--todo:
--		maybe i can use slot 16 to detect fullness instead of available slot etc
--		refueling during doChest etc
--		maybe refuel limit = 1

-- ge4QnKbY

local programState = "done"
local refuelingState = ""

local curX = 0
local curY = 0
local curZ = 0
local subStep = 0

local sizeX = 0
local sizeY = 0
local sizeZ = 0

local useEnderChest = false
local useEnderFuel = false
local useChest = false
local useCobblestone = false

local saveFile = "savedata"

local availableSlots = 0
local outputSlot = 0
local cobbleSlot = 0

local function getYesNo()
	local i
	local event, param

	while true do
		event, param = os.pullEvent("key")

		if param == 21 then
			return true
		end
		if param == 49 then
			return false
		end
	end
end

local function requestFuel()
	local i
	local c = false
	local event, param

	print("Press F to refuel from slot 16")
	print("Press Q to exit the program")

	if turtle.getFuelLevel() >= 64 then
		c = true
		print("Press C to continue quarry")
	end

	while true do
		event, param = os.pullEvent("key")

		if param == 33 then --f
			turtle.select(16)
			turtle.refuel()
			if not c and turtle.getFuelLevel() >= 64 then
				c = true
				print("Press C to continue quarry")
			end
		end
		if param == 16 then --q
			return false
		end
		if c and param == 46 then --c
			return true
		end
	end
end


local function restoreProgress()
	if fs.exists(saveFile) then
		local file = fs.open(saveFile,"r")

		programstate = tostring(file.readLine())
		refuelingstate = tostring(file.readLine())

		curX = tonumber(file.readLine())
		curY = tonumber(file.readLine())
		curZ = tonumber(file.readLine())
		subStep = tonumber(file.readLine())
		sizeX = tonumber(file.readLine())
		sizeY = tonumber(file.readLine())
		sizeZ = tonumber(file.readLine())

		if file.readLine() == "true" then useEnderChest = true else useEnderChest = false end
		if file.readLine() == "true" then useEnderFuel = true else useEnderFuel = false end
		if file.readLine() == "true" then useChest = true else useChest = false end
		if file.readLine() == "true" then useCobblestone = true else useCobblestone = false end

		file.close()
	end
end

local function saveProgress()
	local file = fs.open(saveFile,"w")

	file.write(tostring(programstate).."\n")
	file.write(tostring(refuelingstate).."\n")

	file.write(tostring(curX).."\n")
	file.write(tostring(curY).."\n")
	file.write(tostring(curZ).."\n")
	file.write(tostring(subStep).."\n")

	file.write(tostring(sizeX).."\n")
	file.write(tostring(sizeY).."\n")

	file.write(tostring(useEnderChest).."\n")
	file.write(tostring(useEnderFuel).."\n")
	file.write(tostring(useChest).."\n")
	file.write(tostring(useCobblestone).."\n")

	file.close()
end

--should eliminate these
local function moveForward()
	turtle.dig()
	while not turtle.forward() do
		sleep(0)
		turtle.dig()
	end
end
local function moveUp()
	turtle.digUp()
	while not turtle.up() do
		sleep(0)
		turtle.digUp()
	end
end
local function moveDown()
	turtle.digDown()
	while not turtle.down() do
		sleep(0)
		turtle.digDown()
	end
end

local function doRefuel()
	refuelingState = "refuel"
	saveProgress()

	while turtle.getFuelLevel() < 64 do

		if turtle.getItemCount(2) > 0 then
			turtle.select(2)
			while not turtle.placeUp() do
				sleep(0)
				turtle.digUp()
			end
		end

		turtle.select(16)
		turtle.drop()
		for maxstacks = 1, 1 do
			turtle.suckUp()
			if not turtle.refuel() then turtle.drop() end
		end
	end

	turtle.select(2)
	turtle.digUp()
	refuelingState = ""
	saveProgress()
end

local function doEmpty()
	refuelingState = "empty"
	saveProgress()

	if turtle.getItemCount(1) > 0 then
		turtle.select(1)
		while not turtle.placeUp() do
			sleep(0)
			turtle.digUp()
		end
	end

	for slot = outputSlot, 16 do
		while turtle.getItemCount(slot) > 0 do
			turtle.select(slot)
			turtle.dropUp()
			sleep(0)
		end
	end

	turtle.select(1)
	turtle.digUp()
	refuelingState = ""
	saveProgress()
end

local function doChest()
	programState = "chest"
	saveProgress()

