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

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

-- how often computer shall retry
local updaterate = 2 -- times a sec

-- where the chests are in relation to the furnace
local outputToFurnace = "north"
local inputToFurnace = "west"
-- directions: north,south,east,west,up,down

-- slots in the furnace inventory
local inputSlot = 0
local fuelSlot = 1
local outputSlot = 2

-- 1 for normal furnace
-- 1.25 for IC2 iron furnace
local furnaceModifier = 1

local fuel = {
	-- {id,dmg,burntime},
	{id=263,dmg=0,burn=8},--coal
	{id=263,dmg=1,burn=8},--charcoal
	{id=5,dmg=-1,burn=1.5},--planks
	--{id=17,dmg=-1,burn=1.5},--wood
	{id=6,dmg=-1,burn=.5},--sapling
	{id=280,dmg=0,burn=.5},--stick
}

local input = peripheral.wrap("front")
or error("Unable to wrap input chest!",0)
local output = peripheral.wrap("right")
or error("Unable to wrap output chest!",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

-- statement = boolean
-- fuel = table
local function isFuel(item)
	for _,fuel in pairs(fuel) do
		if item.id == fuel.id
		and (item.dmg == fuel.dmg
		or fuel.dmg == -1) then
			return true,fuel
		end
	end
	return false
end

-- returns slot,fuel,item
local function findFuel()
	local items = getAllStacks(input)
	for slot,item in pairs(items) do
		local state,fuel = isFuel(item)
		if state then
			return slot,fuel,item
		end
	end
end

-- returns slot,item
local function findItem()
	local slot,fuel = findFuel()
	if slot and fuel then
		local items = getAllStacks(input)
		for slot,item in pairs(items) do
			local state = isFuel(item)
			if not state then
				if item.qty >= fuel.burn then
					return slot,item
				end
			end
		end
	end
end

local function emptyFurnace()
	output.pullItem(outputToFurnace,outputSlot,64)
end

local function isFurnaceEmpty()
	local timeout = os.startTimer(2)
	modem.open(1)
	local msg = textutils.serialize({task="furnace",value="question"})
	modem.transmit(1,1,msg)
	
	local state = false
	
	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 type(msg.value) == "boolean" then
					state = msg.value
					break
				end
			end
		elseif ev == "timer" then
			if p1 == timeout then
				state = false
				break
			end
		end
	end
	modem.close(1)
	return state
end

local function cook()
	-- check with computer
	if isFurnaceEmpty() then
		-- get fuel and item
		local fuelslot,fuel,fuelitem = findFuel()
		local itemslot,item = findItem()
		
		-- no fuel/item found: cancel out
		if not fuel then return end
		if not item then return end
		
		local maxburn = fuelitem.qty*fuel.burn
		local fuelmove,itemmove
		if item.qty > maxburn * furnaceModifier then
			-- # of items are more then we can burn
			fuelmove = fuelitem.qty
			itemmove = maxburn
		else
			-- we have more or enough fuel for all items
			fuelmove = math.floor(item.qty/(fuel.burn*furnaceModifier))
			itemmove = item.qty - (item.qty%(fuel.burn*furnaceModifier))
		end
		
		-- debugging
		print("Moving "..tostring(fuelmove).." peices of "..tostring(fuelitem.name).." to fuel slot.")
		print("Moving "..tostring(itemmove).." peices of "..tostring(item.name).." to input slot.")
		
		-- move items
		-- pushItemItemIntoSlot(direction, fromSlot, maxQuantity, intoSlot)
		input.pushItemIntoSlot(inputToFurnace,fuelslot,fuelmove,fuelSlot)
		input.pushItemIntoSlot(inputToFurnace,itemslot,itemmove,inputSlot)
	else
		emptyFurnace()
	end
end

print("Checks input chest for valid fuel and items to burn.")
print("If theres items in the furnace i shall not insert more.")
print("Checks "..updaterate.." times a second,")
print("i.e. "..1/updaterate.." seconds between each update.")
while true do
	cook()
	sleep(1/updaterate)
end