ComputerCraft/Tree_Farm/farmtree.lua

--[[Tree Farming App by Al Sweigart
Plants tree and cuts it down.]]

os.loadAPI('hare.lua') -- Load the hare module

local NUM_OF_TREES = 4
local TREE_SAPLING = 'spruce'

-- Check if choptree program exists
if not fs.exists('choptree.lua') then
    error('You must install choptree app first')
end

while true do
   -- Check if turtle has enough fuel
    if turtle.getFuelLevel() < (2 * (3 * NUM_OF_TREES)) then
	hare.selectItem('minecraft:' .. TREE_SAPLING .. 'log')
	turtle.refuel(2)
    end
    
    -- Empty everything except for the saplings
    for i = 1, 16 do
	local item = turtle.getItemDetail(i)

	if item ~= nil and item['name'] ~= 'minecraft:' .. TREE_SAPLING .. '_sapling' then
	    turtle.select(i)
	    turtle.drop()
	end
    end

 
    -- Check if we have saplings in our inventory
    if not hare.selectItem('minecraft:' .. TREE_SAPLING .. '_sapling') then
        error('Out of ' .. TREE_SAPLING .. ' saplings')
    end
    
    -- Build a Loop, where we plant and cut trees
    for i = 1, NUM_OF_TREES do
	turtle.back()
	turtle.back()
	turtle.back()
	turtle.turnRight()
	blockExists, item = turtle.inspect()
	if blockExists and item['name'] == 'minecraft:' .. TREE_SAPLING .. '_log' then
	    hare.selectEmtySlot()
            shell.run('choptree.lua') -- Run Choptree
	elseif blockExists and item['name'] ~= 'minecraft:' .. TREE_SAPLING .. '_sapling' then
	    print('Error! Wrong block')
	elseif not blockExists then
	    turtle.forward()
	    local success, underneath = turtle.inspectDown()
	    if underneath['name'] ~= 'minecraft:dirt' and underneath['name'] ~= 'minecraft:grass_block' then
                print('Error. No Dirt or Grass underneath to plant a tree. Found: ' .. underneath['name'])
		turtle.back()
	    else
		turtle.back()
		hare.selectItem('minecraft:' .. TREE_SAPLING .. '_sapling')
		turtle.place()
	    end
	end
	turtle.turnLeft()
    end

    -- Move forward to the chest again
    for i = 1, (3 * NUM_OF_TREES) do
        turtle.forward()
    end
  
end