technic/technic_chests/register.lua

local chest_mark_colors = {
	'Black',
	'Blue',
	'Brown',
	'Cyan',
	'Dark Green',
	'Dark Grey',
	'Green',
	'Grey',
	'Magenta',
	'Orange',
	'Pink',
	'Red',
	'Violet',
	'White',
	'Yellow',
}


local function colorid_to_postfix(id)
	return (chest_mark_colors[id] and "_"..chest_mark_colors[id] or ""):lower():gsub(" ", "_")
end


local function get_color_buttons()
	local buttons_string = ""
	for y = 0, 3 do
		for x = 0, 3 do
			local file_name = "technic_colorbutton"..(y * 4 + x)..".png"
			buttons_string = buttons_string.."image_button["
				..(8.1 + x * 0.7)..","..(6.1 + y * 0.7)
				..";0.8,0.8;"..file_name..";color_button"
				..(y * 4 + x + 1)..";]"
		end
	end
	return buttons_string
end


local function check_color_buttons(pos, meta, chest_name, fields)
	for i = 1, 16 do
		if fields["color_button"..i] then
			technic.swap_node(pos, chest_name..colorid_to_postfix(i))
			meta:set_string("color", chest_mark_colors[i])
			return
		end
	end
end


local function get_receive_fields(name, data)
	if not data.infotext and not data.color then
		return nil
	end
	local lname = name:lower()
	return function(pos, formname, fields, sender)
		local meta = minetest.get_meta(pos)
		local node = minetest.get_node(pos)
		local page = "main"
		if fields.edit_infotext then
			page = "edit_infotext"
		end
		if fields.save_infotext then
			meta:set_string("infotext", fields.infotext_box)
		end
		local formspec = data.formspec
		local formspec_infotext = minetest.formspec_escape(meta:get_string("infotext"))
		if page == "main" and data.infotext then
			formspec = formspec.."image_button[2.1,0.1;0.8,0.8;"
					.."technic_pencil_icon.png;edit_infotext;]"
					.."label[3,0;"..formspec_infotext.."]"
		end
		if page == "edit_infotext" then
			formspec = formspec.."image_button[2.1,0.1;0.8,0.8;"
					.."technic_checkmark_icon.png;save_infotext;]"
					.."field[3.3,0.2;4.8,1;"
					.."infotext_box;Edit chest description:;"
					..formspec_infotext.."]"
		end
		if data.color then
			-- This sets the node
			local nn = "technic:"..lname..(data.locked and "_locked" or "").."_chest"
			check_color_buttons(pos, meta, nn, fields)
			local color = meta:get_string("color")
			formspec = formspec.."label[8.2,9;Color Filter: "..color.."]"
		end
		meta:set_string("formspec", formspec)
	end
end


function technic.chests:register(name, data)
	local lname = name:lower()

	local width = math.max(data.color and 11 or 8, data.width)

	local locked_after_place = nil
	local front = {"technic_"..lname.."_chest_front.png"}
	data.formspec = "invsize["..width..",10;]"..
			"label[0,0;"..name.." Chest]"..
			"list[current_name;main;0,1;"..width..",4;]"..
			"list[current_player;main;0,6;8,4;]"..
			"background[-0.19,-0.25;"..width..".4,10.75;ui_form_bg.png]"..
			"background[0,1;"..width..",4;technic_"..lname.."_chest_inventory.png]"..
			"background[0,6;8,4;ui_main_inventory.png]"
	if data.color then
		data.formspec = data.formspec..get_color_buttons()
	end

	if data.locked then
		locked_after_place = function(pos, placer)
			local meta = minetest.get_meta(pos)
			meta:set_string("owner", placer:get_player_name() or "")
			meta:set_string("infotext", name.." Locked Chest (owned by "..
					meta:get_string("owner")..")")
		end
		table.insert(front, "technic_"..lname.."_chest_lock_overlay.png")
	end

	local def = {
		description = name..(data.locked and " Locked" or "").." Chest",
		tiles = {"technic_"..lname.."_chest_top.png", "technic_"..lname.."_chest_top.png",
			"technic_"..lname.."_chest_side.png", "technic_"..lname.."_chest_side.png",
			"technic_"..lname.."_chest_side.png", table.concat(front, "^")},
		paramtype2 = "facedir",
		groups = self.groups,
		tube = self.tube,
		legacy_facedir_simple = true,
		sounds = default.node_sound_wood_defaults(),
		after_place_node = locked_after_place,
		on_construct = function(pos)
			local meta = minetest.get_meta(pos)
			meta:set_string("formspec", data.formspec
				..(data.color and "label[8.2,9;Color Filter: None" or "")
				..(data.infotext and "image_button[2.1,0.1;0.8,0.8;"
					.."technic_pencil_icon.png;edit_infotext;]" or ""))
			meta:set_string("infotext", name.." Chest")
			local inv = meta:get_inventory()
			inv:set_size("main", data.width * 4)
		end,
		can_dig = self.can_dig,
		on_receive_fields = get_receive_fields(name, data),
		on_metadata_inventory_move = self.on_inv_move,
		on_metadata_inventory_put = self.on_inv_put,
		on_metadata_inventory_take = self.on_inv_take,
	}
	if data.locked then
		def.allow_metadata_inventory_move = self.inv_move
		def.allow_metadata_inventory_put = self.inv_put
		def.allow_metadata_inventory_take = self.inv_take
	end

	local nn = "technic:"..lname..(data.locked and "_locked" or "").."_chest"

	minetest.register_node(":"..nn, def)

	if data.color then
		front[3] = front[2]
		for i = 1, 15 do
			local postfix = colorid_to_postfix(i)
			local colordef = {}
			for k, v in pairs(def) do
				colordef[k] = v
			end
			colordef.drop = nn
			colordef.groups = self.groups_noinv
			front[2] = "technic_chest_overlay"..postfix..".png"
			colordef.tiles[6] = table.concat(front, "^")
			minetest.register_node(":"..nn..postfix, colordef)
		end
	end

end