feat(call): implement group calling and enhance call management

Introduces group calling capabilities, including group invites and participant
lifecycle management. Enhances the existing call system with support for
media types (voice/video) and improved participant tracking.

- Add `GroupInvite` and `ParticipantJoin/Leave` to `CallService`.
- Implement WebSocket handlers for `call_group_invite` and
  `call_participant_join`.
- Update `CallSession` model to support group IDs, media types, and
  tracking who ended the call.
- Integrate `GroupService` into `CallService` via dependency injection.
- Add error constants for group call limitations and participant capacity.
- Update LiveKit webhook handling to process participant leave events.

Refactor grade synchronization to remove semester-based filtering in favor
of a more flexible user-based approach and improve GPA summary updates.

internal/service/call_service.go

@@ -9,6 +9,7 @@ import (
 	"time"
 
 	redispkg "with_you/internal/pkg/redis"
+	"with_you/internal/pkg/utils"
 
 	"with_you/internal/config"
 	apperrors "with_you/internal/errors"
@@ -34,15 +35,17 @@ const (
 
 // activeCallRedisData Redis 中存储的通话数据（精简字段）
 type activeCallRedisData struct {
-	ID             string `json:"id"`
-	ConversationID string `json:"conversation_id"`
-	CallerID       string `json:"caller_id"`
-	CalleeID       string `json:"callee_id"`
-	CallType       string `json:"call_type"`
-	Status         string `json:"status"`
-	MediaType      string `json:"media_type"`
-	CreatedAt      int64  `json:"created_at"`
-	StartedAt      int64  `json:"started_at"` // 0 means nil
+	ID             string   `json:"id"`
+	ConversationID string   `json:"conversation_id"`
+	CallerID       string   `json:"caller_id"`
+	CalleeID       string   `json:"callee_id,omitempty"` // 兼容旧数据，1v1时仍有值
+	CallType       string   `json:"call_type"`
+	Status         string   `json:"status"`
+	MediaType      string   `json:"media_type"`
+	GroupID        string   `json:"group_id,omitempty"`
+	CreatedAt      int64    `json:"created_at"`
+	StartedAt      int64    `json:"started_at"` // 0 means nil
+	ParticipantIDs []string `json:"participant_ids"`
 }
 
 // ActiveCall 内存中的活跃通话
@@ -50,7 +53,8 @@ type ActiveCall struct {
 	ID             string
 	ConversationID string
 	CallerID       string
-	CalleeID       string
+	CalleeID       string // 1v1通话的被叫方ID（兼容）
+	GroupID        string // 群组通话的群组ID
 	CallType       model.CallType
 	Status         model.CallStatus
 	MediaType      string // voice 或 video
@@ -66,15 +70,19 @@ type ActiveParticipant struct {
 	UserID   string
 	Status   model.ParticipantStatus
 	JoinedAt *time.Time
+	LeftAt   *time.Time
 }
 
 // CallService 通话服务接口
 type CallService interface {
 	Invite(ctx context.Context, callerID, calleeID, conversationID, mediaType string) (*ActiveCall, bool, error)
+	GroupInvite(ctx context.Context, callerID, groupID, conversationID, mediaType string) (*ActiveCall, error)
 	Accept(ctx context.Context, callID, userID string) (*ActiveCall, error)
 	Reject(ctx context.Context, callID, userID string) error
 	Busy(ctx context.Context, callID, userID string) error
 	End(ctx context.Context, callID, userID string, reason string) (*ActiveCall, error)
+	ParticipantJoin(ctx context.Context, callID, userID string) error
+	ParticipantLeave(ctx context.Context, callID, userID string, reason string) error
 	SetMuted(ctx context.Context, callID, userID string, muted bool) error
 	Ready(ctx context.Context, callID, userID string) error
 	GetActiveCall(ctx context.Context, callID string) *ActiveCall
@@ -83,11 +91,12 @@ type CallService interface {
 }
 
 type callService struct {
-	callRepo repository.CallRepository
-	hub      ws.MessagePublisher
-	config   *config.Config
-	db       *gorm.DB
-	redis    *redispkg.Client
+	callRepo     repository.CallRepository
+	hub          ws.MessagePublisher
+	config       *config.Config
+	db           *gorm.DB
+	redis        *redispkg.Client
+	groupService GroupService
 
