[MM-53167] Persist participants list

server/channel_state.go

@@ -23,8 +23,8 @@ type userState struct {
 }
 
 type callStats struct {
-	Participants   int   `json:"participants"`
-	ScreenDuration int64 `json:"screen_duration"`
+	Participants   map[string]struct{} `json:"participants"`
+	ScreenDuration int64               `json:"screen_duration"`
 }
 
 type callState struct {
@@ -313,7 +313,7 @@ func (p *Plugin) cleanCallState(channelID string, state *channelState) error {
 	state.NodeID = ""
 
 	if state.Call != nil {
-		if _, err := p.updateCallPostEnded(state.Call.PostID); err != nil {
+		if _, err := p.updateCallPostEnded(state.Call.PostID, mapKeys(state.Call.Stats.Participants)); err != nil {
 			return err
 		}
 		state.Call = nil

server/plugin.go

@@ -325,7 +325,7 @@ func (p *Plugin) createCallStartedPost(state *channelState, userID, channelID, t
 	return createdPost.Id, threadID, nil
 }
 
-func (p *Plugin) updateCallPostEnded(postID string) (float64, error) {
+func (p *Plugin) updateCallPostEnded(postID string, participants []string) (float64, error) {
 	post, appErr := p.API.GetPost(postID)
 	if appErr != nil {
 		return 0, appErr
@@ -342,6 +342,7 @@ func (p *Plugin) updateCallPostEnded(postID string) (float64, error) {
 	post.DelProp("attachments")
 	post.AddProp("attachments", []*model.SlackAttachment{&slackAttachment})
 	post.AddProp("end_at", time.Now().UnixMilli())
+	post.AddProp("participants", participants)
 
 	_, appErr = p.API.UpdatePost(post)
 	if appErr != nil {

server/session.go

@@ -137,8 +137,13 @@ func (p *Plugin) addUserSession(state *channelState, userID, connID, channelID s
 		JoinAt: time.Now().UnixMilli(),
 	}
 	state.Call.Sessions[connID] = struct{}{}
-	if len(state.Call.Users) > state.Call.Stats.Participants {
-		state.Call.Stats.Participants = len(state.Call.Users)
+
+	if state.Call.Stats.Participants == nil {
+		state.Call.Stats.Participants = map[string]struct{}{}
+	}
+
+	if userID != p.getBotID() {
+		state.Call.Stats.Participants[userID] = struct{}{}
 	}
 
 	if err := p.kvSetChannelState(channelID, state); err != nil {
@@ -322,15 +327,15 @@ func (p *Plugin) removeSession(us *session) error {
 
 	// Check if call has ended.
 	if prevState.Call != nil && currState.Call == nil {
-		dur, err := p.updateCallPostEnded(prevState.Call.PostID)
+		dur, err := p.updateCallPostEnded(prevState.Call.PostID, mapKeys(prevState.Call.Stats.Participants))
 		if err != nil {
 			return err
 		}
 		p.track(evCallEnded, map[string]interface{}{
 			"ChannelID":      us.channelID,
 			"CallID":         prevState.Call.ID,
 			"Duration":       dur,
-			"Participants":   prevState.Call.Stats.Participants,
+			"Participants":   len(prevState.Call.Stats.Participants),
 			"ScreenDuration": prevState.Call.Stats.ScreenDuration,
 		})
 	}

server/utils.go

@@ -120,3 +120,11 @@ func checkMinVersion(minVersion, currVersion string) error {
 
 	return nil
 }
+
+func mapKeys[K comparable, V any](m map[K]V) []K {
+	keys := make([]K, 0, len(m))
+	for k := range m {
+		keys = append(keys, k)
+	}
+	return keys
+}