refactor: split node agent and Go control plane

node-agent/WxAgent.Core/WechatGroupMemberQuery.cs

@@ -0,0 +1,38 @@
+namespace WxAgent.Core;
+
+public sealed record WechatDatabaseGroupMember(long MemberId, string Username, string DisplayName, bool IsOwner);
+
+public sealed record WechatGroupMemberPage(string GroupUsername, IReadOnlyList<WechatDatabaseGroupMember> Members, int? NextOffset)
+{
+    public bool HasMore => NextOffset is not null;
+}
+
+public static class WechatGroupMemberQuery
+{
+    public const string Sql = """
+        SELECT m.member_id, c.username, c.nick_name, c.remark, cr.owner
+        FROM chat_room AS cr
+        JOIN chatroom_member AS m ON m.room_id = cr.id
+        JOIN contact AS c ON c.id = m.member_id
+        WHERE cr.username = $group
+        ORDER BY m.member_id LIMIT $limit OFFSET $offset;
+        """;
+
+    public static IReadOnlyList<KeyValuePair<string, object?>> Parameters(string groupUsername, int limit, int offset)
+    {
+        if (string.IsNullOrWhiteSpace(groupUsername) || !groupUsername.EndsWith("@chatroom", StringComparison.Ordinal))
+            throw new WxAgentException(WxAgentErrorCode.InvalidArgument, "A stable @chatroom username is required.");
+        if (limit is < 1 or > 10000 || offset < 0 || offset > int.MaxValue - limit)
+            throw new WxAgentException(WxAgentErrorCode.InvalidArgument, "Member limit must be 1-10000 and offset must leave room for the next page.");
+        return new KeyValuePair<string, object?>[]
+        {
+            new("$group", groupUsername), new("$limit", limit + 1), new("$offset", offset)
+        };
+    }
+
+    public static WechatGroupMemberPage Page(string groupUsername, IReadOnlyList<WechatDatabaseGroupMember> rows, int limit, int offset)
+    {
+        _ = Parameters(groupUsername, limit, offset);
+        return new(groupUsername, rows.Take(limit).ToArray(), rows.Count > limit ? offset + limit : null);
+    }
+}