ComputerCraft Mining Turtle - Stripmining

print("STRIPMINE STARTEN")
print("PN Creep4Play fuer mehr Info.")
os.sleep(4)
term.clear()
term.setCursorPos(1,1)

function digU()
  while turtle.detectUp() do
    turtle.digUp()
  end
end

function digF()
  while turtle.detect() do
    turtle.dig()
  end
end

function digD()
  while turtle.detectDown() do
    turtle.digDown()
  end
end

function goU(proof)
  repeat
    digU()
    if proof then
      if not proofFuel(false) then
        return false
      end
    end
  until turtle.up()
  return true
end

function goF(proof)
  repeat
    digF()
    if proof then
      if not proofFuel(false) then
        return false
      end
    end
  until turtle.forward()
  return true
end

function goD(proof)
  repeat
    digD()
    if proof then
      if not proofFuel(false) then
        return false
      end
    end
  until turtle.down()
  return true
end

function proofFuel(wait)
  while turtle.getFuelLevel()<(mainGone+subGone+2) do
    local broken=false
    for i=16,1,-1 do
      if turtle.getItemCount(i)>0 then
        turtle.select(i)
        if turtle.refuel(1) then
          broken=true
          break
        end
      end
    end
    if not broken then
      if wait then
        os.sleep(1)
      else
        return false
      end
    end
    turtle.select(1)
  end
  return true
end

function goBack()
  turtle.turnRight()
  turtle.turnRight()
  if inSub then
    for i=1,subGone do
      goF(false)
    end
    if (thisSub%2)==0 then
      turtle.turnLeft()
    else
      turtle.turnRight()
    end
  end
  for i=1,mainGone do
    goF(false)
  end
  local fuel=false
  for i=3,16 do
    if turtle.getItemCount(i)>0 then
      turtle.select(i)
      if not turtle.refuel(0) then
        turtle.drop()
      elseif fuel then
        turtle.drop()
      else
        fuel=true
      end
    end
  end
  turtle.select(1)
  turtle.turnRight()
  turtle.turnRight()
end

function invFull()
  for i=1,16 do
    if turtle.getItemCount(i)==0 then
      return false
    end
  end
  return true
end

function awaitFuel()
  term.clear()
  term.setCursorPos(1,1)
  print("Stripmining:")
  print("")
  print("Add more fuel to continue.")
  goBack()
  proofFuel(true)
  term.clear()
  term.setCursorPos(1,1)
  print("Stripmining:")
  print("")
  print("Put some cobblestones on slot 1.")
  print("Put torches on slot 2.")
  print("Put fuel on any slot.")
  print("Number of strips: "..subNumber)
  print("Length of strips: "..subLength)
end

function place()
  if not turtle.detectDown() then
    if turtle.getItemCount(1)>1 then
      turtle.placeDown()
      return
    end
    for i=3,16 do
      if turtle.compareTo(i) then
        turtle.select(i)
        turtle.placeDown()
        turtle.select(1)
        break
      end
    end
  end
end

term.clear()
term.setCursorPos(1,1)
print("Stripmining:")
print("")
print("Put some cobblestones on slot 1.")
print("Put torches on slot 2.")
print("Put fuel on any slot.")
print("Number of strips:")
repeat
  term.setCursorPos(19,6)
  print("          ")
  term.setCursorPos(19,6)
  subNumber=tonumber(read())
until subNumber>0
term.setCursorPos(1,7)
print("Length of strips:")
repeat
  term.setCursorPos(19,7)
  print("          ")
  term.setCursorPos(19,7)
  subLength=tonumber(read())
until subLength>0
thisSub=0
for i1=1,subNumber do
  local broken=false
  thisSub=thisSub+1
  inSub=false
  subGone=0
  repeat
    broken=false
    mainGone=0
    for i2=1,(thisSub+(thisSub%2))*2 do
      if not goF(true) then
        awaitFuel()
        broken=true
        break
      end
      mainGone=mainGone+1
      place()
      if (thisSub%2)==1 then
        if i2>(thisSub-1)*2 then
          digU()
        end
      else
        if i2==(thisSub-1)*2 then
          turtle.select(2)
          turtle.placeUp()
          turtle.select(1)
        end
      end
    end
  until not broken
  if (thisSub%2)==0 then
    turtle.turnRight()
  else
    turtle.turnLeft()
  end
  inSub=true
  for iS=1,subLength do
    if not goF(true) then
      awaitFuel()
      broken=true
      break
    end
    subGone=subGone+1
    place()
    digU()
    if invFull() then
      break
    end
  end
  if not broken then
    goBack()
  end
end
term.clear()
term.setCursorPos(1,1)
print("STRIPMINE FERTIG")
print("PN Creep4Play fuer mehr Info.")