Remove feeds associated with a channel when it is deleted

feed_info.c

@@ -207,6 +207,29 @@ zblock_feed_info_err zblock_feed_info_delete_all_guild(PGconn *conn, u64snowflak
 	return result;
 }
 
+// deletes all feeds associated with a channel from the database
+zblock_feed_info_err zblock_feed_info_delete_all_channel(PGconn *conn, u64snowflake channel_id) {
+	if (!conn) return ZBLOCK_FEED_INFO_INVALID_ARGS;
+
+	uint64_t channel_id_be = htobe64(channel_id);
+	const char *const params[] = {(char *) &channel_id_be};
+	const int param_lengths[] = {sizeof(channel_id_be)};
+	const int param_formats[] = {1};
+	PGresult *res = PQexecParams(conn,
+		"DELETE FROM feeds WHERE channel_id = $1::bigint",
+		1, NULL, params, param_lengths, param_formats, 1
+	);
+
+	zblock_feed_info_err result = ZBLOCK_FEED_INFO_OK;
+	if (PQresultStatus(res) != PGRES_COMMAND_OK) {
+		log_error(PQresultErrorMessage(res));
+		result = ZBLOCK_FEED_INFO_DBERROR;
+	}
+
+	PQclear(res);
+	return result;
+}
+
 // updates the last_pubDate field of a given feed in the database
 zblock_feed_info_err zblock_feed_info_update(PGconn *conn, zblock_feed_info_minimal *feed) {
 	if (!conn || !feed) return ZBLOCK_FEED_INFO_INVALID_ARGS;

feed_info.h

@@ -63,6 +63,9 @@ zblock_feed_info_err zblock_feed_info_delete(PGconn *conn, const char *url, u64s
 // deletes all feeds associated with a guild from the database
 zblock_feed_info_err zblock_feed_info_delete_all_guild(PGconn *conn, u64snowflake guild_id);
 
+// deletes all feeds associated with a channel from the database
+zblock_feed_info_err zblock_feed_info_delete_all_channel(PGconn *conn, u64snowflake channel_id);
+
 // updates the last_pubDate field of a given feed in the database
 zblock_feed_info_err zblock_feed_info_update(PGconn *conn, zblock_feed_info_minimal *feed);
 

main.c

@@ -560,6 +560,13 @@ static void on_guild_delete(struct discord *client, const struct discord_guild *
 	}
 }
 
+static void on_channel_delete(struct discord *client, const struct discord_channel *event) {
+	(void) client;
+	if (zblock_feed_info_delete_all_channel(database_conn, event->id)) {
+		log_error("Unable to delete all feeds from channel %" PRIu64 ". You probably want to clean this up.", event->id);
+	}
+}
+
 // delay before the first feed retrieval (in ms)
 #define FEED_TIMER_DELAY 15000
 
@@ -598,6 +605,7 @@ int main(void) {
 	discord_set_on_ready(client, &on_ready);
 	discord_set_on_interaction_create(client, &on_interaction);
 	discord_set_on_guild_delete(client, &on_guild_delete);
+	discord_set_on_channel_delete(client, &on_channel_delete);
 
 	// register timers
 	discord_timer_interval(client, timer_retrieve_feeds, NULL, NULL, FEED_TIMER_DELAY, FEED_TIMER_INTERVAL, -1);