smeltery

ores = {"iron_", "tin_", "copper_", "lead_", "silver_", "gold_", "platinum_", "nickel_", "aluminum_"}
currentOre = 1

function nextOre()
  name = string.lower(ores[currentOre])
  if currentOre == #ores then
    currentOre = 1
  else
    currentOre = currentOre +1
  end
  return name
end

function nextOreSlots()
  local ore = nextOre()
  local oreSlots = {}
  print("Looking for "..ore)
  for tSlot=1,16 do
    -- turtle.select(tSlot)
    local details = turtle.getItemDetail(tSlot)
    if details ~= nil then
      name = string.lower(details.name)
      print("--"..name.."--")
      if string.match(name, ore) ~= nil then
        --turtle slot contains active ore
        oreSlots[#oreSlots+1] = tSlot
      end
    end
  end
  return oreSlots
end

function dropSlots(oreSlots)
  for i=1,#oreSlots do
    local tSlot = oreSlots[i]
    print("Dropping slot "..tSlot.." in smeltery")
    turtle.select(tSlot)
    turtle.dropUp()
  end
end

function hasLiquid(smelter)
  local content = smelter.getInfo().contents
  if not content then
    return false
  else
    local name = content.rawName
    local amount = content.amount
    --print("--found "..name.."("..amount.." mB)")
    return true
  end
end

function hasSolid(smelter)
  local size = smelter.getInventorySize()
  for slot=1,size do
    local s = smelter.getStackInSlot(slot)
    if s ~= nil then
      local name = s.name
      --print("--found "..name.." in slot "..slot)
      return true
    end
  end
  return false
end

function isSmelterBusy(side)
  local smelter = peripheral.wrap(side)
  local s = hasSolid(smelter)
  local l = hasLiquid(smelter)
  return s or l
end

while true do

  while isSmelterBusy("top") do
    sleep(1)
  end

  dropSlots(nextOreSlots())

  sleep(1)
end