diff --git a/client/c2c_processor.go b/client/c2c_processor.go
index 8b44f8a7..064bdfd9 100644
--- a/client/c2c_processor.go
+++ b/client/c2c_processor.go
@@ -71,7 +71,7 @@ func (c *QQClient) c2cMessageSyncProcessor(rsp *msg.GetMessageResponse, info *ne
 		_, _ = c.sendAndWait(c.buildDeleteMessageRequestPacket(delItems))
 	}
 	if rsp.GetSyncFlag() != msg.SyncFlag_STOP {
-		c.Debug("continue sync with flag: %v", rsp.SyncFlag)
+		c.debug("continue sync with flag: %v", rsp.SyncFlag)
 		seq, pkt := c.buildGetMessageRequestPacket(rsp.GetSyncFlag(), time.Now().Unix())
 		_, _ = c.sendAndWait(seq, pkt, info.Params)
 	}
@@ -80,12 +80,12 @@ func (c *QQClient) c2cMessageSyncProcessor(rsp *msg.GetMessageResponse, info *ne
 func (c *QQClient) commMsgProcessor(pMsg *msg.Message, info *network.IncomingPacketInfo) {
 	strKey := fmt.Sprintf("%d%d%d%d", pMsg.Head.GetFromUin(), pMsg.Head.GetToUin(), pMsg.Head.GetMsgSeq(), pMsg.Head.GetMsgUid())
 	if _, ok := c.msgSvcCache.GetAndUpdate(strKey, time.Hour); ok {
-		c.Debug("c2c msg %v already exists in cache. skip.", pMsg.Head.GetMsgUid())
+		c.debug("c2c msg %v already exists in cache. skip.", pMsg.Head.GetMsgUid())
 		return
 	}
 	c.msgSvcCache.Add(strKey, unit{}, time.Hour)
 	if c.lastC2CMsgTime > int64(pMsg.Head.GetMsgTime()) && (c.lastC2CMsgTime-int64(pMsg.Head.GetMsgTime())) > 60*10 {
-		c.Debug("c2c msg filtered by time. lastMsgTime: %v  msgTime: %v", c.lastC2CMsgTime, pMsg.Head.GetMsgTime())
+		c.debug("c2c msg filtered by time. lastMsgTime: %v  msgTime: %v", c.lastC2CMsgTime, pMsg.Head.GetMsgTime())
 		return
 	}
 	c.lastC2CMsgTime = int64(pMsg.Head.GetMsgTime())
@@ -95,7 +95,7 @@ func (c *QQClient) commMsgProcessor(pMsg *msg.Message, info *network.IncomingPac
 	if decoder, _ := peekC2CDecoder(pMsg.Head.GetMsgType()); decoder != nil {
 		decoder(c, pMsg, info)
 	} else {
-		c.Debug("unknown msg type on c2c processor: %v - %v", pMsg.Head.GetMsgType(), pMsg.Head.GetC2CCmd())
+		c.debug("unknown msg type on c2c processor: %v - %v", pMsg.Head.GetMsgType(), pMsg.Head.GetC2CCmd())
 	}
 }
 
@@ -137,7 +137,7 @@ func privateMessageDecoder(c *QQClient, pMsg *msg.Message, _ *network.IncomingPa
 		}
 		c.PrivateMessageEvent.dispatch(c, c.parsePrivateMessage(pMsg))
 	default:
-		c.Debug("unknown c2c cmd on private msg decoder: %v", pMsg.Head.GetC2CCmd())
+		c.debug("unknown c2c cmd on private msg decoder: %v", pMsg.Head.GetC2CCmd())
 	}
 }
 
@@ -225,7 +225,7 @@ func troopAddMemberBroadcastDecoder(c *QQClient, pMsg *msg.Message, _ *network.I
 		if group != nil && group.FindMember(pMsg.Head.GetAuthUin()) == nil {
 			mem, err := c.GetMemberInfo(group.Code, pMsg.Head.GetAuthUin())
 			if err != nil {
-				c.Debug("error to fetch new member info: %v", err)
+				c.debug("error to fetch new member info: %v", err)
 				return
 			}
 			group.Update(func(info *GroupInfo) {
@@ -255,7 +255,7 @@ func troopSystemMessageDecoder(c *QQClient, pMsg *msg.Message, info *network.Inc
 	reader := binary.NewReader(pMsg.Body.MsgContent)
 	groupCode := uint32(reader.ReadInt32())
 	if info := c.FindGroup(int64(groupCode)); info != nil && pMsg.Head.GetGroupName() != "" && info.Name != pMsg.Head.GetGroupName() {
-		c.Debug("group %v name updated. %v -> %v", groupCode, info.Name, pMsg.Head.GetGroupName())
+		c.debug("group %v name updated. %v -> %v", groupCode, info.Name, pMsg.Head.GetGroupName())
 		info.Name = pMsg.Head.GetGroupName()
 	}
 }
@@ -267,7 +267,7 @@ func msgType0x211Decoder(c *QQClient, pMsg *msg.Message, info *network.IncomingP
 	sub4 := msg.SubMsgType0X4Body{}
 	if err := proto.Unmarshal(pMsg.Body.MsgContent, &sub4); err != nil {
 		err = errors.Wrap(err, "unmarshal sub msg 0x4 error")
-		c.Error("unmarshal sub msg 0x4 error: %v", err)
+		c.error("unmarshal sub msg 0x4 error: %v", err)
 		return
 	}
 	if sub4.NotOnlineFile != nil && sub4.NotOnlineFile.GetSubcmd() == 1 { // subcmd: 1 -> sendPacket, 2-> recv
diff --git a/client/client.go b/client/client.go
index e5fe70d0..8aced500 100644
--- a/client/client.go
+++ b/client/client.go
@@ -55,6 +55,7 @@ type QQClient struct {
 
