all: add support for topics and refactor other things

pkg/connector/store/topic.go

@@ -0,0 +1,62 @@
+// mautrix-telegram - A Matrix-Telegram puppeting bridge.
+// Copyright (C) 2025 Tulir Asokan
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package store
+
+import (
+	"context"
+
+	"go.mau.fi/util/dbutil"
+	"go.mau.fi/util/exsync"
+)
+
+type topicKey struct {
+	ChannelID int64
+	TopicID   int
+}
+
+type TopicQuery struct {
+	db             *dbutil.Database
+	existingTopics *exsync.Set[topicKey]
+}
+
+const (
+	getAllTopicsQuery = `SELECT topic_id FROM telegram_topic WHERE channel_id=$1`
+	addTopicQuery     = `INSERT INTO telegram_topic (channel_id, topic_id) VALUES ($1, $2) ON CONFLICT DO NOTHING`
+	deleteTopicQuery  = `DELETE FROM telegram_topic WHERE channel_id=$1 AND topic_id=$2`
+)
+
+func (s *TopicQuery) Add(ctx context.Context, channelID int64, topicID int) (err error) {
+	if channelID == 0 {
+		return nil
+	}
+	if s.existingTopics.Add(topicKey{ChannelID: channelID, TopicID: topicID}) {
+		_, err = s.db.Exec(ctx, addTopicQuery, channelID, topicID)
+	}
+	return
+}
+
+func (s *TopicQuery) Delete(ctx context.Context, channelID int64, topicID int) (err error) {
+	s.existingTopics.Remove(topicKey{ChannelID: channelID, TopicID: topicID})
+	_, err = s.db.Exec(ctx, deleteTopicQuery, channelID, topicID)
+	return
+}
+
+var intScanner = dbutil.ConvertRowFn[int](dbutil.ScanSingleColumn[int])
+
+func (s *TopicQuery) GetAll(ctx context.Context, channelID int64) (topics []int, err error) {
+	return intScanner.NewRowIter(s.db.Query(ctx, getAllTopicsQuery, channelID)).AsList()
+}