migrate WS chat/reaction/presence handlers to service layer

Handlers now delegate all business logic (validation, permission checks,
DB operations) to MessageService and ChannelService instead of calling
*db.DB directly. This eliminates logic duplication and enables the
service layer's permission cache.

https://claude.ai/code/session_01CBFF3r84ywkJRWwuqw8zD8

Server/ws/handlers_chat.go

@@ -2,11 +2,9 @@ package ws
 
 import (
 	"context"
-	"fmt"
-	"log/slog"
-	"time"
+	"errors"
 
-	"github.com/owncord/server/permissions"
+	"github.com/owncord/server/service"
 )
 
 // registerChatHandlers registers all chat-related V2 message handlers.
@@ -16,346 +14,134 @@ func registerChatHandlers(r *HandlerRegistry, deps ChatDeps) {
 	r.RegisterV2(MsgTypeChatDelete, handleChatDeleteV2, deps)
 }
 
-// handleChatSendV2 processes a chat_send command.
+// handleChatSendV2 processes a chat_send command via the MessageService.
 func handleChatSendV2(_ context.Context, cmd Command, info ClientInfo, deps any) Result {
 	d := deps.(ChatDeps)
 	sendCmd := cmd.(ChatSendCmd)
-	userID := info.UserID
-	channelID := sendCmd.ChannelID()
 
-	// Rate limit.
-	ratKey := fmt.Sprintf("chat:%d", userID)
-	if d.Limiter != nil && !d.Limiter.Allow(ratKey, chatRateLimit, chatWindow) {
-		return Result{Error: ClientError{Code: ErrCodeRateLimited, Message: "too many messages"}}
-	}
-
-	if channelID <= 0 {
-		return Result{Error: ClientError{Code: ErrCodeBadRequest, Message: "channel_id must be a positive integer"}}
-	}
-
-	ch, err := d.DB.GetChannel(channelID)
-	if err != nil || ch == nil {
-		return Result{Error: ClientError{Code: ErrCodeNotFound, Message: "channel not found"}}
-	}
-
-	isDM := ch.Type == "dm"
-
-	// Permission check.
-	if r := chatSendPermCheck(d, userID, channelID, isDM); r != nil {
-		return *r
-	}
-
-	// Slow mode.
-	if !isDM && ch.SlowMode > 0 && !hasPerm(d.DB, d.Permissions, userID, channelID, permissions.ManageMessages) {
-		slowKey := fmt.Sprintf("slow:%d:%d", userID, channelID)
-		if d.Limiter != nil && !d.Limiter.Allow(slowKey, 1, time.Duration(ch.SlowMode)*time.Second) {
-			return Result{Error: ClientError{Code: ErrCodeSlowMode, Message: fmt.Sprintf("channel has %ds slow mode", ch.SlowMode)}}
-		}
-	}
-
-	// Validate content — check raw length before sanitizing to prevent
-	// CPU/memory amplification from huge payloads hitting bluemonday.
-	rawContent := sendCmd.Content()
-	attachmentIDs := sendCmd.Attachments()
-	if len(rawContent) > maxMessageLen*4 {
-		return Result{Error: ClientError{Code: ErrCodeBadRequest, Message: "message content exceeds maximum length of 4000 characters"}}
-	}
-	content := sanitizer.Sanitize(rawContent)
-	if content == "" && len(attachmentIDs) == 0 {
-		return Result{Error: ClientError{Code: ErrCodeBadRequest, Message: "message content cannot be empty"}}
-	}
-	if len([]rune(content)) > maxMessageLen {
-		return Result{Error: ClientError{Code: ErrCodeBadRequest, Message: "message content exceeds maximum length of 4000 characters"}}
-	}
-
-	// Attachment permission.
-	if !isDM && len(attachmentIDs) > 0 {
-		if r := requirePerm(d.DB, d.Permissions, userID, channelID, permissions.AttachFiles, "ATTACH_FILES"); r != nil {
-			return *r
-		}
-	}
-
-	// Persist message.
-	msgID, err := d.DB.CreateMessage(channelID, userID, content, sendCmd.ReplyTo())
+	result, err := d.MessageSvc.SendMessage(service.SendMessageParams{
+		ChannelID:     sendCmd.ChannelID(),
+		UserID:        info.UserID,
+		Username:      info.Username,
+		Avatar:        info.Avatar,
+		RoleName:      info.RoleName,
+		Content:       sendCmd.Content(),
+		ReplyTo:       sendCmd.ReplyTo(),
+		AttachmentIDs: sendCmd.Attachments(),
+	})
 	if err != nil {
-		slog.Error("ws handleChatSendV2 CreateMessage", "err", err)
-		return Result{Error: ClientError{Code: ErrCodeInternal, Message: "failed to save message"}}
+		return serviceErrorToResult(err)
 	}
 
