-- Furnace control
-- Setup:
-- (from above)
-- Comp - Outp
-- Inpu - Furn
-- the second computer under the furnace,
-- and a wired modem connecting the 2 computers

-- Computer 1: http://pastebin.com/06cjixf9
-- Computer 2: (this one) http://pastebin.com/RjyREdT2

-- Screenshots of setup:
-- 1 http://i.imgur.com/t9GFE2r.png
-- 2 http://i.imgur.com/WjnunBC.png

local furnace = peripheral.wrap("top")
or error("Unable to wrap furnace!",0)

local modemside = "bottom"
local modem
if peripheral.getType(modemside) == "modem" then
	modem = peripheral.wrap(modemside)
	or error("Unable to wrap modem!",0)
else error("No modem found, please correct!",0) end

local function getAllStacks(inv)
	local t = {}
	local size = inv.getInventorySize()
	for slot = 1,size do
		local item = inv.getStackInSlot(slot) or {}
		
		item.rawName = item.rawName or ""
		item.qty = item.qty or 0
		item.dmg = item.dmg or 0
		item.name = item.name or ""
		item.id = item.id or 0
		
		t[slot] = item
	end
	return t
end

local function isEmpty()
	local items = getAllStacks(furnace)
	for slot,item in pairs(items) do
		if item.qty > 0 then
			return false
		end
	end
	return true
end

modem.open(1)
print("Waits for control computer to ask if the furnace is empty.")
while true do
	local ev,p1,p2,p3,p4,p5 = os.pullEvent()
	
	if ev == "modem_message" and p1 == modemside and p2 == 1 then
		local msg = textutils.unserialize(p4)
		if type(msg) == "table" then
			if msg.task == "furnace"
			and msg.value == "question" then
				local reply = textutils.serialize({task="furnace",value=isEmpty()})
				modem.transmit(1,1,reply)
			end
		end
	end
end