farm

local length = 27
local width = 27
local seedType = "potato"
local goods = "potato"
local timeOut = 600
local holding = 64
local fuel = {"coal","log"}

function forward()
 if not turtle.forward() then
  turtle.attack()
  turtle.dig()
  forward()
 end
end
function backward()
 if not turtle.back() then
  turtle.turnLeft()
  turtle.turnLeft()
  forward()
  turtle.turnRight()
  turtle.turnRight()
 end
end
function isGrown()
 s,d =  turtle.inspectDown()
 if s then
  if d.state.age == 7 then
    return 2
  else
   return 1
  end
 else
  return 0
 end
end
function selectSeed()
 for slot=1,16 do
  turtle.select(tonumber(slot))
  if turtle.getItemCount() ~= 0 then
   if turtle.getItemDetail().name == "minecraft:"..seedType then
    return
   end
  end
 end
end
function farmCrop()
 g = isGrown()
 if g==2 then
  turtle.digDown()
  selectSeed()
  turtle.placeDown()
 elseif g==0 then
  selectSeed()
  turtle.placeDown()
 end
end
function farmLine()
 farmCrop()
 for i=2,length do
  forward()
  farmCrop()
 end
 for i=2,length do
  backward()
 end
end
function farmDoubleLine()
 farmCrop()
 for i=2,length do
  forward()
  farmCrop()
 end
 turtle.turnLeft()
 forward()
 turtle.turnRight()
 farmCrop()
 for i=2,length do
  backward()
  farmCrop()
 end
end
function farmAll()
 x = 1
 while true do
  if width-x == 0 then
   farmLine()
   x=x+1
   break
  else
   farmDoubleLine()
   x=x+2
  end
  turtle.turnLeft()
  forward()
  turtle.turnRight()
 end
 turtle.turnLeft()
 for i=2,width do
   backward()
 end
 turtle.turnRight()
end
function selectGood()
 for slot=1,16 do
  turtle.select(slot)
  if turtle.getItemCount() ~= 0 then
   if turtle.getItemDetail().name == "minecraft:"..goods then
    return true
   end
  end
 end
 return false
end
function storeGoods()
 backward()
 h = 0
 while selectGood() do
  h = h + turtle.getItemCount()
  if h > holding then
   turtle.dropDown()
  end
 end
 print("goods stored")
 forward()
end
local fuelPerRotation = width*length + length +width +2
function isFuel()
 if turtle.getItemCount() ~= 0 then
  item = turtle.getItemDetail().name
  for i=1,#fuel do
   if item == "minecraft:"..fuel[i] then
    return true
   end
  end
 end
 return false
end
function refuel()
 if turtle.getFuelLevel() > fuelPerRotation then
  return true
 end
 print("refueling")
 for slot=1,16 do
  turtle.select(slot)
  if isFuel() then
   c = turtle.getItemCount()
   for i=1,c do
    if turtle.getFuelLevel() > fuelPerRotation then
     return
    end
    turtle.refuel(1)
   end
  end
 end
 out = turtle.getFuelLevel() > fuelPerRotation
 return out
end
--MAINLOOP--
while true do
 refuel()
 farmAll()
 storeGoods()
 print("waiting")
 sleep(timeOut)
end

print("FarmingProgram-Ended")