local t_concat = table.concat;

local path_sep = package.config:sub(1,1);

local path_util = {}

-- Helper function to resolve relative paths (needed by config)

function path_util.resolve_relative_path(parent_path, path)

	if path then

		-- Some normalization

		parent_path = parent_path:gsub("%"..path_sep.."+$", "");

		path = path:gsub("^%.%"..path_sep.."+", "");

		local is_relative;

		if path_sep == "/" and path:sub(1,1) ~= "/" then

			is_relative = true;

		elseif path_sep == "\\" and (path:sub(1,1) ~= "/" and (path:sub(2,3) ~= ":\\" and path:sub(2,3) ~= ":/")) then

			is_relative = true;

		end

		if is_relative then

			return parent_path..path_sep..path;

		end

	end

	return path;

end

-- Helper function to convert a glob to a Lua pattern

function path_util.glob_to_pattern(glob)

	return "^"..glob:gsub("[%p*?]", function (c)

		if c == "*" then

			return ".*";

		elseif c == "?" then

			return ".";

		else

			return "%"..c;

		end

	end).."$";

end

function path_util.join(a, b, c, ...) -- (... : string) --> string

	-- Optimization: Avoid creating table for most uses

	if b then

		if c then

			if ... then

				return t_concat({a,b,c,...}, path_sep);

			end

			return a..path_sep..b..path_sep..c;

		end

		return a..path_sep..b;

	end

	return a;

end

function path_util.complement_lua_path(installer_plugin_path)

	-- Checking for duplicates

	-- The commands using luarocks need the path to the directory that has the /share and /lib folders.

	local lua_version = _VERSION:match(" (.+)$");

	local lua_path_sep = package.config:sub(3,3);

	local dir_sep = package.config:sub(1,1);

	local sub_path = dir_sep.."lua"..dir_sep..lua_version..dir_sep;

	if not string.find(package.path, installer_plugin_path, 1, true) then

		package.path = package.path..lua_path_sep..installer_plugin_path..dir_sep.."share"..sub_path.."?.lua";

		package.path = package.path..lua_path_sep..installer_plugin_path..dir_sep.."share"..sub_path.."?"..dir_sep.."init.lua";

	end

	if not string.find(package.path, installer_plugin_path, 1, true) then

		package.cpath = package.cpath..lua_path_sep..installer_plugin_path..dir_sep.."lib"..sub_path.."?.so";

	end

end

return path_util;