--- Microexpansion network
-- @type network
-- @field #table controller_pos the position of the controller
-- @field #number power_load the power currently provided to the network
-- @field #number power_storage the power that can be stored for the next tick
local network = {
	power_load = 0,
	power_storage = 0
}
local me = microexpansion
me.network = network

--- construct a new network
-- @function [parent=#network] new
-- @param #table o the object to become a network or nil
-- @return #table the new network object
function network.new(o)
	return setmetatable(o or {}, {__index = network})
end

--- check if a node can be connected
-- @function [parent=#network] can_connect
-- @param #table np the position of the node to be checked
--   the node itself or the name of the node
-- @return #boolean whether this node has the group me_connect
function network.can_connect(np)
  local nn
  if type(np)=="string" then
    nn = np
  else
    if np.name then
      nn = np.name
    else
      local node = me.get_node(np)
      nn = node.name
    end
  end
	return minetest.get_item_group(nn, "me_connect") > 0
end

--- get all adjacent connected nodes
-- @function [parent=#network] adjacent_connected_nodes
-- @param #table pos the position of the base node
-- @param #boolean include_ctrl whether to check for the controller
-- @return #table all nodes that have the group me_connect
function network.adjacent_connected_nodes(pos, include_ctrl)
	local adjacent = {
		{x=pos.x+1, y=pos.y,   z=pos.z},
		{x=pos.x-1, y=pos.y,   z=pos.z},
		{x=pos.x,   y=pos.y+1, z=pos.z},
		{x=pos.x,   y=pos.y-1, z=pos.z},
		{x=pos.x,   y=pos.y,   z=pos.z+1},
		{x=pos.x,   y=pos.y,   z=pos.z-1},
	}

	local nodes = {}

	for _,apos in pairs(adjacent) do
	 local napos = me.get_node(apos)
	 local nn = napos.name
	 if network.can_connect(nn) then
		if include_ctrl == false then
			if nn ~= "microexpansion:ctrl" then
				table.insert(nodes,{pos = apos, name = nn})
			end
		else
			table.insert(nodes,{pos = apos, name = nn})
		end
	 end
	end

	return nodes
end

--- provide power to the network
-- @function [parent=#network] provide
-- @param #number power the amount of power provided
function network:provide(power)
	self.power_load = self.power_load + power
end

--- demand power from the network
-- @function [parent=#network] demand
-- @param #number power the amount of power demanded
-- @return #boolean whether the power was provided
function network:demand(power)
	if self.power_load - power < 0 then
		return false
	end
	self.power_load = self.power_load - power
	return true
end

--- add power capacity to the network
-- @function [parent=#network] add_power_capacity
-- @param #number power the amount of power that can be stored
function network:add_power_capacity(power)
	self.power_storage = self.power_storage + power
end

--- add power capacity to the network
-- @function [parent=#network] add_power_capacity
-- @param #number power the amount of power that can't be stored anymore
function network:remove_power_capacity(power)
	self.power_storage = self.power_storage - power
	if self.power_storage < 0 then
		minetest.log("warning","[Microexpansion] power storage of network "..self.." dropped below zero")
	end
end

--- remove overload
-- to be called by the controller every turn
-- @function [parent=#network] remove_overload
function network:remove_overload()
	self.power_load = math.min(self.power_load, self.power_storage)
end

--- get a drives item capacity
-- @function get_drive_capacity
-- @param #table pos the position of the drive
-- @return #number the number of items that can be stored in the drive
local function get_drive_capacity(pos)
	local cap = 0
	local meta = minetest.get_meta(pos)
	local inv = meta:get_inventory()
	for i = 1, inv:get_size("main") do
		cap = cap + me.get_cell_size(inv:get_stack("main", i):get_name())
	end
	return cap
end

