-- I, 20kdc, release this into the public domain.
-- No warranty is provided, implied or otherwise.

-- 'Copper' networking implementation
-- for EEPROM usage. Filters to hostname and broadcast for ease of use.

-- Expects 'base'.

-- Variables:
-- R1 to R4: Tuning parameters in the order in the "big" version.
-- RT: timers
-- RA: weAcked
-- RN: needsAck, but no success callback, so just the timer.

-- Functions:
-- RU: Current time.
-- RP: Add timer.
-- RK: Kill timer.
-- RC: Message receive raw.
-- RF: Refresh system.
-- RG: Generate 1 random char (as a number)
-- RS: Send message.

R1,R2,R3,R4=0x40,60,12,2.5
RT,RA,RN,RU={},{},{},computer.uptime
function RP(f,x)
	if#RT<R1 then
		local t={f,RU()+x}
		table.insert(RT,t)
		return t
	end
end
function RK(t)
	for i=1,#RT do
		if t==RT[i]then
			table.remove(RT,i)
		end
	end
end

function RC(r,f,t,d)
	if d and#d>=7then
		-- Keep in mind the ID used by tables is (originalPacketToName..GID)
		-- ',k' unspecified value "trick"
		local p,b,g,k=d:byte(2)+(d:byte(1)*256),d:byte(7),d:sub(1,5)

		if b==0x01or b==0x00then
			k=t..g
			if not RA[k] then
				r(f,t,p,d:sub(8))
			else
				RK(RA[k])
			end
			RA[k]=RP(function()RA[k]=nil end,R2)
			-- Only ACK under certain conditions.
			if not(b~=0x01or t~=TH)then
				TS(f,d:sub(1,6).."\x02")
			end
		end

		k=f..g

		if b==0x02 and RN[k]then
			RK(RN[k])
			RN[k]=nil
		end
	end
end

-- Refresh function to clean up & execute timers.
function RF()
	local i,t=1,RU()
	while#RT>i do
		if t>RT[i][2]then
			table.remove(RT,i)[1]()
		else
			i=i+1
		end
	end
end

-- It is shorter to have this than not have it or localize it. *sigh*
function RG()
	return math.random(256)-1
end

function RS(t,p,d)
	-- j,x unspecified. x is used in j.
	local g,a,j,x=S.char(math.floor(p/256),p%256,RG(),RG(),RG()),-1
	j=function()
		a=a+1
		x=nil
		if a~=R3 then
			TS(t,g..S.char(a,1)..d)
			x=RP(j,R4)
		end
		RN[t..g]=x
	end j()
end