-- advschem/init.lua

local advschem = {}

-- Directory delimeter fallback (normally comes from builtin)
if not DIR_DELIM then
	DIR_DELIM = "/"
end
local export_path_full = table.concat({minetest.get_worldpath(), "schems"}, DIR_DELIM)

local text_color = "#D79E9E"
local text_color_number = 0xD79E9E

advschem.markers = {}

-- [local function] Renumber table
local function renumber(t)
	local res = {}
	for _, i in pairs(t) do
		res[#res + 1] = i
	end
	return res
end

---
--- Formspec API
---

local contexts = {}
local form_data = {}
local tabs = {}
local forms = {}

-- [function] Add form
function advschem.add_form(name, def)
	def.name = name
	forms[name] = def

	if def.tab then
		tabs[#tabs + 1] = name
	end
end

-- [function] Generate tabs
function advschem.generate_tabs(current)
	local retval = "tabheader[0,0;tabs;"
	for _, t in pairs(tabs) do
		local f = forms[t]
		if f.tab ~= false and f.caption then
			retval = retval..f.caption..","

			if type(current) ~= "number" and current == f.name then
				current = _
			end
		end
	end
	retval = retval:sub(1, -2) -- Strip last comma
	retval = retval..";"..current.."]" -- Close tabheader
	return retval
end

-- [function] Handle tabs
function advschem.handle_tabs(pos, name, fields)
	local tab = tonumber(fields.tabs)
	if tab and tabs[tab] and forms[tabs[tab]] then
		advschem.show_formspec(pos, name, forms[tabs[tab]].name)
		return true
	end
end

-- [function] Show formspec
function advschem.show_formspec(pos, player, tab, show, ...)
	if forms[tab] then
		if type(player) == "string" then
			player = minetest.get_player_by_name(player)
		end
		local name = player:get_player_name()

		if show ~= false then
			if not form_data[name] then
				form_data[name] = {}
			end

			local form = forms[tab].get(form_data[name], pos, name, ...)
			if forms[tab].tab then
				form = form..advschem.generate_tabs(tab)
			end

			minetest.show_formspec(name, "advschem:"..tab, form)
			contexts[name] = pos

			-- Update player attribute
			if forms[tab].cache_name ~= false then
				player:set_attribute("advschem:tab", tab)
			end
		else
			minetest.close_formspec(pname, "advschem:"..tab)
		end
	end
end

-- [event] On receive fields
minetest.register_on_player_receive_fields(function(player, formname, fields)
	local formname = formname:split(":")

	if formname[1] == "advschem" and forms[formname[2]] then
		local handle = forms[formname[2]].handle
		local name = player:get_player_name()
		if contexts[name] then
			if not form_data[name] then
				form_data[name] = {}
			end

			if not advschem.handle_tabs(contexts[name], name, fields) and handle then
				handle(form_data[name], contexts[name], name, fields)
			end
		end
	end
end)

-- Helper function. Scans probabilities of all nodes in the given area and returns a prob_list
advschem.scan_metadata = function(pos1, pos2)
	local prob_list = {}

	for x=pos1.x, pos2.x do
	for y=pos1.y, pos2.y do
	for z=pos1.z, pos2.z do
		local scanpos = {x=x, y=y, z=z}
		local node = minetest.get_node_or_nil(scanpos)

		local prob, force_place
		if node == nil or node.name == "advschem:void" then
			prob = 0
			force_place = false
		else
			local meta = minetest.get_meta(scanpos)

			prob = tonumber(meta:get_string("advschem_prob")) or 127
			local fp = meta:get_string("advschem_force_place")
			if fp == "true" then
				force_place = true
			else
				force_place = false
			end
		end

		local ostrpos = minetest.pos_to_string(scanpos)
		prob_list[ostrpos] = {
			pos = scanpos,
			prob = prob,
			force_place = force_place,
		}
	end
	end
	end

	return prob_list
end

-- Sets probability and force_place metadata of an item.
-- Also updates item description.
-- The itemstack is updated in-place.
local function set_item_metadata(itemstack, prob, force_place)
	local smeta = itemstack:get_meta()
	local prob_desc = "\nProbability: "..(prob) or
			smeta:get_string("advschem_prob") or "Not Set"
	-- Update probability
	if prob and prob >= 0 and prob < 127 then
		smeta:set_string("advschem_prob", tostring(prob))
	elseif prob and prob == 127 then
		-- Clear prob metadata for default probability
		prob_desc = ""
		smeta:set_string("advschem_prob", nil)
	else
		prob_desc = "\nProbability: "..(smeta:get_string("advschem_prob") or
				"Not Set")
	end

