, routing)
       val header = BbbClientMsgHeader(SelectRandomViewerRespMsg.NAME, liveMeeting.props.meetingProp.intId, msg.header.userId)
@@ -31,11 +32,27 @@ trait SelectRandomViewerReqMsgHdlr extends RightsManagementTrait {
       val reason = "No permission to select random user."
       PermissionCheck.ejectUserForFailedPermission(meetingId, msg.header.userId, reason, outGW, liveMeeting)
     } else {
-      val users = Users2x.findNotPresentersNorModerators(liveMeeting.users2x)
+      val users = Users2x.getRandomlyPickableUsers(liveMeeting.users2x, false)
+
+      val usersPicked = Users2x.getRandomlyPickableUsers(liveMeeting.users2x, reduceDuplicatedPick)
+
       val randNum = new scala.util.Random
+      val pickedUser = if (usersPicked.size == 0) "" else usersPicked(randNum.nextInt(usersPicked.size)).intId
+
+      if (reduceDuplicatedPick) {
+        if (usersPicked.size == 1) {
+          // Initialise the exemption
+          val usersToUnexempt = Users2x.findAll(liveMeeting.users2x)
+          usersToUnexempt foreach { u =>
+            Users2x.setUserExempted(liveMeeting.users2x, u.intId, false)
+          }
+        } else if (usersPicked.size > 1) {
+          Users2x.setUserExempted(liveMeeting.users2x, pickedUser, true)
+        }
+      }
       
       val userIds = users.map { case (v) => v.intId }
-      broadcastEvent(msg, userIds, if (users.size == 0) -1 else randNum.nextInt(users.size))
+      broadcastEvent(msg, userIds, pickedUser)
     }
   }
 }

akka-bbb-apps/src/main/scala/org/bigbluebutton/core/models/Users2x.scala

@@ -71,8 +71,13 @@ object Users2x {
     users.toVector.filter(u => !u.presenter)
   }
 
-  def findNotPresentersNorModerators(users: Users2x): Vector[UserState] = {
+  def getRandomlyPickableUsers(users: Users2x, reduceDup: Boolean): Vector[UserState] = {
-    users.toVector.filter(u => !u.presenter && u.role != Roles.MODERATOR_ROLE)
+
+    if (reduceDup) {
+      users.toVector.filter(u => !u.presenter && u.role != Roles.MODERATOR_ROLE && !u.userLeftFlag.left && !u.pickExempted)
+    } else {
+      users.toVector.filter(u => !u.presenter && u.role != Roles.MODERATOR_ROLE && !u.userLeftFlag.left)
+    }
   }
 
   def findViewers(users: Users2x): Vector[UserState] = {
@@ -150,6 +155,16 @@ object Users2x {
     }
   }
 
+  def setUserExempted(users: Users2x, intId: String, exempted: Boolean): Option[UserState] = {
+    for {
+      u <- findWithIntId(users, intId)
+    } yield {
+      val newUser = u.modify(_.pickExempted).setTo(exempted)
+      users.save(newUser)
+      newUser
+    }
+  }
+  
   def hasPresenter(users: Users2x): Boolean = {
     findPresenter(users) match {
       case Some(p) => true
@@ -294,6 +309,7 @@ case class UserState(
     lastActivityTime:      Long         = System.currentTimeMillis(),
     lastInactivityInspect: Long         = 0,
     clientType:            String,
+    pickExempted:          Boolean,
     userLeftFlag:          UserLeftFlag
 )
 

akka-bbb-apps/src/main/scala/org/bigbluebutton/core/running/HandlerHelpers.scala

@@ -64,6 +64,7 @@ trait HandlerHelpers extends SystemConfiguration {
         locked = MeetingStatus2x.getPermissions(liveMeeting.status).lockOnJoin,
         avatar = regUser.avatarURL,
         clientType = clientType,
+        pickExempted = false,
         userLeftFlag = UserLeftFlag(false, 0)
       )
     }

akka-bbb-apps/src/main/scala/org/bigbluebutton/core2/testdata/FakeTestData.scala

@@ -69,7 +69,7 @@ trait FakeTestData {
     UserState(intId = regUser.id, extId = regUser.externId, name = regUser.name, role = regUser.role,
       guest = regUser.guest, authed = regUser.authed, guestStatus = regUser.guestStatus,
       emoji = "none", locked = false, presenter = false, avatar = regUser.avatarURL, clientType = "unknown",
-      userLeftFlag = UserLeftFlag(false, 0))
+      pickExempted = false, userLeftFlag = UserLeftFlag(false, 0))
   }
 
