local S = minetest.get_translator("lzr_editor")
local FS = function(...) return minetest.formspec_escape(S(...)) end
local NS = function(s) return end

local F = minetest.formspec_escape

-- Text color the special autosave level will be highlighted
-- in the save/load dialog
local AUTOSAVE_HIGHLIGHT = "#FF8060"

-- List of items to give to player on editor entry
local INITIAL_EDITOR_ITEMS = {
	-- hotbar slots
	"lzr_tools:ultra_pickaxe",
	"screwdriver2:screwdriver",
	"lzr_teleporter:teleporter_off",
	"lzr_laser:emitter_on",
	"lzr_laser:detector",
	"lzr_laser:mirror",
	"lzr_laser:crate",
	"lzr_treasure:chest_wood_locked",
	-- rest of inventory
	"lzr_tools:ultra_bucket",
	"lzr_laser:emit_toggler",
	"lzr_laser:barricade",
	"lzr_laser:emitter_takable_on",
	"lzr_laser:detector_takable",
	"lzr_laser:mirror_takable",
	"lzr_laser:crate_takable",
	"lzr_treasure:chest_wood_unlocked",
}

lzr_editor = {}
lzr_editor.first_time = true

-- The level state holds the metadata for
-- the level that is being currently edited.
-- INITIAL_LEVEL_STATE is the default state
-- and the state when the editor starts.
local INITIAL_LEVEL_STATE = {
	name = "",
	file_name = "",
	size = lzr_globals.DEFAULT_LEVEL_SIZE,
	wall = lzr_globals.DEFAULT_WALL_NODE,
	window = lzr_globals.DEFAULT_WINDOW_NODE,
	ceiling = lzr_globals.DEFAULT_CEILING_NODE,
	floor = lzr_globals.DEFAULT_FLOOR_NODE,
	ambient = lzr_ambience.DEFAULT_AMBIENCE,
	sky = lzr_globals.DEFAULT_SKY,
	npc_texts = lzr_globals.DEFAULT_NPC_TEXTS,
	weather = lzr_globals.DEFAULT_WEATHER,
}
local level_state = table.copy(INITIAL_LEVEL_STATE)

-- Used to store the current contents for the
-- textlist contents of the custom level file list.
-- (this assumes singleplayer)
local level_file_textlist_state = {}

-- Give useful starter items to player
local function give_initial_items(player)
	local inv = player:get_inventory()
	-- Clear inventory first
	inv:set_list("main", {})
	-- Add itmes
	local errored = false
	for i=1, #INITIAL_EDITOR_ITEMS do
		local item = INITIAL_EDITOR_ITEMS[i]
		local leftover = inv:add_item("main", item)
		if not leftover:is_empty() then
			minetest.log("error", "[lzr_editor] Could not give initial item "..item.." (leftover="..leftover:to_string().."). "..
				"get_size('main')="..inv:get_size("main").."; get_list('main')="..dump(inv:get_list("main")))
			errored = true
		end
	end
	if errored then
		minetest.log("error", "[lzr_editor] Could not give one or more initial items")
	end
end

-- Returns true if pos is within the current bounds
-- of the actively edited level.
function lzr_editor.is_in_level_bounds(pos)
	local offset = table.copy(level_state.size)
	offset = vector.offset(offset, -1, -1, -1)
	return vector.in_area(pos, lzr_globals.LEVEL_POS, vector.add(lzr_globals.LEVEL_POS, offset))
end

-- Enter editor state (if not already in it).
-- Returns true if state changed, false if already in editor.
function lzr_editor.enter_editor(player)
	local state = lzr_gamestate.get_state()
	if state == lzr_gamestate.EDITOR then
		return false
	else
		lzr_levels.clear_playfield(level_state.size)

		level_state = table.copy(INITIAL_LEVEL_STATE)
		local pos = lzr_globals.LEVEL_POS
		local size = level_state.size

		lzr_levels.build_room({pos=pos, size=size, spawn_pos=pos, yaw=0})
		lzr_gui.show_level_bounds(player, pos, size)
		lzr_gamestate.set_state(lzr_gamestate.EDITOR)
		return true
	end
end

local check_for_slash = function(str)
	if string.match(str, "[/\\]") then
		return true
	else
		return false
	end
end

local save_level = function(level_name, is_autosave)
	if lzr_gamestate.get_state() ~= lzr_gamestate.EDITOR then
		return false
	end
	if check_for_slash(level_name) then
		return false
	end
	minetest.mkdir(minetest.get_worldpath().."/levels")

	local filename = minetest.get_worldpath().."/levels/"..level_name..".mts"
	local size = vector.subtract(level_state.size, vector.new(1, 1, 1))