 	transport *network.Transport
 	oicq      *oicq.Codec
+	logger    Logger
 
 	// internal state
 	handlers        HandlerMap
@@ -420,7 +421,7 @@ func (c *QQClient) SubmitSMS(code string) (*LoginResponse, error) {
 func (c *QQClient) RequestSMS() bool {
 	rsp, err := c.sendAndWait(c.buildSMSRequestPacket())
 	if err != nil {
-		c.Error("request sms error: %v", err)
+		c.error("request sms error: %v", err)
 		return false
 	}
 	return rsp.(LoginResponse).Error == SMSNeededError
@@ -428,7 +429,7 @@ func (c *QQClient) RequestSMS() bool {
 
 func (c *QQClient) init(tokenLogin bool) error {
 	if len(c.sig.G) == 0 {
-		c.Warning("device lock is disable. http api may fail.")
+		c.warning("device lock is disable. http api may fail.")
 	}
 	c.highwaySession.Uin = strconv.FormatInt(c.Uin, 10)
 	if err := c.registerClient(); err != nil {
@@ -703,7 +704,7 @@ func (c *QQClient) SolveFriendRequest(req *NewFriendRequest, accept bool) {
 
 func (c *QQClient) getSKey() string {
 	if c.sig.SKeyExpiredTime < time.Now().Unix() && len(c.sig.G) > 0 {
-		c.Debug("skey expired. refresh...")
+		c.debug("skey expired. refresh...")
 		_, _ = c.sendAndWait(c.buildRequestTgtgtNopicsigPacket())
 	}
 	return string(c.sig.SKey)
diff --git a/client/decoders.go b/client/decoders.go
index f1cb8ec2..2de61f18 100644
--- a/client/decoders.go
+++ b/client/decoders.go
@@ -171,9 +171,9 @@ func decodeLoginResponse(c *QQClient, _ *network.IncomingPacketInfo, payload []b
 			ErrorMessage: t146r.ReadStringShort(),
 		}, nil
 	}
-	c.Debug("unknown login response: %v", t)
+	c.debug("unknown login response: %v", t)
 	for k, v := range m {
-		c.Debug("Type: %v Value: %v", strconv.FormatInt(int64(k), 16), hex.EncodeToString(v))
+		c.debug("Type: %v Value: %v", strconv.FormatInt(int64(k), 16), hex.EncodeToString(v))
 	}
 	return nil, errors.Errorf("unknown login response: %v", t) // ?
 }
@@ -188,7 +188,7 @@ func decodeClientRegisterResponse(c *QQClient, _ *network.IncomingPacketInfo, pa
 	svcRsp.ReadFrom(jce.NewJceReader(data.Map["SvcRespRegister"]["QQService.SvcRespRegister"][1:]))
 	if svcRsp.Result != "" || svcRsp.ReplyCode != 0 {
 		if svcRsp.Result != "" {
-			c.Error("reg error: %v", svcRsp.Result)
+			c.error("reg error: %v", svcRsp.Result)
 		}
 		return nil, errors.New("reg failed")
 	}
@@ -318,7 +318,7 @@ func decodePushReqPacket(c *QQClient, _ *network.IncomingPacketInfo, payload []b
 					if strings.Contains(s.Server, "com") {
 						continue
 					}
-					c.Debug("got new server addr: %v location: %v", s.Server, s.Location)
+					c.debug("got new server addr: %v location: %v", s.Server, s.Location)
 					adds = append(adds, &net.TCPAddr{
 						IP:   net.ParseIP(s.Server),
 						Port: int(s.Port),
@@ -341,7 +341,7 @@ func decodePushReqPacket(c *QQClient, _ *network.IncomingPacketInfo, payload []b
 			fmtPkt := jce.NewJceReader(jceBuf)
 			list := &jce.FileStoragePushFSSvcList{}
 			list.ReadFrom(fmtPkt)
-			c.Debug("got file storage svc push.")
+			c.debug("got file storage svc push.")
 			// c.fileStorageInfo = list
 			rsp := cmd0x6ff.C501RspBody{}
 			if err := proto.Unmarshal(list.BigDataChannel.PbBuf, &rsp); err == nil && rsp.RspBody != nil {
diff --git a/client/entities.go b/client/entities.go
index d2351b56..6f12069b 100644
--- a/client/entities.go
+++ b/client/entities.go
@@ -175,12 +175,6 @@ type (
 		client *QQClient
 	}
 
-	LogEvent struct {
-		Type    string
-		Message string
-		Dump    []byte
-	}
-
 	ServerUpdatedEvent struct {
 		Servers []jce.SsoServerInfo
 	}
diff --git a/client/events.go b/client/events.go
index 43a095ab..ba7071c9 100644
--- a/client/events.go
+++ b/client/events.go
@@ -46,8 +46,6 @@ type eventHandlers struct {
 	guildChannelDestroyedHandlers        []func(*QQClient, *GuildChannelOperationEvent)
 	memberJoinedGuildHandlers            []func(*QQClient, *MemberJoinGuildEvent)
 