	-- Update force place
	if force_place == true then
		smeta:set_string("advschem_force_place", "true")
	elseif force_place == false then
		smeta:set_string("advschem_force_place", nil)
	end

	-- Update description
	local desc = minetest.registered_items[itemstack:get_name()].description
	local meta_desc = smeta:get_string("description")
	if meta_desc and meta_desc ~= "" then
		desc = meta_desc
	end

	local original_desc = smeta:get_string("original_description")
	if original_desc and original_desc ~= "" then
		desc = original_desc
	else
		smeta:set_string("original_description", desc)
	end

	local force_desc = ""
	if smeta:get_string("advschem_force_place") == "true" then
		force_desc = "\n".."Force placement"
	end

	desc = desc..minetest.colorize(text_color, prob_desc..force_desc)

	smeta:set_string("description", desc)

	return itemstack
end

---
--- Formspec Tabs
---

advschem.add_form("main", {
	tab = true,
	caption = "Main",
	get = function(self, pos, name)
		local meta = minetest.get_meta(pos):to_table().fields
		local strpos = minetest.pos_to_string(pos)

		local border_button
		if meta.schem_border == "true" and advschem.markers[strpos] then
			border_button = "button[3.5,7.5;3,1;border;Hide border]"
		else
			border_button = "button[3.5,7.5;3,1;border;Show border]"
		end

		-- TODO: Show information regarding volume, pos1, pos2, etc... in formspec
		return [[
			size[7,8]
			label[0.5,-0.1;Position: ]]..strpos..[[]
			label[3,-0.1;Owner: ]]..name..[[]

			field[0.8,1;5,1;name;Schematic name:;]]..minetest.formspec_escape(meta.schem_name or "")..[[]
			button[5.3,0.69;1.2,1;save_name;Save]
			tooltip[save_name;Save schematic name]
			field_close_on_enter[name;false]

			button[0.5,1.5;6,1;export;Export schematic]
			textarea[0.8,2.5;6.2,5;;The schematic will be exported as a .mts file and stored in]]..
			"\n" .. export_path_full .. DIR_DELIM .. [[<name>.mts.;]
			field[0.8,7;2,1;x;X size:;]]..meta.x_size..[[]
			field[2.8,7;2,1;y;Y size:;]]..meta.y_size..[[]
			field[4.8,7;2,1;z;Z size:;]]..meta.z_size..[[]
			field_close_on_enter[x;false]
			field_close_on_enter[y;false]
			field_close_on_enter[z;false]

			button[0.5,7.5;3,1;save;Save size]
		]]..
		border_button
	end,
	handle = function(self, pos, name, fields)
		local realmeta = minetest.get_meta(pos)
		local meta = realmeta:to_table().fields
		local strpos = minetest.pos_to_string(pos)

		-- Toggle border
		if fields.border then
			if meta.schem_border == "true" and advschem.markers[strpos] then
				advschem.unmark(pos)
				meta.schem_border = "false"
			else
				advschem.mark(pos)
				meta.schem_border = "true"
			end
		end

		local update_positions = false
		-- Save size vector values
		if (fields.save or fields.key_enter_field == "x" or
				fields.key_enter_field == "y" or fields.key_enter_field == "z")
				and (fields.x and fields.y and fields.z and fields.x ~= ""
				and fields.y ~= "" and fields.z ~= "") then
			local x, y, z = tonumber(fields.x), tonumber(fields.y), tonumber(fields.z)

			if x then
				meta.x_size = math.max(x, 1)
			end
			if y then
				meta.y_size = math.max(y, 1)
			end
			if z then
				meta.z_size = math.max(z, 1)
			end