	--orient toward x
	local limit

	limit = 1
	while subStep < limit do
		subStep = subStep + 1
		saveProgress()
		if (curX % 2 == 0) == isReversed then
			--facing = 1
			turtle.turnRight()
		else
			--facing = 3
			turtle.turnLeft()
		end
	end

	limit = limit + curY
	while subStep < limit do
		subStep = subStep + 1
		saveProgress()
		moveUp()
	end

	limit = limit + curX
	while subStep < limit do
		subStep = subStep + 1
		saveProgress()
		moveForward()
	end

	limit = limit + 1
	while subStep < limit do
		subStep = subStep + 1
		saveProgress()
		turtle.turnLeft()
	end

	limit = limit + curZ
	while subStep < limit do
		subStep = subStep + 1
		saveProgress()
		moveForward()
	end

	limit = limit + 1
	while subStep < limit do
		for slot = outputSlot, 16 do
			turtle.select(slot)
			while not turtle.drop() do
				sleep(0)
			end
		end
		subStep = subStep + 1
		saveProgress()
		turtle.turnRight()
		turtle.turnRight()
	end

	limit = limit + curZ
	while subStep < limit do
		subStep = subStep + 1
		saveProgress()
		moveForward()
	end

	limit = limit + 1
	while subStep < limit do
		subStep = subStep + 1
		saveProgress()
		turtle.turnRight()
	end

	limit = limit + curX
	while subStep < limit do
		subStep = subStep + 1
		saveProgress()
		moveForward()
	end

	limit = limit + curY
	while subStep < limit do
		subStep = subStep + 1
		saveProgress()
		moveDown()
	end

	limit = limit + 1
	while subStep < limit do
		subStep = subStep + 1
		saveProgress()
		if (curX % 2 == 0) == isReversed then
			--facing = 1
			turtle.turnRight()
		else
			--facing = 3
			turtle.turnLeft()
		end
	end

	turtle.select(cobbleSlot)
	programState = "quarry"
	subStep = 0
	saveProgress()
end

local function doReturn()
	programState = "return"
	saveProgress()

	--orient toward x
	local limit

	limit = 1
	while subStep < limit do
		subStep = subStep + 1
		saveProgress()
		if (curX % 2 == 0) == isReversed then
			--facing = 1
			turtle.turnRight()
		else
			--facing = 3
			turtle.turnLeft()
		end
	end

	limit = limit + curY
	while subStep < limit do
		subStep = subStep + 1
		saveProgress()
		moveUp()
	end

	limit = limit + curX
	while subStep < limit do
		subStep = subStep + 1
		saveProgress()
		moveForward()
	end

	limit = limit + 1
	while subStep < limit do
		subStep = subStep + 1
		saveProgress()
		turtle.turnLeft()
	end

	limit = limit + curZ
	while subStep < limit do
		subStep = subStep + 1
		saveProgress()
		moveForward()
	end

	if useChest then
		limit = limit + 1
		while subStep < limit do
			for slot = outputSlot, 16 do
				turtle.select(slot)
				while not turtle.drop() do
					sleep(0)
				end
			end
			subStep = subStep + 1
			saveProgress()
		end
	end

	turtle.turnRight()
	turtle.turnRight()
	turtle.select(1)
	programState = "done"
	subStep = 0
	saveProgress()
end

local function checkInventory()

	if turtle.getItemCount(16) == 0 then
		return
	end

	if useCobblestone then
		turtle.select(cobbleSlot)
		turtle.drop(turtle.getItemCount(cobbleSlot) - 1)
		for slot = outputSlot, 16 do
			while turtle.compareTo(slot) do
				turtle.select(slot)
				turtle.drop()

				for swap = 16, slot, -1 do
					if turtle.getItemCount(swap) > 0 then
						turtle.select(swap)
						turtle.transferTo(slot)
						break
					end
				end

				turtle.select(cobbleSlot)
			end
		end
		if turtle.getItemCount(16) == 0 then
			return
		end
	end


	if useEnderChest then
		doEmpty()
	elseif useChest then
		doChest()
	else
		print("Inventory Full")
		local full = true
		while full do
			full = false
			sleep(5)
			for slot = outputSlot, 16 do
				if turtle.getItemCount(slot) > 0 then
					full = true
					break
				end
			end
		end
	end

end

local function doQuarry()

	if turtle.getFuelLevel() < 64 then
		if useEnderFuel then
			doRefuel()
		else
			if not requestFuel() then
				programState = "done"
				return
			end
		end
	end

	turtle.select(cobbleSlot)

	if curY > 0 then
		checkInventory()
		turtle.digUp()
	end
	if curY < sizeY - 1 then
		checkInventory()
		turtle.digDown()
	end

	checkInventory()
	if curX % 2 == 0 then
		if isReversed then

			if curZ == 0 then
				if curX == 0 then
					if curY >= sizeY - 2 then
						programState = "return"
						return
					else
						checkInventory()
						for y = 1, 3 do
							if curY >= sizeY - 2 then
								break
							end
							curY = curY + 1
							moveDown()
						end
						turtle.turnRight()
						turtle.turnRight()
						isReversed = false
					end
				else
					curX = curX - 1
					turtle.turnRight()
					moveForward()
					turtle.turnRight()
				end
			else
				curZ = curZ - 1
				moveForward()
			end