 	// 内存中的活跃通话状态
 	activeCalls       map[string]*ActiveCall     // callID -> ActiveCall
@@ -103,6 +112,7 @@ func NewCallService(
 	cfg *config.Config,
 	db *gorm.DB,
 	redisClient *redispkg.Client,
+	groupService GroupService,
 ) CallService {
 	svc := &callService{
 		callRepo:          callRepo,
@@ -110,6 +120,7 @@ func NewCallService(
 		config:            cfg,
 		db:                db,
 		redis:             redisClient,
+		groupService:      groupService,
 		activeCalls:       make(map[string]*ActiveCall),
 		activeCallsByUser: make(map[string]map[string]bool),
 		activeCallsByConv: make(map[string]string),
@@ -124,9 +135,13 @@ func NewCallService(
 	return svc
 }
 
-// generateCallID 生成通话ID
+// generateCallID 生成通话ID（使用雪花算法，与数据库ID一致）
 func (s *callService) generateCallID() string {
-	id := time.Now().UnixNano()
+	id, err := utils.GetSnowflake().GenerateID()
+	if err != nil {
+		zap.L().Error("Failed to generate snowflake call ID", zap.Error(err))
+		return strconv.FormatInt(time.Now().UnixNano(), 10)
+	}
 	return strconv.FormatInt(id, 10)
 }
 
@@ -141,6 +156,12 @@ func (s *callService) redisStoreCall(call *ActiveCall) {
 	if call.StartedAt != nil {
 		startedAt = call.StartedAt.UnixMilli()
 	}
+
+	participantIDs := make([]string, 0, len(call.Participants))
+	for id := range call.Participants {
+		participantIDs = append(participantIDs, id)
+	}
+
 	data := activeCallRedisData{
 		ID:             call.ID,
 		ConversationID: call.ConversationID,
@@ -149,8 +170,10 @@ func (s *callService) redisStoreCall(call *ActiveCall) {
 		CallType:       string(call.CallType),
 		Status:         string(call.Status),
 		MediaType:      call.MediaType,
+		GroupID:        call.GroupID,
 		CreatedAt:      call.CreatedAt.UnixMilli(),
 		StartedAt:      startedAt,
+		ParticipantIDs: participantIDs,
 	}
 	jsonData, err := json.Marshal(data)
 	if err != nil {
@@ -159,13 +182,13 @@ func (s *callService) redisStoreCall(call *ActiveCall) {
 	}
 
 	callKey := redisCallKeyPrefix + call.ID
-	callerKey := redisCallByUserPrefix + call.CallerID
-	calleeKey := redisCallByUserPrefix + call.CalleeID
 
 	pipe := s.redis.Pipeline()
 	pipe.Set(ctx, callKey, jsonData, redisCallTTL)
-	pipe.Set(ctx, callerKey, call.ID, redisCallTTL)
-	pipe.Set(ctx, calleeKey, call.ID, redisCallTTL)
+	// 为每个参与者建立索引
+	for userID := range call.Participants {
+		pipe.Set(ctx, redisCallByUserPrefix+userID, call.ID, redisCallTTL)
+	}
 	if _, err := pipe.Exec(ctx); err != nil {
 		zap.L().Error("Failed to store call in Redis", zap.String("call_id", call.ID), zap.Error(err))
 	}
@@ -180,10 +203,11 @@ func (s *callService) redisRemoveCall(call *ActiveCall) {
 
 	keys := []string{
 		redisCallKeyPrefix + call.ID,
-		redisCallByUserPrefix + call.CallerID,
-		redisCallByUserPrefix + call.CalleeID,
 		redisCallAcceptPrefix + call.ID,
 	}
+	for userID := range call.Participants {
+		keys = append(keys, redisCallByUserPrefix+userID)
+	}
 	if err := s.redis.Del(ctx, keys...); err != nil {
 		zap.L().Error("Failed to remove call from Redis", zap.String("call_id", call.ID), zap.Error(err))
 	}
@@ -207,18 +231,38 @@ func (s *callService) redisGetCall(callID string) *ActiveCall {
 		return nil
 	}
 
