local st = require "util.stanza";

local nodeprep = require "util.encodings".stringprep.nodeprep;

local block_users = module:get_option_set("block_registrations_users", { "admin" });

local block_patterns = module:get_option_set("block_registrations_matching", {});

local require_pattern = module:get_option_string("block_registrations_require");

function is_blocked(username)

        -- Check if the username is simply blocked

        if block_users:contains(username) then return true; end

        for pattern in block_patterns do

                if username:match(pattern) then

                        return true;

                end

        end

        -- Not blocked, but check that username matches allowed pattern

        if require_pattern and not username:match(require_pattern) then

                return true;

        end

end

module:hook("stanza/iq/jabber:iq:register:query", function(event)

        local session, stanza = event.origin, event.stanza;

        if stanza.attr.type == "set" then

                local query = stanza.tags[1];

                local username = nodeprep(query:get_child_text("username"));

                if username and is_blocked(username) then

                        session.send(st.error_reply(stanza, "modify", "policy-violation", "Username is blocked"));

                        return true;

                end

        end

end, 10);