From c03ca13f1768e3d4d842a40c5a5afaa3d53aa1e1 Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Mon, 30 Apr 2018 08:51:03 -0700
Subject: [PATCH] modules/federation/federation: Add feds backfill event grid
 w/ cmd.

---
 modules/console.cc               | 37 ++++++++++++
 modules/federation/federation.cc | 98 ++++++++++++++++++++++++++++++++
 2 files changed, 135 insertions(+)

diff --git a/modules/console.cc b/modules/console.cc
index b73be179b..516d5791a 100644
--- a/modules/console.cc
+++ b/modules/console.cc
@@ -3513,6 +3513,43 @@ console_cmd__feds__head(opt &out, const string_view &line)
 	return true;
 }
 
+bool
+console_cmd__feds__backfill(opt &out, const string_view &line)
+{
+	const params param{line, " ",
+	{
+		"room_id", "event_id", "[limit]"
+	}};
+
+	const auto &room_id
+	{
+		m::room_id(param.at(0))
+	};
+
+	const m::event::id &event_id
+	{
+		param.at(1)
+	};
+
+	const size_t limit
+	{
+		param.at(2, size_t(4))
+	};
+
+	using prototype = void (const m::room::id &,
+	                        const m::event::id &,
+	                        const size_t &,
+	                        std::ostream &);
+
+	static m::import<prototype> feds__backfill
+	{
+		"federation_federation", "feds__backfill"
+	};
+
+	feds__backfill(room_id, event_id, limit, out);
+	return true;
+}
+
 bool
 console_cmd__feds__resend(opt &out, const string_view &line)
 {
diff --git a/modules/federation/federation.cc b/modules/federation/federation.cc
index af20e5b77..b0d100948 100644
--- a/modules/federation/federation.cc
+++ b/modules/federation/federation.cc
@@ -269,3 +269,101 @@ feds__head(const m::room::id &room_id,
 
 	return;
 }
+
+extern "C" void
+feds__backfill(const m::room::id &room_id,
+               const m::event::id &event_id,
+               const size_t &limit,
+               std::ostream &out)
+{
+	struct req
+	:m::v1::backfill
+	{
+		char origin[256];
+		char buf[16_KiB];
+
+		req(const m::room::id &room_id, const m::event::id &event_id, const string_view &origin, const size_t &limit)
+		:m::v1::backfill{[&]
+		{
+			m::v1::backfill::opts opts;
+			opts.remote = string_view{this->origin, strlcpy(this->origin, origin)};
+			opts.event_id = event_id;
+			opts.limit = limit;
+			opts.dynamic = true;
+			return m::v1::backfill{room_id, mutable_buffer{buf}, std::move(opts)};
+		}()}
+		{}
+	};
+
+	std::list<req> reqs;
+	const m::room::origins origins{room_id};
+	origins.for_each([&out, &room_id, &event_id, &limit, &reqs]
+	(const string_view &origin)
+	{
+		const auto emsg
+		{
+			ircd::server::errmsg(origin)
+		};
+
+		if(!emsg) try
+		{
+			reqs.emplace_back(room_id, event_id, origin, limit);
+		}
+		catch(const std::exception &e)
+		{
+			return;
+		}
+	});
+
+	auto all
+	{
+		ctx::when_all(begin(reqs), end(reqs))
+	};
+
+	all.wait(30s, std::nothrow);
+
+	std::map<string_view, std::set<const req *>> grid;
+
+	for(auto &req : reqs) try
+	{
+		if(req.wait(1ms, std::nothrow))
+		{
+			const auto code{req.get()};
+			const json::object &response{req};
+			const json::array pdus
+			{
+				response.at("pdus")
+			};
+
+			for(const json::object &pdu : pdus)
+			{
+				const auto &event_id
+				{
+					unquote(pdu.at("event_id"))
+				};
+
+				grid[event_id].emplace(&req);
+			}
+		}
+		else cancel(req);
+	}
+	catch(const std::exception &e)
+	{
+		out << "- " << req.origin << " " << e.what() << std::endl;
+	}
+
+	size_t i(0);
+	for(const auto &p : grid)
+		out << i++ << " " << p.first << std::endl;
+
+	for(size_t j(0); j < i; ++j)
+		out << "| " << j << " ";
+	out << "|" << std::endl;
+
+	for(const auto &req : reqs)
+	{
+		for(const auto &p : grid)
+			out << "| " << (p.second.count(&req)? '+' : ' ') << " ";
+		out << "| " << req.origin << std::endl;
+	}
+}