+	// 构建参与者列表
+	participants := make(map[string]*ActiveParticipant)
+	for _, pid := range data.ParticipantIDs {
+		status := model.ParticipantStatusInvited
+		if pid == data.CallerID {
+			status = model.ParticipantStatusJoined
+		}
+		participants[pid] = &ActiveParticipant{
+			UserID: pid,
+			Status: status,
+		}
+	}
+	// 兼容旧数据：无 ParticipantIDs 时使用 CallerID/CalleeID
+	if len(participants) == 0 && data.CalleeID != "" {
+		participants[data.CallerID] = &ActiveParticipant{
+			UserID: data.CallerID, Status: model.ParticipantStatusJoined,
+		}
+		participants[data.CalleeID] = &ActiveParticipant{
+			UserID: data.CalleeID, Status: model.ParticipantStatusInvited,
+		}
+	}
+
 	call := &ActiveCall{
 		ID:             data.ID,
 		ConversationID: data.ConversationID,
 		CallerID:       data.CallerID,
 		CalleeID:       data.CalleeID,
+		GroupID:        data.GroupID,
 		CallType:       model.CallType(data.CallType),
 		Status:         model.CallStatus(data.Status),
 		MediaType:      data.MediaType,
-				Participants: map[string]*ActiveParticipant{
-			data.CallerID: {UserID: data.CallerID, Status: model.ParticipantStatusJoined},
-			data.CalleeID: {UserID: data.CalleeID, Status: model.ParticipantStatusInvited},
-		},
+		Participants:   participants,
 	}
 
 	call.CreatedAt = time.UnixMilli(data.CreatedAt)
@@ -226,10 +270,11 @@ func (s *callService) redisGetCall(callID string) *ActiveCall {
 		t := time.UnixMilli(data.StartedAt)
 		call.StartedAt = &t
 		// 如果已经开始，被叫方也已加入
-		call.Participants[data.CalleeID] = &ActiveParticipant{
-			UserID:   data.CalleeID,
-			Status:   model.ParticipantStatusJoined,
-			JoinedAt: call.StartedAt,
+		if data.CalleeID != "" {
+			if p, ok := call.Participants[data.CalleeID]; ok {
+				p.Status = model.ParticipantStatusJoined
+				p.JoinedAt = call.StartedAt
+			}
 		}
 	}
 
@@ -243,10 +288,9 @@ func (s *callService) redisRefreshTTL(call *ActiveCall) {
 	}
 	ctx := context.Background()
 
-	keys := []string{
-		redisCallKeyPrefix + call.ID,
-		redisCallByUserPrefix + call.CallerID,
-		redisCallByUserPrefix + call.CalleeID,
+	keys := []string{redisCallKeyPrefix + call.ID}
+	for userID := range call.Participants {
+		keys = append(keys, redisCallByUserPrefix+userID)
 	}
 	for _, key := range keys {
 		_, _ = s.redis.Expire(ctx, key, redisCallTTL)
@@ -506,7 +550,7 @@ func (s *callService) Reject(ctx context.Context, callID, userID string) error {
 	s.redisRemoveCall(call)
 
 	// 保存到数据库作为历史记录
-	s.saveCallHistory(call, model.CallStatusRejected, 0)
+	s.saveCallHistory(call, model.CallStatusRejected, 0, userID)
 
 	// 通知拨打方
 	s.hub.PublishToUserOnline(call.CallerID, "call_rejected", map[string]any{
@@ -543,7 +587,7 @@ func (s *callService) Busy(ctx context.Context, callID, userID string) error {
 	s.redisRemoveCall(call)
 
