Turtle Tunnles

-- grid_mine.lua
-- Mines a grid of parallel tunnels at y=0 until out of fuel.
-- Configure the tunnel length and spacing below:

local tunnelLength = 16     -- how long each tunnel runs before shifting over
local spacing      = 4      -- how many blocks between adjacent tunnels

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-- Helper: try to refuel if out of fuel; returns true if there is fuel available
local function refuelIfNeeded()
  if turtle.getFuelLevel() > 0 then
    return true
  end
  -- try each slot for 1 item
  for slot = 1,16 do
    turtle.select(slot)
    if turtle.refuel(1) then
      print(("Refueled from slot %d → fuel=%d"):format(slot, turtle.getFuelLevel()))
      turtle.select(1)
      return true
    end
  end
  -- no fuel found
  print("❌ Out of fuel, stopping.")
  return false
end

-- ensure we start with slot 1 selected
turtle.select(1)

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-- 1) Get starting GPS position
local x,y,z = gps.locate()
-- round to integer
x = math.floor(x + 0.5)
y = math.floor(y + 0.5)
z = math.floor(z + 0.5)
print(("Starting at GPS x=%d, y=%d, z=%d"):format(x,y,z))

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-- 2) Move down (digging) to y=0 if above it
if y > 0 then
  print("Moving down to y=0 level...")
  while y > 0 do
    if not refuelIfNeeded() then return end
    if not turtle.down() then
      turtle.digDown()
      if not turtle.down() then
        error("Blocked below, cannot reach y=0")
      end
    end
    y = y - 1
    print("  now at y="..y)
  end
elseif y < 0 then
  print("⚠️  Already below y=0 (y="..y.."), unexpected.")
end

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-- 3) Mine an endless grid of tunnels until fuel runs out
local direction = 1  -- 1 = moving “forward” along +X, -1 = moving backward

while true do
  -- each tunnel segment
  for i = 1, tunnelLength do
    if not refuelIfNeeded() then return end
    if turtle.detect() then turtle.dig() end
    turtle.forward()
  end

  -- shift over by `spacing` blocks to start the next tunnel
  if direction == 1 then
    turtle.turnRight()
  else
    turtle.turnLeft()
  end

  for i = 1, spacing do
    if not refuelIfNeeded() then return end
    if turtle.detect() then turtle.dig() end
    turtle.forward()
  end

  if direction == 1 then
    turtle.turnRight()
  else
    turtle.turnLeft()
  end

  direction = -direction
end