		else

			if curZ == sizeZ - 1 then
				if curX == sizeX - 1 then
					if curY >= sizeY - 2 then
						programState = "return"
						return
					else
						checkInventory()
						for y = 1, 3 do
							if curY >= sizeY - 2 then
								break
							end
							curY = curY + 1
							moveDown()
						end
						turtle.turnRight()
						turtle.turnRight()
						isReversed = true
					end
				else
					curX = curX + 1
					turtle.turnRight()
					moveForward()
					turtle.turnRight()
				end
			else
				curZ = curZ + 1
				moveForward()
			end

		end

	else --  curX % 2 ~= 0

		if isReversed then

			if curZ == sizeZ - 1 then
				if curX == 0 then
					if curY >= sizeY - 2 then
						programState = "return"
						return
					else
						checkInventory()
						for y = 1, 3 do
							if curY >= sizeY - 2 then
								break
							end
							curY = curY + 1
							moveDown()
						end
						turtle.turnLeft()
						turtle.turnLeft()
						isReversed = true
					end
				else
					curX = curX - 1
					turtle.turnLeft()
					moveForward()
					turtle.turnLeft()
				end
			else
				curZ = curZ + 1
				moveForward()
			end

		else

			if curZ == 0 then
				if curX == sizeX - 1 then
					if curY >= sizeY - 2 then
						programState = "return"
						return
					else
						checkInventory()
						for y = 1, 3 do
							if curY >= sizeY - 2 then
								break
							end
							curY = curY + 1
							moveDown()
						end
						turtle.turnLeft()
						turtle.turnLeft()
						isReversed = true
					end
				else
					curX = curX + 1
					turtle.turnLeft()
					moveForward()
					turtle.turnLeft()
				end
			else
				curZ = curZ - 1
				moveForward()
			end

		end

	end
	saveProgress()
end

local function getArgs()

	if sizeX == nil or sizeY == nil or sizeZ == nil then
		return false
	end

	sizeX = tonumber(sizeX)
	sizeY = tonumber(sizeY)
	sizeZ = tonumber(sizeZ)

	programState = "done"
	refuelingState = ""
	curX = 0
	curY = 0
	curZ = 0
	subStep = 0

	useEnderChest = false
	useEnderFuel = false
	useChest = false
	useCobblestone = false

	print("Excavate right " .. sizeX .. ", down " .. sizeY .. ", forward " .. sizeZ)
	print("Is this correct?")
	if not getYesNo() then
		return false
	end

	print("Use Ender Chest in slot 1 for output?")
	useEnderChest = getYesNo()
	if useEnderChest then
		print("Use Ender Chest in slot 2 for fuel?")
		useEnderFuel = getYesNo()
	else
		print("Use Chest behind turtle for output?")
		useChest = getYesNo()
	end

	if useEnderChest then
		if useEnderFuel then
			outputSlot = 3
		else
			outputSlot = 2
		end
	else
		outputSlot = 1
	end

	print("Discard Cobblestone? (requires cobblestone in slot" .. outputSlot .. ")")
	useCobblestone = getYesNo()

	local fuelRequired = (sizeX * sizeZ) * math.ceil(sizeY / 3) + sizeY

	print("Fuel Required: " .. fuelRequired)
	print("Fuel Current: " .. turtle.getFuelLevel())
	if not useEnderFuel and turtle.getFuelLevel() < fuelRequired then
		if not requestFuel() then
			return false
		end
	end

	print("Start Quarry with these parameters?")
	if not getYesNo() then
		return false
	end

	programState = "init"
	saveProgress()
	return true
end

local function main()

	if refuelingstate == "refuel" then
		doRefuel()
	end

	if refuelingstate == "empty" then
		doEmpty()
	end

	if useEnderChest then
		if turtle.getItemCount(1) == 0 then
			print("Place Ender Chest in slot 1")
			while turtle.getItemCount(1) == 0 do
				sleep(1)
			end
		end
		if useEnderFuel then
			if turtle.getItemCount(2) == 0 then
				print("Place Ender Chest in slot 2")
				while turtle.getItemCount(2) == 0 do
					sleep(1)
				end
			end
			outputSlot = 3
		else
			outputSlot = 2
		end
	else
		outputSlot = 1
	end
	cobbleSlot = outputSlot
	if useCobblestone then
		if turtle.getItemCount(cobbleSlot) == 0 then
			print("Place Cobblestone in slot " .. cobbleSlot)
			while turtle.getItemCount(cobbleSlot) == 0 do
				sleep(1)
			end
		end
		outputSlot = outputSlot + 1
	end


	while true do

		if programState == "quarry" then
			doQuarry()
		end
		if programState == "chest" then
			doChest()
		end
		if programState == "init" then
			if curY < sizeY - 1 then
				curY = curY + 1
				moveDown()
			end
			programState = "quarry"
		end
		if programState == "return" then
			doReturn()
			break
		end

	end

end


restoreProgress()
if programState == "done" then
	sizeX, sizeY, sizeZ = ...
	if not getArgs() then
		print("Usage")
		print("    startup x y z")
		return
	end
end

main()