-	// Link attachments.
+	// Build attachment data for broadcast.
 	var attData []map[string]any
-	if len(attachmentIDs) > 0 {
-		linked, linkErr := d.DB.LinkAttachmentsToMessage(msgID, attachmentIDs)
-		if linkErr != nil {
-			slog.Error("ws handleChatSendV2 LinkAttachments", "err", linkErr, "msg_id", msgID)
-			if delErr := d.DB.DeleteMessage(msgID, userID, true); delErr != nil {
-				slog.Error("ws handleChatSendV2 DeleteMessage (cleanup)", "err", delErr, "msg_id", msgID)
-			}
-			return Result{Error: ClientError{Code: ErrCodeInternal, Message: "failed to send message with attachments"}}
-		}
-		if linked > 0 {
-			attMap, attErr := d.DB.GetAttachmentsByMessageIDs([]int64{msgID})
-			if attErr != nil {
-				slog.Error("ws handleChatSendV2 GetAttachments", "err", attErr)
-			} else {
-				for _, ai := range attMap[msgID] {
-					attData = append(attData, map[string]any{
-						"id":       ai.ID,
-						"filename": ai.Filename,
-						"size":     ai.Size,
-						"mime":     ai.Mime,
-						"url":      ai.URL,
-					})
-				}
-			}
-		}
+	for _, ai := range result.Attachments {
+		attData = append(attData, map[string]any{
+			"id":       ai.ID,
+			"filename": ai.Filename,
+			"size":     ai.Size,
+			"mime":     ai.Mime,
+			"url":      ai.URL,
+		})
 	}
 
-	// Fetch message for timestamp.
-	msg, err := d.DB.GetMessage(msgID)
-	if err != nil || msg == nil {
-		slog.Error("ws handleChatSendV2 GetMessage after create", "err", err)
-		return Result{Error: ClientError{Code: ErrCodeInternal, Message: "failed to retrieve message"}}
-	}
+	reply := buildChatSendOK(info.ReqID, result.MessageID, result.Timestamp)
+	broadcast := buildChatMessage(result.MessageID, sendCmd.ChannelID(), info.UserID,
+		info.Username, info.Avatar, info.RoleName, result.Content, result.Timestamp,
+		sendCmd.ReplyTo(), attData)
 
-	slog.Debug("message sent", "user", info.Username, "channel_id", channelID, "msg_id", msgID)
-
-	reply := buildChatSendOK(info.ReqID, msgID, msg.Timestamp)
-	broadcast := buildChatMessage(msgID, channelID, userID, info.Username, info.Avatar, info.RoleName, content, msg.Timestamp, sendCmd.ReplyTo(), attData)
-
-	if !isDM {
+	if !result.IsDM {
 		return Result{
 			Reply:  reply,
-			Events: []Event{MessageSentChannelEvent{channelID: channelID, payload: broadcast}},
+			Events: []Event{MessageSentChannelEvent{channelID: sendCmd.ChannelID(), payload: broadcast}},
 		}
 	}
 