	-- TODO: Don't save the lasers
	local ok = minetest.create_schematic(lzr_globals.LEVEL_POS, vector.add(lzr_globals.LEVEL_POS, size), {}, filename, {})

	local csv_filename = minetest.get_worldpath().."/levels/"..level_name..".csv"
	local npc_texts_csv = ""
	if level_state.npc_texts and level_state.npc_texts.goldie then
		npc_texts_csv = level_state.npc_texts.goldie or ""
	end
	local csv_contents = lzr_csv.write_csv({{
		level_name..".mts",
		level_state.name,
		level_state.wall .. "|" .. level_state.window .. "|" .. level_state.floor .. "|" .. level_state.ceiling,
		level_state.ambient,
		level_state.sky,
		npc_texts_csv,
		level_state.weather,
	}})
	local ok_csv = minetest.safe_file_write(csv_filename, csv_contents)

	if ok and ok_csv then
		minetest.log("action", "[lzr_editor] Level written to "..filename.." and "..csv_filename)
		if not is_autosave then
			level_state.file_name = level_name
		end
		return true, filename, csv_filename
	elseif ok then
		minetest.log("error", "[lzr_editor] Level written to "..filename..", but failed to write CSV!")
		return false, filename, csv_filename
	else
		minetest.log("error", "[lzr_editor] Failed to write level to "..filename)
		return false, filename, csv_filename
	end
end

-- Exit editor state (if not already outside of editor).
-- Returns true if state changed, false if already out of editor.
local function exit_editor(player)
	level_state.file_name = ""
	local state = lzr_gamestate.get_state()
	if state ~= lzr_gamestate.EDITOR then
		return false
	else
		lzr_levels.go_to_menu()
		return true
	end
end

minetest.register_chatcommand("editor_save", {
	description = S("Save current level"),
	params = S("<level name>"),
	func = function(name, param)
		if lzr_gamestate.get_state() ~= lzr_gamestate.EDITOR then
			return false, S("Not in editor mode!")
		end
		if param == "" then
			return false, S("No level name provided.")
		end
		local level_name = param
		if check_for_slash(level_name) then
			return false, S("Level name must not contain slash or backslash!")
		end
		local ok, filename, filename2 = save_level(level_name)
		if ok and filename and filename2 then
			return true, S("Level saved to @1 and @2.", filename, filename2)
		elseif of and filename then
			return true, S("Level saved to @1, but could not write metadata to @2.", filename, filename2)
		else
			return false, S("Error writing level file!")
		end
	end,
})

-- Returns true if the given file exists, false otherwise.
-- * path: Path to file (without file name)
-- * filename: File name of file (without path)
local file_exists = function(path, filename)
	local levels = minetest.get_dir_list(path, false)
	for l=1, #levels do
		if levels[l] == filename then
			return true
		end
	end
	return false
end

local load_level = function(level_name, player)
	if lzr_gamestate.get_state() ~= lzr_gamestate.EDITOR then
		return false
	end

	if check_for_slash(level_name) then
		return false
	end
	local filename = level_name..".mts"
	local ok = file_exists(minetest.get_worldpath().."/levels", filename)
	if not ok then
		return false
	end
	local schem = minetest.read_schematic(minetest.get_worldpath().."/levels/"..filename, {write_yslice_prob="none"})
	if schem then
		local csv_file = io.open(minetest.get_worldpath().."/levels/"..level_name..".csv", "r")
		if csv_file then
			local csv_string = csv_file:read("*a")
			csv_file:close()
			local csv_parsed = lzr_csv.parse_csv(csv_string)
			if csv_parsed and #csv_parsed >= 1 then
				level_state.name = csv_parsed[1][2]
				local bounds = csv_parsed[1][3]
				local exploded_bounds = string.split(bounds, "|")
				if exploded_bounds then
					level_state.wall = exploded_bounds[1]
					level_state.window = exploded_bounds[2]
					level_state.floor = exploded_bounds[3]
					level_state.ceiling = exploded_bounds[4]
				end
				level_state.ambient = csv_parsed[1][4]
				level_state.sky = csv_parsed[1][5] or lzr_globals.DEFAULT_SKY
				level_state.npc_texts = csv_parsed[1][6]
				if level_state.npc_texts then
					level_state.npc_texts = { goldie = level_state.npc_texts }
				else
					level_state.npc_texts = lzr_globals.DEFAULT_NPC_TEXTS
				end
				level_state.weather = csv_parsed[1][7] or lzr_globals.DEFAULT_WEATHER
			else
				minetest.log("error", "[lzr_editor] Error parsing CSV file for "..level_name)
			end
		else
			minetest.log("error", "[lzr_editor] No CSV file found for "..level_name)
		end