			-- Set positions to be updated
			update_positions = true
		end

		-- Save schematic name
		if fields.save_name or fields.key_enter_field == "name" and fields.name and
				fields.name ~= "" then
			meta.schem_name = fields.name
		end

		-- Export schematic
		if fields.export and meta.schem_name and meta.schem_name ~= "" then
			local pos1, pos2 = advschem.size(pos)
			local path = export_path_full .. DIR_DELIM
			minetest.mkdir(path)

			local plist = advschem.scan_metadata(pos1, pos2)
			local probability_list = {}
			for _, i in pairs(plist) do
				local prob = i.prob
				if i.force_place == true then
					prob = prob + 128
				end

				probability_list[#probability_list + 1] = {
					pos = minetest.string_to_pos(_),
					prob = prob,
				}
			end

			local slist = minetest.deserialize(meta.slices)
			local slice_list = {}
			for _, i in pairs(slist) do
				slice_list[#slice_list + 1] = {
					ypos = pos.y + i.ypos,
					prob = i.prob,
				}
			end

			local filepath = path..meta.schem_name..".mts"
			local res = minetest.create_schematic(pos1, pos2, probability_list, filepath, slice_list)

			if res then
				minetest.chat_send_player(name, minetest.colorize("#00ff00",
						"Exported schematic to "..filepath))
			else
				minetest.chat_send_player(name, minetest.colorize("red",
						"Failed to export schematic to "..filepath))
			end
		end

		-- Save meta before updating visuals
		local inv = realmeta:get_inventory():get_lists()
		realmeta:from_table({fields = meta, inventory = inv})

		-- Update border
		if not fields.border and meta.schem_border == "true" then
			advschem.mark(pos)
		end

		-- Update formspec
		if not fields.quit then
			advschem.show_formspec(pos, minetest.get_player_by_name(name), "main")
		end

		if update_positions then
			local pos1, pos2 = advschem.size(pos)
			pos1, pos2 = advschem.sort_pos(pos1, pos2)
		end
	end,
})

advschem.add_form("slice", {
	caption = "Y Slices",
	tab = true,
	get = function(self, pos, name, visible_panel)
		local meta = minetest.get_meta(pos):to_table().fields

		self.selected = self.selected or 1
		local selected = tostring(self.selected)
		local slice_list = minetest.deserialize(meta.slices)
		local slices = ""
		for _, i in pairs(slice_list) do
			local insert = "Y = "..tostring(i.ypos).."; Probability = "..tostring(i.prob)
			slices = slices..minetest.formspec_escape(insert)..","
		end
		slices = slices:sub(1, -2) -- Remove final comma

		local form = [[
			size[7,8]
			table[0,0;6.8,6;slices;]]..slices..[[;]]..selected..[[]
		]]

		if self.panel_add or self.panel_edit then
			local ypos_default, prob_default = "", ""
			local done_button = "button[5,7.18;2,1;done_add;Done]"
			if self.panel_edit then
				done_button = "button[5,7.18;2,1;done_edit;Done]"
				ypos_default = slice_list[self.selected].ypos
				prob_default = slice_list[self.selected].prob
			end

			form = form..[[
				field[0.3,7.5;2.5,1;ypos;Y position (max. ]]..(meta.y_size - 1)..[[):;]]..ypos_default..[[]
				field[2.8,7.5;2.5,1;prob;Probability (0-127):;]]..prob_default..[[]
				field_close_on_enter[ypos;false]
				field_close_on_enter[prob;false]
			]]..done_button
		end

		if not self.panel_edit then
			form = form.."button[0,6;2,1;add;+ Add slice]"
		end

		if slices ~= "" and self.selected and not self.panel_add then
			if not self.panel_edit then
				form = form..[[
					button[2,6;2,1;remove;- Remove slice]
					button[4,6;2,1;edit;+/- Edit slice]
				]]
			else
				form = form..[[
					button[2,6;2,1;remove;- Remove slice]
					button[4,6;2,1;edit;+/- Edit slice]
				]]
			end
		end

