local len = utf8.len or function(s)

	local _, count = s:gsub("[%z\001-\127\194-\253][\128-\191]*", "");

	return count;

end;

local function getchar(n)

	local stty_ret = os.execute("stty raw -echo 2>/dev/null");

	local ok, char;

	if stty_ret then

		ok, char = pcall(io.read, n or 1);

		os.execute("stty sane");

	else

		ok, char = pcall(io.read, "*l");

		if ok then

			char = char:sub(1, n or 1);

		end

	end

	if ok then

		return char;

	end

end

local function getline()

	local ok, line = pcall(io.read, "*l");

	if ok then

		return line;

	end

end

local function getpass()

	local stty_ret = os.execute("stty -echo 2>/dev/null");

	if not stty_ret then

		io.write("\027[08m"); -- ANSI 'hidden' text attribute

	end

	local ok, pass = pcall(io.read, "*l");

	if stty_ret then

		os.execute("stty sane");

	else

		io.write("\027[00m");

	end

	io.write("\n");

	if ok then

		return pass;

	end

end

local function show_yesno(prompt)

	io.write(prompt, " ");

	local choice = getchar():lower();

	io.write("\n");

	if not choice:match("%a") then

		choice = prompt:match("%[.-(%U).-%]$");

		if not choice then return nil; end

	end

	return (choice == "y");

end

local function read_password()

	local password;

	while true do

		io.write("Enter new password: ");

		password = getpass();

		if not password then

			print("No password - cancelled");

			return;

		end

		io.write("Retype new password: ");

		if getpass() ~= password then

			if not show_yesno [=[Passwords did not match, try again? [Y/n]]=] then

				return;

			end

		else

			break;

		end

	end

	return password;

end

local function show_prompt(prompt)

	io.write(prompt, " ");

	local line = getline();

	line = line and line:gsub("\n$","");

	return (line and #line > 0) and line or nil;

end

local function printf(fmt, ...)

	print(fmt:format(...));

end

local function padright(s, width)

	return s..string.rep(" ", width-len(s));

end

local function padleft(s, width)

	return string.rep(" ", width-len(s))..s;

end

local pat = "[%z\001-\127\194-\253][\128-\191]*";

local function utf8_cut(s, pos)

	return s:match("^"..pat:rep(pos)) or s;

end

if utf8.len and utf8.offset then

	function utf8_cut(s, pos)

		return s:sub(1, utf8.offset(s, pos+1)-1);

	end

end

local function ellipsis(s, width)

	if len(s) <= width then return s; end

	if width == 1 then return "…"; end

	return utf8_cut(s, width - 1) .. "…";

end

local function new_table(col_specs, max_width)

	max_width = max_width or tonumber(os.getenv("COLUMNS")) or 80;

	local separator = " | ";

	local widths = {};

	local total_width = max_width - #separator * (#col_specs-1);

	local free_width = total_width;

	-- Calculate width of fixed-size columns

	for i = 1, #col_specs do

		local width = col_specs[i].width or "0";

		if not(type(width) == "string" and width:sub(-1) == "%") then

			local title = col_specs[i].title;

			width = math.max(tonumber(width), title and (#title+1) or 0);

			widths[i] = width;

			free_width = free_width - width;

			if i > 1 then

				free_width = free_width - #separator;

			end

		end

	end

	-- Calculate width of %-based columns

	for i = 1, #col_specs do

		if not widths[i] then

			local pc_width = tonumber((col_specs[i].width:gsub("%%$", "")));

			widths[i] = math.floor(free_width*(pc_width/100));

		end

	end

	return function (row)

		local titles;

		if not row then

			titles, row = true, array.pluck(col_specs, "title", "");

		end

		local output = {};

		for i, column in ipairs(col_specs) do

			local width = widths[i];

			local v = row[not titles and column.key or i];

			if not titles and column.mapper then

				v = column.mapper(v, row);

			end

			if v == nil then

				v = column.default or "";

			else

				v = tostring(v);

			end

			if len(v) < width then

				if column.align == "right" then

					v = padleft(v, width);

				else

					v = padright(v, width);

				end

			elseif len(v) > width then

				v = ellipsis(v, width);

			end

			table.insert(output, v);

		end

		return table.concat(output, separator);

	end;

end

return {

	getchar = getchar;

	getline = getline;

	getpass = getpass;

	show_yesno = show_yesno;

	read_password = read_password;

	show_prompt = show_prompt;

	printf = printf;

	padleft = padleft;

	padright = padright;

	ellipsis = ellipsis;

	table = new_table;

};