 	// 保存到数据库作为历史记录
-	s.saveCallHistory(call, model.CallStatusMissed, 0)
+	s.saveCallHistory(call, model.CallStatusMissed, 0, "")
 
 	// 通知拨打方
 	s.hub.PublishToUserOnline(call.CallerID, "call_busy", map[string]any{
@@ -602,7 +646,7 @@ func (s *callService) End(ctx context.Context, callID, userID string, reason str
 	s.redisRemoveCall(call)
 
 	// 保存到数据库作为历史记录
-	s.saveCallHistory(call, endStatus, duration)
+	s.saveCallHistory(call, endStatus, duration, userID)
 
 	// 通知其他参与者
 	for pUserID := range call.Participants {
@@ -654,6 +698,174 @@ func (s *callService) GetActiveCall(ctx context.Context, callID string) *ActiveC
 	return s.getActiveCall(callID)
 }
 
+// GroupInvite 发起群组通话
+func (s *callService) GroupInvite(ctx context.Context, callerID, groupID, conversationID, mediaType string) (*ActiveCall, error) {
+	if s.groupService == nil {
+		return nil, apperrors.ErrGroupCallNotSupported
+	}
+
+	// 验证调用者是群组成员
+	member, err := s.groupService.GetMember(groupID, callerID)
+	if err != nil {
+		return nil, apperrors.ErrNotGroupMember
+	}
+	if member == nil {
+		return nil, apperrors.ErrNotGroupMember
+	}
+
+	// 检查会话是否有活跃通话
+	if active := s.getActiveCallByConversation(conversationID); active != nil {
+		return nil, apperrors.Wrap(fmt.Errorf("call %s", active.ID), apperrors.ErrCallInProgress)
+	}
+
+	// 获取群组成员
+	members, _, err := s.groupService.GetMembers(groupID, 1, 50)
+	if err != nil {
+		return nil, apperrors.Wrap(err, apperrors.ErrInternal)
+	}
+
+	now := time.Now()
+	callID := s.generateCallID()
+
+	// 构建参与者列表
+	participants := map[string]*ActiveParticipant{
+		callerID: {UserID: callerID, Status: model.ParticipantStatusJoined, JoinedAt: &now},
+	}
+	for _, m := range members {
+		if m.UserID != callerID {
+			participants[m.UserID] = &ActiveParticipant{
+				UserID: m.UserID,
+				Status: model.ParticipantStatusInvited,
+			}
+		}
+	}
+
+	call := &ActiveCall{
+		ID:             callID,
+		ConversationID: conversationID,
+		CallerID:       callerID,
+		GroupID:        groupID,
+		CallType:       model.CallTypeGroup,
+		Status:         model.CallStatusCalling,
+		MediaType:      mediaType,
+		CreatedAt:      now,
+		Participants:   participants,
+	}
+
+	s.storeActiveCall(call)
+	s.redisStoreCall(call)
+
+	// 通知所有在线成员
+	payload := map[string]any{
+		"call_id":         call.ID,
+		"conversation_id": conversationID,
+		"caller_id":       callerID,
+		"call_type":       "group",
+		"media_type":      mediaType,
+		"group_id":        groupID,
+		"created_at":      now.UnixMilli(),
+		"lifetime":        CallLifetimeMs,
+	}
+
+	for pID := range participants {
+		if pID != callerID {
+			s.hub.PublishToUserOnline(pID, "call_incoming", payload)
+		}
+	}
+
+	return call, nil
+}
+
+// ParticipantJoin 参与者加入通话
+func (s *callService) ParticipantJoin(ctx context.Context, callID, userID string) error {
+	call := s.getActiveCall(callID)
+	if call == nil {
+		return apperrors.ErrCallNotFound
+	}
+
+	s.mu.Lock()
+	p, ok := call.Participants[userID]
+	if !ok {
+		s.mu.Unlock()
+		return apperrors.ErrNotCallParticipant
+	}
+	now := time.Now()
+	p.Status = model.ParticipantStatusJoined
+	p.JoinedAt = &now
+
+	// 如果是第一个被叫方加入，标记通话已接通
+	if call.Status == model.CallStatusCalling {
+		call.Status = model.CallStatusConnected
+		call.StartedAt = &now
+	}
+	s.mu.Unlock()
+
+	s.redisStoreCall(call)
+
+	// 通知其他参与者
+	for pID := range call.Participants {
+		if pID != userID {
+			s.hub.PublishToUserOnline(pID, "call_participant_joined", map[string]any{
+				"call_id": callID,
+				"user_id": userID,
+			})
+		}
+	}
+
+	return nil
+}
+
+// ParticipantLeave 参与者离开通话
+func (s *callService) ParticipantLeave(ctx context.Context, callID, userID string, reason string) error {
+	call := s.getActiveCall(callID)
+	if call == nil {
+		return apperrors.ErrCallNotFound
+	}
+
+	s.mu.Lock()
+	p, ok := call.Participants[userID]
+	if !ok {
+		s.mu.Unlock()
+		return apperrors.ErrNotCallParticipant
+	}
+
+	now := time.Now()
+	p.Status = model.ParticipantStatusLeft
+	p.LeftAt = &now
+
+	// 计算剩余活跃参与者数量
+	activeCount := 0
+	for _, pp := range call.Participants {
+		if pp.Status == model.ParticipantStatusJoined {
+			activeCount++
+		}
+	}
+	shouldEnd := false
+	if call.CallType == model.CallTypeGroup && activeCount <= 1 {
+		shouldEnd = true
+	} else if call.CallType == model.CallTypePrivate {
+		shouldEnd = true
+	}
+	s.mu.Unlock()
+
+	// 通知其他参与者
+	for pID := range call.Participants {
+		if pID != userID {
+			s.hub.PublishToUserOnline(pID, "call_participant_left", map[string]any{
+				"call_id": callID,
+				"user_id": userID,
+				"reason":  reason,
+			})
+		}
+	}
+
+	if shouldEnd {
+		_, _ = s.End(ctx, callID, userID, reason)
+	}
+
+	return nil
+}
+
 // Ready 标记参与者已加入 LiveKit 房间
 func (s *callService) Ready(ctx context.Context, callID, userID string) error {
 	call := s.getActiveCall(callID)
@@ -686,16 +898,23 @@ func (s *callService) GetCallHistory(ctx context.Context, userID string, page, p
 