		return form
	end,
	handle = function(self, pos, name, fields)
		local meta = minetest.get_meta(pos)
		local player = minetest.get_player_by_name(name)

		if fields.slices then
			local slices = fields.slices:split(":")
			self.selected = tonumber(slices[2])
		end

		if fields.add then
			if not self.panel_add then
				self.panel_add = true
				advschem.show_formspec(pos, player, "slice")
			else
				self.panel_add = nil
				advschem.show_formspec(pos, player, "slice")
			end
		end

		local ypos, prob = tonumber(fields.ypos), tonumber(fields.prob)
		if (fields.done_add or fields.done_edit) and fields.ypos and fields.prob and
		fields.ypos ~= "" and fields.prob ~= "" and ypos and prob and
				 ypos <= (meta:get_int("y_size") - 1) and prob >= 0 and prob <= 255 then
			local slice_list = minetest.deserialize(meta:get_string("slices"))
			local index = #slice_list + 1
			if fields.done_edit then
				index = self.selected
			end

			slice_list[index] = {ypos = ypos, prob = prob}

			meta:set_string("slices", minetest.serialize(slice_list))

			-- Update and show formspec
			self.panel_add = nil
			advschem.show_formspec(pos, player, "slice")
		end

		if fields.remove and self.selected then
			local slice_list = minetest.deserialize(meta:get_string("slices"))
			slice_list[self.selected] = nil
			meta:set_string("slices", minetest.serialize(renumber(slice_list)))

			-- Update formspec
			self.selected = 1
			self.panel_edit = nil
			advschem.show_formspec(pos, player, "slice")
		end

		if fields.edit then
			if not self.panel_edit then
				self.panel_edit = true
				advschem.show_formspec(pos, player, "slice")
			else
				self.panel_edit = nil
				advschem.show_formspec(pos, player, "slice")
			end
		end
	end,
})

advschem.add_form("probtool", {
	cache_name = false,
	caption = "Schematic Node Probability Tool",
	get = function(self, pos, name)
		local player = minetest.get_player_by_name(name)
		if not player then
			return
		end
		local probtool = player:get_wielded_item()
		if probtool:get_name() ~= "advschem:probtool" then
			return
		end

		local meta = probtool:get_meta()
		local prob = tonumber(meta:get_string("advschem_prob"))
		local force_place = meta:get_string("advschem_force_place")

		if not prob then
			prob = 127
		end
		if force_place == nil or force_place == "" then
			force_place = "false"
		end
		local form = "size[5,4]"..
			"label[0,0;Schematic Node Probability Tool]"..
			"field[0.75,1;4,1;prob;Probability (0-127);"..prob.."]"..
			"checkbox[0.60,1.5;force_place;Force placement;" .. force_place .. "]" ..
			"button_exit[0.25,3;2,1;cancel;Cancel]"..
			"button_exit[2.75,3;2,1;submit;Apply]"..
			"tooltip[prob;Probability that the node will be placed]"..
			"tooltip[force_place;If enabled, the node will replace nodes other than air and ignore]"..
			"field_close_on_enter[prob;false]"
		return form
	end,
	handle = function(self, pos, name, fields)
		if fields.submit then
			local prob = tonumber(fields.prob)
			if prob then
				local player = minetest.get_player_by_name(name)
				if not player then
					return
				end
				local probtool = player:get_wielded_item()
				if probtool:get_name() ~= "advschem:probtool" then
					return
				end

				local force_place = self.force_place == true

				set_item_metadata(probtool, prob, force_place)

				player:set_wielded_item(probtool)
			end
		end
		if fields.force_place == "true" then
			self.force_place = true
		elseif fields.force_place == "false" then
			self.force_place = false
		end
	end,
})

