local turtleUtils = {}

local DEFAULT_IDLE_TIME = 2

turtleUtils.getInventory = function(side)
  side = side or 'front'
  local inv = peripheral.wrap(side)

  if inv and peripheral.hasType(inv, 'inventory') then
    return inv
  end

  return nil
end

turtleUtils.getItemName = function(slotIndex)
  local item = turtle.getItemDetail(i)
  return item and item.name
end

turtleUtils.getItemCount = function(slotIndex)
  return turtle.getItemCount(slotIndex)
end

local function waitFor(predicate, sleepTime)
  sleepTime = sleepTime or DEFAULT_IDLE_TIME

  while true do
    local result = predicate()

    if result ~= nil and result ~= false then
      return result
    end

    os.sleep(sleepTime)
  end
end

turtleUtils.waitForInventory = function(side, sleepTime)
  return waitFor(function()
    return turtleUtils.getInventory(side)
  end, sleepTime)
end

turtleUtils.waitForMatureCrop = function(inspectFn, sleepTime)
  inspectFn = inspectFn or turtle.inspect

  return waitFor(function()
    return turtleUtils.getMatureCrop(inspectFn)
  end, sleepTime)
end

turtleUtils.trySuck = function(suckFn, sleepTime)
  suckFn = suckFn or turtle.suck
  sleepTime = sleepTime or DEFAULT_IDLE_TIME

  while not suckFn() do
    os.sleep(sleepTime)
  end
end

turtleUtils.trySuckUp = function()
  return turtleUtils.trySuck(turtle.suckUp)
end

turtleUtils.trySuckDown = function()
  return turtleUtils.trySuck(turtle.suckDown)
end

turtleUtils.tryDrop = function(dropFn, sleepTime)
  dropFn = dropFn or turtle.drop
  sleepTime = sleepTime or DEFAULT_IDLE_TIME

  while true do
    if turtle.getItemCount() == 0 then
      return false
    end

    local dropOk = dropFn();

    if (dropOk) then
      return true
    end

    os.sleep(sleepTime)
  end
end

turtleUtils.tryDropUp = function()
  return turtleUtils.tryDrop(turtle.dropUp)
end

turtleUtils.tryDropDown = function()
  return turtleUtils.tryDrop(turtle.dropDown)
end

turtleUtils.dropSlot = function(slotIndex, dropFn)
  dropFn = dropFn or turtle.drop

  if turtle.getItemCount(slotIndex) == 0 then
    return false
  end

  if turtle.getSelectedSlot() ~= slotIndex then
    turtle.select(slotIndex)
  end

  local ok, err = dropFn()

  if not ok then
    return false
  end

  return true
end

turtleUtils.digAll = function()
  while turtle.dig() do end
end

turtleUtils.countFreeSlots = function()
  local freeSlots = 0

  for i=1, 16, 1 do
    if turtle.getItemCount(i) == 0 then
      freeSlots = freeSlots + 1
    end
  end

  return freeSlots
end

turtleUtils.getFuelPercentage = function()
  return (turtle.getFuelLevel() / turtle.getFuelLimit()) * 100
end

turtleUtils.getMatureCrop = function(inspectFn)
  inspectFn = inspectFn or turtle.inspect

  local isBlock, block = inspectFn()
  local blockStateAge = block and block.state and block.state.age

  if blockStateAge == 7 then
    return block.name
  end

  return nil
end

turtleUtils.selectFirstEmptySlot = function()
  for i = 1, 16, 1 do
    if turtle.getItemCount(i) == 0 then
      turtle.select(i)
      return true
    end
  end

  return false
end

turtleUtils.selectItemByName = function(itemName)
  for i = 1, 16, 1 do
    if itemName == turtleUtils.getItemName(i) then
      turtle.select(i)
      return true
    end
  end

  return false
end

turtleUtils.refuel = function(minFuel, suckFn, sleepTime)
  suckFn = suckFn or turtle.suck
  sleepTime = sleepTime or DEFAULT_IDLE_TIME

  if not turtleUtils.selectFirstEmptySlot() then
    return false, 'turtle inventory is full'
  end

  while turtle.getFuelLevel() < minFuel do
    local suckRes = suckFn()

    if suckRes then
      local ok = turtle.refuel()

      if not ok then
        return false, 'selected item is not considered as fuel'
      end
    else
      os.sleep(sleepTime)
    end
  end

  return true
end

turtleUtils.refuelAllFromInventory = function()
  local initialSelectedSlot = turtle.getSelectedSlot()

  for i=1, 16, 1 do
    if turtle.getItemCount(i) > 0 then
      turtle.select(i)
      turtle.refuel()
    end
  end

  if turtle.getSelectedSlot() ~= initialSelectedSlot then
    turtle.select(initialSelectedSlot)
  end
end

-- utils function used by "compactInventory"
local function getItemsMap()
  local result = {}

  for i=1, 16, 1 do
    local itemName = turtleUtils.getItemName(i)

    if itemName then
      local nbSlotUsed = result[itemName] or 0
      result[itemName] = nbSlotUsed + 1
    end
  end

  return result
end

local function getSlotsWithSpaces(itemName)
  local slots = {}

  for i=1, 16, 1 do
    if turtleUtils.getItemName(i) == itemName then
      if turtle.getItemSpace(i) > 0 then
        table.insert(slots, i)
      end
    end
  end

  return slots
end

local function compactItem(itemName)
  while true do
    local slots = getSlotsWithSpaces(itemName)

    if #slots < 2 then
      break
    end

    turtle.select(slots[1])
    turtle.transferTo(slots[2], turtle.getItemSpace(slots[2]))
  end
end

-- Compact the internal turtle inventory (return the number of freed slots)
turtleUtils.compactInventory = function()
  local initialNbFreeSlots = turtle.countFreeSlots()
  local initialSelectedSlot = turtle.getSelectedSlot()
  local itemsMap = getItemsMap()

  for itemName, nbSlotUsed in pairs(itemsMap) do
    if nbSlotUsed > 1 then
      compactItem(itemName)
    end
  end

  if initialSelectedSlot ~= turtle.getSelectedSlot() then
    turtle.select(initialSelectedSlot)
  end

  return turtle.countFreeSlots() - initialNbFreeSlots
end

return turtleUtils