		level_state.size = table.copy(schem.size)
		level_state.name = level_state.name or ""
		level_state.wall = level_state.wall or lzr_globals.DEFAULT_WALL_NODE
		level_state.window = level_state.window or lzr_globals.DEFAULT_WINDOW_NODE
		level_state.ceiling = level_state.ceiling or lzr_globals.DEFAULT_CEILING_NODE
		level_state.floor = level_state.floor or lzr_globals.DEFAULT_FLOOR_NODE
		level_state.ambient = level_state.ambient or lzr_ambience.DEFAULT_AMBIENCE
		level_state.sky = level_state.sky or lzr_globals.DEFAULT_SKY
		level_state.npc_texts = level_state.npc_texts or lzr_globals.DEFAULT_NPC_TEXTS
		level_state.weather = level_state.weather or lzr_globals.DEFAULT_WEATHER

		local bounding_nodes = {
			node_wall = level_state.wall,
			node_window = level_state.window,
			node_ceiling = level_state.ceiling,
			node_floor = level_state.floor,
		}
		lzr_levels.prepare_and_build_custom_level(schem, nil, nil, bounding_nodes)
		lzr_gui.show_level_bounds(player, lzr_globals.LEVEL_POS, schem.size)

		if lzr_ambience.ambience_exists(level_state.ambient) then
			lzr_ambience.set_ambience(level_state.ambient)
		else
			level_state.ambient = "none"
			lzr_ambience.set_ambience("none")
		end
		if lzr_sky.sky_exists(level_state.sky) then
			lzr_sky.set_sky(level_state.sky)
		else
			lzr_sky.set_sky(lzr_globals.DEFAULT_SKY)
		end
		if lzr_weather.weather_exists(level_state.weather) then
			lzr_weather.set_weather(level_state.weather)
		else
			lzr_weather.set_weather(lzr_globals.DEFAULT_WEATHER)
		end

		level_state.file_name = level_name
		minetest.log("action", "[lzr_editor] Level loaded from "..filename)
		return true
	else
		minetest.log("error", "[lzr_editor] Failed to read level from "..filename)
		return false
	end
end


minetest.register_chatcommand("editor_load", {
	description = S("Load level"),
	params = S("<level name>"),
	func = function(name, param)
		local player = minetest.get_player_by_name(name)
		if lzr_gamestate.get_state() ~= lzr_gamestate.EDITOR then
			return false, S("Not in editor mode!")
		end
		if param == "" then
			return false, S("No level name provided.")
		end
		local level_name = param
		if check_for_slash(level_name) then
			return false, S("Level name must not contain slash or backslash!")
		end
		local ok = file_exists(minetest.get_worldpath().."/levels", level_name..".mts")
		if not ok then
			return false, S("Level file does not exist!")
		end

		local ok = load_level(level_name, player)
		if ok then
			return true, S("Level loaded.")
		else
			return false, S("Error reading level file!")
		end
	end,
})

minetest.register_chatcommand("editor", {
	description = S("Start or exit level editor"),
	params = S("[ enter | exit ]"),
	func = function(name, param)
		local player = minetest.get_player_by_name(name)
		if param == "" or param == "enter" then
			local ok = lzr_editor.enter_editor(player)
			if ok then
				return true
			else
				return false, S("Already in level editor!")
			end
		elseif param == "exit" then
			local ok = exit_editor(player)
			if ok then
				return true
			else
				return false, S("Not in level editor!")
			end
		end
		return false
	end,
})