-	// consider Logger interface?
-	logHandlers                 []func(*QQClient, *LogEvent)
 	serverUpdatedHandlers       []func(*QQClient, *ServerUpdatedEvent) bool
 	groupMessageReceiptHandlers sync.Map
 }
@@ -84,10 +82,6 @@ func (c *QQClient) OnServerUpdated(f func(*QQClient, *ServerUpdatedEvent) bool)
 	c.eventHandlers.serverUpdatedHandlers = append(c.eventHandlers.serverUpdatedHandlers, f)
 }
 
-func (c *QQClient) OnLog(f func(*QQClient, *LogEvent)) {
-	c.eventHandlers.logHandlers = append(c.eventHandlers.logHandlers, f)
-}
-
 func NewUinFilterPrivate(uin int64) func(*message.PrivateMessage) bool {
 	return func(msg *message.PrivateMessage) bool {
 		return msg.Sender.Uin == uin
@@ -186,17 +180,6 @@ func (c *QQClient) dispatchGroupMessageReceiptEvent(e *groupMessageReceiptEvent)
 	})
 }
 
-func (c *QQClient) dispatchLogEvent(e *LogEvent) {
-	if e == nil {
-		return
-	}
-	for _, f := range c.eventHandlers.logHandlers {
-		cover(func() {
-			f(c, e)
-		})
-	}
-}
-
 func cover(f func()) {
 	defer func() {
 		if pan := recover(); pan != nil {
diff --git a/client/global.go b/client/global.go
index f54dac35..6af74243 100644
--- a/client/global.go
+++ b/client/global.go
@@ -369,46 +369,3 @@ func unpackOIDBPackage(payload []byte, rsp proto.Message) error {
 	}
 	return nil
 }
-
-func (c *QQClient) Error(msg string, args ...interface{}) {
-	c.dispatchLogEvent(&LogEvent{
-		Type:    "ERROR",
-		Message: fmt.Sprintf(msg, args...),
-	})
-}
-
-func (c *QQClient) Warning(msg string, args ...interface{}) {
-	c.dispatchLogEvent(&LogEvent{
-		Type:    "WARNING",
-		Message: fmt.Sprintf(msg, args...),
-	})
-}
-
-func (c *QQClient) Info(msg string, args ...interface{}) {
-	c.dispatchLogEvent(&LogEvent{
-		Type:    "INFO",
-		Message: fmt.Sprintf(msg, args...),
-	})
-}
-
-func (c *QQClient) Debug(msg string, args ...interface{}) {
-	c.dispatchLogEvent(&LogEvent{
-		Type:    "DEBUG",
-		Message: fmt.Sprintf(msg, args...),
-	})
-}
-
-func (c *QQClient) Trace(msg string, args ...interface{}) {
-	c.dispatchLogEvent(&LogEvent{
-		Type:    "TRACE",
-		Message: fmt.Sprintf(msg, args...),
-	})
-}
-
-func (c *QQClient) Dump(msg string, data []byte, args ...interface{}) {
-	c.dispatchLogEvent(&LogEvent{
-		Type:    "DUMP",
-		Message: fmt.Sprintf(msg, args...),
-		Dump:    data,
-	})
-}
diff --git a/client/group_file.go b/client/group_file.go
index eec1dac3..bcdc5078 100644
--- a/client/group_file.go
+++ b/client/group_file.go
@@ -71,7 +71,7 @@ func init() {
 func (c *QQClient) GetGroupFileSystem(groupCode int64) (fs *GroupFileSystem, err error) {
 	defer func() {
 		if pan := recover(); pan != nil {
-			c.Error("get group fs error: %v\n%s", pan, debug.Stack())
+			c.error("get group fs error: %v\n%s", pan, debug.Stack())
 			err = errors.New("fs error")
 		}
 	}()
diff --git a/client/group_msg.go b/client/group_msg.go
index 34f519aa..acac1a86 100644
--- a/client/group_msg.go
+++ b/client/group_msg.go
@@ -61,7 +61,7 @@ func (c *QQClient) SendGroupMessage(groupCode int64, m *message.SendingMessage,
 				Message:    m.Elements,
 			}))
 		if err != nil {
-			c.Error("%v", err)
+			c.error("%v", err)
 			return nil
 		}
 		ret := c.sendGroupMessage(groupCode, false, &message.SendingMessage{Elements: []message.IMessageElement{lmsg}})
@@ -178,7 +178,7 @@ func (c *QQClient) uploadGroupLongMessage(groupCode int64, m *message.ForwardMes
 		}
 		err := c.highwaySession.Upload(addr, input)
 		if err != nil {
