--

-- Prosody IM

-- Copyright (C) 2010 Waqas Hussain

-- Copyright (C) 2010 Jeff Mitchell

-- Copyright (C) 2013 Mikael Nordfeldth

-- Copyright (C) 2013 Matthew Wild, finally came to fix it all

--

-- This project is MIT/X11 licensed. Please see the

-- COPYING file in the source package for more information.

--

local lpty = assert(require "lpty", "mod_auth_external requires lpty: https://code.google.com/p/prosody-modules/wiki/mod_auth_external#Installation");

local log = module._log;

local host = module.host;

local script_type = module:get_option_string("external_auth_protocol", "generic");

assert(script_type == "ejabberd" or script_type == "generic", "Config error: external_auth_protocol must be 'ejabberd' or 'generic'");

local command = module:get_option_string("external_auth_command", "");

local read_timeout = module:get_option_number("external_auth_timeout", 5);

assert(not host:find(":"), "Invalid hostname");

local usermanager = require "core.usermanager";

local new_sasl = require "util.sasl".new;

local pty = lpty.new({ throw_errors = false, no_local_echo = true, use_path = false });

function send_query(text)

	if not pty:hasproc() then

		local status, ret = pty:exitstatus();

		if status and (status ~= "exit" or ret ~= 0) then

			log("warn", "Auth process exited unexpectedly with %s %d, restarting", status, ret or 0);

			return nil;

		end

		local ok, err = pty:startproc(command);

		if not ok then

			log("error", "Failed to start auth process '%s': %s", command, err);

			return nil;

		end

		log("debug", "Started auth process");

	end

	pty:send(text);

	return pty:read(read_timeout);

end

function do_query(kind, username, password)

	if not username then return nil, "not-acceptable"; end

	local query = (password and "%s:%s:%s:%s" or "%s:%s:%s"):format(kind, username, host, password);

	local len = #query

	if len > 1000 then return nil, "policy-violation"; end

	if script_type == "ejabberd" then

		local lo = len % 256;

		local hi = (len - lo) / 256;

		query = string.char(hi, lo)..query;

	end

	if script_type == "generic" then

		query = query..'\n';

	end

	local response = send_query(query);

	if (script_type == "ejabberd" and response == "\0\2\0\0") or

		(script_type == "generic" and response:gsub("\r?\n$", "") == "0") then

			return nil, "not-authorized";

	elseif (script_type == "ejabberd" and response == "\0\2\0\1") or

		(script_type == "generic" and response:gsub("\r?\n$", "") == "1") then

			return true;

	else

		if response then

		else

			log("warn", "Error while waiting for result from auth process: %s", response or "unknown error");

		end

		return nil, "internal-server-error";

	end

end

local host = module.host;

local provider = {};

function provider.test_password(username, password)

	return do_query("auth", username, password);

end

function provider.set_password(username, password)

	return do_query("setpass", username, password);

end

function provider.user_exists(username)

	return do_query("isuser", username);

end

function provider.create_user(username, password) return nil, "Account creation/modification not available."; end

function provider.get_sasl_handler()

	local testpass_authentication_profile = {

		plain_test = function(sasl, username, password, realm)

			return usermanager.test_password(username, realm, password), true;

		end,

	};

	return new_sasl(host, testpass_authentication_profile);

end

module:provides("auth", provider);