-- Prosody IM

-- Copyright (C) 2012 Florian Zeitz

-- Copyright (C) 2019 Kim Alvefur

--

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

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

--

local encodings = require "prosody.util.encodings";

assert(encodings.confusable, "This module requires that Prosody be built with ICU");

local skeleton = encodings.confusable.skeleton;

local usage = require "prosody.util.prosodyctl".show_usage;

local usermanager = require "prosody.core.usermanager";

local storagemanager = require "prosody.core.storagemanager";

local skeletons

function module.load()

	if module.host ~= "*" then

		skeletons = module:open_store("skeletons");

	end

end

module:hook("user-registered", function(user)

	local skel = skeleton(user.username);

	local ok, err = skeletons:set(skel, { username = user.username });

	if not ok then

		module:log("error", "Unable to store mimicry data (%q => %q): %s", user.username, skel, err);

	end

end);

module:hook_global("user-deleted", function(user)

	if user.host ~= module.host then return end

	local skel = skeleton(user.username);

	local ok, err = skeletons:set(skel, nil);

	if not ok and err then

		module:log("error", "Unable to clear mimicry data (%q): %s", skel, err);

	end

end);

module:hook("user-registering", function(user)

	local existing, err = skeletons:get(skeleton(user.username));

	if existing then

		module:log("debug", "Attempt to register username '%s' which could be confused with '%s'", user.username, existing.username);

		user.allowed = false;

	elseif err then

		module:log("error", "Unable to check if new username '%s' can be confused with any existing user: %s", err);

	end

end);

function module.command(arg)

	if (arg[1] ~= "bootstrap" or not arg[2]) then

		usage("mod_mimicking bootstrap <host>", "Initialize username mimicry database");

		return;

	end

	local host = arg[2];

	local host_session = prosody.hosts[host];

	if not host_session then

		return "No such host";

	end

	storagemanager.initialize_host(host);

	usermanager.initialize_host(host);

	skeletons = storagemanager.open(host, "skeletons");

	local count = 0;

	for user in usermanager.users(host) do

		local skel = skeleton(user);

		local existing, err = skeletons:get(skel);

		if existing and existing.username ~= user then

			module:log("warn", "Existing usernames '%s' and '%s' are confusable", existing.username, user);

		elseif err then

			module:log("error", "Error checking for existing mimicry data (%q = %q): %s", user, skel, err);

		end

		local ok, err = skeletons:set(skel, { username = user });

		if ok then

			count = count + 1;

		elseif err then

			module:log("error", "Unable to store mimicry data (%q => %q): %s", user, skel, err);

		end

	end

	module:log("info", "%d usernames indexed", count);

end