 
 // saveCallHistory 保存通话历史到数据库
-func (s *callService) saveCallHistory(call *ActiveCall, status model.CallStatus, duration int64) {
+func (s *callService) saveCallHistory(call *ActiveCall, status model.CallStatus, duration int64, endedBy string) {
 	ctx := context.Background()
 	now := time.Now()
 
+	var endedByPtr *string
+	if endedBy != "" {
+		endedByPtr = &endedBy
+	}
+
 	dbCall := &model.CallSession{
 		ID:             call.ID,
 		ConversationID: call.ConversationID,
 		CallerID:       call.CallerID,
 		CallType:       call.CallType,
+		MediaType:      call.MediaType,
 		Status:         status,
+		EndedBy:        endedByPtr,
 		StartedAt:      call.StartedAt,
 		EndedAt:        &now,
 		Duration:       duration,

internal/service/grade_sync_service.go

@@ -81,7 +81,7 @@ func (s *gradeSyncService) SyncUserGrades(ctx context.Context, userID string, re
 	}
 
 	grades := s.convertGrades(userID, &resultData)
-	if err := s.saveGrades(ctx, userID, resultData.Semester, grades); err != nil {
+	if err := s.saveGrades(ctx, userID, grades); err != nil {
 		s.logger.Error("failed to save grades",
 			zap.String("user_id", userID),
 			zap.Error(err))
@@ -89,7 +89,12 @@ func (s *gradeSyncService) SyncUserGrades(ctx context.Context, userID string, re
 	}
 
