-- Code by Sokomine (https://github.com/Sokomine/xconnected)
-- License : GPLv3
-- Optimized by kilbith

local xwall_get_candidate = {}
local profiles = {
	{0, "_c0", 0}, {1, "_c1", 1}, {2, "_c1", 0}, {4, "_c1", 3},
	{8, "_c1", 2}, {5, "_ln", 1}, {10, "_ln", 0}, {3, "_c2", 0},
	{6, "_c2", 3}, {12, "_c2", 2}, {9, "_c2", 1}, {7, "_c3", 3},
	{11, "_c3", 0}, {13, "_c3", 1}, {14, "_c3", 2}, {15, "_c4", 1}
}

for _, p in pairs(profiles) do
	local p1, p2, p3 = p[1], p[2], p[3]
	xwall_get_candidate[p1] = {p2, p3}
end

local directions = {
	{x = 1, y = 0, z = 0}, {x = 0, y = 0, z = 1},
	{x = -1, y = 0, z = 0}, {x = 0, y = 0, z = -1}
}

-- source: mesecons util.lua
-- creates a deep copy of the table
local function clone_table(table) 
	if type(table) ~= "table" then return table end -- no need to copy
	local newtable = {}

	for idx, item in pairs(table) do
		if type(item) == "table" then
			newtable[idx] = clone_table(item)
		else
			newtable[idx] = item
		end
	end

	return newtable
end

local xwall_update_one_node = function(pos, name, digged)
	if not pos or not name or not minetest.registered_nodes[name] then return end
	local candidates = {0, 0, 0, 0}
	local pow2 = {1, 2, 4, 8}
	local id = 0

	for i = 1, #directions do
		local dir = directions[i]
		local node = minetest.get_node({x=pos.x + dir.x, y=pos.y, z=pos.z + dir.z})

		if node and node.name and minetest.registered_nodes[node.name] then
			local ndef = minetest.registered_nodes[node.name]
			if ndef.drop == name or (ndef.groups and ndef.groups.xwall) then
				candidates[i] = node.name
				id = id + pow2[i]
			end
			if ndef.walkable ~= false and ndef.drawtype ~= "nodebox" then
				candidates[i] = 0
				id = id + pow2[i]
			end
		end
	end

	if digged then return candidates end

	local newnode = xwall_get_candidate[id]
	if newnode and newnode[1] then
		local newname = string.sub(name, 1, string.len(name) -3)..newnode[1]
		if newname and minetest.registered_nodes[newname] then
			minetest.swap_node(pos, {name=newname, param2=newnode[2]})
		elseif newnode[1] == '_c0' and not minetest.registered_nodes[newname] then
			minetest.swap_node(pos, {name=name, param2=0})
		end
	end

	return candidates
end

local xwall_update = function(pos, name, active, has_been_digged)
	if not pos or not name or not minetest.registered_nodes[name] then return end

	local c = xwall_update_one_node(pos, name, has_been_digged)
	for j = 1, #directions do
		local dir2 = directions[j]
		if c[j] ~= 0 and c[j] ~= "ignore" then
			xwall_update_one_node({x=pos.x + dir2.x, y=pos.y, z=pos.z + dir2.z}, c[j], false)
		end
	end
end

local xwall_register = function(name, def, node_box_data)
	for k, v in pairs(node_box_data) do
		def.drawtype = "nodebox"
		def.paramtype = "light"
		def.paramtype2 = "facedir"
		def.drop = name.."_ln"
		def.node_box = {
			type = "fixed",
			fixed = node_box_data[k]
		}

		if not def.tiles then
			def.tiles = def.textures
		end
		if not def.groups then
			def.groups = {xwall=1, cracky=3}
		else
			def.groups.xwall = 1
		end

		local newdef = clone_table(def)
		if k == "ln" then
			newdef.on_construct = function(pos)
				return xwall_update(pos, name.."_ln", true, nil)
			end
		else
			newdef.groups.not_in_creative_inventory = 1
		end
		newdef.after_dig_node = function(pos, oldnode, oldmetadata, digger)
			return xwall_update(pos, name.."_ln", true, true)
		end

		minetest.register_node(name.."_"..k, newdef)
	end
end

local xwall_construct_node_box_data = function(node_box_list, center_node_box_list, node_box_line)
	local res = {}
	res.c0, res.c1, res.c2, res.c3, res.c4 = {}, {}, {}, {}, {}
	local pos0, pos1, pos2, pos3, pos4 = #res.c0, #res.c1, #res.c2, #res.c3, #res.c4

	for _, v in pairs(node_box_list) do
		pos1 = pos1 + 1
		pos2 = pos2 + 1
		pos3 = pos3 + 1
		pos4 = pos4 + 1
		res.c1[pos1] = v
		res.c2[pos2] = v
		res.c3[pos3] = v
		res.c4[pos4] = v
	end

	for _, v in pairs(node_box_list) do
		pos2 = pos2 + 1
		pos3 = pos3 + 1
		pos4 = pos4 + 1
		res.c2[pos2] = {v[3], v[2], v[1], v[6], v[5], v[4]}
		res.c3[pos3] = {v[3], v[2], v[1], v[6], v[5], v[4]}
		res.c4[pos4] = {v[3], v[2], v[1], v[6], v[5], v[4]}
	end

	for _, v in pairs(node_box_list) do
		pos3 = pos3 + 1
		pos4 = pos4 + 1
		res.c3[pos3] = {v[4], v[2], v[3]-0.5, v[1], v[5], v[6]-0.5}
		res.c4[pos4] = {v[4], v[2], v[3]-0.5, v[1], v[5], v[6]-0.5}
	end

	for _, v in pairs(node_box_list) do
		pos4 = pos4 + 1
		res.c4[pos4] = {v[3]-0.5, v[2], v[4], v[6]-0.5, v[5], v[1]}
	end

	for _, v in pairs(center_node_box_list) do
		pos0 = pos0 + 1
		pos1 = pos1 + 1
		pos2 = pos2 + 1
		pos3 = pos3 + 1
		pos4 = pos4 + 1
		res.c0[pos0] = v
		res.c1[pos1] = v
		res.c2[pos2] = v
		res.c3[pos3] = v
		res.c4[pos4] = v
	end	

	if #res.c0 < 1 then
		res.c0 = nil
	end

	res.ln = node_box_line
	return res
end

local xwall_register_wall = function(name, tiles, def)
	local node_box_data = xwall_construct_node_box_data(
		{{ -3/16, -0.5, 0,  3/16, 5/16, 0.5 }},
		{{ -4/16, -0.5, -4/16, 4/16, 0.5, 4/16 }},
		{{ -3/16, -0.5, -0.5, 3/16, 5/16, 0.5 }}
	)

	if def then return end
	def = { 
		description = string.upper(string.sub(name, 8, 8))..string.sub(name, 9, -6).." "..
				string.upper(string.sub(name, -4, -4))..string.sub(name, -3),
		textures = {tiles, tiles, tiles, tiles},
		sounds = xdecor.stone,
		groups = {cracky=3, stone=1, pane=1},
		collision_box = {
			type = "fixed",
			fixed = {-0.5, -0.5, -0.25, 0.5, 1, 0.25}
		}
	}
	xwall_register(name, def, node_box_data)
end

xwall_register_wall("xdecor:cobble_wall", "default_cobble.png")
xwall_register_wall("xdecor:mossycobble_wall", "default_mossycobble.png")