---
--- API
---

--- Copies and modifies positions `pos1` and `pos2` so that each component of
-- `pos1` is less than or equal to the corresponding component of `pos2`.
-- Returns the new positions.
function advschem.sort_pos(pos1, pos2)
	if not pos1 or not pos2 then
		return
	end

	pos1, pos2 = table.copy(pos1), table.copy(pos2)
	if pos1.x > pos2.x then
		pos2.x, pos1.x = pos1.x, pos2.x
	end
	if pos1.y > pos2.y then
		pos2.y, pos1.y = pos1.y, pos2.y
	end
	if pos1.z > pos2.z then
		pos2.z, pos1.z = pos1.z, pos2.z
	end
	return pos1, pos2
end

-- [function] Prepare size
function advschem.size(pos)
	local pos1   = vector.new(pos)
	local meta   = minetest.get_meta(pos)
	local node   = minetest.get_node(pos)
	local param2 = node.param2
	local size   = {
		x = meta:get_int("x_size"),
		y = math.max(meta:get_int("y_size") - 1, 0),
		z = meta:get_int("z_size"),
	}

	if param2 == 1 then
		local new_pos = vector.add({x = size.z, y = size.y, z = -size.x}, pos)
		pos1.x = pos1.x + 1
		new_pos.z = new_pos.z + 1
		return pos1, new_pos
	elseif param2 == 2 then
		local new_pos = vector.add({x = -size.x, y = size.y, z = -size.z}, pos)
		pos1.z = pos1.z - 1
		new_pos.x = new_pos.x + 1
		return pos1, new_pos
	elseif param2 == 3 then
		local new_pos = vector.add({x = -size.z, y = size.y, z = size.x}, pos)
		pos1.x = pos1.x - 1
		new_pos.z = new_pos.z - 1
		return pos1, new_pos
	else
		local new_pos = vector.add(size, pos)
		pos1.z = pos1.z + 1
		new_pos.x = new_pos.x - 1
		return pos1, new_pos
	end
end

-- [function] Mark region
function advschem.mark(pos)
	advschem.unmark(pos)

	local id = minetest.pos_to_string(pos)
	local owner = minetest.get_meta(pos):get_string("owner")
	local pos1, pos2 = advschem.size(pos)
	pos1, pos2 = advschem.sort_pos(pos1, pos2)

	local thickness = 0.2
	local sizex, sizey, sizez = (1 + pos2.x - pos1.x) / 2, (1 + pos2.y - pos1.y) / 2, (1 + pos2.z - pos1.z) / 2
	local m = {}
	local low = true
	local offset

	-- XY plane markers
	for _, z in ipairs({pos1.z - 0.5, pos2.z + 0.5}) do
		if low then
			offset = -0.01
		else
			offset = 0.01
		end
		local marker = minetest.add_entity({x = pos1.x + sizex - 0.5, y = pos1.y + sizey - 0.5, z = z + offset}, "advschem:display")
		if marker ~= nil then
			marker:set_properties({
				visual_size={x=(sizex+0.01) * 2, y=sizey * 2},
			})
			marker:get_luaentity().id = id
			marker:get_luaentity().owner = owner
			table.insert(m, marker)
		end
		low = false
	end

	low = true
	-- YZ plane markers
	for _, x in ipairs({pos1.x - 0.5, pos2.x + 0.5}) do
		if low then
			offset = -0.01
		else
			offset = 0.01
		end

		local marker = minetest.add_entity({x = x + offset, y = pos1.y + sizey - 0.5, z = pos1.z + sizez - 0.5}, "advschem:display")
		if marker ~= nil then
			marker:set_properties({
				visual_size={x=(sizez+0.01) * 2, y=sizey * 2},
			})
			marker:set_yaw(math.pi / 2)
			marker:get_luaentity().id = id
			marker:get_luaentity().owner = owner
			table.insert(m, marker)
		end
		low = false
	end

	advschem.markers[id] = m
	return true
end

-- [function] Unmark region
function advschem.unmark(pos)
	local id = minetest.pos_to_string(pos)
	if advschem.markers[id] then
		local retval
		for _, entity in ipairs(advschem.markers[id]) do
			entity:remove()
			retval = true
		end
		return retval
	end
end