-			c.Error("highway upload long message error: %v", err)
+			c.error("highway upload long message error: %v", err)
 			continue
 		}
 		return genLongTemplate(rsp.MsgResid, m.Brief(), ts), nil
@@ -340,9 +340,9 @@ func decodeMsgSendResponse(c *QQClient, _ *network.IncomingPacketInfo, payload [
 	switch rsp.GetResult() {
 	case 0: // OK.
 	case 55:
-		c.Error("sendPacket msg error: %v Bot has blocked target's content", rsp.GetResult())
+		c.error("sendPacket msg error: %v Bot has blocked target's content", rsp.GetResult())
 	default:
-		c.Error("sendPacket msg error: %v %v", rsp.GetResult(), rsp.GetErrMsg())
+		c.error("sendPacket msg error: %v %v", rsp.GetResult(), rsp.GetErrMsg())
 	}
 	return nil, nil
 }
@@ -353,7 +353,7 @@ func decodeGetGroupMsgResponse(c *QQClient, info *network.IncomingPacketInfo, pa
 		return nil, errors.Wrap(err, "failed to unmarshal protobuf message")
 	}
 	if rsp.GetResult() != 0 {
-		c.Error("get msg error: %v %v", rsp.GetResult(), rsp.GetErrmsg())
+		c.error("get msg error: %v %v", rsp.GetResult(), rsp.GetErrmsg())
 		return nil, errors.Errorf("get msg error: %v msg: %v", rsp.GetResult(), rsp.GetErrmsg())
 	}
 	var ret []*message.GroupMessage
@@ -363,7 +363,7 @@ func decodeGetGroupMsgResponse(c *QQClient, info *network.IncomingPacketInfo, pa
 		}
 		if m.Content != nil && m.Content.GetPkgNum() > 1 && !info.Params.Bool("raw") {
 			if m.Content.GetPkgIndex() == 0 {
-				c.Debug("build fragmented message from history")
+				c.debug("build fragmented message from history")
 				i := m.Head.GetMsgSeq() - m.Content.GetPkgNum()
 				builder := &messageBuilder{}
 				for {
@@ -412,10 +412,10 @@ func decodeAtAllRemainResponse(_ *QQClient, _ *network.IncomingPacketInfo, paylo
 func (c *QQClient) parseGroupMessage(m *msg.Message) *message.GroupMessage {
 	group := c.FindGroup(m.Head.GroupInfo.GetGroupCode())
 	if group == nil {
-		c.Debug("sync group %v.", m.Head.GroupInfo.GetGroupCode())
+		c.debug("sync group %v.", m.Head.GroupInfo.GetGroupCode())
 		info, err := c.GetGroupInfo(m.Head.GroupInfo.GetGroupCode())
 		if err != nil {
-			c.Error("error to sync group %v : %+v", m.Head.GroupInfo.GetGroupCode(), err)
+			c.error("error to sync group %v : %+v", m.Head.GroupInfo.GetGroupCode(), err)
 			return nil
 		}
 		group = info
@@ -424,7 +424,7 @@ func (c *QQClient) parseGroupMessage(m *msg.Message) *message.GroupMessage {
 	if len(group.Members) == 0 {
 		mem, err := c.GetGroupMembers(group)
 		if err != nil {
-			c.Error("error to sync group %v member : %+v", m.Head.GroupInfo.GroupCode, err)
+			c.error("error to sync group %v member : %+v", m.Head.GroupInfo.GroupCode, err)
 			return nil
 		}
 		group.Members = mem
diff --git a/client/guild.go b/client/guild.go
index 56d9791e..df4da040 100644
--- a/client/guild.go
+++ b/client/guild.go
@@ -710,7 +710,7 @@ func convertChannelInfo(info *channel.GuildChannelInfo) *ChannelInfo {
 func (c *QQClient) syncChannelFirstView() {
 	rsp, err := c.sendAndWaitDynamic(c.buildSyncChannelFirstViewPacket())
 	if err != nil {
-		c.Error("sync channel error: %v", err)
+		c.error("sync channel error: %v", err)
 		return
 	}
 	firstViewRsp := new(channel.FirstViewRsp)
@@ -723,7 +723,7 @@ func (c *QQClient) syncChannelFirstView() {
 		c.GuildService.Nickname = self.Nickname
 		c.GuildService.AvatarUrl = self.AvatarUrl
 	} else {
-		c.Error("get self guild profile error: %v", err)
+		c.error("get self guild profile error: %v", err)
 	}
 }
 