-	// DM path: open DM for recipients, send dm_channel_open, then sequenced message.
-	participantIDs, pErr := d.DB.GetDMParticipantIDs(channelID)
-	if pErr != nil {
-		slog.Error("ws handleChatSendV2 GetDMParticipantIDs", "err", pErr, "channel_id", channelID)
-		// Message is saved; return the ACK but skip broadcast.
-		return Result{Reply: reply}
-	}
-
+	// DM path: build dm_channel_open events + sequenced message.
 	var events []Event
-	sender, _ := d.DB.GetUserByID(userID)
-	for _, pid := range participantIDs {
-		if pid == userID {
-			continue
-		}
-		if openErr := d.DB.OpenDM(pid, channelID); openErr != nil {
-			slog.Error("ws handleChatSendV2 OpenDM", "err", openErr, "recipient_id", pid, "channel_id", channelID)
-			continue
-		}
-		if sender != nil {
+	if result.SenderUser != nil {
+		for _, pid := range result.OpenedDMFor {
 			events = append(events, DMChannelOpenEvent{
 				targetUserID: pid,
-				payload:      buildDMChannelOpen(channelID, sender),
+				payload:      buildDMChannelOpen(sendCmd.ChannelID(), result.SenderUser),
 			})
 		}
 	}
 
 	events = append(events, MessageSentDMEvent{
-		channelID:      channelID,
-		participantIDs: participantIDs,
+		channelID:      sendCmd.ChannelID(),
+		participantIDs: result.ParticipantIDs,
 		payload:        broadcast,
 	})
 
 	return Result{Reply: reply, Events: events}
 }
 
-// chatSendPermCheck validates send permission for DM and non-DM channels.
-func chatSendPermCheck(d ChatDeps, userID, channelID int64, isDM bool) *Result {
-	if isDM {
-		ok, dmErr := d.DB.IsDMParticipant(userID, channelID)
-		if dmErr != nil {
-			slog.Error("ws chatSendPermCheck IsDMParticipant", "err", dmErr)
-			r := Result{Error: ClientError{Code: ErrCodeInternal, Message: "failed to check DM participation"}}
-			return &r
-		}
-		if !ok {
-			r := Result{Error: ClientError{Code: ErrCodeForbidden, Message: "you are not a participant in this DM"}}
-			return &r
-		}
-		recipient, recErr := d.DB.GetDMRecipient(channelID, userID)
-		if recErr == nil && recipient != nil {
-			blocked, blkErr := d.DB.IsEitherBlocked(userID, recipient.ID)
-			if blkErr != nil {
-				slog.Error("ws chatSendPermCheck IsEitherBlocked", "err", blkErr)
-				r := Result{Error: ClientError{Code: ErrCodeInternal, Message: "failed to check block status"}}
-				return &r
-			}
-			if blocked {
-				r := Result{Error: ClientError{Code: ErrCodeForbidden, Message: "cannot send messages — user is blocked"}}
-				return &r
-			}
-		}
-		return nil
-	}
-	return requirePerm(d.DB, d.Permissions, userID, channelID, permissions.ReadMessages|permissions.SendMessages, "SEND_MESSAGES")
-}
-
-// handleChatEditV2 processes a chat_edit command.
+// handleChatEditV2 processes a chat_edit command via the MessageService.
 func handleChatEditV2(_ context.Context, cmd Command, info ClientInfo, deps any) Result {
 	d := deps.(ChatDeps)
 	editCmd := cmd.(ChatEditCmd)
-	userID := info.UserID
-	msgID := editCmd.MessageID()
 
-	// Rate limit.
-	ratKey := fmt.Sprintf("chat_edit:%d", userID)
-	if d.Limiter != nil && !d.Limiter.Allow(ratKey, chatRateLimit, chatWindow) {
-		return Result{Error: ClientError{Code: ErrCodeRateLimited, Message: "too many edits"}}
+	result, err := d.MessageSvc.EditMessage(info.UserID, editCmd.MessageID(), editCmd.Content())
+	if err != nil {
+		return serviceErrorToResult(err)
 	}
 
