feat(channel): enhance channel service with caching and repository updates

- Updated ChannelService to include caching for channel lists, improving performance and reducing database load.
- Introduced cache invalidation methods to ensure channel list consistency after modifications.
- Modified ChannelRepository to remove unused ListByIDs method, streamlining the repository interface.
- Updated wire generation to inject cache into ChannelService for enhanced functionality.
- Added new cache key constants for channel-related data management.

internal/service/channel_service.go

@@ -1,10 +1,16 @@
 package service
 
 import (
+	"time"
+
+	"carrot_bbs/internal/cache"
 	"carrot_bbs/internal/model"
 	"carrot_bbs/internal/repository"
 )
 
+// 频道全量列表缓存 TTL（频道变更少，可较长；管理端写入后会主动失效）
+const channelAllListCacheTTL = 10 * time.Minute
+
 type ChannelService interface {
 	ListActive() ([]*model.Channel, error)
 	ListAll() ([]*model.Channel, error)
@@ -16,32 +22,68 @@ type ChannelService interface {
 
 type channelServiceImpl struct {
 	channelRepo *repository.ChannelRepository
+	cache       cache.Cache
 }
 
-func NewChannelService(channelRepo *repository.ChannelRepository) ChannelService {
-	return &channelServiceImpl{channelRepo: channelRepo}
+func NewChannelService(channelRepo *repository.ChannelRepository, c cache.Cache) ChannelService {
+	return &channelServiceImpl{channelRepo: channelRepo, cache: c}
 }
 
-func (s *channelServiceImpl) ListActive() ([]*model.Channel, error) {
-	return s.channelRepo.ListActive()
+func (s *channelServiceImpl) invalidateChannelListCache() {
+	if s.cache != nil {
+		cache.InvalidateChannelList(s.cache)
+	}
 }
 
-func (s *channelServiceImpl) ListAll() ([]*model.Channel, error) {
+func (s *channelServiceImpl) listAllFromDB() ([]*model.Channel, error) {
 	return s.channelRepo.ListAll()
 }
 
-func (s *channelServiceImpl) MapByIDs(ids []string) (map[string]*model.Channel, error) {
-	list, err := s.channelRepo.ListByIDs(ids)
+func (s *channelServiceImpl) ListAll() ([]*model.Channel, error) {
+	if s.cache == nil {
+		return s.listAllFromDB()
+	}
+	cs := cache.GetSettings()
+	return cache.GetOrLoadTyped(s.cache, cache.ChannelsAllListKey(), channelAllListCacheTTL, cs.JitterRatio, cs.NullTTL, s.listAllFromDB)
+}
+
+func (s *channelServiceImpl) ListActive() ([]*model.Channel, error) {
+	all, err := s.ListAll()
 	if err != nil {
 		return nil, err
 	}
-	m := make(map[string]*model.Channel, len(list))
-	for _, ch := range list {
-		if ch != nil {
-			m[ch.ID] = ch
+	out := make([]*model.Channel, 0, len(all))
+	for _, ch := range all {
+		if ch != nil && ch.IsActive {
+			c := *ch
+			out = append(out, &c)
 		}
 	}
-	return m, nil
+	return out, nil
+}
+
+// MapByIDs 始终基于全量频道列表（Redis 命中则零 SQL，否则一次 ListAll），与 ListActive / 公开列表共用同一缓存快照。
+func (s *channelServiceImpl) MapByIDs(ids []string) (map[string]*model.Channel, error) {
+	if len(ids) == 0 {
+		return nil, nil
+	}
+	all, err := s.ListAll()
+	if err != nil {
+		return nil, err
+	}
+	byID := make(map[string]*model.Channel, len(all))
+	for _, ch := range all {
+		if ch != nil {
+			byID[ch.ID] = ch
+		}
+	}
+	out := make(map[string]*model.Channel, len(ids))
+	for _, id := range ids {
+		if ch, ok := byID[id]; ok {
+			out[id] = ch
+		}
+	}
+	return out, nil
 }
 
 func (s *channelServiceImpl) Create(name, slug, description string, sortOrder int, isActive bool) (*model.Channel, error) {
@@ -55,6 +97,7 @@ func (s *channelServiceImpl) Create(name, slug, description string, sortOrder in
 	if err := s.channelRepo.Create(channel); err != nil {
 		return nil, err
 	}
+	s.invalidateChannelListCache()
 	return channel, nil
 }
 
@@ -71,10 +114,16 @@ func (s *channelServiceImpl) Update(id, name, slug, description string, sortOrde
 	if err := s.channelRepo.Update(channel); err != nil {
 		return nil, err
 	}
+	s.invalidateChannelListCache()
 	return channel, nil
 }
 
 func (s *channelServiceImpl) Delete(id string) error {
-	return s.channelRepo.Delete(id)
+	err := s.channelRepo.Delete(id)
+	if err != nil {
+		return err
+	}
+	s.invalidateChannelListCache()
+	return nil
 }