 }

akka-bbb-apps/src/universal/conf/application.conf

@@ -76,6 +76,7 @@ apps {
   ejectOnViolation = false
   endMeetingWhenNoMoreAuthedUsers = false
   endMeetingWhenNoMoreAuthedUsersAfterMinutes = 2
+  reduceDuplicatedPick = false
 }
 
 analytics {

bbb-common-message/src/main/scala/org/bigbluebutton/common2/msgs/UsersMsgs.scala

@@ -409,4 +409,4 @@ case class SelectRandomViewerReqMsgBody(requestedBy: String)
  */
 object SelectRandomViewerRespMsg { val NAME = "SelectRandomViewerRespMsg" }
 case class SelectRandomViewerRespMsg(header: BbbClientMsgHeader, body: SelectRandomViewerRespMsgBody) extends StandardMsg
-case class SelectRandomViewerRespMsgBody(requestedBy: String, userIds: Vector[String], choice: Integer)
+case class SelectRandomViewerRespMsgBody(requestedBy: String, userIds: Vector[String], choice: String)

bigbluebutton-html5/imports/api/meetings/server/handlers/selectRandomViewer.js

@@ -8,7 +8,7 @@ export default function randomlySelectedUser({ header, body }) {
   check(meetingId, String);
   check(requestedBy, String);
   check(userIds, Array);
-  check(choice, Number);
+  check(choice, String);
 
   updateRandomViewer(meetingId, userIds, choice, requestedBy);
 }

bigbluebutton-html5/imports/api/meetings/server/modifiers/updateRandomViewer.js

@@ -5,7 +5,7 @@ import { check } from 'meteor/check';
 export default function updateRandomUser(meetingId, userIds, choice, requesterId) {
   check(meetingId, String);
   check(userIds, Array);
-  check(choice, Number);
+  check(choice, String);
   check(requesterId, String);
 
   const selector = {
@@ -13,7 +13,7 @@ export default function updateRandomUser(meetingId, userIds, choice, requesterId
   };
 
   const userList = [];
-  if (choice < 0) { // no viewer
+  if (choice == "") { // no viewer
     userList.push([requesterId,0]);
   } else if (userIds.length == 1) {
     userList.push([userIds[0],0]);
@@ -26,7 +26,7 @@ export default function updateRandomUser(meetingId, userIds, choice, requesterId
       }
       userList.push([userId, intervals.shift()]);
     }
-    userList[userList.length-1][0] = userIds[choice]; // last one should be chosen in akka-app
+    userList[userList.length-1][0] = choice; // last one should be chosen in akka-app
   }
 
   if (userIds.length == 2) {

bigbluebutton-html5/imports/ui/components/modal/random-user/component.jsx

@@ -126,7 +126,8 @@ class RandomUserSelect extends Component {
     const counter = SELECT_RANDOM_USER_COUNTDOWN ? this.state.count : 0;
     if (mappedRandomlySelectedUsers.length < counter + 1) return null;
 
-    const selectedUser = mappedRandomlySelectedUsers[counter][0];
+    const selectedUser = SELECT_RANDOM_USER_COUNTDOWN ? mappedRandomlySelectedUsers[counter][0] :
+      mappedRandomlySelectedUsers[mappedRandomlySelectedUsers.length - 1][0];
     const countDown = SELECT_RANDOM_USER_COUNTDOWN ?
       mappedRandomlySelectedUsers.length - this.state.count - 1 : 0;