-	if msgID <= 0 {
-		return Result{Error: ClientError{Code: ErrCodeBadRequest, Message: "message_id must be positive integer"}}
-	}
-
-	// Validate content — check raw length before sanitizing to prevent
-	// CPU/memory amplification from huge payloads hitting bluemonday.
-	rawContent := editCmd.Content()
-	if len(rawContent) > maxMessageLen*4 {
-		return Result{Error: ClientError{Code: ErrCodeBadRequest, Message: "message too long"}}
-	}
-	content := sanitizer.Sanitize(rawContent)
-	if content == "" {
-		return Result{Error: ClientError{Code: ErrCodeBadRequest, Message: "content cannot be empty"}}
-	}
-	if len([]rune(content)) > maxMessageLen {
-		return Result{Error: ClientError{Code: ErrCodeBadRequest, Message: "message too long"}}
-	}
-
-	// Fetch message (opaque error to prevent IDOR).
-	msg, err := d.DB.GetMessage(msgID)
-	if err != nil || msg == nil {
-		return Result{Error: ClientError{Code: ErrCodeForbidden, Message: "cannot edit this message"}}
-	}
-
-	// BUG-126: Reject edits on soft-deleted messages.
-	if msg.Deleted {
-		return Result{Error: ClientError{Code: ErrCodeForbidden, Message: "cannot edit this message"}}
-	}
-
-	// Channel type for DM-aware permissions.
-	editCh, chErr := d.DB.GetChannel(msg.ChannelID)
-	editIsDM := chErr == nil && editCh != nil && editCh.Type == "dm"
-
-	if editIsDM {
-		ok, dmErr := d.DB.IsDMParticipant(userID, msg.ChannelID)
-		if dmErr != nil || !ok {
-			return Result{Error: ClientError{Code: ErrCodeForbidden, Message: "cannot edit this message"}}
-		}
-	} else if !hasPerm(d.DB, d.Permissions, userID, msg.ChannelID, permissions.SendMessages) {
-		return Result{Error: ClientError{Code: ErrCodeForbidden, Message: "cannot edit this message"}}
-	}
-
-	// EditMessage checks ownership internally.
-	if err := d.DB.EditMessage(msgID, userID, content); err != nil {
-		return Result{Error: ClientError{Code: ErrCodeForbidden, Message: "cannot edit this message"}}
-	}
-
-	// Re-fetch for updated edited_at timestamp.
-	msg, err = d.DB.GetMessage(msgID)
-	if err != nil || msg == nil {
-		slog.Error("ws handleChatEditV2 GetMessage after edit", "err", err, "msg_id", msgID)
-		return Result{Error: ClientError{Code: ErrCodeInternal, Message: "edit saved but broadcast failed"}}
-	}
-
-	editedAt := ""
-	if msg.EditedAt != nil {
-		editedAt = *msg.EditedAt
-	}
-	slog.Debug("message edited", "user_id", userID, "msg_id", msgID, "channel_id", msg.ChannelID)
-
-	editedPayload := buildChatEdited(msgID, msg.ChannelID, content, editedAt)
-	if editIsDM {
-		participantIDs, pErr := d.DB.GetDMParticipantIDs(msg.ChannelID)
-		if pErr != nil {
-			slog.Error("handleChatEditV2 GetDMParticipantIDs", "err", pErr, "channel_id", msg.ChannelID)
-			return Result{}
-		}
+	editedPayload := buildChatEdited(result.MessageID, result.ChannelID, result.Content, result.EditedAt)
+	if result.IsDM {
 		return Result{Events: []Event{MessageEditedDMEvent{
-			channelID:      msg.ChannelID,
-			participantIDs: participantIDs,
+			channelID:      result.ChannelID,
+			participantIDs: result.ParticipantIDs,
 			payload:        editedPayload,
 		}}}
 	}
 	return Result{Events: []Event{MessageEditedChannelEvent{
-		channelID: msg.ChannelID,
+		channelID: result.ChannelID,
 		payload:   editedPayload,
 	}}}
 }
 
-// handleChatDeleteV2 processes a chat_delete command.
+// handleChatDeleteV2 processes a chat_delete command via the MessageService.
 func handleChatDeleteV2(_ context.Context, cmd Command, info ClientInfo, deps any) Result {
 	d := deps.(ChatDeps)
 	deleteCmd := cmd.(ChatDeleteCmd)
-	userID := info.UserID
-	msgID := deleteCmd.MessageID()
 
