From cd78f802b22dd0feb1e841f5826b1f297c9980dc Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Thu, 2 Mar 2023 21:15:54 -0800
Subject: [PATCH] modules/admin/rooms: Implement GET /forward_extremities.

---
 matrix/matrix.cc       |   1 +
 modules/Makefile.am    |   2 +
 modules/admin/rooms.cc | 131 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 134 insertions(+)
 create mode 100644 modules/admin/rooms.cc

diff --git a/matrix/matrix.cc b/matrix/matrix.cc
index 75328aaf4..67d259a49 100644
--- a/matrix/matrix.cc
+++ b/matrix/matrix.cc
@@ -183,6 +183,7 @@ ircd::m::module_names
 	"admin_deactivate",
 	"admin_server_version",
 	"admin_federation",
+	"admin_rooms",
 };
 
 /// This is a list of modules that are considered "optional" and any loading
diff --git a/modules/Makefile.am b/modules/Makefile.am
index b8e14cb70..bbd8ac92f 100644
--- a/modules/Makefile.am
+++ b/modules/Makefile.am
@@ -562,12 +562,14 @@ admin_admin_users_la_SOURCES = admin/users.cc
 admin_admin_deactivate_la_SOURCES = admin/deactivate.cc
 admin_admin_server_version_la_SOURCES = admin/server_version.cc
 admin_admin_federation_la_SOURCES = admin/federation.cc
+admin_admin_rooms_la_SOURCES = admin/rooms.cc
 
 admin_module_LTLIBRARIES = \
 	admin/admin_users.la \
 	admin/admin_deactivate.la \
 	admin/admin_server_version.la \
 	admin/admin_federation.la \
+	admin/admin_rooms.la \
 	###
 
 ###############################################################################
diff --git a/modules/admin/rooms.cc b/modules/admin/rooms.cc
new file mode 100644
index 000000000..a1759a363
--- /dev/null
+++ b/modules/admin/rooms.cc
@@ -0,0 +1,131 @@
+// The Construct
+//
+// Copyright (C) The Construct Developers, Authors & Contributors
+// Copyright (C) 2016-2020 Jason Volk <jason@zemos.net>
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice is present in all copies. The
+// full license for this software is available in the LICENSE file.
+
+namespace ircd::m::admin
+{
+	static resource::response handle_get_forward_extremis(client &, const resource::request &, const room::id &);
+	static resource::response handle_get(client &, const resource::request &);
+
+	extern resource::method get_method;
+	extern resource rooms_resource;
+};
+
+ircd::mapi::header
+IRCD_MODULE
+{
+	"Admin (undocumented) :Rooms"
+};
+
+decltype(ircd::m::admin::rooms_resource)
+ircd::m::admin::rooms_resource
+{
+	"/_synapse/admin/v1/rooms/",
+	{
+		"(undocumented) Admin Rooms",
+		resource::DIRECTORY
+	}
+};
+
+decltype(ircd::m::admin::get_method)
+ircd::m::admin::get_method
+{
+	rooms_resource, "GET", handle_get,
+	{
+		get_method.REQUIRES_OPER
+	}
+};
+
+ircd::m::resource::response
+ircd::m::admin::handle_get(client &client,
+                           const resource::request &request)
+{
+	char buf[768];
+	const string_view &room_id_or_alias
+	{
+		request.parv[0]?
+			url::decode(buf, request.parv[0]):
+			string_view{}
+	};
+
+	const m::room::id::buf room_id
+	{
+		room_id_or_alias?
+			m::room_id(room_id_or_alias):
+			m::room::id::buf{}
+	};
+
+	const auto &cmd
+	{
+		request.parv[1]
+	};
+
+	if(cmd == "forward_extremities")
+		return handle_get_forward_extremis(client, request, room_id);
+
+	throw m::NOT_FOUND
+	{
+		"/admin/rooms command not found"
+	};
+}
+
+ircd::m::resource::response
+ircd::m::admin::handle_get_forward_extremis(client &client,
+                                            const resource::request &request,
+                                            const room::id &room_id)
+{
+	const m::room::head room_head
+	{
+		room_id
+	};
+
+	m::resource::response::chunked::json response
+	{
+		client, http::OK
+	};
+
+	json::stack::member
+	{
+		response, "count", json::value
+		{
+			long(room_head.count())
+		}
+	};
+
+	json::stack::array results
+	{
+		response, "results"
+	};
+
+	room_head.for_each([&results]
+	(const auto &event_idx, const auto &event_id)
+	{
+		json::stack::object result
+		{
+			results
+		};
+
+		json::stack::member
+		{
+			result, "event_id", event_id
+		};
+
+		json::stack::member
+		{
+			result, "depth", json::value
+			{
+				m::get(std::nothrow, event_idx, "depth", 0L)
+			}
+		};
+
+		return true;
+	});
+
+	return response;
+}