--[[

	Tube Library
	============

	Copyright (C) 2017 Joachim Stolberg

	LGPLv2.1+
	See LICENSE.txt for more information

	distributor.lua:
	A more complex node acting as server and client.
	This node claims a position number and registers its message and items interface.
	The Distributor supports the following messages:
	 - topic = "start", payload  = nil
	 - topic = "stop" , payload  = nil

]]--

-- Return a key/value table with all items and the corresponding stack numbers
local function invlist_content_as_kvlist(list)
	local res = {}
	for idx,items in ipairs(list) do
		local name = items:get_name()
		if name ~= "" then
			res[name] = idx
		end
	end
	return res
end

-- Return the total number of list entries
local function invlist_num_entries(list)
	local res = 0
	for _,items in ipairs(list) do
		local name = items:get_name()
		if name ~= "" then
			res = res + items:get_count()
		end
	end
	return res
end

-- Return a flat table with all items
local function invlist_entries_as_list(list)
	local res = {}
	for _,items in ipairs(list) do
		local name = items:get_name()
		local count = items:get_count()
		if name ~= "" then
			for i = 1,count do
				res[#res+1] = name
			end
		end
	end
	return res
end


local function AddToTbl(kvTbl, new_items)
	for _, l in ipairs(new_items) do 
		kvTbl[l] = true 
	end
	return kvTbl
end


local function distributor_formspec(running)
	return "size[8,8.5]"..
	default.gui_bg..
	default.gui_bg_img..
	default.gui_slots..
	"list[context;src;0,0;2,4;]"..
	"image[2,1.5;1,1;gui_furnace_arrow_bg.png^[transformR270]"..
	"button_exit[2,3;1,1;button;OK]"..
	"checkbox[3,0;running1;On;"..dump(running[1]).."]"..
	"checkbox[3,1;running2;On;"..dump(running[2]).."]"..
	"checkbox[3,2;running3;On;"..dump(running[3]).."]"..
	"checkbox[3,3;running4;On;"..dump(running[4]).."]"..
	"image[3.6,0;0.3,1;tubelib_red.png]"..
	"image[3.6,1;0.3,1;tubelib_green.png]"..
	"image[3.6,2;0.3,1;tubelib_blue.png]"..
	"image[3.6,3;0.3,1;tubelib_yellow.png]"..
	"list[context;red;4,0;4,1;]"..
	"list[context;green;4,1;4,1;]"..
	"list[context;blue;4,2;4,1;]"..
	"list[context;yellow;4,3;4,1;]"..
	"list[current_player;main;0,4.5;8,4;]"..
	"listring[context;src]"..
	"listring[current_player;main]"
end

local function allow_metadata_inventory_put(pos, listname, index, stack, player)
	local meta = minetest.get_meta(pos)
	local inv = meta:get_inventory()
	local list = inv:get_list(listname)
	
	if minetest.is_protected(pos, player:get_player_name()) then
		return 0
	end
	if listname == "src" then
		return stack:get_count()
	elseif invlist_num_entries(list) < 4 then
		return 1
	else
		return 0
	end
end

local function allow_metadata_inventory_take(pos, listname, index, stack, player)
	if minetest.is_protected(pos, player:get_player_name()) then
		return 0
	end
	return stack:get_count()
end

local function allow_metadata_inventory_move(pos, from_list, from_index, to_list, to_index, count, player)
	local meta = minetest.get_meta(pos)
	local inv = meta:get_inventory()
	local stack = inv:get_stack(from_list, from_index)
	return allow_metadata_inventory_put(pos, to_list, to_index, stack, player)
end

local SlotColors = {"red", "green", "blue", "yellow"}
local Num2Ascii = {"F", "L", "B", "R"}		-- color to side translation
local FilterCache = {}						-- local cache for filter settings

local function filter_settings(pos)
	local hash = minetest.hash_node_position(pos)
	local meta = minetest.get_meta(pos)
	local inv = meta:get_inventory()
	local facedir = meta:get_int("facedir")
	local running = minetest.deserialize(meta:get_string("running"))
	local kvFilterItemNames = {}  	-- {<item:name> = true,...}
	local kvSide2ItemNames = {}		-- {"F" = {<item:name>,...},...}
	
