feat: implement chat merging and logging in Safew

- Introduced a new function `mergeAndLog` in the Watcher to handle merging Safew chats and logging newly discovered chats.
- Added a test `TestNewSafewChatsSkipsKnownIDs` to ensure that known chat IDs are skipped during the merging process.
- Enhanced the polling mechanism to improve chat management and reduce duplicates.

internal/safew/watcher.go

@@ -188,7 +188,7 @@ func (w *Watcher) pollOnce(ctx context.Context, token string, timeout int) error
 	if err != nil {
 		return err
 	}
-	if err := w.store.MergeSafewChats(ctx, token, chats); err != nil {
+	if err := w.mergeAndLog(ctx, token, chats); err != nil {
 		return err
 	}
 	if next != offset {
@@ -197,6 +197,43 @@ func (w *Watcher) pollOnce(ctx context.Context, token string, timeout int) error
 	return nil
 }
 
+func (w *Watcher) mergeAndLog(ctx context.Context, token string, chats []adapter.SafewChat) error {
+	if len(chats) == 0 {
+		return nil
+	}
+	existing, err := w.store.ListSafewChats(ctx, token)
+	if err != nil {
+		return w.store.MergeSafewChats(ctx, token, chats)
+	}
+	known := map[string]struct{}{}
+	for _, c := range existing {
+		known[c.ID] = struct{}{}
+	}
+	if err := w.store.MergeSafewChats(ctx, token, chats); err != nil {
+		return err
+	}
+	for _, c := range newSafewChats(known, chats) {
+		slog.Info("safew chat discovered", "id", c.ID, "type", c.Type, "title", c.Title)
+	}
+	return nil
+}
+
+func newSafewChats(known map[string]struct{}, chats []adapter.SafewChat) []adapter.SafewChat {
+	var out []adapter.SafewChat
+	seen := map[string]struct{}{}
+	for _, c := range chats {
+		if _, ok := known[c.ID]; ok {
+			continue
+		}
+		if _, ok := seen[c.ID]; ok {
+			continue
+		}
+		seen[c.ID] = struct{}{}
+		out = append(out, c)
+	}
+	return out
+}
+
 func isSafewAuth(err error) bool {
 	var e *adapter.SafewAuthError
 	return errors.As(err, &e)

internal/safew/watcher_test.go

@@ -115,6 +115,18 @@ func TestEnsurePollsInBackground(t *testing.T) {
 	w.Stop()
 }
 
+func TestNewSafewChatsSkipsKnownIDs(t *testing.T) {
+	known := map[string]struct{}{"1": {}}
+	got := newSafewChats(known, []adapter.SafewChat{
+		{ID: "1", Title: "old"},
+		{ID: "2", Title: "测试AI", Type: "group"},
+		{ID: "2", Title: "dup"},
+	})
+	if len(got) != 1 || got[0].ID != "2" || got[0].Title != "测试AI" {
+		t.Fatalf("%#v", got)
+	}
+}
+
 func TestPollConflictIsRetryable(t *testing.T) {
 	err := errors.New("safew getUpdates status 400: BAD_REQUEST: Conflict: terminated by other getUpdates request; make sure that only one bot instance is running")
 	if !isGetUpdatesConflict(err) {