os.loadAPI('/fuel')

function refreshInventory()
	turtle.down()
	turtle.down()
	local current = 3
	while (current < 16) do
		turtle.select(current)
		turtle.dropDown()
		current = current + 1
	end
	turtle.select(1)
	turtle.suckDown(4)	--Get new sapling
	turtle.up()
	turtle.up()
end

function isTree()
	turtle.select(2)
	return turtle.compare()
end

function chopTree()
	local dist = 0
	--get in the tree to make sure we do this efficiently
	turtle.dig()
	turtle.forward()
	--clear most of the tree
	while (turtle.detect() and dist < 60) do
		turtle.dig()
		turtle.turnRight()
		turtle.dig()
		if (turtle.detectUp()) then
			turtle.digUp()
		end
		turtle.up()
		turtle.turnLeft()
		dist = dist + 1
	end
	--position for the last column on the way down
	turtle.turnRight()
	turtle.forward()
	turtle.turnLeft()
	--clear the last column as we go down the tree
	while (dist > 0) do
		dist = dist - 1
		turtle.dig()
		turtle.down()
	end
	turtle.dig()
	--reset turtle to initial position
	turtle.turnLeft()
	turtle.turnLeft()
	turtle.forward()
	turtle.turnRight()
	turtle.forward()
	turtle.turnRight()
end

function plantTree()
	turtle.forward()
	turtle.forward()
	turtle.turnRight()
	turtle.place()	--back right
	turtle.turnRight()
	turtle.forward()
	turtle.turnLeft()
	turtle.place()	--front right
	turtle.turnLeft()
	turtle.place()	--back left
	turtle.turnLeft()
	turtle.turnLeft()
	turtle.forward()
	turtle.turnRight()
	turtle.turnRight()
	turtle.place()	--front left
end

local canRefuel = true
while (true) do
	while (turtle.getFuelLevel() < 400) then
		if (fuel.canRefuel()) then
			fuel.fuelUp()
		else
			print('Cannot refuel')
			canRefuel = false
			break
		end
	end
	if (not canRefuel) then
		break
	end
	if (isTree()) then
		chopTree()
		refreshInventory()
		plantTree()
	end
	sleep(30)
end