-	// Rate limit.
-	ratKey := fmt.Sprintf("chat_delete:%d", userID)
-	if d.Limiter != nil && !d.Limiter.Allow(ratKey, chatRateLimit, chatWindow) {
-		return Result{Error: ClientError{Code: ErrCodeRateLimited, Message: "too many deletes"}}
+	result, err := d.MessageSvc.DeleteMessage(info.UserID, deleteCmd.MessageID())
+	if err != nil {
+		return serviceErrorToResult(err)
 	}
 
-	if msgID <= 0 {
-		return Result{Error: ClientError{Code: ErrCodeBadRequest, Message: "message_id must be positive integer"}}
-	}
-
-	// Fetch message (opaque error to prevent IDOR).
-	msg, err := d.DB.GetMessage(msgID)
-	if err != nil || msg == nil {
-		return Result{Error: ClientError{Code: ErrCodeForbidden, Message: "cannot delete this message"}}
-	}
-
-	// Channel type for DM-aware permissions.
-	delCh, chErr := d.DB.GetChannel(msg.ChannelID)
-	delIsDM := chErr == nil && delCh != nil && delCh.Type == "dm"
-
-	if delIsDM {
-		ok, dmErr := d.DB.IsDMParticipant(userID, msg.ChannelID)
-		if dmErr != nil || !ok {
-			return Result{Error: ClientError{Code: ErrCodeForbidden, Message: "cannot delete this message"}}
-		}
-	} else {
-		// Mod override: ManageMessages allows deleting any message.
-		// Own-message delete requires SendMessages (a muted user cannot delete).
-		isMsgOwner := msg.UserID == userID
-		canManage := hasPerm(d.DB, d.Permissions, userID, msg.ChannelID, permissions.ManageMessages)
-		canDelete := canManage || (isMsgOwner && hasPerm(d.DB, d.Permissions, userID, msg.ChannelID, permissions.SendMessages))
-		if !canDelete {
-			return Result{Error: ClientError{Code: ErrCodeForbidden, Message: "cannot delete this message"}}
-		}
-	}
-
-	// In DMs, users can only delete their own messages (no mod override).
-	isMod := !delIsDM && hasPerm(d.DB, d.Permissions, userID, msg.ChannelID, permissions.ManageMessages)
-	if err := d.DB.DeleteMessage(msgID, userID, isMod); err != nil {
-		return Result{Error: ClientError{Code: ErrCodeForbidden, Message: "cannot delete this message"}}
-	}
-
-	slog.Debug("message deleted", "user_id", userID, "msg_id", msgID, "channel_id", msg.ChannelID, "is_mod", isMod)
-	_ = d.DB.LogAudit(userID, "message_delete", "message", msgID,
-		fmt.Sprintf("channel %d, mod_action=%v", msg.ChannelID, isMod))
-
-	deletedPayload := buildChatDeleted(msgID, msg.ChannelID)
-	if delIsDM {
-		participantIDs, pErr := d.DB.GetDMParticipantIDs(msg.ChannelID)
-		if pErr != nil {
-			slog.Error("handleChatDeleteV2 GetDMParticipantIDs", "err", pErr, "channel_id", msg.ChannelID)
-			return Result{}
-		}
+	deletedPayload := buildChatDeleted(result.MessageID, result.ChannelID)
+	if result.IsDM {
 		return Result{Events: []Event{MessageDeletedDMEvent{
-			channelID:      msg.ChannelID,
-			participantIDs: participantIDs,
+			channelID:      result.ChannelID,
+			participantIDs: result.ParticipantIDs,
 			payload:        deletedPayload,
 		}}}
 	}
 	return Result{Events: []Event{MessageDeletedChannelEvent{
-		channelID: msg.ChannelID,
+		channelID: result.ChannelID,
 		payload:   deletedPayload,
 	}}}
 }
+
+// serviceErrorToResult converts a service-layer error to a WS Result.
+func serviceErrorToResult(err error) Result {
+	switch {
+	case errors.Is(err, service.ErrRateLimited):
+		return Result{Error: ClientError{Code: ErrCodeRateLimited, Message: err.Error()}}
+	case errors.Is(err, service.ErrSlowMode):
+		return Result{Error: ClientError{Code: ErrCodeSlowMode, Message: err.Error()}}
+	case errors.Is(err, service.ErrBadRequest):
+		return Result{Error: ClientError{Code: ErrCodeBadRequest, Message: err.Error()}}
+	case errors.Is(err, service.ErrNotFound):
+		return Result{Error: ClientError{Code: ErrCodeNotFound, Message: err.Error()}}
+	case errors.Is(err, service.ErrForbidden), errors.Is(err, service.ErrBlocked),
+		errors.Is(err, service.ErrDeletedMessage):
+		return Result{Error: ClientError{Code: ErrCodeForbidden, Message: err.Error()}}
+	case errors.Is(err, service.ErrConflict):
+		return Result{Error: ClientError{Code: ErrCodeConflict, Message: err.Error()}}
+	default:
+		return Result{Error: ClientError{Code: ErrCodeInternal, Message: err.Error()}}
+	}
+}

