local ItemStack = {}
ItemStack.__index = ItemStack

function ItemStack:fromDetail(inv, detail, slot)
    local obj = {
        slot = slot,
        inv = inv
    }

    if detail == nil then
        obj.maxCount = inv.getItemLimit(slot)
    else
        obj.name = detail.name
        obj.damage = detail.damage
        obj.maxDamage = detail.maxDamage
        obj.count = detail.count
        obj.maxCount = detail.maxCount
        obj.enchantments = detail.enchantments
    end

    setmetatable(obj, self)
    obj.__index = obj

    return obj
end

function ItemStack:clone(withSlot)
    local obj = {
        slot = withSlot or self.slot,
        inv = self.inv,
        name = self.name,
        damage = self.damage,
        maxDamage = self.maxDamage,
        count = self.count,
        maxCount = self.maxCount,
        enchantments = self.enchantments
    }

    setmetatable(obj, self)
    obj.__index = obj

    return obj
end

function ItemStack:toSerializable()
  local ser = {
    slot = self.slot,
    maxCount = self.maxCount
  }

  if self.count ~= nil then
    -- Not empty
    ser.name = self.name
    ser.damage = self.damage
    ser.maxDamage = self.maxDamage
    ser.count = self.count
    ser.enchantments = self.enchantments
  end

  return ser
end

function ItemStack:fromSerializable(ser, inv)
    ser.inv = inv

    setmetatable(ser, self)
    ser.__index = ser

    return ser
end

function ItemStack:getCount()
  return self.count or 0
end

function ItemStack:isEmpty()
  return self.count == nil or self.count == 0
end

function ItemStack:hasChanged(listObj, thorough)
  local listItem = listObj[self.slot]
  if listItem == nil or listItem.name ~= self.name or listItem.count ~= self.count then
    return true
  end

  return thorough and (self ~= self:fromDetail(self.inv, self.inv.getItemDetail(self.slot), self.slot))
end

function ItemStack:_modify(countDelta, stack)
  local newCount = self.count + countDelta
  if newCount < 0 then
    error("ERROR: New stack count is negative: "..newCount)
  end

  if newCount == 0 then
    -- Clear data
    self.maxCount = self.inv.getItemLimit(self.slot)
    self.name = nil
    self.damage = nil
    self.maxDamage = nil
    self.count = nil
    self.maxCount = nil
    self.enchantments = nil
  else
    -- If stack is empty, copy stack data from source
    if self:isEmpty() then
      self.maxCount = stack.maxCount
      self.name = stack.name
      self.damage = stack.damage
      self.maxDamage = stack.maxDamage
      self.maxCount = stack.maxCount
      self.enchantments = stack.enchantments
    end

    self.count = newCount
  end
end

function ItemStack:transferTo(target, count)
  local cap = math.min(count, target.maxCount - target.getCount(), self:getCount())

  -- If we can't transfer any data, then 
  if cap == 0 then
    return count == 0, 0
  end

  local result, xfer = pcall(self.inv.pushItems, peripheral.getName(target.inv), self.slot, cap, target.slot)

  if not result then
    return false, xfer
  end

  self:_modify(-xfer, self)
  target:_modify(xfer, self)

  return xfer == count, xfer
end

local function objEquals(o1, o2)
  local objType = type(o1)
  if objType ~= type(o2) then
    return false
  end

  if objType == "table" then
    if #o1 ~= #o2 then
        return false
    end

    for i,v in ipairs(o1) do
        if not objEquals(v, o2[i]) then
            return false
        end
    end

    for k,v in pairs(o1) do
        if not objEquals(v, o2[k]) then
            return false
        end
    end

    return true
  else
    return o1 == o2
  end
end

function ItemStack:__eq(other)
  return type(other) == "table" and
          self.count == other.count and
          self.maxCount == other.maxCount and
          self:canTransfer(other)
end


-- Determines if two stacks can be transferred to eachother
function ItemStack:canTransfer(stack)
  return self.name == stack.name and
          self.damage == stack.damage and
          self.maxDamage == stack.maxDamage and
          objEquals(self.enchantments, stack.enchantments)
end

local function queryField(query, field)
  local queryType = type(query)
  if queryType == "nil" then
    return true
  elseif queryType == "function" then
    return query(field)
  end

  return objEquals(query, field)
end

--- Matches a query object/function(s)
--- @param query table | function
function ItemStack:matches(query)
  if query == nil then
    return true
  elseif type(query) == "function" then
    return query(self)
  end

  return queryField(query.name, self.name) and
          queryField(query.damage, self.damage) and
          queryField(query.count, self.count) and
          queryField(query.maxDamage, self.maxDamage) and
          queryField(query.enchantments, self.enchantments) and
          queryField(query.maxCount, self.maxCount)
end

return ItemStack