promoting single member in room

internal/controller/helper.controller.go

@@ -116,6 +116,17 @@ func (c controller) helperDisconn(ctx context.Context, roomId string, memberId s
 	}
 
 	if !disconnectMemberResp.IsRoomDeleted {
+		if disconnectMemberResp.PromotedMemberConn != nil {
+			if err := c.writeToConn(ctx, disconnectMemberResp.PromotedMemberConn, &Output{
+				Type: "IS_ADMIN_UPDATED",
+				Payload: map[string]any{
+					//?
+					"is_admin": true,
+				},
+			}); err != nil {
+				return fmt.Errorf("failed to write to conn: %w", err)
+			}
+		}
 		if err := c.broadcast(ctx, disconnectMemberResp.Conns, &Output{
 			Type: "MEMBER_DISCONNECTED",
 			Payload: map[string]any{

internal/service/member.service.go

@@ -201,9 +201,10 @@ type DisconnectMemberParams struct {
 }
 
 type DisconnectMemberResponse struct {
-	Conns         []*websocket.Conn
-	Members       []Member
-	IsRoomDeleted bool
+	Conns              []*websocket.Conn
+	Members            []Member
+	PromotedMemberConn *websocket.Conn
+	IsRoomDeleted      bool
 }
 
 func (s service) DisconnectMember(ctx context.Context, params *DisconnectMemberParams) (DisconnectMemberResponse, error) {
@@ -309,6 +310,21 @@ func (s service) DisconnectMember(ctx context.Context, params *DisconnectMemberP
 		return DisconnectMemberResponse{}, fmt.Errorf("failed to get conns: %w", err)
 	}
 
+	// promote single left member to admin
+	if len(members) == 1 && !members[0].IsAdmin {
+		if err := s.roomRepo.UpdateMemberIsAdmin(ctx, params.RoomId, members[0].Id, true); err != nil {
+			return DisconnectMemberResponse{}, fmt.Errorf("failed to update member is admin: %w", err)
+		}
+		members[0].IsAdmin = true
+
+		return DisconnectMemberResponse{
+			PromotedMemberConn: conns[0],
+			Conns:              conns,
+			Members:            members,
+			IsRoomDeleted:      false,
+		}, nil
+	}
+
 	return DisconnectMemberResponse{
 		Conns:         conns,
 		Members:       members,