Turtle Chunk Miner

-- Turtle Miner
-- by SparkyBearBomb
--
-- feel free to use this code
--
-- edit mining constraints here

local X = 16 -- Forward and Backwards (away from placed position)
local Y = 20 -- Up and Down
local Z = 16 -- Left and Right

-- X and Z are set for a chunk size (16 blocks)
-- use F9 key to see chunk borders
-- ensure the first block is pre mined by hand
-- coal will be required in slot 1

-----------------------------------------------
--Turtle Miner - Version History
--
-- Version 1.1 - 18 AUG 17
-- - Initial Version Release

-----------------------------------------------

x = 1
y = 1
z = 1

running = "yes"
direction = "up"

function mineX()
  while turtle.detect() == true do
    turtle.dig()
  end
  turtle.forward()
  x = x + 1
end

function mineZ()
  while turtle.detect() == true do
    turtle.dig()
  end
    turtle.forward()
  z = z + 1
end

function mineY()
  turtle.turnRight()
  while z > 1 do
    data()
    turtle.forward()
    z = z - 1
  end
  turtle.turnRight()
  if turtle.detectDown() == true then
    turtle.digDown()
  end
  turtle.down()
  y = y + 1
  direction = "up"
  x = 1
  z = 1
end

function finished()
  while y > 1 do
    turtle.up()
    y = y - 1
    data()
  end
  turtle.turnRight()
  while z > 1 do
    turtle.forward()
    z = z - z
    data()
  end
  running = "no"
  data()
end

function fuel()
  while turtle.getFuelLevel() < 200 do
    term.clear()
    term.setCursorPos(1,1)
    print("Refueling")
    print("Ensure slot 1 has coal more than 5 coal")
    sleep(5)
    turtle.refuel(5)
  end
end

function data()
  term.clear()
  term.setCursorPos(1,1)
  print("Running = ".. running)
  print("X = ".. x)
  print("Y = ".. y)
  print("Z = ".. z)
  print("fuel = ".. turtle.getFuelLevel())
end

while running == "yes" do

data()

  fuel()
  if y < Y then
    if z < Z then
      if x < X then
        mineX()
      else
        if direction == "up" then
          turtle.turnRight()
          mineZ()
          turtle.turnRight()
          x = 1
          direction = "down"
        else
          turtle.turnLeft()
          mineZ()
          turtle.turnLeft()
          x = 1
          direction = "up"
        end
      end
    else
      if (z == Z) and (x < X) then
         mineX()
      else
        mineY()
      end
    end
  else
    if (y == Y) and (z < Z) and (x < X) then
         mineX()
    else
      if (y == Y) and (z < Z) and (x == X) then
        if direction == "up" then
          turtle.turnRight()
          mineZ()
          turtle.turnRight()
          x = 1
          direction = "down"
        else
          turtle.turnLeft()
          mineZ()
          turtle.turnLeft()
          x = 1
          direction = "up"
        end
      else
        if (y == Y) and (z == Z) and (x < X) then
          mineX()
        else
          finished()
        end
      end
    end
  end
end