--- a/src/lib/Chat.luan	Tue Mar 04 07:05:12 2025 -0700
+++ b/src/lib/Chat.luan	Tue Mar 04 07:38:43 2025 -0700
@@ -3,6 +3,9 @@
 local ipairs = Luan.ipairs or error()
 local Time = require "luan:Time.luan"
 local time_now = Time.now or error()
+local Table = require "luan:Table.luan"
+local sort = Table.sort or error()
+local concat = Table.concat or error()
 local Http = require "luan:http/Http.luan"
 local Db = require "site:/lib/Db.luan"
 local run_in_transaction = Db.run_in_transaction or error()
@@ -18,6 +21,7 @@
 		id = doc.id
 		user_ids = doc.chat_user_ids
 		updated = doc.chat_updated
+		key = doc.chat_key
 	}
 end
 
@@ -27,11 +31,18 @@
 		id = chat.id
 		chat_user_ids = chat.user_ids or error()
 		chat_updated = chat.updated or error()
+		chat_key = chat.key or error()
 	}
 end
 
+local function get_chat_key(user_ids)
+	sort(user_ids)
+	return concat(user_ids,"~")
+end
+
 function Chat.new(chat)
 	chat.updated = chat.updated or time_now()
+	chat.key = chat.key or get_chat_key(chat.user_ids)
 
 	function chat.save()
 		local doc = to_doc(chat)
@@ -103,4 +114,10 @@
 	return doc and doc.type=="chat" and from_doc(doc) or nil
 end
 
+function Chat.get_by_user_ids(user_ids)
+	local key = get_chat_key(user_ids)
+	local doc = Db.get_document("chat_key:"..key)
+	return doc and from_doc(doc)
+end
+
 return Chat