@@ -754,7 +754,7 @@ func decodeGuildPushFirstView(c *QQClient, _ *network.IncomingPacketInfo, payloa
 			}
 			channels, err := c.GuildService.FetchChannelList(info.GuildId)
 			if err != nil {
-				c.Warning("waring: fetch guild %v channel error %v. will use sync node to fill channel list field", guild.GuildId, err)
+				c.warning("waring: fetch guild %v channel error %v. will use sync node to fill channel list field", guild.GuildId, err)
 				for _, node := range guild.ChannelNodes {
 					meta := new(channel.ChannelMsgMeta)
 					_ = proto.Unmarshal(node.Meta, meta)
diff --git a/client/guild_eventflow.go b/client/guild_eventflow.go
index d40f559d..8ebd10e1 100644
--- a/client/guild_eventflow.go
+++ b/client/guild_eventflow.go
@@ -80,7 +80,7 @@ func decodeGuildEventFlowPacket(c *QQClient, _ *network.IncomingPacketInfo, payl
 			}
 			eventBody := new(channel.EventBody)
 			if err := proto.Unmarshal(common.PbElem, eventBody); err != nil {
-				c.Error("failed to unmarshal guild channel event body: %v", err)
+				c.error("failed to unmarshal guild channel event body: %v", err)
 				continue
 			}
 			c.processGuildEventBody(m, eventBody)
@@ -106,7 +106,7 @@ func (c *QQClient) processGuildEventBody(m *channel.ChannelMsgContent, eventBody
 	var guild *GuildInfo
 	if m.Head.RoutingHead.GetGuildId() != 0 {
 		if guild = c.GuildService.FindGuild(m.Head.RoutingHead.GetGuildId()); guild == nil {
-			c.Warning("process channel event error: guild not found.")
+			c.warning("process channel event error: guild not found.")
 			return
 		}
 	}
@@ -118,7 +118,7 @@ func (c *QQClient) processGuildEventBody(m *channel.ChannelMsgContent, eventBody
 			}
 			channelInfo, err := c.GuildService.FetchChannelInfo(guild.GuildId, chanId.GetChanId())
 			if err != nil {
-				c.Warning("process create channel event error: fetch channel info error: %v", err)
+				c.warning("process create channel event error: fetch channel info error: %v", err)
 				continue
 			}
 			guild.Channels = append(guild.Channels, channelInfo)
@@ -148,7 +148,7 @@ func (c *QQClient) processGuildEventBody(m *channel.ChannelMsgContent, eventBody
 		if oldInfo == nil {
 			info, err := c.GuildService.FetchChannelInfo(m.Head.RoutingHead.GetGuildId(), eventBody.ChangeChanInfo.GetChanId())
 			if err != nil {
-				c.Error("error to decode channel info updated event: fetch channel info failed: %v", err)
+				c.error("error to decode channel info updated event: fetch channel info failed: %v", err)
 				return
 			}
 			guild.Channels = append(guild.Channels, info)
@@ -159,7 +159,7 @@ func (c *QQClient) processGuildEventBody(m *channel.ChannelMsgContent, eventBody
 		}
 		newInfo, err := c.GuildService.FetchChannelInfo(m.Head.RoutingHead.GetGuildId(), eventBody.ChangeChanInfo.GetChanId())
 		if err != nil {
-			c.Error("error to decode channel info updated event: fetch channel info failed: %v", err)
+			c.error("error to decode channel info updated event: fetch channel info failed: %v", err)
 			return
 		}
 		for i := range guild.Channels {
@@ -178,13 +178,13 @@ func (c *QQClient) processGuildEventBody(m *channel.ChannelMsgContent, eventBody
 	case eventBody.JoinGuild != nil:
 		/* 应该不会重复推送把, 不会吧不会吧
 		if mem := guild.FindMember(eventBody.JoinGuild.GetMemberTinyid()); mem != nil {
-			c.Info("ignore join guild event: member %v already exists", mem.TinyId)
+			c.info("ignore join guild event: member %v already exists", mem.TinyId)
 			return
 		}
 		*/
 		profile, err := c.GuildService.FetchGuildMemberProfileInfo(guild.GuildId, eventBody.JoinGuild.GetMemberTinyid())
 		if err != nil {
-			c.Error("error to decode member join guild event: get member profile error: %v", err)
+			c.error("error to decode member join guild event: get member profile error: %v", err)
 			return
 		}
 		info := &GuildMemberInfo{
@@ -210,7 +210,7 @@ func (c *QQClient) processGuildEventBody(m *channel.ChannelMsgContent, eventBody
 		if eventBody.UpdateMsg.GetEventType() == 4 { // 消息贴表情更新 (包含添加或删除)
 			t, err := c.GuildService.pullChannelMessages(m.Head.RoutingHead.GetGuildId(), m.Head.RoutingHead.GetChannelId(), eventBody.UpdateMsg.GetMsgSeq(), eventBody.UpdateMsg.GetMsgSeq(), eventBody.UpdateMsg.GetEventVersion()-1, false)
 			if err != nil || len(t) == 0 {
-				c.Error("process guild event flow error: pull eventMsg message error: %v", err)
+				c.error("process guild event flow error: pull eventMsg message error: %v", err)
 				return
 			}
 			// 自己的消息被贴表情会单独推送一个tips, 这里不需要解析
diff --git a/client/image.go b/client/image.go
index 1fd10409..7a723e72 100644
--- a/client/image.go
+++ b/client/image.go
@@ -141,7 +141,7 @@ ok:
 	width := int32(i.Width)
 	height := int32(i.Height)
 	if err != nil && target.SourceType != message.SourceGroup {
-		c.Warning("waring: decode image error: %v. this image will be displayed by wrong size in pc guild client", err)
+		c.warning("waring: decode image error: %v. this image will be displayed by wrong size in pc guild client", err)
 		width = 200
 		height = 200
 	}
diff --git a/client/log.go b/client/log.go
new file mode 100644
index 00000000..f0299d2f
--- /dev/null
+++ b/client/log.go
@@ -0,0 +1,33 @@
+package client
+
+type Logger interface {
+	Info(format string, args ...any)
+	Warning(format string, args ...any)
+	Error(format string, args ...any)
+	Debug(format string, args ...any)
+	Dump(dumped []byte, format string, args ...any)
+}
+
+func (c *QQClient) SetLogger(logger Logger) {
+	c.logger = logger
+}
+
+func (c *QQClient) info(msg string, args ...any) {
+	c.logger.Info(msg, args...)
+}
+
+func (c *QQClient) warning(msg string, args ...any) {
+	c.logger.Warning(msg, args...)
+}
+
+func (c *QQClient) error(msg string, args ...any) {
+	c.logger.Error(msg, args...)
+}
+
+func (c *QQClient) debug(msg string, args ...any) {
+	c.logger.Debug(msg, args...)
+}
+
+func (c *QQClient) dump(msg string, data []byte, args ...any) {
+	c.logger.Dump(data, msg, args...)
+}
diff --git a/client/network.go b/client/network.go
index 0554c816..b826bae2 100644
--- a/client/network.go
+++ b/client/network.go
@@ -45,22 +45,22 @@ func (c *QQClient) ConnectionQualityTest() *ConnectionQualityInfo {
 		var err error
 