-- Unlimited node placement in editor mode
minetest.register_on_placenode(function(pos, newnode, placer, oldnode, itemstack)
	if placer and placer:is_player() then
		return lzr_gamestate.get_state() == lzr_gamestate.EDITOR
	end
end)

-- Don't pick node up if the item is already in the inventory
local old_handle_node_drops = minetest.handle_node_drops
function minetest.handle_node_drops(pos, drops, digger)
	if not digger or not digger:is_player() or
		lzr_gamestate.get_state() ~= lzr_gamestate.EDITOR then
		return old_handle_node_drops(pos, drops, digger)
	end
	local inv = digger:get_inventory()
	if inv then
		for _, item in ipairs(drops) do
			if not inv:contains_item("main", item, true) then
				inv:add_item("main", item)
			end
		end
	end
end

lzr_gamestate.register_on_enter_state(function(state)
	if state == lzr_gamestate.EDITOR then
		local player = minetest.get_player_by_name("singleplayer")
		local message = S("Welcome to the Level Editor!").."\n"..
				S("See LEVEL_EDITOR.md for instructions.")

		lzr_player.set_editor_inventory(player)
		lzr_gui.set_editor_gui(player)
		lzr_ambience.set_ambience(lzr_ambience.DEFAULT_AMBIENCE)
		lzr_sky.set_sky(lzr_globals.DEFAULT_SKY)
		lzr_weather.set_weather(lzr_globals.DEFAULT_WEATHER)

		give_initial_items(player)

		lzr_privs.grant_edit_privs(player)

		if lzr_editor.first_time then
			minetest.chat_send_player("singleplayer", message)
			lzr_editor.first_time = false
		end
	end
end)

lzr_gamestate.register_on_exit_state(function(state)
	if state == lzr_gamestate.EDITOR then
		minetest.log("action", "[lzr_editor] Autosaving level on editor exit")
		save_level(lzr_globals.AUTOSAVE_NAME, true)
		local player = minetest.get_player_by_name("singleplayer")
		if player then
			lzr_privs.revoke_edit_privs(player)
		end
	end
end)

local show_settings_dialog = function(player)
	-- Shorthand function to get the current dropdown index of
	-- a multiple-choice item (ambience, sky, weather) as well
	-- as a string to insert in the dropdown[] formspec element
	local get_current_thing = function(thing_type, thing_getter)
		local thing_list = ""
		local current_thing = 1
		local things = thing_getter()
		for t=1, #things do
			-- Construct string for dropdown[]
			thing_list = thing_list .. F(things[t])
			-- Current thing found!
			if things[t] == level_state[thing_type] then
				current_thing = t
			end
			-- Append comma except at end
			if t < #things then
				thing_list = thing_list .. ","
			end
		end
		return thing_list, current_thing
	end

	local ambient_list, current_ambient = get_current_thing("ambient", lzr_ambience.get_ambiences)
	local sky_list, current_sky = get_current_thing("sky", lzr_sky.get_skies)
	local weather_list, current_weather = get_current_thing("weather", lzr_weather.get_weathers)

	-- TODO: Use this string when we have a parrot model
	local goldie_speech = NS("Goldie speech")

	local form = "formspec_version[4]"..
		"size[9,11.7]"..
		"box[0,0;9,0.8;#00000080]"..
		"label[0.4,0.4;"..FS("Level settings").."]"..
		"field[0.5,1.3;8,0.6;level_name;"..FS("Name")..";"..F(level_state.name).."]"..
		"label[0.5,2.3;Size]"..
		"field[1.6,2.3;1,0.6;level_size_x;"..FS("X")..";"..F(tostring(level_state.size.x)).."]"..
		"field[2.62,2.3;1,0.6;level_size_y;"..FS("Y")..";"..F(tostring(level_state.size.y)).."]"..
		"field[3.63,2.3;1,0.6;level_size_z;"..FS("Z")..";"..F(tostring(level_state.size.z)).."]"..
		"field[0.5,3.3;8,0.6;level_wall;"..FS("Wall node")..";"..F(level_state.wall).."]"..
		"field[0.5,4.3;8,0.6;level_window;"..FS("Window node")..";"..F(level_state.window).."]"..
		"field[0.5,5.3;8,0.6;level_floor;"..FS("Floor node")..";"..F(level_state.floor).."]"..
		"field[0.5,6.3;8,0.6;level_ceiling;"..FS("Ceiling node")..";"..F(level_state.ceiling).."]"..
		"field[0.5,7.3;8,0.6;level_npc_goldie;"..FS("Information block text")..";"..F(level_state.npc_texts.goldie).."]"..