-- Show node probability for player in HUD
function advschem.mark_node_prob(player, pos, prob, force_place)
	local wpstring = ""
	if prob then
		wpstring = wpstring .. prob
	end
	if wpstring == "" then
		wpstring = wpstring .. " "
	end
	if force_place == true then
		wpstring = wpstring .. "[F]"
	end
	if wpstring ~= "" then
		return player:hud_add({
			hud_elem_type = "waypoint",
			name = wpstring,
			number = text_color_number,
			world_pos = pointed_thing.under,
		})
	end
end

---
--- Registrations
---

-- [priv] schematic_override
minetest.register_privilege("schematic_override", {
	description = "Allows you to access advschem nodes not owned by you",
	give_to_singleplayer = false,
})

-- [node] Schematic creator
minetest.register_node("advschem:creator", {
	description = "Schematic Creator",
	_doc_items_longdesc = "The schematic creator is used to save a region of the world into a schematic file (.mts).",
	_doc_items_usagehelp = "To get started, place the block facing directly in front of any bottom left corner of the structure you want to save. This block can only be accessed by the placer or by anyone with the “schematic_override” privilege.".."\n"..
"To save a region, rightclick the block, enter the size, a schematic name and hit “Export schematic”. The file will always be saved in the world directory. You can use this name in the /placeschem command.".."\n"..
"The other features of the schematic creator are optional and are used to allow to add randomness and fine-tuning.".."\n"..
"Y slices are used to remove entire slices based on chance. For each slice of the schematic region along the Y axis, you can specify that it occours only with a certain chance. In the Y slice tab, you have to specify the Y slice height (0 = bottom) and a probability from 0 to 127 (127 is for 100%). By default, all Y slices occour always.".."\n"..
"With a schematic node probability tool, you can set a probability for each node and enable them to overwrite all nodes when placed as schematic. This tool must be used prior to the file export.",
	tiles = {"advschem_creator_top.png", "advschem_creator_bottom.png",
			"advschem_creator_sides.png"},
	groups = { dig_immediate = 2},
	paramtype2 = "facedir",
	is_ground_content = false,

	after_place_node = function(pos, player)
		local name = player:get_player_name()
		local meta = minetest.get_meta(pos)

		meta:set_string("owner", name)
		meta:set_string("infotext", "Schematic Creator\n(owned by "..name..")")
		meta:set_string("prob_list", minetest.serialize({}))
		meta:set_string("slices", minetest.serialize({}))

		local node = minetest.get_node(pos)
		local dir  = minetest.facedir_to_dir(node.param2)

		meta:set_int("x_size", 1)
		meta:set_int("y_size", 1)
		meta:set_int("z_size", 1)

		local inv = meta:get_inventory()
		inv:set_size("probability", 1)

		local pos1, pos2 = advschem.size(pos)

		-- Don't take item from itemstack
		return true
	end,
	can_dig = function(pos, player)
		local name = player:get_player_name()
		local meta = minetest.get_meta(pos)
		if meta:get_string("owner") == name or
				minetest.check_player_privs(player, "schematic_override") == true then
			return true
		end

		return false
	end,
	on_rightclick = function(pos, node, player)
		local meta = minetest.get_meta(pos)
		local name = player:get_player_name()
		if meta:get_string("owner") == name or
				minetest.check_player_privs(player, "schematic_override") == true then
			-- Get player attribute
			local tab = player:get_attribute("advschem:tab")
			if not forms[tab] or not tab then
				tab = "main"
			end

			advschem.show_formspec(pos, player, tab, true)
		end
	end,
	after_destruct = function(pos)
		advschem.unmark(pos)
	end,
})

