MM-57786 Fix Shared Channels plugin api (#26753)

* always ping on plugin registration; SharedChannel.IsValid allow no team for GM

* wait for services to start before ping

* ping plugin remotes synchronously on startup

* remove the waitForInterClusterServices stuff

* don't set remoteid when inviting remote to channel

* Update server/public/model/remote_cluster_test.go

Co-authored-by: Ibrahim Serdar Acikgoz <serdaracikgoz86@gmail.com>

* address review comments

---------

Co-authored-by: Mattermost Build <build@mattermost.com>
Co-authored-by: Ibrahim Serdar Acikgoz <serdaracikgoz86@gmail.com>

server/platform/services/sharedchannel/channelinvite.go

@@ -72,6 +72,37 @@ func (scs *Service) SendChannelInvite(channel *model.Channel, userId string, rc
 
 	msg := model.NewRemoteClusterMsg(TopicChannelInvite, json)
 
+	// onInvite is called after invite is sent, whether to a remote cluster or plugin.
+	onInvite := func(_ model.RemoteClusterMsg, rc *model.RemoteCluster, resp *remotecluster.Response, err error) {
+		if err != nil || !resp.IsSuccess() {
+			scs.sendEphemeralPost(channel.Id, userId, fmt.Sprintf("Error sending channel invite for %s: %s", rc.DisplayName, combineErrors(err, resp.Err)))
+			return
+		}
+
+		scr := &model.SharedChannelRemote{
+			ChannelId:         sc.ChannelId,
+			CreatorId:         userId,
+			RemoteId:          rc.RemoteId,
+			IsInviteAccepted:  true,
+			IsInviteConfirmed: true,
+			LastPostCreateAt:  model.GetMillis(),
+			LastPostUpdateAt:  model.GetMillis(),
+		}
+		if _, err = scs.server.GetStore().SharedChannel().SaveRemote(scr); err != nil {
+			scs.sendEphemeralPost(channel.Id, userId, fmt.Sprintf("Error confirming channel invite for %s: %v", rc.DisplayName, err))
+			return
+		}
+		scs.NotifyChannelChanged(sc.ChannelId)
+		scs.sendEphemeralPost(channel.Id, userId, fmt.Sprintf("`%s` has been added to channel.", rc.DisplayName))
+	}
+
+	if rc.IsPlugin() {
+		// for now plugins are considered fully invited automatically
+		// TODO: MM-57537 create plugin hook that passes invitation to plugins if BitflagOptionAutoInvited is not set
+		onInvite(msg, rc, &remotecluster.Response{Status: remotecluster.ResponseStatusOK}, nil)
+		return nil
+	}
+
 	ctx, cancel := context.WithTimeout(context.Background(), remotecluster.SendTimeout)
 	defer cancel()
 

server/platform/services/sharedchannel/service_api.go

@@ -121,7 +121,7 @@ func (scs *Service) InviteRemoteToChannel(channelID, remoteID, userID string, sh
 			ChannelId: channelID,
 			CreatorId: userID,
 			Home:      true,
-			RemoteId:  remoteID,
+			RemoteId:  "", // channel originates locally
 		}
 		if _, err = scs.ShareChannel(sc); err != nil {
 			return model.NewAppError("InviteRemoteToChannel", "api.command_share.share_channel.error",

server/platform/services/sharedchannel/sync_recv.go

@@ -219,7 +219,7 @@ func (scs *Service) upsertSyncUser(c request.CTX, user *model.User, channel *mod
 	return userSaved, nil
 }
 
-func (scs *Service) insertSyncUser(rctx request.CTX, user *model.User, channel *model.Channel, rc *model.RemoteCluster) (*model.User, error) {
+func (scs *Service) insertSyncUser(rctx request.CTX, user *model.User, _ *model.Channel, rc *model.RemoteCluster) (*model.User, error) {
 	var err error
 	var userSaved *model.User
 	var suffix string
@@ -270,7 +270,7 @@ func (scs *Service) insertSyncUser(rctx request.CTX, user *model.User, channel *
 	return nil, fmt.Errorf("error inserting sync user %s: %w", user.Id, err)
 }
 
-func (scs *Service) updateSyncUser(rctx request.CTX, patch *model.UserPatch, user *model.User, channel *model.Channel, rc *model.RemoteCluster) (*model.User, error) {
+func (scs *Service) updateSyncUser(rctx request.CTX, patch *model.UserPatch, user *model.User, _ *model.Channel, rc *model.RemoteCluster) (*model.User, error) {
 	var err error
 	var update *model.UserUpdate
 	var suffix string

server/platform/services/sharedchannel/sync_send_remote.go

@@ -107,6 +107,10 @@ func (scs *Service) syncForRemote(task syncTask, rc *model.RemoteCluster) error
 		if scr, err = scs.server.GetStore().SharedChannel().SaveRemote(scr); err != nil {
 			return fmt.Errorf("cannot auto-create shared channel remote (channel_id=%s, remote_id=%s): %w", task.channelID, rc.RemoteId, err)
 		}
+		scs.server.Log().Log(mlog.LvlSharedChannelServiceDebug, "Auto-invited remote to channel (BitflagOptionAutoInvited)",
+			mlog.String("remote", rc.DisplayName),
+			mlog.String("channel_id", task.channelID),
+		)
 	} else if err != nil {
 		return err
 	}