 	if resultData.GpaSummary != nil {
-		summary := s.convertGpaSummary(userID, resultData.Semester, resultData.GpaSummary)
+		if err := s.gradeRepo.DeleteGpaSummaryByUser(ctx, userID); err != nil {
+			s.logger.Warn("failed to delete old gpa summary",
+				zap.String("user_id", userID),
+				zap.Error(err))
+		}
+		summary := s.convertGpaSummary(userID, resultData.GpaSummary)
 		if err := s.gradeRepo.SaveGpaSummary(ctx, summary); err != nil {
 			s.logger.Warn("failed to save gpa summary",
 				zap.String("user_id", userID),
@@ -128,11 +133,11 @@ func (s *gradeSyncService) convertGrades(userID string, data *pb.GradesResultDat
 	return grades
 }
 
-func (s *gradeSyncService) convertGpaSummary(userID, semester string, gpa *pb.GpaSummary) *model.GpaSummary {
+func (s *gradeSyncService) convertGpaSummary(userID string, gpa *pb.GpaSummary) *model.GpaSummary {
 	return &model.GpaSummary{
 		ID:               uuid.New().String(),
 		UserID:           userID,
-		Semester:         semester,
+		Semester:         gpa.Semesters,
 		AverageGpa:       gpa.AverageGpa,
 		Rank:             gpa.Rank,
 		ExamTotalGpa:     gpa.ExamTotalGpa,
@@ -142,8 +147,8 @@ func (s *gradeSyncService) convertGpaSummary(userID, semester string, gpa *pb.Gp
 	}
 }
 
-func (s *gradeSyncService) saveGrades(ctx context.Context, userID, semester string, grades []*model.Grade) error {
-	if err := s.gradeRepo.DeleteByUserAndSemester(ctx, userID, semester); err != nil {
+func (s *gradeSyncService) saveGrades(ctx context.Context, userID string, grades []*model.Grade) error {
+	if err := s.gradeRepo.DeleteByUser(ctx, userID); err != nil {
 		return fmt.Errorf("failed to delete old grades: %w", err)
 	}
 	if len(grades) == 0 {

internal/service/livekit_service.go

@@ -17,9 +17,15 @@ import (
 	"google.golang.org/protobuf/encoding/protojson"
 )
 
+// RoomConfig 房间配置选项
+type RoomConfig struct {
+	MaxParticipants uint32
+	EmptyTimeout    uint32 // 秒
+}
+
 // LiveKitService LiveKit 令牌生成和 Webhook 处理服务
 type LiveKitService interface {
-	GenerateToken(roomName, userID string, canPublish, canSubscribe bool) (string, error)
+	GenerateToken(roomName, userID string, canPublish, canSubscribe bool, roomCfg ...RoomConfig) (string, error)
 	ProcessWebhook(ctx context.Context, body []byte, authHeader string) (*livekit.WebhookEvent, error)
 }
 
@@ -37,7 +43,7 @@ func NewLiveKitService(cfg *config.Config, logger *zap.Logger) LiveKitService {
 }
 
 // GenerateToken 为指定 room 和 user 生成 LiveKit 访问令牌
-func (s *liveKitService) GenerateToken(roomName, userID string, canPublish, canSubscribe bool) (string, error) {
+func (s *liveKitService) GenerateToken(roomName, userID string, canPublish, canSubscribe bool, roomCfg ...RoomConfig) (string, error) {
 	if !s.config.Enabled {
 		return "", fmt.Errorf("livekit is not enabled")
 	}
@@ -57,8 +63,9 @@ func (s *liveKitService) GenerateToken(roomName, userID string, canPublish, canS
 		Room:           roomName,
 		CanPublish:     &canPublish,
 		CanSubscribe:   &canSubscribe,
-		CanPublishData: &canSubscribe,
+		CanPublishData: &canPublish,
 	}
+
 	at.SetVideoGrant(grant)
 
 	token, err := at.ToJWT()