	-- collect all filter settings
	for idx,slot in ipairs(SlotColors) do
		local side = Num2Ascii[idx]
		if running[idx] == true then
			local list = inv:get_list(slot)
			local filter = invlist_entries_as_list(list)
			AddToTbl(kvFilterItemNames, filter)
			kvSide2ItemNames[side] = filter
		end
	end
	
	FilterCache[hash] = {
		kvFilterItemNames = kvFilterItemNames, 
		kvSide2ItemNames = kvSide2ItemNames
	}
end

local function start_the_machine(pos)
	local node = minetest.get_node(pos)
	node.name = "tubelib:distributor_active"
	minetest.swap_node(pos, node)
	minetest.get_node_timer(pos):start(2)
	local meta = minetest.get_meta(pos)
	local number = meta:get_string("number")
	meta:set_string("infotext", "Tubelib Distributor "..number..": running")
end

local function stop_the_machine(pos)
	local node = minetest.get_node(pos)
	node.name = "tubelib:distributor"
	minetest.swap_node(pos, node)
	minetest.get_node_timer(pos):stop()
	local meta = minetest.get_meta(pos)
	local number = meta:get_string("number")
	meta:set_string("infotext", "Tubelib Distributor "..number..": stopped")
end

-- move items to the output slots
local function keep_running(pos, elapsed)
	local meta = minetest.get_meta(pos)
	local facedir = meta:get_int("facedir")
	local slot_idx = meta:get_int("slot_idx") or 1
	meta:set_int("slot_idx", (slot_idx + 1) % 4)
	local side = Num2Ascii[slot_idx+1]
	local listname = SlotColors[slot_idx+1]
	local inv = meta:get_inventory()
	local list = inv:get_list("src")
	local kvSrc = invlist_content_as_kvlist(list)
	
	-- calculate the filter settings only once
	local hash = minetest.hash_node_position(pos)
	if FilterCache[hash] == nil then
		filter_settings(pos)
	end
	
	-- read data from Cache 
	-- all filter items as key/value  {<item:name> = true,...}
	local kvFilterItemNames = FilterCache[hash].kvFilterItemNames
	-- filter items of one slot as list  {<item:name>,...}
	local names = FilterCache[hash].kvSide2ItemNames[side]
	
	if names == nil then
		-- filter closed
		return true
	end
	
	-- move items from configured filters to the output
	if next(names) then
		for _,name in ipairs(names) do
			if kvSrc[name] then
				local item = tubelib.get_this_item(inv, "src", kvSrc[name])		-- <<=== tubelib
				if item then
					if not tubelib.push_items(pos, facedir, side, item) then	-- <<=== tubelib
						tubelib.put_item(inv, "src", item)
					end
				end
			end
		end
	end
	
	-- move additional items from unconfigured filters to the output
	if next(names) == nil then
		for name,_ in pairs(kvSrc) do
			if kvFilterItemNames[name] == nil then  -- not in the filter so far?
				local item = tubelib.get_this_item(inv, "src", kvSrc[name])			-- <<=== tubelib
				if item then
					if not tubelib.push_items(pos, facedir, side, item) then		-- <<=== tubelib
						tubelib.put_item(inv, "src", item)
					end
				end
			end
		end
	end
	return true
end

local function on_receive_fields(pos, formname, fields, player)
	if minetest.is_protected(pos, player:get_player_name()) then
		return
	end
	local meta = minetest.get_meta(pos)
	local running = minetest.deserialize(meta:get_string("running"))
	if fields.running1 ~= nil then
		running[1] = fields.running1 == "true"
	elseif fields.running2 ~= nil then
		running[2] = fields.running2 == "true"
	elseif fields.running3 ~= nil then
		running[3] = fields.running3 == "true"
	elseif fields.running4 ~= nil then
		running[4] = fields.running4 == "true"
	end
	meta:set_string("running", minetest.serialize(running))
	meta:set_string("formspec", distributor_formspec(running))
	if fields.button ~= nil then
		filter_settings(pos)
		if running[1] or running[2] or running[3] or running[4] then
			start_the_machine(pos)
		else
			stop_the_machine(pos)
		end
	end
end