 		if r.ChatServerLatency, err = qualityTest(c.servers[c.currServerIndex].String()); err != nil {
-			c.Error("test chat server latency error: %v", err)
+			c.error("test chat server latency error: %v", err)
 			r.ChatServerLatency = 9999
 		}
 
 		if addr, err := net.ResolveIPAddr("ip", "ssl.htdata.qq.com"); err == nil {
 			if r.LongMessageServerLatency, err = qualityTest((&net.TCPAddr{IP: addr.IP, Port: 443}).String()); err != nil {
-				c.Error("test long message server latency error: %v", err)
+				c.error("test long message server latency error: %v", err)
 				r.LongMessageServerLatency = 9999
 			}
 		} else {
-			c.Error("resolve long message server error: %v", err)
+			c.error("resolve long message server error: %v", err)
 			r.LongMessageServerLatency = 9999
 		}
 		if c.highwaySession.AddrLength() > 0 {
 			if r.SrvServerLatency, err = qualityTest(c.highwaySession.SsoAddr[0].String()); err != nil {
-				c.Error("test srv server latency error: %v", err)
+				c.error("test srv server latency error: %v", err)
 				r.SrvServerLatency = 9999
 			}
 		}
@@ -78,7 +78,7 @@ func (c *QQClient) ConnectionQualityTest() *ConnectionQualityInfo {
 	if _, err := utils.HttpGetBytes("https://ssl.htdata.qq.com", ""); err == nil {
 		r.LongMessageServerResponseLatency = time.Since(start).Milliseconds()
 	} else {
-		c.Error("test long message server response latency error: %v", err)
+		c.error("test long message server response latency error: %v", err)
 		r.LongMessageServerResponseLatency = 9999
 	}
 	wg.Wait()
@@ -87,7 +87,7 @@ func (c *QQClient) ConnectionQualityTest() *ConnectionQualityInfo {
 
 // connect 连接到 QQClient.servers 中的服务器
 func (c *QQClient) connect() error {
-	c.Info("connect to server: %v", c.servers[c.currServerIndex].String())
+	c.info("connect to server: %v", c.servers[c.currServerIndex].String())
 	err := c.TCP.Connect(c.servers[c.currServerIndex])
 	c.currServerIndex++
 	if c.currServerIndex == len(c.servers) {
@@ -98,7 +98,7 @@ func (c *QQClient) connect() error {
 		if c.retryTimes > len(c.servers) {
 			return errors.New("All servers are unreachable")
 		}
-		c.Error("connect server error: %v", err)
+		c.error("connect server error: %v", err)
 		return err
 	}
 	c.once.Do(func() {
@@ -129,12 +129,12 @@ func (c *QQClient) quickReconnect() {
 	c.Disconnect()
 	time.Sleep(time.Millisecond * 200)
 	if err := c.connect(); err != nil {
-		c.Error("connect server error: %v", err)
+		c.error("connect server error: %v", err)
 		c.DisconnectedEvent.dispatch(c, &ClientDisconnectedEvent{Message: "quick reconnect failed"})
 		return
 	}
 	if err := c.registerClient(); err != nil {
-		c.Error("register client failed: %v", err)
+		c.error("register client failed: %v", err)
 		c.Disconnect()
 		c.DisconnectedEvent.dispatch(c, &ClientDisconnectedEvent{Message: "register error"})
 		return
@@ -251,23 +251,23 @@ func (c *QQClient) sendAndWaitDynamic(seq uint16, pkt []byte) ([]byte, error) {
 
 // plannedDisconnect 计划中断线事件
 func (c *QQClient) plannedDisconnect(_ *network.TCPListener) {
-	c.Debug("planned disconnect.")
+	c.debug("planned disconnect.")
 	c.stat.DisconnectTimes.Add(1)
 	c.Online.Store(false)
 }
 
