From 5c879bd380e93acde012bc602d9496cfff1ae843 Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Fri, 7 Sep 2018 06:22:09 -0700
Subject: [PATCH] ircd::m::receipt: Start central interface to get receipt
 information.

---
 include/ircd/m/receipt.h |  5 +++++
 ircd/m/m.cc              | 31 +++++++++++++++++++++++++++++++
 modules/m_receipt.cc     | 31 +++++++++++++++++++++++++++++++
 3 files changed, 67 insertions(+)

diff --git a/include/ircd/m/receipt.h b/include/ircd/m/receipt.h
index 7603e67d9..c80bc3060 100644
--- a/include/ircd/m/receipt.h
+++ b/include/ircd/m/receipt.h
@@ -13,6 +13,11 @@
 
 namespace ircd::m::receipt
 {
+	// [GET]
+	bool read(const id::room &, const id::user &, const event::id::closure &);
+	id::event read(id::event::buf &out, const id::room &, const id::user &);
+
+	// [SET]
 	id::event::buf read(const id::room &, const id::user &, const id::event &, const time_t &);
 	id::event::buf read(const id::room &, const id::user &, const id::event &); // now
 };
diff --git a/ircd/m/m.cc b/ircd/m/m.cc
index db25e9fc6..5b5728a3c 100644
--- a/ircd/m/m.cc
+++ b/ircd/m/m.cc
@@ -853,6 +853,37 @@ ircd::m::receipt::read(const id::room &room_id,
 	return function(room_id, user_id, event_id, ms);
 }
 
+ircd::m::event::id
+ircd::m::receipt::read(id::event::buf &out,
+                       const id::room &room_id,
+                       const id::user &user_id)
+{
+	const event::id::closure copy{[&out]
+	(const event::id &event_id)
+	{
+		out = event_id;
+	}};
+
+	return read(room_id, user_id, copy)?
+		event::id{out}:
+		event::id{};
+}
+
+bool
+ircd::m::receipt::read(const id::room &room_id,
+                       const id::user &user_id,
+                       const event::id::closure &closure)
+{
+	using prototype = bool (const id::room &, const id::user &, const id::event::closure &);
+
+	static import<prototype> function
+	{
+		"m_receipt", "last_receipt__event_id"
+	};
+
+	return function(room_id, user_id, closure);
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 //
 // m/typing.h
diff --git a/modules/m_receipt.cc b/modules/m_receipt.cc
index 8081fc4ce..54698ad89 100644
--- a/modules/m_receipt.cc
+++ b/modules/m_receipt.cc
@@ -16,6 +16,7 @@ IRCD_MODULE
 	"Matrix Receipts"
 };
 
+extern "C" bool last_receipt__event_id(const m::room::id &, const m::user::id &, const m::event::id::closure &);
 static void handle_m_receipt_m_read(const m::room::id &, const m::user::id &, const m::event::id &, const time_t &);
 static void handle_m_receipt_m_read(const m::room::id &, const m::user::id &, const m::edu::m_receipt::m_read &);
 static void handle_m_receipt_m_read(const m::room::id &, const json::object &);
@@ -212,3 +213,33 @@ catch(const std::exception &e)
 		e.what()
 	};
 }
+
+bool
+last_receipt__event_id(const m::room::id &room_id,
+                       const m::user::id &user_id,
+                       const m::event::id::closure &closure)
+{
+	static const m::event::fetch::opts fopts
+	{
+		m::event::keys::include
+		{
+			"content"
+		}
+	};
+
+	const m::user::room user_room
+	{
+		user_id, nullptr, &fopts
+	};
+
+	return user_room.get(std::nothrow, "ircd.read", room_id, [&closure]
+	(const m::event &event)
+	{
+		const m::event::id &event_id
+		{
+			unquote(at<"content"_>(event).get("event_id"))
+		};
+
+		closure(event_id);
+	});
+}