minetest.register_node("tubelib:distributor", {
	description = "Tubelib Distributor",
	tiles = {
		-- up, down, right, left, back, front
		'tubelib_distributor.png',
		'tubelib_distributor.png',
		'tubelib_distributor_yellow.png',
		'tubelib_distributor_green.png',
		"tubelib_distributor_red.png",
		"tubelib_distributor_blue.png",
	},

	after_place_node = function(pos, placer)
		local number = tubelib.get_node_number(pos, "tubelib:distributor")		-- <<=== tubelib
		local meta = minetest.get_meta(pos)
		local facedir = minetest.dir_to_facedir(placer:get_look_dir(), false)
		local placer_name = placer:get_player_name()

		local running = {false,false,false,false}
		meta:set_string("infotext", "Tubelib Distributor "..number..": stopped")
		meta:set_string("formspec", distributor_formspec(running))
		meta:set_string("running", minetest.serialize(running))
		meta:set_string("number", number)
		meta:set_int("facedir", facedir)
		local inv = meta:get_inventory()
		inv:set_size('src', 8)
		inv:set_size('yellow', 4)
		inv:set_size('green', 4)
		inv:set_size('red', 4)
		inv:set_size('blue', 4)
	end,

	on_receive_fields = on_receive_fields,

	on_dig = function(pos, node, puncher, pointed_thing)
		if minetest.is_protected(pos, puncher:get_player_name()) then
			return
		end
		local meta = minetest.get_meta(pos)
		local inv = meta:get_inventory()
		if inv:is_empty("src") then
			minetest.node_dig(pos, node, puncher, pointed_thing)
			tubelib.remove_node(pos)												-- <<=== tubelib
		end
	end,

	allow_metadata_inventory_put = allow_metadata_inventory_put,
	allow_metadata_inventory_take = allow_metadata_inventory_take,
	allow_metadata_inventory_move = allow_metadata_inventory_move,

	paramtype2 = "facedir",
	groups = {cracky=1},
	is_ground_content = false,
})


minetest.register_node("tubelib:distributor_active", {
	description = "Tubelib Distributor",
	tiles = {
		-- up, down, right, left, back, front
		{
			image = "tubelib_distributor_active.png",
			backface_culling = false,
			animation = {
				type = "vertical_frames",
				aspect_w = 32,
				aspect_h = 32,
				length = 2.0,
			},
		},
		'tubelib_distributor.png',
		'tubelib_distributor_yellow.png',
		'tubelib_distributor_green.png',
		"tubelib_distributor_red.png",
		"tubelib_distributor_blue.png",
	},

	on_receive_fields = on_receive_fields,
	
	allow_metadata_inventory_put = allow_metadata_inventory_put,
	allow_metadata_inventory_take = allow_metadata_inventory_take,
	allow_metadata_inventory_move = allow_metadata_inventory_move,

	on_timer = keep_running,

	paramtype2 = "facedir",
	groups = {crumbly=0, not_in_creative_inventory=1},
	is_ground_content = false,
})

minetest.register_craft({
	output = "tubelib:distributor 2",
	recipe = {
		{"group:wood", 		"default:steel_ingot",  "group:wood"},
		{"tubelib:tube1", 	"default:mese_crystal",	"tubelib:tube1"},
		{"group:wood", 		"default:steel_ingot",  "group:wood"},
	},
})


--------------------------------------------------------------- tubelib
tubelib.register_node("tubelib:distributor", {"tubelib:distributor_active"}, {
	on_pull_item = function(pos)
		local meta = minetest.get_meta(pos)
		local inv = meta:get_inventory()
		return tubelib.get_item(inv, "src")
	end,
	on_push_item = function(pos, item)
		local meta = minetest.get_meta(pos)
		local inv = meta:get_inventory()
		return tubelib.put_item(inv, "src", item)
	end,
	on_recv_message = function(pos, topic, payload)
		if topic == "start" then
			start_the_machine(pos)
		elseif topic == "stop" then
			stop_the_machine(pos)
		end
	end,
})	
--------------------------------------------------------------- tubelib