Server/ws/handlers_presence.go

@@ -2,17 +2,11 @@ package ws
 
 import (
 	"context"
-	"fmt"
-	"log/slog"
+	"errors"
 
-	"github.com/owncord/server/permissions"
+	"github.com/owncord/server/service"
 )
 
-// validPresenceStatuses is the set of accepted status values for presence_update.
-var validPresenceStatuses = map[string]bool{
-	"online": true, "idle": true, "dnd": true, "offline": true,
-}
-
 // registerPresenceHandlers registers presence, typing, and channel focus handlers.
 // All three are V2 handlers.
 func registerPresenceHandlers(r *HandlerRegistry, deps PresenceDeps) {
@@ -30,39 +24,18 @@ func handleTypingV2(_ context.Context, cmd Command, info ClientInfo, deps any) R
 	channelID := typingCmd.ChannelID()
 	userID := info.UserID
 
-	// Rate limit.
-	ratKey := fmt.Sprintf("typing:%d:%d", userID, channelID)
-	if d.Limiter != nil && !d.Limiter.Allow(ratKey, typingRateLimit, typingWindow) {
-		return Result{} // silently drop; no error for typing throttle
-	}
-
-	// Channel lookup.
-	ch, err := d.DB.GetChannel(channelID)
+	ch, err := d.ChannelSvc.HandleTyping(userID, channelID, d.Limiter)
 	if err != nil || ch == nil {
-		return Result{} // silently drop for unknown channels
-	}
-
-	// Permission check.
-	if ch.Type == "dm" {
-		ok, dmErr := d.DB.IsDMParticipant(userID, channelID)
-		if dmErr != nil || !ok {
-			return Result{} // silently drop — not a DM participant
-		}
-	} else {
-		if !hasPerm(d.DB, d.Permissions, userID, channelID, permissions.ReadMessages) {
-			return Result{} // silently drop — no read permission
-		}
+		return Result{} // silently drop
 	}
 
 	payload := buildTypingMsg(channelID, userID, info.Username)
 
 	if ch.Type == "dm" {
-		// For DM channels, get participant IDs and send to each excluding sender.
-		participantIDs, pErr := d.DB.GetDMParticipantIDs(channelID)
+		participantIDs, pErr := d.ChannelSvc.GetDMParticipantIDs(channelID)
 		if pErr != nil {
-			return Result{} // silently drop on error
+			return Result{}
 		}
-		// Build one TypingDMEvent per other participant (UserTargetedEvent routing).
 		var events []Event
 		for _, pid := range participantIDs {
 			if pid == userID {
@@ -76,7 +49,6 @@ func handleTypingV2(_ context.Context, cmd Command, info ClientInfo, deps any) R
 		return Result{Events: events}
 	}
 
