local st = require "util.stanza";

local send = require "core.sessionmanager".send_to_session;

local sm_bind_resource = require "core.sessionmanager".bind_resource;

local usermanager_validate_credentials = require "core.usermanager".validate_credentials;

local t_concat, t_insert = table.concat, table.insert;

local tostring = tostring;

local log = require "util.logger".init("mod_saslauth");

local xmlns_sasl ='urn:ietf:params:xml:ns:xmpp-sasl';

local xmlns_bind ='urn:ietf:params:xml:ns:xmpp-bind';

local xmlns_stanzas ='urn:ietf:params:xml:ns:xmpp-stanzas';

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

add_handler("c2s_unauthed", "auth", xmlns_sasl,

		function (session, stanza)

			if not session.sasl_handler then

				session.sasl_handler = new_sasl(stanza.attr.mechanism, 

					function (username, password)

						-- onAuth

						require "core.usermanager"

						if usermanager_validate_credentials(session.host, username, password) then

							return true;

						end

						return false;

					end,

					function (username)

						-- onSuccess

						local success, err = sessionmanager.make_authenticated(session, username);

						if not success then

							sessionmanager.destroy_session(session);

							return;

						end

						session.sasl_handler = nil;

						session:reset_stream();

					end,

					function (reason)

						-- onFail

						log("debug", "SASL failure, reason: %s", reason);

					end,

					function (stanza)

						-- onWrite

						log("debug", "SASL writes: %s", tostring(stanza));

						send(session, stanza);

					end

				);

				session.sasl_handler:feed(stanza);	

			else

				error("Client tried to negotiate SASL again", 0);

			end

		end);

add_event_hook("stream-features", 

					function (session, features)												

						if not session.username then

							t_insert(features, "<mechanisms xmlns='urn:ietf:params:xml:ns:xmpp-sasl'>");

								t_insert(features, "<mechanism>PLAIN</mechanism>");

							t_insert(features, "</mechanisms>");

						else

							t_insert(features, "<bind xmlns='urn:ietf:params:xml:ns:xmpp-bind'><required/></bind>");

							t_insert(features, "<session xmlns='urn:ietf:params:xml:ns:xmpp-session'/>");

						end

						--send [[<register xmlns="http://jabber.org/features/iq-register"/> ]]

					end);

add_iq_handler("c2s", "urn:ietf:params:xml:ns:xmpp-bind", 

		function (session, stanza)

			log("debug", "Client tried to bind to a resource");

			local resource;

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

				local bind = stanza.tags[1];

				if bind and bind.attr.xmlns == xmlns_bind then

					resource = bind:child_with_name("resource");

					if resource then

						resource = resource[1];

					end

				end

			end

			local success, err = sm_bind_resource(session, resource);

			if not success then

				local reply = st.reply(stanza);

				reply.attr.type = "error";

				if err == "conflict" then

					reply:tag("error", { type = "modify" })

						:tag("conflict", { xmlns = xmlns_stanzas });

				elseif err == "constraint" then

					reply:tag("error", { type = "cancel" })

						:tag("resource-constraint", { xmlns = xmlns_stanzas });

				elseif err == "auth" then

					reply:tag("error", { type = "cancel" })

						:tag("not-allowed", { xmlns = xmlns_stanzas });

				end

				send(session, reply);

			else

				local reply = st.reply(stanza);

				reply:tag("bind", { xmlns = xmlns_bind})

					:tag("jid"):text(session.full_jid);

				send(session, reply);

			end

		end);

add_iq_handler("c2s", "urn:ietf:params:xml:ns:xmpp-session", 

		function (session, stanza)

			log("debug", "Client tried to bind to a resource");

			send(session, st.reply(stanza));

		end);