farmTrees.lua

os.loadAPI("inv")
os.loadAPI("t")

local LOG = "minecraft:log"
local SAP = "minecraft:sapling"
local COAL = "minecraft:coal"

local x = 0
local y = 0

function chestyStuff()
	-- We can't see what's on the chest
	-- so we just grab everything
	while turtle.suck() do end
	inv.stackItems()
	-- and we drop back all the logs
	while inv.selectItem(LOG) do
		turtle.drop()
	end
	-- Drop all but one stack of coal
	while inv.getItemCount(COAL) > 128 do
		inv.selectItem(COAL)
		turtle.drop()
	end
	while inv.getItemCount(SAP) > 128 do
		inv.selectItem(SAP)
		turtle.drop()
	end
end

function refuelIfNeeded()
	local fuelLevel = turtle.getFuelLevel()
	if fuelLevel < 70 then
		print("Fuel level is " .. fuelLevel .. ", refueling...")
		if inv.selectItem(COAL) then
			turtle.refuel(1)
			print("Refueled! new level is " .. turtle.getFuelLevel())
			return true
		end
		printError("No fuel in inventory!")
	end
	return false
end

function placeSapling()
	for i=1, 16 do
		turtle.select(i)
		local data = turtle.getItemDetail()
		if (data and data.name == SAP) then
			turtle.place()
			break
		end
	end
end

function chop()
	turtle.dig()
	t.fw()
	local success = true
	local data
	while success do
		success, data = turtle.inspectUp()
		if data.name == LOG then
			t.digUp()
			t.up()
		else
			break
		end
	end
	while turtle.detectDown() == false do
		success = t.down()
	end
	turtle.back()
	placeSapling()
end

function inFrontOfTree()
	local success, data
	success, data = turtle.inspect()
		
	if data.name == LOG then
		return true
	end
	return false
end

function rowOfTrees()
	local foundAny = false
	local success, data = turtle.inspect()
	if success and (data.name == LOG or data.name == SAP) then
		foundAny = true
		if data.name == LOG then
			inv.selectItem(LOG)
			chop()
		end
		turtle.turnRight()
		t.fw(3)
		x = x+3
		turtle.turnLeft()
		rowOfTrees()
	end
	if x > 0 then
		turtle.turnLeft()
		while x > 0 do
			t.fw()
			x = x-1
		end
		turtle.turnRight()
	end
	return foundAny
end

function columns(colCount)
	for column=1, colCount do
		refuelIfNeeded()
		
		turtle.turnRight()
		t.fw()
		x = x + 1
		turtle.turnLeft()
		
		local foundAny = rowOfTrees()
		
		if foundAny == false or column >= colCount then
			break
		else
			t.fw(3)
			y = y + 3
		end
	end
	-- Go back
	turtle.turnLeft()
	turtle.turnLeft()
	while y > 0 do
		t.fw()
		y = y - 1
	end
	turtle.turnRight()
	turtle.turnRight()
end

while true do
	refuelIfNeeded()
	
	columns(8)

	turtle.turnLeft()
	chestyStuff()
	turtle.turnRight()
	
	sleep(10)
end