ultitree

function refuel()
	if turtle.getFuelLevel() < 20 then
		turtle.select(1)
		turtle.refuel(1)
	end
end

function restock()
	go_to_restock()
	take_items()
	drop_off_items()
	go_back_from_restock()
end

function needs_restocking()
	turtle.select(1)
	if turtle.getItemCount() < 4 then
		return true
	end
	turtle.select(2)
	if turtle.getItemCount() < 4 then
		return true
	end
	turtle.select(5)
	if turtle.getItemCount() > 0 then
		return true
	end
	return false
end

function take_items()
	turtle.turnLeft()

	turtle.select(1)
	while turtle.getItemCount() < 4 do
		turtle.suck(32 - turtle.getItemCount())
	end

	turtle.select(2)
	while turtle.getItemCount() < 8 do
		turtle.suckDown(32 - turtle.getItemCount())
	end

	turtle.turnRight()
end

function drop_off_items()
	for i=3, 16 do
		turtle.select(i)
		items = turtle.getItemDetail()
		if items then
			if items.name == "minecraft:log" then
				turtle.dropUp()
			else
				if items.name == "minecraft:sapling" then
					turtle.dropDown()
				else
					turtle.dropUp()
					print("Unknown item picked up: " .. items.name)
				end
			end
		end
	end
end


function go_to_restock()
	refuel()
	turtle.turnRight()
	turtle.turnRight()
	turtle.dig()
	turtle.forward()
	turtle.dig()
	turtle.forward()
	turtle.dig()
	turtle.forward()
	turtle.dig()
	turtle.forward()
	turtle.turnRight()
	turtle.turnRight()
end

function go_back_from_restock()
	refuel()
	turtle.dig()
	turtle.forward()
	turtle.dig()
	turtle.forward()
	turtle.dig()
	turtle.forward()
	turtle.dig()
	turtle.forward()
	turtle.dig()
end

function harvest()
	refuel()

	turtle.select(1)
	turtle.dig()
	turtle.forward()

	while true do
		refuel()
		turtle.dig()
		turtle.digUp()
		turtle.up()
		a, b = turtle.inspectUp()
		if not (a) or b.name == "minecraft:leaves" then
			break
		end
	end

	for i=1, 2 do
		refuel()
		turtle.dig()
		turtle.digUp()
		turtle.up()
	end
	refuel()
	turtle.turnRight()
	turtle.dig()
	turtle.forward()
	turtle.turnLeft()

	while true do
		refuel()
		turtle.dig()
		turtle.digDown()
		turtle.down()
		a, b = turtle.inspectDown()
		if a and (b.name == "minecraft:dirt") or (b.name == "minecraft:grass") then
			break
		end
	end

	turtle.dig()
	turtle.turnLeft()
	turtle.forward()
	turtle.turnRight()
	turtle.back()
end

function plant()
	planted = true
	refuel()
	turtle.select(1)
	turtle.dig()
	turtle.suck()
	turtle.forward()
	turtle.suck()
	turtle.dig()
	turtle.forward()
	turtle.suck()
	turtle.dig()
	turtle.turnRight()
	turtle.suck()
	turtle.select(2)
	turtle.place()
	turtle.turnLeft()
	turtle.back()
	turtle.place()
	turtle.turnRight()
	turtle.suck()
	turtle.place()
	turtle.turnLeft()
	turtle.back()
	turtle.place()
end

blockExists, block = turtle.inspect()
if not (blockExists and (block.name == "minecraft:log" or block.name == "minecraft:sapling")) then
	take_items()
	go_back_from_restock()
end

while true do
	refuel()

	blockExists, block = turtle.inspect()
	if blockExists then
		if block.name == "minecraft:sapling" then
			sleep(1)
			turtle.select(1)
			turtle.suckUp()
		else
			harvest()
		end
	else
		plant()
	end

	if needs_restocking() then
		restock()
	end
end