-	// Regular channel: ExcludeSenderEvent routing.
 	return Result{
 		Events: []Event{
 			TypingChannelEvent{
@@ -94,26 +66,12 @@ func handlePresenceV2(_ context.Context, cmd Command, info ClientInfo, deps any)
 	d := deps.(PresenceDeps)
 	presenceCmd := cmd.(PresenceUpdateCmd)
 	userID := info.UserID
-
-	// Rate limit.
-	ratKey := fmt.Sprintf("presence:%d", userID)
-	if d.Limiter != nil && !d.Limiter.Allow(ratKey, presenceRateLimit, presenceWindow) {
-		return Result{Error: ClientError{Code: ErrCodeRateLimited, Message: "too many presence updates"}}
-	}
-
-	// Validate status.
 	status := presenceCmd.Status()
-	if !validPresenceStatuses[status] {
-		return Result{Error: ClientError{Code: ErrCodeBadRequest, Message: "status must be online|idle|dnd|offline"}}
+
+	if err := d.ChannelSvc.HandlePresenceUpdate(userID, status, d.Limiter); err != nil {
+		return serviceErrorToResult(err)
 	}
 
-	// Update DB.
-	if err := d.DB.UpdateUserStatus(userID, status); err != nil {
-		slog.Error("ws handlePresenceV2 UpdateUserStatus", "err", err, "user_id", userID)
-		return Result{Error: ClientError{Code: ErrCodeInternal, Message: "failed to update status"}}
-	}
-
-	// Broadcast to all connected clients.
 	return Result{
 		Events: []Event{
 			PresenceEvent{payload: buildPresenceMsg(userID, status)},
@@ -128,38 +86,13 @@ func handleChannelFocusV2(_ context.Context, cmd Command, info ClientInfo, deps
 	d := deps.(PresenceDeps)
 	focusCmd := cmd.(ChannelFocusCmd)
 	chID := focusCmd.ChannelID()
-	userID := info.UserID
 
-	if chID <= 0 {
-		return Result{} // silently drop invalid channel_id
-	}
-
-	// Channel lookup.
-	ch, chErr := d.DB.GetChannel(chID)
-	if chErr != nil || ch == nil {
-		return Result{} // silently drop — channel not found
-	}
-
-	// Permission check.
-	if ch.Type == "dm" {
-		ok, dmErr := d.DB.IsDMParticipant(userID, chID)
-		if dmErr != nil || !ok {
-			return Result{Error: ClientError{Code: ErrCodeForbidden, Message: "not a participant in this DM"}}
-		}
-	} else {
-		if denied := requirePerm(d.DB, d.Permissions, userID, chID, permissions.ReadMessages, "READ_MESSAGES"); denied != nil {
-			return *denied
-		}
-	}
-
-	slog.Debug("channel_focus", "user_id", userID, "channel_id", chID)
-
-	// Mark channel as read by updating read_states to the latest message.
-	latestID, latestErr := d.DB.GetLatestMessageID(chID)
-	if latestErr == nil && latestID > 0 {
-		if rsErr := d.DB.UpdateReadState(userID, chID, latestID); rsErr != nil {
-			slog.Warn("handleChannelFocusV2 UpdateReadState", "err", rsErr, "user_id", userID, "channel_id", chID)
+	_, err := d.ChannelSvc.HandleChannelFocus(info.UserID, chID)
+	if err != nil {
+		if errors.Is(err, service.ErrForbidden) {
+			return Result{Error: ClientError{Code: ErrCodeForbidden, Message: "access denied"}}
 		}
+		return Result{} // silently drop other errors
 	}
 
 	return Result{SetChannelID: &chID}

Server/ws/handlers_reaction.go

@@ -2,10 +2,8 @@ package ws
 
 import (
 	"context"
-	"fmt"
-	"log/slog"
 
-	"github.com/owncord/server/permissions"
+	"github.com/owncord/server/service"
 )
 
 // registerReactionHandlers registers reaction_add and reaction_remove V2 handlers.
@@ -33,90 +31,27 @@ func reactionV2Handler(add bool) HandlerV2 {
 			emoji = c.Emoji()
 		}
 