		"label[0.5,8.1;"..FS("Ambience").."]"..
		"dropdown[0.5,8.3;3.5,0.6;level_ambient;"..ambient_list..";"..current_ambient..";false]"..

		"label[0.5,9.2;"..FS("Sky").."]"..
		"dropdown[0.5,9.4;3.5,0.6;level_sky;"..sky_list..";"..current_sky..";false]"..

		"label[5,9.2;"..FS("Weather").."]"..
		"dropdown[5,9.4;3.5,0.6;level_weather;"..weather_list..";"..current_weather..";false]"..

		"button_exit[0.5,10.5;3.5,0.7;level_ok;"..FS("OK").."]"..
		"button_exit[5,10.5;3.5,0.7;level_cancel;"..FS("Cancel").."]"..
		"field_close_on_enter[level_ok;true]"
	minetest.show_formspec(player:get_player_name(), "lzr_editor:level_settings", form)
end

local show_save_load_dialog = function(player, save, level_name)
	if not level_name then
		level_name = ""
	end
	local txt_caption
	local txt_action
	local action
	if save then
		txt_caption = S("Save level as …")
		txt_action = S("Save")
		action = "save"
	else
		txt_caption = S("Load level …")
		txt_action = S("Load")
		action = "load"
	end

	local levels_files = minetest.get_dir_list(minetest.get_worldpath().."/levels", false)
	local levels = {}
	for l=1, #levels_files do
		if string.lower(string.sub(levels_files[l], -4, -1)) == ".mts" then
			local name = string.sub(levels_files[l], 1, -5)
			table.insert(levels, name)
		end
	end
	table.sort(levels)
	level_file_textlist_state = levels
	local levels_str = ""
	for l=1, #levels do
		local entry = levels[l]
		if entry == lzr_globals.AUTOSAVE_NAME then
			entry = AUTOSAVE_HIGHLIGHT .. entry
		end
		levels_str = levels_str .. entry
		if l < #levels then
			levels_str = levels_str .. ","
		end
	end

	local level_list_elem = ""
	if #levels > 0 then
		level_list_elem = "label[0.5,1.5;"..FS("File list:").."]" ..
			"textlist[0.5,2;8,4;level_list;"..levels_str.."]"
	end

	local form = "formspec_version[4]"..
		"size[9,9]"..
		"box[0,0;9,0.8;#00000080]"..
		"label[0.4,0.4;"..F(txt_caption).."]"..
		level_list_elem..
		"field[0.5,6.6;7,0.6;file_name;"..FS("File name")..";"..minetest.formspec_escape(level_name).."]"..
		"label[7.7,6.9;.mts]"..
		"button_exit[0.5,7.7;3.5,0.7;"..action..";"..F(txt_action).."]"..
		"button_exit[5,7.7;3.5,0.7;cancel;"..FS("Cancel").."]"..
		"field_close_on_enter["..action..";true]"

	local formname
	if save then
		formname = "lzr_editor:level_save"
	else
		formname = "lzr_editor:level_load"
	end
	minetest.show_formspec(player:get_player_name(), formname, form)
end