 // unexpectedDisconnect 非预期断线事件
 func (c *QQClient) unexpectedDisconnect(_ *network.TCPListener, e error) {
-	c.Error("unexpected disconnect: %v", e)
+	c.error("unexpected disconnect: %v", e)
 	c.stat.DisconnectTimes.Add(1)
 	c.Online.Store(false)
 	if err := c.connect(); err != nil {
-		c.Error("connect server error: %v", err)
+		c.error("connect server error: %v", err)
 		c.DisconnectedEvent.dispatch(c, &ClientDisconnectedEvent{Message: "connection dropped by server."})
 		return
 	}
 	if err := c.registerClient(); err != nil {
-		c.Error("register client failed: %v", err)
+		c.error("register client failed: %v", err)
 		c.Disconnect()
 		c.DisconnectedEvent.dispatch(c, &ClientDisconnectedEvent{Message: "register error"})
 		return
@@ -284,7 +284,7 @@ func (c *QQClient) netLoop() {
 			continue
 		}
 		if l < 4 || l > 1024*1024*10 { // max 10MB
-			c.Error("parse incoming packet error: invalid packet length %v", l)
+			c.error("parse incoming packet error: invalid packet length %v", l)
 			errCount++
 			if errCount > 2 {
 				go c.quickReconnect()
@@ -295,7 +295,7 @@ func (c *QQClient) netLoop() {
 		resp, err := c.transport.ReadResponse(data)
 		// pkt, err := packets.ParseIncomingPacket(data, c.sig.D2Key)
 		if err != nil {
-			c.Error("parse incoming packet error: %v", err)
+			c.error("parse incoming packet error: %v", err)
 			if errors.Is(err, network.ErrSessionExpired) || errors.Is(err, network.ErrPacketDropped) {
 				c.Disconnect()
 				go c.DisconnectedEvent.dispatch(c, &ClientDisconnectedEvent{Message: "session expired"})
@@ -310,7 +310,7 @@ func (c *QQClient) netLoop() {
 		if resp.EncryptType == network.EncryptTypeEmptyKey {
 			m, err := c.oicq.Unmarshal(resp.Body)
 			if err != nil {
-				c.Error("decrypt payload error: %v", err)
+				c.error("decrypt payload error: %v", err)
 				if errors.Is(err, oicq.ErrUnknownFlag) {
 					go c.quickReconnect()
 				}
@@ -319,7 +319,7 @@ func (c *QQClient) netLoop() {
 			resp.Body = m.Body
 		}
 		errCount = 0
-		c.Debug("rev pkt: %v seq: %v", resp.CommandName, resp.SequenceID)
+		c.debug("rev pkt: %v seq: %v", resp.CommandName, resp.SequenceID)
 		c.stat.PacketReceived.Add(1)
 		pkt := &packets.IncomingPacket{
 			SequenceId:  uint16(resp.SequenceID),
@@ -329,8 +329,8 @@ func (c *QQClient) netLoop() {
 		go func(pkt *packets.IncomingPacket) {
 			defer func() {
 				if pan := recover(); pan != nil {
-					c.Error("panic on decoder %v : %v\n%s", pkt.CommandName, pan, debug.Stack())
-					c.Dump("packet decode error: %v - %v", pkt.Payload, pkt.CommandName, pan)
+					c.error("panic on decoder %v : %v\n%s", pkt.CommandName, pan, debug.Stack())
+					c.dump("packet decode error: %v - %v", pkt.Payload, pkt.CommandName, pan)
 				}
 			}()
 
