digger2.lua

--[[
Digger2: A simple program to dig a cross pattern

Author: Brandon Weaver (keystonelemur / baweaver)

Notes:
--]]

local tArgs = { ... }

if tArgs[1] == 'help' then
  print('Usage:')
  print('  lava [distance] [drop]')
  return
end

-- Distance to mine
local distance = tArgs[1] or 1

-- Shorten the turtle name
local t = turtle

-- Finds the shortage of fuel for the round trip
local function checkFuelDeficit()
  return (2 * distance - t.getFuelLevel()) + 2
end

-- Confirm that we have adequate fuel for the trip
local level = checkFuelDeficit()
if level > 0 then
  -- Attempt to correct the deficit
  print('Insufficient fuel of'..level..' units, attempting refuel...')
  t.refuel()

  -- See if that worked, or end the program
  local newLevel = checkFuelDeficit()
  if newLevel > 0 then
    print('Cannot make trip, fuel is short by'..newLevel..' units. Goodbye')
    return
  end
end

print('Mining '..distance..' squares')
print('')

local function turnAround()
  t.turnRight()
  t.turnRight()
end

local function until_clear(checkFn, digFn)
  while checkFn() do
    digFn()
    sleep(0.1)
  end
end

-- Clear a forward path
local function clearDown()
  -- Make sure to deal with sand and friends
  until_clear(t.detect, t.dig)
  until_clear(t.detectDown, t.digDown)
  until_clear(t.detectUp, t.digUp)

  t.turnRight()
  until_clear(t.detect, t.dig)

  turnAround()
  until_clear(t.detect, t.dig)

  t.turnRight()

  t.digDown()
  t.forward()
end

-- Make it come back to the origin
local function returnHome()
  turnAround()

  for returnLocation = 0, distance do
     -- Make sure to deal with sand and friends
    until_clear(t.detect, t.dig)

    t.forward()
  end
end

-- Main program loop
for currentLocation = 0, distance do
  -- Do you REALLY want it every block notifications?
  if currentLocation % 5 == 0 then
    print('Mined '..currentLocation..' blocks')
  end

  clearDown()
end

returnHome()