udig

-- change mx for width, my for length and mz for height, the turtle will dig down and to the right
mx = 100
my = 100
mz = 18
-- Don't change anything bellow this line

x = 1
y = 1
z = 1

cx = 1
cy = 1
cz = 1

posx = 1
posy = 1

function f()
 if turtle.forward() == false then
  repeat
  turtle.dig()
  sleep(0.25)
  until turtle.forward() == true
 end
end

function savepos()
  local f1=io.open("posx", "w")
  local f2=io.open("posy", "w")
  f1:write(cx)
  f2:write(cy)
  f1:close()
  f2:close()
  return true
end

function loadpos()
  local f1 = io.open("posx", "r")
  local f2 = io.open("posy", "r")
  posx = tonumber(f1:read())
  posy = tonumber(f2:read())
  f1:close()
  f2:close()
end

function d()
 if turtle.down() == false then
  repeat
  turtle.digDown()
  sleep(0.25)
  until turtle.down() == true
 end
end

function u()
 if turtle.up() == false then
  repeat
  turtle.digUp()
  sleep(0.25)
  until turtle.up() == true
 end
end

function check()
 for i = 1,15 do
  if turtle.getItemCount(i) == 0 then
   return true
  end
 end
end

function dropall()
 for dropSlot = 1,16 do
  turtle.select(dropSlot)
  turtle.drop()
 end
 turtle.select(1)
 turtle.turnRight()
 turtle.turnRight()
end

function down()
 while cz < mz do
  d()
  cz = cz+1
 end
end

function up()
 while cz > z do
  u()
  cz = cz-1
 end
end

function bdig()
 if cz == z and cx == x then
  goback()
  dropall()
 else
  up()
  goback()
  dropall()
 end
end

function refuel()

end

function goback()
 print("y - ",posy)
 print("x - ",posx)
 turtle.turnLeft()
 while cx > x do
  f()
  cx = cx - 1
 end
 turtle.turnLeft()
 while cy > y do
  f()
  cy = cy - 1
 end
end

function udig()
 while check() and cy < my do
  f()
  turtle.digUp()
  down()
  up()
  cy = cy+1
  savepos()
 end
 bdig()
end

while true do
 loadpos()
 if posx == x  and posy ~= my then
  while cy < posy do
   f()
   cy = cy + 1
  end
  udig()
 elseif posx < mx and posy == my then
  turtle.turnRight()
  while cx < posx + 1 do
   turtle.digUp()
   f()
   cx = cx + 1
  end
  turtle.turnLeft()
  udig()
 elseif posx < mx and posy ~= my then
  turtle.turnRight()
  while cx < posx do
   turtle.digUp()
   f()
   cx = cx + 1
  end
  turtle.turnLeft()
  while cy < posy do
   turtle.digUp()
   f()
   cy = cy + 1
  end
  udig()
 elseif posy == my and posx == mx then
  print("Complete")
  break
 end
end