minetest.register_on_player_receive_fields(function(player, formname, fields)
	local pname = player:get_player_name()
	if formname == "lzr_editor:level_settings" then
		if fields.level_cancel or (not fields.level_ok and not fields.key_enter) then
			return
		end
		local invalid = false
		if not fields.level_name or not tonumber(fields.level_size_x) or not tonumber(fields.level_size_y) or not tonumber(fields.level_size_z)
		or not fields.level_floor or not fields.level_ceiling or not fields.level_window or not fields.level_wall
		or not fields.level_ambient or not fields.level_sky or not fields.level_npc_goldie or not fields.level_weather then
			return
		end
		local old_level_size = table.copy(level_state.size)
		level_state.name = fields.level_name
		level_state.size.x = math.floor(tonumber(fields.level_size_x))
		level_state.size.y = math.floor(tonumber(fields.level_size_y))
		level_state.size.z = math.floor(tonumber(fields.level_size_z))
		for _, axis in pairs({"x","y","z"}) do
			if level_state.size[axis] > lzr_globals.PLAYFIELD_SIZE[axis]-1 then
				level_state.size[axis] = lzr_globals.PLAYFIELD_SIZE[axis]-1
			end
			if level_state.size[axis] < lzr_globals.PLAYFIELD_SIZE_MIN[axis]-1 then
				level_state.size[axis] = lzr_globals.PLAYFIELD_SIZE_MIN[axis]-1
			end
		end
		local old_floor = level_state.floor
		local old_window = level_state.window
		local old_ceiling = level_state.ceiling
		local old_wall = level_state.wall
		level_state.floor = fields.level_floor
		level_state.window = fields.level_window
		level_state.ceiling = fields.level_ceiling
		level_state.wall = fields.level_wall
		level_state.ambient = fields.level_ambient
		level_state.sky = fields.level_sky
		level_state.npc_texts = {}
		level_state.npc_texts.goldie = fields.level_npc_goldie
		level_state.weather = fields.level_weather

		local rebuild_room = false
		local nodes = {}
		nodes.node_floor = level_state.floor
		nodes.node_window = level_state.window
		nodes.node_ceiling = level_state.ceiling
		nodes.node_wall = level_state.wall
		if old_floor ~= nodes.floor or old_window ~= nodes.window or old_ceiling ~= nodes.ceiling or old_wall ~= nodes.wall then
			for k,v in pairs(nodes) do
				if not minetest.registered_nodes[v] then
					nodes[k] = lzr_globals.DEFAULT_WALL_NODE
					level_state[string.sub(k, 6)] = lzr_globals.DEFAULT_WALL_NODE
				end
			end
			rebuild_room = true
		end
		if not vector.equals(level_state.size, old_level_size) then
			rebuild_room = true
		end

		if rebuild_room then
			minetest.log("action", "[lzr_editor] Autosaving level on level rebuild")
			save_level(lzr_globals.AUTOSAVE_NAME, true)

			lzr_levels.resize_room(old_level_size, level_state.size, nodes)
			rebuild_room = true
			lzr_gui.show_level_bounds(player, lzr_globals.LEVEL_POS, level_state.size)
		end

		if lzr_ambience.ambience_exists(level_state.ambient) then
			lzr_ambience.set_ambience(level_state.ambient)
		else
			lzr_ambience.set_ambience("none")
		end
		if lzr_sky.sky_exists(level_state.sky) then
			lzr_sky.set_sky(level_state.sky)
		else
			lzr_sky.set_sky(lzr_globals.DEFAULT_SKY)
		end
		if lzr_weather.weather_exists(level_state.weather) then
			lzr_weather.set_weather(level_state.weather)
		else
			lzr_weather.set_weather(lzr_globals.DEFAULT_WEATHER)
		end

		return
	elseif formname == "lzr_editor:level_save" or formname == "lzr_editor:level_load" then
		if fields.level_list then
			local evnt = minetest.explode_textlist_event(fields.level_list)
			if evnt.type == "CHG" or evnt.type == "DBL" then
				local file = level_file_textlist_state[evnt.index]
				if file then
					if formname == "lzr_editor:level_save" then
						show_save_load_dialog(player, true, file)
					else
						show_save_load_dialog(player, false, file)
					end
					return
				end
			end
		elseif (fields.load or (formname == "lzr_editor:level_load" and fields.key_enter)) and fields.file_name then
			if fields.file_name == "" then
				minetest.chat_send_player(pname, S("No level name provided."))
				return
			end
			if check_for_slash(fields.file_name) then
				minetest.chat_send_player(pname, S("File name must not contain slash or backslash!"))
				return false
			end
			local exists = file_exists(minetest.get_worldpath().."/levels", fields.file_name..".mts")
			if not exists then
				minetest.chat_send_player(pname, S("Level file does not exist!"))
				return
			end
			local ok, filename = load_level(fields.file_name, player)
			if ok then
				minetest.chat_send_player(pname, S("Level loaded."))
			else
				minetest.chat_send_player(pname, S("Error reading level file!"))
			end
		elseif (fields.save or (formname == "lzr_editor:level_save" and fields.key_enter)) and fields.file_name then
			if fields.file_name == "" then
				minetest.chat_send_player(pname, S("No level name provided."))
				return
			end
			if check_for_slash(fields.file_name) then
				minetest.chat_send_player(pname, S("File name must not contain slash or backslash!"))
				return false
			end
			local ok, filename, filename2 = save_level(fields.file_name)
			if ok and filename and filename2 then
				minetest.chat_send_player(pname, S("Level saved to @1 and @2.", filename, filename2))
			elseif ok and filename then
				minetest.chat_send_player(pname, S("Level saved to @1, but could not write metadata to @2.", filename, filename2))
			else
				minetest.chat_send_player(pname, S("Error writing level file!"))
			end
		end
		return
	end