-		// Rate limit.
-		ratKey := fmt.Sprintf("reaction:%d", userID)
-		if d.Limiter != nil && !d.Limiter.Allow(ratKey, reactionRateLimit, reactionWindow) {
-			return Result{Error: ClientError{Code: ErrCodeRateLimited, Message: "too many reactions"}}
-		}
-
-		// Validate fields.
-		if msgID <= 0 {
-			return Result{Error: ClientError{Code: ErrCodeBadRequest, Message: "message_id must be positive integer"}}
-		}
-		if emoji == "" {
-			return Result{Error: ClientError{Code: ErrCodeBadRequest, Message: "emoji cannot be empty"}}
-		}
-		if len(emoji) > 32 {
-			return Result{Error: ClientError{Code: ErrCodeBadRequest, Message: "emoji too long"}}
-		}
-		// Reject control characters (U+0000-U+001F, U+007F) to prevent injection.
-		for _, r := range emoji {
-			if r < 0x20 || r == 0x7F {
-				return Result{Error: ClientError{Code: ErrCodeBadRequest, Message: "emoji contains invalid characters"}}
-			}
-		}
-		// Sanitize HTML to prevent stored XSS via emoji field.
-		if sanitized := sanitizer.Sanitize(emoji); sanitized != emoji {
-			return Result{Error: ClientError{Code: ErrCodeBadRequest, Message: "emoji contains invalid characters"}}
-		}
-
-		// Look up message.
-		msg, err := d.DB.GetMessage(msgID)
-		if err != nil || msg == nil {
-			// Normalize: same error whether message doesn't exist or is in a
-			// channel the user can't see (prevents IDOR information leak).
-			return Result{Error: ClientError{Code: ErrCodeBadRequest, Message: "reaction failed"}}
-		}
-
-		// BUG-126: Reject reactions on soft-deleted messages.
-		if msg.Deleted {
-			return Result{Error: ClientError{Code: ErrCodeBadRequest, Message: "reaction failed"}}
-		}
-
-		// Check channel type for DM-aware permission handling.
-		reactCh, chErr := d.DB.GetChannel(msg.ChannelID)
-		reactIsDM := chErr == nil && reactCh != nil && reactCh.Type == "dm"
-
-		if reactIsDM {
-			ok, dmErr := d.DB.IsDMParticipant(userID, msg.ChannelID)
-			if dmErr != nil || !ok {
-				return Result{Error: ClientError{Code: ErrCodeBadRequest, Message: "reaction failed"}}
-			}
-		} else {
-			if denied := requirePerm(d.DB, d.Permissions, userID, msg.ChannelID, permissions.AddReactions, "ADD_REACTIONS"); denied != nil {
-				return *denied
-			}
-		}
-
-		// Execute reaction.
-		action := "add"
+		var result *service.ReactionResult
+		var err error
 		if add {
-			err = d.DB.AddReaction(msgID, userID, emoji)
+			result, err = d.MessageSvc.AddReaction(userID, msgID, emoji)
 		} else {
-			action = "remove"
-			err = d.DB.RemoveReaction(msgID, userID, emoji)
+			result, err = d.MessageSvc.RemoveReaction(userID, msgID, emoji)
 		}
 		if err != nil {
-			// Sanitize: never leak raw DB constraint errors to client.
-			slog.Warn("reaction failed", "action", action, "msg_id", msgID, "user_id", userID, "err", err)
-			return Result{Error: ClientError{Code: ErrCodeConflict, Message: "reaction failed"}}
+			return serviceErrorToResult(err)
 		}
 
-		reactionPayload := buildReactionUpdate(msgID, msg.ChannelID, userID, emoji, action)
-		if reactIsDM {
-			participantIDs, pErr := d.DB.GetDMParticipantIDs(msg.ChannelID)
-			if pErr != nil {
-				slog.Error("reactionV2Handler GetDMParticipantIDs", "err", pErr, "channel_id", msg.ChannelID)
-				return Result{}
-			}
+		reactionPayload := buildReactionUpdate(result.MessageID, result.ChannelID, result.UserID, result.Emoji, result.Action)
+		if result.IsDM {
 			return Result{Events: []Event{ReactionDMEvent{
-				channelID:      msg.ChannelID,
-				participantIDs: participantIDs,
+				channelID:      result.ChannelID,
+				participantIDs: result.ParticipantIDs,
 				payload:        reactionPayload,
 			}}}
 		}
 		return Result{Events: []Event{ReactionChannelEvent{
-			channelID: msg.ChannelID,
+			channelID: result.ChannelID,
 			payload:   reactionPayload,
 		}}}
 	}