@@ -346,7 +346,7 @@ func (c *QQClient) netLoop() {
 						Params:      info.getParams(),
 					}, pkt.Payload)
 					if err != nil {
-						c.Debug("decode pkt %v error: %+v", pkt.CommandName, err)
+						c.debug("decode pkt %v error: %+v", pkt.CommandName, err)
 					}
 				}
 				if ok {
@@ -358,7 +358,7 @@ func (c *QQClient) netLoop() {
 				// does not need decoder
 				f.fun(pkt.Payload, nil)
 			} else {
-				c.Debug("Unhandled Command: %s\nSeq: %d\nThis message can be ignored.", pkt.CommandName, pkt.SequenceId)
+				c.debug("Unhandled Command: %s\nSeq: %d\nThis message can be ignored.", pkt.CommandName, pkt.SequenceId)
 			}
 		}(pkt)
 	}
diff --git a/client/notify.go b/client/notify.go
index c9cda9e5..df2e8aa0 100644
--- a/client/notify.go
+++ b/client/notify.go
@@ -139,7 +139,7 @@ func (c *QQClient) msgGrayTipProcessor(groupCode int64, tipInfo *notify.AIOGrayT
 			}
 		}
 		if event.Uin == 0 {
-			c.Error("process special title updated tips error: missing cmd")
+			c.error("process special title updated tips error: missing cmd")
 			return
 		}
 		if mem := c.FindGroup(groupCode).FindMember(event.Uin); mem != nil {
diff --git a/client/offline_file.go b/client/offline_file.go
index 0fd8099e..f02223c3 100644
--- a/client/offline_file.go
+++ b/client/offline_file.go
@@ -36,15 +36,15 @@ func (c *QQClient) buildOfflineFileDownloadRequestPacket(uuid []byte) (uint16, [
 func decodeOfflineFileDownloadResponse(c *QQClient, _ *network.IncomingPacketInfo, payload []byte) (interface{}, error) {
 	rsp := cmd0x346.C346RspBody{}
 	if err := proto.Unmarshal(payload, &rsp); err != nil {
-		c.Error("unmarshal cmd0x346 rsp body error: %v", err)
+		c.error("unmarshal cmd0x346 rsp body error: %v", err)
 		return nil, errors.Wrap(err, "unmarshal cmd0x346 rsp body error")
 	}
 	if rsp.ApplyDownloadRsp == nil {
-		c.Error("decode apply download 1200 error: apply rsp is nil.")
+		c.error("decode apply download 1200 error: apply rsp is nil.")
 		return nil, errors.New("apply rsp is nil")
 	}
 	if rsp.ApplyDownloadRsp.RetCode != 0 {
-		c.Error("decode apply download 1200 error: %v", rsp.ApplyDownloadRsp.RetCode)
+		c.error("decode apply download 1200 error: %v", rsp.ApplyDownloadRsp.RetCode)
 		return nil, errors.Errorf("apply download rsp error: %d", rsp.ApplyDownloadRsp.RetCode)
 	}
 	return "http://" + rsp.ApplyDownloadRsp.DownloadInfo.DownloadDomain + rsp.ApplyDownloadRsp.DownloadInfo.DownloadUrl, nil
diff --git a/client/online_push.go b/client/online_push.go
index f0f397d4..b843e858 100644
--- a/client/online_push.go
+++ b/client/online_push.go
@@ -118,7 +118,7 @@ func decodeOnlinePushReqPacket(c *QQClient, info *network.IncomingPacketInfo, pa
 					return nil, errors.Wrap(err, "decode online push 0x210 error")
 				}
 			} else {
-				c.Debug("unknown online push 0x210 sub type 0x%v", strconv.FormatInt(subType, 16))
+				c.debug("unknown online push 0x210 sub type 0x%v", strconv.FormatInt(subType, 16))
 			}
 		}
 	}
@@ -241,7 +241,7 @@ func msgType0x210Sub44Decoder(c *QQClient, protobuf []byte) error {
 	if s44.GroupSyncMsg.GrpCode == 0 { // member sync
 		return errors.New("invalid group code")
 	}
-	c.Debug("syncing members.")
+	c.debug("syncing members.")
 	if group := c.FindGroup(s44.GroupSyncMsg.GrpCode); group != nil {
 		group.lock.Lock()
 		defer group.lock.Unlock()
diff --git a/client/qidian.go b/client/qidian.go
index 1054ac5d..ca07c707 100644
--- a/client/qidian.go
+++ b/client/qidian.go
@@ -52,7 +52,7 @@ func (c *QQClient) getQiDianAddressDetailList() ([]*FriendInfo, error) {
 	ret := []*FriendInfo{}
 	for _, detail := range rsp.GetAddressDetailListRspBody.AddressDetail {
 		if len(detail.Qq) == 0 {
-			c.Warning("address detail %v QQ is 0", string(detail.Name))
+			c.warning("address detail %v QQ is 0", string(detail.Name))
 			continue
 		}
 		ret = append(ret, &FriendInfo{
diff --git a/client/sync.go b/client/sync.go
index 3a182114..ae0bf24f 100644
--- a/client/sync.go
+++ b/client/sync.go
@@ -90,7 +90,7 @@ func (c *QQClient) SyncSessions() (*SessionSyncResponse, error) {
 		if e.GroupNum != -1 {
 			groupNum = e.GroupNum
 		}
-		c.Debug("sync session %v/%v", len(ret.GroupSessions), groupNum)
+		c.debug("sync session %v/%v", len(ret.GroupSessions), groupNum)
 		if groupNum != -1 && len(ret.GroupSessions) >= int(groupNum) {
 			notifyChan <- true
 		}
diff --git a/client/system_msg.go b/client/system_msg.go
index e3a36255..c01a5999 100644
--- a/client/system_msg.go
+++ b/client/system_msg.go
@@ -60,7 +60,7 @@ func (c *QQClient) GetGroupSystemMessages() (*GroupSystemMessages, error) {
 
 func (c *QQClient) exceptAndDispatchGroupSysMsg() {
 	if c.groupSysMsgCache == nil {
-		c.Error("warning: groupSysMsgCache is nil")
+		c.error("warning: groupSysMsgCache is nil")
 		c.groupSysMsgCache, _ = c.GetGroupSystemMessages()
 		return
 	}
@@ -243,12 +243,12 @@ func decodeSystemMsgGroupPacket(c *QQClient, _ *network.IncomingPacketInfo, payl
 					ActionUinNick: st.Msg.ActionUinQqNick,
 				})
 			default:
-				c.Debug("unknown group system message type: %v", st.Msg.GroupMsgType)
+				c.debug("unknown group system message type: %v", st.Msg.GroupMsgType)
 			}
 		case 3: // ?
 		case 5: // 自身状态变更(管理员/加群退群)
 		default:
-			c.Debug("unknown group system msg: %v", st.Msg.SubType)
+			c.debug("unknown group system msg: %v", st.Msg.SubType)
 		}
 	}
 	return ret, nil
diff --git a/client/tlv_decoders.go b/client/tlv_decoders.go
index 6337abf4..ee8a37e3 100644
--- a/client/tlv_decoders.go
+++ b/client/tlv_decoders.go
@@ -139,11 +139,11 @@ func (c *QQClient) decodeT119R(data []byte) {
 	if t120, ok := m[0x120]; ok {
 		c.sig.SKey = t120
 		c.sig.SKeyExpiredTime = time.Now().Unix() + 21600
-		c.Debug("skey updated: %v", c.sig.SKey)
+		c.debug("skey updated: %v", c.sig.SKey)
 	}
 	if t11a, ok := m[0x11a]; ok {
 		c.Nickname, c.Age, c.Gender = readT11A(t11a)
-		c.Debug("account info updated: " + c.Nickname)
+		c.debug("account info updated: " + c.Nickname)
 	}
 }