	if fields.__lzr_level_editor_exit then
		exit_editor()
		return
	elseif fields.__lzr_level_editor_settings then
		show_settings_dialog(player)
		return
	elseif fields.__lzr_level_editor_save then
		show_save_load_dialog(player, true, level_state.file_name)
		return
	elseif fields.__lzr_level_editor_load then
		show_save_load_dialog(player, false, level_state.file_name)
		return
	elseif fields.__lzr_level_editor_get_item then
		lzr_getitem.show_formspec(pname)
		return
	end
end)

-- Returns list of all custom level file names, sorted.
-- The file name suffix is omitted.
lzr_editor.get_custom_levels = function()
	local levels_files = minetest.get_dir_list(minetest.get_worldpath().."/levels", false)
	local levels = {}
	for l=1, #levels_files do
		if string.lower(string.sub(levels_files[l], -4, -1)) == ".mts" then
			local name = string.sub(levels_files[l], 1, -5)
			table.insert(levels, name)
		end
	end
	table.sort(levels)
	return levels
end

-- Returns proper level name of a custom level.
-- The proper level name is read from a matching CSV file.
-- If no such file is found, the empty string is returned.
-- * level_name: Level file name without suffix
-- * with_fallback: If true, will return "Untitled (<file name>)"
--   instead of the empty string if the level name is empty or undefined
lzr_editor.get_custom_level_name = function(level_name, with_fallback)
	local csv_file = io.open(minetest.get_worldpath().."/levels/"..level_name..".csv", "r")
	local pname
	if csv_file then
		local csv_string = csv_file:read("*a")
		csv_file:close()
		local csv_parsed = lzr_csv.parse_csv(csv_string)
		if csv_parsed and #csv_parsed >= 1 then
			pname = csv_parsed[1][2]
		end
	end
	if not pname then
		pname = ""
	end
	if pname == "" and with_fallback then
		return S("Untitled (@1)", level_name)
	end
	return pname
end

-- Expose invisible blocks in editor mode
local invis_display_timer = 0
local INVIS_DISPLAY_UPDATE_TIME = 1
local INVIS_DISPLAY_RANGE = 8
minetest.register_globalstep(function(dtime)
	local state = lzr_gamestate.get_state()
	if state ~= lzr_gamestate.EDITOR then
		return
	end
	invis_display_timer = invis_display_timer + dtime
	if invis_display_timer < INVIS_DISPLAY_UPDATE_TIME then
		return
	end
	invis_display_timer = 0

	local player = minetest.get_player_by_name("singleplayer")
	if not player then
		return
	end
	local pos = vector.round(player:get_pos())
	local r = INVIS_DISPLAY_RANGE
	local vm = minetest.get_voxel_manip()
	local emin, emax = vm:read_from_map(vector.offset(pos, -r, -r, -r), vector.offset(pos, r, r, r))
	local area = VoxelArea:new({MinEdge = emin, MaxEdge = emax})
	local data = vm:get_data()
	for x=pos.x-r, pos.x+r do
	for y=pos.y-r, pos.y+r do
	for z=pos.z-r, pos.z+r do
		local vi = area:index(x,y,z)
		local nodename = minetest.get_name_from_content_id(data[vi])
		local texture
		if nodename == "lzr_core:barrier" then
			texture = "lzr_core_barrier.png"
		elseif nodename == "lzr_core:rain_membrane" then
			texture = "lzr_core_rain_membrane.png"
		end
		if texture then
			minetest.add_particle({
				pos = {x=x, y=y, z=z},
				texture = texture,
				glow = minetest.LIGHT_MAX,
				size = 8,
				expirationtime = 1.1,
			})
		end
	end
	end
	end
end)