--- get the item capacity of a network
-- @function [parent=#network] get_item_capacity
-- @return #number the total number of items that can be stored in the network
function network:get_item_capacity()
	local cap = 0
	for npos in me.connected_nodes(self.controller_pos) do
		if me.get_node(npos).name == "microexpansion:drive" then
			cap = cap + get_drive_capacity(npos)
		end
	end
	self.capacity_cache = cap
	return cap
end

local function remove_slots(inv,ln,target,csize)
  for i = target, csize do
    local s = inv:get_stack(ln,i)
    if not s:is_empty() then
      inv:set_stack(ln, i, "")
      me.insert_item(s, inv, ln)
    end
  end
  --perhaps allow list removal
  if target < 0 then
    target = 1
  end
  inv:set_size(ln, target)
end

function network:set_storage_space(count,listname)
  local c = count or 1
  local ln = listname or "main"
  local inv = self:get_inventory()
  local csize = inv:get_size(ln)
  local space = 0
  local inside = 0
  local contents = inv:get_list(ln) or {}
  for _,s in pairs(contents) do
    if s:is_empty() then
      space = space + 1
    else
      inside = inside + s:get_count()
    end
  end
  local cap = self:get_item_capacity()
  --the capacity is allocated outside of the condition because it updates the cached capacity
  if count == true then
    if inside < cap then
      c = 1
    else
      c = 0
    end
  end
  local needed = c - space
  if needed > 0 then
    needed = needed + csize
    inv:set_size(ln, needed)
  elseif needed < 0 then
    needed = needed + csize
    remove_slots(inv,ln,needed,csize)
  end
end

function network:update()
  self:set_storage_space(true)
end

function network:get_inventory_name()
  local cp = self.controller_pos
  assert(cp, "trying to get inventory name of a network without controller")
  return "microexpansion_storage_"..cp.x.."_"..cp.y.."_"..cp.z
end

local function create_inventory(net)
  local invname = net:get_inventory_name()
  net.inv = minetest.create_detached_inventory(invname, {
    allow_put = function(inv, listname, index, stack)
      local inside_stack = inv:get_stack(listname, index)
      local stack_name = stack:get_name()
      -- improve performance by skipping unnessecary calls
      if inside_stack:get_name() ~= stack_name or inside_stack:get_count() >= inside_stack:get_stack_max()  then
        if inv:get_stack(listname, index+1):get_name() ~= "" then
          return stack:get_count()
        end
      end
      local max_slots = inv:get_size(listname)
      local max_items = net.capacity_cache

      local slots, items = 0, 0
      -- Get amount of items in drive
      for i = 1, max_slots do
        local dstack = inv:get_stack("main", i)
        if dstack:get_name() ~= "" then
          slots = slots + 1
          local num = dstack:get_count()
          if num == 0 then num = 1 end
          items = items + num
        end
      end
      return math.max(math.min(stack:get_count(),max_items-items),0)
    end,
    on_put = function(inv, listname, _, stack)
      inv:remove_item(listname, stack)
      me.insert_item(stack, inv, listname)
      net:set_storage_space(true)
    end,
    allow_take = function(_, _, _, stack)
      return math.min(stack:get_count(),stack:get_stack_max())
    end,
    on_take = function()
      net:set_storage_space(true)
    end
  })
end

function network:get_inventory()
  if not self.inv then
    create_inventory(self)
    assert(self.inv,"no inventory created")
  end
  return self.inv
end

function network:load_inventory(lists)
  local inv = self:get_inventory()
  for listname,c in pairs(lists) do
    inv:set_size(listname, #c)
    for i,s in pairs(c) do
      inv:set_stack(listname,i,s)
    end
  end
end

function network:save_inventory()
  local contents = {}
  local lists = self.inv:get_lists()
  for listname,c in pairs(lists or {}) do
    local ct = {}
    contents[listname] = ct
    for i,stack in pairs(c) do
      ct[i] = stack:to_string()
    end
  end
  return contents
end

function network:load()
  if self.strinv then
    self:load_inventory(self.strinv)
  end
end

function network:serialize()
  local sert = {}
  for i,v in pairs(self) do
    if i == "inv" then
      sert.strinv = self:save_inventory()
    else
      sert[i] = v
    end
  end
  return sert
end

function network:destruct()
  self.controller_pos = nil
  self.inv = nil
  minetest.remove_detached_inventory(self:get_inventory_name())
end