-- @param attacks between inventory dump
local t = 256

-- @param level to do enchantments
local enchantLevel = 30

-- @param monitor direction (can be nil if no monitor)
local monitorSide = "left"

-- @param experience per kill (use 0 if you don't know)
local XPperKill = 5

-- wrap all peripherals
local xp = peripheral.wrap("right")
local mtr = term

-- if the monitor side was set, wrap it
if monitorSide ~= nil then
  mtr = peripheral.wrap(monitorSide)
end

local color = mtr.isColor()

local name = "Tim the Enchanter v1.0"
local enchants = 0
local totalXP = xp.get()

xp.setAutoCollect(false)
mtr.setCursorBlink(false)

local function display()
  local level = xp.getLevels()
  local W,H = mtr.getSize()

  local row = 4

  if color then
    mtr.setBackgroundColor(colors.black)
  end
  mtr.clear()

  -- write program name and decoration
  mtr.setCursorPos((W-#name)/2, 1)
  mtr.write(name)

  mtr.setCursorPos(1,2)
  mtr.write(string.rep("-", W))

  -- get the length of the progress bar
  local barWidth = W-7
  local barFill = (level * barWidth) / enchantLevel
  if barFill > barWidth then barFill = barWidth end

  -- write the level progress bar
  mtr.setCursorPos(2, row)
  mtr.write("L")

  mtr.setCursorPos(W-2, row)
  mtr.write(string.format("%02d", level))

  if color then
    mtr.setCursorPos(4, row)
    mtr.setBackgroundColor(colors.lightGray)
    mtr.write(string.rep(" ", barWidth))

    mtr.setCursorPos(4, row)
    mtr.setBackgroundColor(colors.red)
    mtr.write(string.rep(" ", barFill))

    -- reset background color
    mtr.setBackgroundColor(colors.black)
  else
    mtr.setCursorPos(4, row)
    mtr.write(string.rep("-", barWidth))

    mtr.setCursorPos(4, row)
    mtr.write(string.rep("#", barFill))
  end

  row = row + 2

  -- write the enchantment info
  mtr.setCursorPos(2, row)
  mtr.write("E")

  local enchantInfo = string.format("%d enchants", enchants)
  mtr.setCursorPos(W-(#enchantInfo), row)
  mtr.write(enchantInfo)

  row = row + 2

  if XPperKill > 0 then
    -- write the kill info
    mtr.setCursorPos(2, row)
    mtr.write("K")

    local killInfo = string.format("~ %d kills", math.floor(totalXP / XPperKill))
    mtr.setCursorPos(W-(#killInfo), row)
    mtr.write(killInfo)

    row = row + 2
  end

  -- write the experience info
  mtr.setCursorPos(2, row)
  mtr.write("XP")

  local xpInfo = string.format("%d total XP", totalXP)
  mtr.setCursorPos(W-(#xpInfo), row)
  mtr.write(xpInfo)

  row = row + 2
end

while true do
  display()

  -- attack and pick up items
  for i=1,t do
    turtle.attack()
    turtle.suck()
    totalXP = totalXP + xp.collect()
  end

  -- empty contents of turtle inventory
  for i=14,1,-1 do
    turtle.select(i)
    turtle.dropDown()
  end

  -- if we have enough levels to enchant
  if xp.getLevels() >= enchantLevel
  then
    -- toss buffered enchant
    turtle.select(16)
    turtle.dropDown()

    -- get more of whatever we are enchanting
    turtle.select(15)
    if turtle.getItemCount(15) == 0 then turtle.suckUp() end
    turtle.transferTo(16, 1)

    -- select the enchant slot and do it
    turtle.select(16)
    xp.enchant(enchantLevel)
    enchants = enchants + 1

    -- hold on to item to "buffer" (so we can see it)
    turtle.select(1)
  end
end