minetest.register_tool("advschem:probtool", {
	description = "Schematic Node Probability Tool",
	_doc_items_longdesc =
"This tool can be used together with a schematic creator to finetune the way how nodes from a schematic are placed.".."\n"..
"It allows you to do two things:".."\n"..
"1) Set a chance for a particular node not to be placed in schematic".."\n"..
"2) Enable a node to replace blocks other than air and ignored when placed in a schematic",
	_doc_items_usagehelp = "Leftclick to select a probability (0-127; 127 is for 100%) and to enable or disable force placement. Now rightclick any node with this tool to apply these settings to the node. This information is preserved in the node until it is destroyed or the tool is used again. Now you can use a schematic creator to save a region as usual, the nodes will now be saved with the special node settings applied.".."\n"..
"Note that this tool only has an effect on the nodes with regards to schematics. The node behaviour itself is not changed at all.",
	wield_image = "advschem_probtool.png",
	inventory_image = "advschem_probtool.png",
	on_use = function(itemstack, placer, pointed_thing)
		-- Open dialog to change the probability to apply to nodes.
		advschem.show_formspec(placer:getpos(), placer, "probtool", true)
	end,
	on_place = function(itemstack, placer, pointed_thing)
		-- This sets the node probability of pointed node to the
		-- currently used probability stored in the tool.

		local pos = pointed_thing.under
		local node = minetest.get_node(pos)
		-- Schematic void are ignored, they always have probability 0
		if node.name == "advschem:void" then
			return itemstack
		end
		local nmeta = minetest.get_meta(pos)
		local imeta = itemstack:get_meta()
		local prob = tonumber(imeta:get_string("advschem_prob"))
		local force_place = imeta:get_string("advschem_force_place")

		if not prob or prob == 127 then
			nmeta:set_string("advschem_prob", nil)
		else
			nmeta:set_string("advschem_prob", prob)
		end
		if force_place == "true" then
			nmeta:set_string("advschem_force_place", "true")
		else
			nmeta:set_string("advschem_force_place", nil)
		end

		return itemstack
	end,
})

minetest.register_node("advschem:void", {
	description = "Schematic Void",
	_doc_items_longdesc = "This is an utility block used in the creation of schematic files. It should be used together with a schematic creator. When saving a schematic, all nodes with a schematic void will be left unchanged when the schematic is placed again. Technically, this is equivalent to a block with the node probability set to 0.",
	_doc_items_usagehelp = "Just place the schematic void like any other block and use the schematic creator to save a portion of the world.",
	tiles = { "advschem_void.png" },
	drawtype = "nodebox",
	is_ground_content = false,
	paramtype = "light",
	walkable = false,
	sunlight_propagates = true,
	node_box = {
		type = "fixed",
		fixed = {
			{ -4/16, -4/16, -4/16, 4/16, 4/16, 4/16 },
		},
	},
	groups = { dig_immediate = 3},
})

-- [entity] Visible schematic border
minetest.register_entity("advschem:display", {
	visual = "upright_sprite",
	textures = {"advschem_border.png"},
	visual_size = {x=10, y=10},
	collisionbox = {0,0,0,0,0,0},
	physical = false,

	on_step = function(self, dtime)
		if not self.id then
			self.object:remove()
		elseif not advschem.markers[self.id] then
			self.object:remove()
		end
	end,
	on_activate = function(self)
		self.object:set_armor_groups({immortal = 1})
	end,
})

-- [chatcommand] Place schematic
minetest.register_chatcommand("placeschem", {
	description = "Place schematic at the position specified or the current "..
			"player position (loaded from "..export_path_full..".",
	privs = {debug = true},
	params = "<schematic name>[.mts] [<x> <y> <z>]",
	func = function(name, param)
		local schem, p = string.match(param, "^([^ ]+) *(.*)$")
		local pos = minetest.string_to_pos(p)

		if not schem then
			return false, "No schematic file specified."
		end

		if not pos then
			pos = minetest.get_player_by_name(name):get_pos()
		end

		-- Automatiically add file name suffix if omitted
		local schem_full
		if string.sub(schem, string.len(schem)-3, string.len(schem)) == ".mts" then
			schem_full = schem
		else
			schem_full = schem .. ".mts"
		end

		local success = minetest.place_schematic(pos, export_path_full .. DIR_DELIM .. schem_full, "random", nil, false)

		if success == nil then
			return false, "Schematic file could not be loaded!"
		else
			return true
		end
	end,
})