local args = {...}

-- overall tunnel length
local LENGTH = tonumber(args[1])
if not LENGTH then print('usage: \'stripmine <length:int> [<throwaway:string>, ...]\'') return end

-- throwaway items
local THROWAWAY = args
for i = 2, #args do
  THROWAWAY['minecraft:' .. args[i]] = true
end

local name = os.getComputerLabel()
local CURRENT = 0

os.setComputerLabel(name .. ': Strip Mining')

local drop = function()
  for i = 1, 16 do
    turtle.select(i)
    if turtle.getItemDetail() and THROWAWAY[turtle.getItemDetail().name] then
      turtle.drop()
    end
  end
end

local torch = function()
  for i = 1, 16 do
    turtle.select(i)
    if turtle.getItemDetail() and turtle.getItemDetail().name == 'minecraft:torch' then
      turtle.turnRight()
      turtle.placeUp()
      turtle.turnLeft()
      return true
    end
  end
  return false
end

local refuel = function()
  local fuel = turtle.getFuelLevel()
  if fuel > 1 then
    return true
  end

  for i = 1, 16 do
    turtle.select(i)
    if turtle.refuel(0) then
      turtle.refuel(math.ceil(turtle.getItemCount(i) / 2))
      return true
    end
  end

  return false
end

local return_origin = function()
  turtle.turnLeft()
  turtle.turnLeft()

  for i = 1, CURRENT do
    turtle.forward()
    refuel()
  end
end

local dig = function()
  if turtle.detect() then
    local success, data = turtle.inspect()
    if success then
      if data.name == 'minecraft:diamond_ore' then
        return true
      end
    end
    turtle.dig()
  end

  return false
end

local found
while CURRENT < LENGTH do
  if not refuel() then
    print('program terminated: not enough fuel')
    os.setComputerLabel(name)
    return
  end

  -- dig lower block
  found = dig()
  if found then break end

  -- dig upper block
  turtle.up()
  found = dig()
  if found then turtle.down(); break end

  -- reset turtle, check if we need to place a torch and move forward
  turtle.down()
  if CURRENT % 10 == 1 then
    if not torch() then
      print('program terminated: not enough torches')
      break
    end
  end
  turtle.forward()
  drop()

  CURRENT = CURRENT + 1
end

return_origin()

if found then
  os.setComputerLabel(name .. ': Found Diamond!')
  print('Found diamonds at xxxyyy!')
else
  os.setComputerLabel(name .. ': Finished!')
end

print('Press any key to return to CraftOS...')
os.pullEventRaw('key')
os.setComputerLabel(name)