From d63ba8db06a3099ee1c46d1a10a0ea03f317b665 Mon Sep 17 00:00:00 2001
From: gamemanj <gamemanj@hotmail.co.uk>
Date: Sat, 18 Mar 2017 16:06:56 +0000
Subject: [PATCH] Hopefully maybe implement the reliability layer.

---
 relib.lua | 93 +++++++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 84 insertions(+), 9 deletions(-)

diff --git a/relib.lua b/relib.lua
index 2ae979b..ca9f0d4 100644
--- a/relib.lua
+++ b/relib.lua
@@ -11,25 +11,81 @@ local culib = require("culib")
 return function (hostname, transmit, onRReceive, time)
 	-- node.hostname should be used for hostname generally.
 	local node
+
+	-- The maximum amount of timers (used to cap memory usage)
+	local tuningMaxTimers = 0x200
+	local tuningClearAntiduplicate = 120
+	local tuningAttempts = 8
+	local tuningAttemptTime = 4
+
+	-- Just an array, no special index.
+	-- Contents : {
+	--     trigger function,
+	--     expiry time
+	-- }
+	local timers = {}
+	-- Indexes are globalIds, values are timers for deleting entries out of this table.
+	local weAcked = {}
+	-- Indexes are globalIds, values are { successFunc, deathTimer }
+	local needsAck = {}
+
+	local function addTimer(trig, expi)
+		if #timers < tuningMaxTimers then
+			local t = {trig, expi}
+			table.insert(timers, t)
+			return t
+		end
+		return nil
+	end
+	local function killTimer(t)
+		for i = 1, #timers do
+			if timers[i] == t then
+				table.remove(timers, i)
+				return
+			end
+		end
+	end
+	local function gen3Random()
+		return string.char(math.random(256) - 1) .. string.char(math.random(256) - 1) .. string.char(math.random(256) - 1)
+	end
+	local function genGlobalId(port)
+		local low = math.abs(math.floor(port)) % 256
+		local high = math.abs(math.floor(port / 256)) % 256
+		local portD = string.char(high) .. string.char(low)
+		return portD .. gen3Random()
+	end
+
 	local onReceive = function (nfrom, nto, data)
 		if data:len() < 6 then return end
 		local port = data:byte(2) + (data:byte(1) * 256)
-		if data:byte(7) == 0x0F then
+		local tp = data:byte(7)
+		local globalId = data:sub(1, 5)
+		if tp == 0x00 then
 			onRReceive(nfrom, nto, port, data, true)
 			return
 		end
+		if nto ~= node.hostname then return end
+		if (tp == 0x01) and weAcked[nto .. globalId] then
+			-- Only send one acknowledgement per packet,
+			--  so timers aren't generated by external packets
+			-- Not a perfect system but, eh.
+			weAcked[nto .. globalId] = addTimer(function ()
+				weAcked[nto .. globalId] = nil
+			end, tuningClearAntiduplicate)
+			onRReceive(nfrom, nto, port, data, false)
+			node.output(nto, nfrom, data:sub(1, 6) .. "\x02")
+		end
+		if (tp == 0x02) and needsAck[nfrom .. globalId] then
+			needsAck[nfrom .. globalId][1](nfrom)
+			killTimer(needsAck[nfrom .. globalId][2])
+			needsAck[nfrom .. globalId] = nil
+		end
 		if nto ~= node.hostname then
 			return
 		end
 	end
 	node = culib(hostname, transmit, onReceive, time)
 
-	-- Just an array, no special index.
-	-- Contents : {
-	--     trigger = function(),
-	--     expiry = time,
-	-- }
-	local timers = {}
 	local relib = {}
 	relib.refresh = function ()
 		node.refresh()
@@ -44,7 +100,26 @@ return function (hostname, transmit, onRReceive, time)
 		end
 	end
 	relib.input = node.input
-	relib.output = function ()
-		
+	relib.output = function (nto, port, data, unreliable, onSucceed, onFailure)
+		local gid = genGlobalId(port)
+		if unreliable then
+			node.output(node.hostname, nto, gid .. "\x00\x00" .. data)
+			return
+		end
+		local na = {onSucceed}
+		local attempt = -1
+		local doAttempt
+		doAttempt = function ()
+			attempt = attempt + 1
+			if attempt == tuningAttempts then
+				onFailure()
+				return
+			end
+			node.output(node.hostname, nto, gid .. string.char(attempt) .. "\x01" .. data)
+			na[2] = addTimer(doAttempt, tuningAttemptTime)
+		end
+		needsAck[nto .. gid] = na
+		doAttempt()
 	end
+	return relib
 end